abstracts of the 34th bcla annual clinical conference, birmingham, 2010

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Contact Lens & Anterior Eye 33 (2010) 256–300

Contents lists available at ScienceDirect

Contact Lens & Anterior Eye

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bstracts

bstracts of the 34th BCLA Annual Clinical Conference, Birmingham, 2010

ONFERENCE SESSION 1a

volving and merging ophthalmic metrics

ichael Twa

-mail address: [email protected]

his course is designed to update experienced clinicians on a rangef diagnostic innovations in ophthalmic instrumentation, includ-ng the latest in corneal topography, anterior segment imaging,nd ocular wavefront measurements. Attendees will lean about thevolution and maturation of these technologies as well as currentrends towards common integrated diagnostic platforms. Partici-ants will learn about recent developments in corneal topography

ncluding improvements in hardware and software such as expertystems and integrated risk factor calculators. Methods for theetection of early keratoconus and tracking disease progressionill be discussed in the context of the possible future developments

or this relatively mature diagnostic technology. Anterior segmentmaging has benefited greatly from advances in optical coherenceomography (OCT). Attendees will learn about the evolution of thismaging technology as well as how further developments may rev-lutionize our understanding of corneal disease. Wavefront sensingas become more common in clinical practice recently. The basicsf wavefront interpretation will be explained and the usefulness ofhis technology for diagnosis and management of corneal diseaseill be discussed. Current trends in instrumentation suggest weill continue to see more combination devices capable of providingultiple diagnostic capabilities on a single platform. Participantsill learn about the challenges and progress towards integration ofavefront sensing and corneal topography.

ONFERENCE SESSION 1b

CT, new developments if, when, and what should I buy?

ill Harvey


s far back as 1878, Albert Michelson hypothesized that, if it wereossible to split a beam of light into two parts and then trans-it them along perpendicular paths, it might be possible upon

eceiving the returning beams to detect any differences in phaseetween them. This difference or interference would give valuableata about the surfaces from which the light has been reflected.his was the basis of the Michelson Interferometer, and went on

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to become the basis of the Zeiss Stratus OCT. In this instrument, alight beam is sent simultaneously to the eye and a reference mir-ror. The light penetrates through retinal tissues and is reflectedback. The returning light is compared to the reference and thisallows software to reconstruct a representation of the underly-ing tissues. This ability to, in effect, show a cross section throughretina makes the machine invaluable in monitoring lesions such asmacular hole or oedema, retinal elevation, anterior chamber depth,corneal thickness, anterior chamber angle, disc topography and soon. This presentation will begin by explaining the principles behindoptical coherence tomography. This should then allow the dele-gate to better understand how factors such as the resolution of theincident radiation and the software analysis of individual reflectivepoints improves the quality of the image and to some degrees thedifference between available systems. There will then be an expla-nation of the various features of currently available instrumentsincluding those from Topcon (both desktop and slit lamp), the desk-top and handheld Optovue, the Zeiss Cirrus, Stratus and Visante, theHeidelberg Spectralis and SL-OCT, and the Nidek instrument still indevelopment. They will be considered in terms of their ease of use,their versatility of function, their intercompatibility with other sys-tems and instruments, their incorporation of any specialist featuresand their cost. For each instrument, the usefulness will be explainedwith regard to optometric and contact lens practice. Clinical caseswill illustrate the presentation.

OCT, the new topography

Nicholas Rumney

E-mail address: [email protected]

Anterior segment OCT is a very new and almost untested additionto the diagnostic consulting room let alone the contact lens fittingroom. This paper will detail progress made in anterior segment OCTso far with respect to both qualitative and quantitative assessment.Qualitatively anterior segment OCT adds value in the contact lensconsulting room by enabling gross assessment of shape (kerato-conus), the significance of the sag of the lens in vaulting the corneaand tightness of fit over the limbal zone. Quantitative assessmentincludes pachymetry, corneal curvature anterior chamber angle
and even topography without the artefact of the tear film. Instru-ments that deliver anterior segment OCT will be discussed andsamples of cases where OCT imaging has altered decision-makingwill be shown.
dx.doi.org/10.1016/j.clae.2010.07.002

http://www.sciencedirect.com/science/journal/13670484

http://www.elsevier.com/locate/clae

mailto:[email protected]



dx.doi.org/10.1016/j.clae.2010.07.002

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Abstracts / Contact Lens &

ONFERENCE SESSION 2

mmunology of contact lenses for the 21st century

avid F. Anderson


llergic disease is truly a 21st Century phenomenon. Despite anncreasingly urban population, the incidence of all allergic diseasesontinues to rise. Couple this with 55 million contact lens wearerslobally, each generating their own uniquely protein-laden biofilmnd the stage is set for confrontation! Fortunately, progress inmmunology and contact lens design is on hand to save the day.rom the basic tenets of immunology in the eye to state of the artontact lens manufacture, we explore how we may achieve peace-ul co-existence.

ONFERENCE SESSION 3

ear Film & Ocular Surface Society: A report from the interna-ional workshop on Meibomian Gland Dysfunction

nternational Workshop on Meibomian Gland Dysfunction members

nthony Bron, Mark Willcox, Jennifer Craig, Eric Papas, Donaldorb, Fiona Stapleton, Jason Nichols


urpose: Meibomian Gland Dysfunction (MGD) may be the lead-ng cause of dry eye syndrome throughout the world. However,lthough this condition impacts the health and well being of mil-ions of people, there is no global consensus on the definition,lassification, diagnosis or therapy of MGD. To obtain such a con-ensus, the Tear Film & Ocular Surface Society (TFOS), a non-profitrganisation, launched the international workshop on Meibomianland Dysfunction. The goals of the MGD workshop were to: (1)onduct an evidence-based evaluation of meibomian gland struc-ure and function in health and disease; (2) develop a contemporarynderstanding of the definition and classification of MGD; (3)ssess methods of diagnosis, evaluation and grading of severityf MGD; (4) develop appropriate norms of clinical trial design tovaluate pharmaceutical interventions for the treatment of MGD;5) develop recommendations for the management and therapy of

GD; and (6) create an executive summary of recommendationsor future research in MGD.

Methods: The workshop, which required over a year to completend finalized its report in early 2010, involved the efforts of 50 lead-ng clinical and basic research experts from around the world. Thesendividuals were assigned to subcommittees, reviewed publishedata and examined the levels of supporting evidence. Subcom-ittee reports were circulated amongst all workshop participants,

resented in open forum and discussed in an interactive manner.Results and conclusions: This session will present the conclusions

nd recommendations of the TFOS International MGD workshop.


herapeutics—The current state of play

ohn Lawrenson


hanges in medicines legislation over the last 5 years have createdew opportunities for optometrists to manage ocular disease inommunity optometric practice and furthermore allows specialist
ptometrists in the Hospital Eye Service to augment extendedlinical roles e.g. in A&E and the management of glaucoma. Theange of therapeutic agents available to all optometrists has beenxpanded and specialist prescribing roles have been developedllowing optometrists to use additional exemptions or train as
or Eye 33 (2010) 256–300 257

supplementary or independent prescribers. A series of resourcesare available to support optometrists in a therapeutic role. Theseinclude evidence-based clinical management guidelines, coveringthe diagnosis and management of ocular conditions presentingwith varying frequency in primary care, electronic drug formula-ries and dedicated web resources.

The pharmacological management of common anterior seg-ment disease

David Evans


This lecture will focus attention on common disease states of theanterior segment (affecting conjunctiva, cornea, adnexa), a briefoverview of the pathophysiology of those diseases, followed bypharmacology of drugs used to manage those diseases. Mechanismof action (pharmacodynamics) of each agent will be described inrelation to disease pathophysiology, i.e. how does the drug alter celland tissue function to alleviate disease. For each group of agents,common ocular and systemic adverse effects will be described, aswill modes of delivery, host elimination, and drug interactions.

CONFERENCE SESSION 4b

Ocular nutrition in relation to ARMD

Cristina Kenney


Age related macular degeneration (ARMD) is a leading cause ofdecreased vision in the elderly population. Studies show thatboth genetic factors and environmental factors play importantroles in the development and progression of ARMD. Risk factorsfor ARMD include smoking, obesity, family history, aging andfemale gender. The eye protects itself through numerous cellularantioxidant enzymes, free radical scavengers and protectivemacular pigments. Over the past few decades there have beenmany nutritional studies to evaluate if diet and healthy life choicescan improve the outcome of ARMD. These include Case–ControlStudies, Population Studies and Randomized Controlled ClinicalTrials. The combination of these studies have provided evidencethat specific vitamin supplements, green leafy vegetables witha high antioxidant content, omega 3 fatty acids or fish, weightcontrol and elimination of smoking can protect patients withARMD.

Glaucoma, a current view

Owen Anderson


The aim of this presentation is to provide a practical approach toglaucoma assessment and management. How to approach a newcase of glaucoma, including the role of initial clinical assessmentand investigations, will be discussed. Practical advice on followingup existing glaucoma cases will be covered, including how to assessfor progression. Finally basic strategies behind treatment will bediscussed. This presentation will provide sensible practical adviceand a logical basis to managing glaucoma. The visual presentationwill concentrate on clinical scenarios. The presentation will have ahigh content of pictures. Management pathways will be provided.

CONFERENCE SESSION 5

The CLEER-Project results

Helmer Schweizer









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58 Abstracts / Contact Lens &

urpose: ECLF initiated the CLEER-Project (Contact Lens Europeanvidence Report) project to gather data on significant adversevents with CLs in Europe. This data will be used to support theequest to regulate the sale of CLs and plano coloured lenses asedical device.Method: ECLF set up a web site at which eye care professionals

ECPs) registered using their professional affiliation (membershipn an ECP country organisation within the EU and ECP residency inhe EU). After this was verified, the ECP was approved as a reporter.hey could then place reports on the same web site. The ques-ionnaire was short in order to encourage data entry (least time)nd mainly consisted of clicks, with the possibility to put text onlynce. The questions focused on the minimal information needed.he project was announced with press releases and e-mails beforets start. Additional press releases and e-mail reminders were sentut on a regular basis during the project.

Results: Originally planned as a yearly project only (1 June 2008o 31 May 2009). The project’s deadline was extended to 31 Decem-er 2009, as the expected number of reports came in slower and

ater then thought. Data from some professional organisations’ ownnd already exiting collection systems were integrated, too. A totalf 276 ECPs registered. They were from 21 countries represent-ng 69% of the potential 29 (27 EU plus Norway and Switzerland)).f the registered ones, 3 were super reporters, i.e. entering data

or an association. Of the 276 registered ones, 68 from 13 coun-ries actually placed reports. 1276 reports were placed (averagef 18.76 per reporter and 98.2 per country, range: 1–645 per coun-ry). Using wearer data (number of wearers per country), an annualncidence rate of 1.15/10,000 was calculated (range 0.01–19.81).his is less than the 4–7 for 10,000 wearers/year rate from Staple-on and Morgan’s work, respectively. 836 (66.5%) were regulated,hile 440 (34.5%) were unregulated. The proportion of the unreg-lated varied from 0.0% to 88.9%. 138 of the 1276 (10.8%) wereith plano coloured lenses. 68.8% of these were unregulated (range

.0–100.0%).Conclusions: The overall results show and confirm, that CL wear

as a low incidence of significant events. Those that experienceuch an event will often not see their regular ECP but show up inhospital emergency room. While efforts were made to reach out

nto those and collect data right there, data protection concernsnd work load did prohibit that. The ratio of events, especiallyith unregulated sales, is higher for the plano coloured lenses.

his is in line with the expected results and supports the call fora) regulate plano coloured lenses as medical devices and b) theonditions under which they are sold. The UK has the strongestegulation about the sale of all contact lenses in place already. Its also the country with one of the smallest number of events per0,000 wearers/year (0.06). Only Spain had a lower number (0.01).pain also a restrictive regulation about the sale of contact lensesia alternative channels, mainly Internet. The other countries’ rateser 10,000 wearers/year are about 10 times or more higher than theK one. This also supports the call for a regulation.

hinning and ectasia—What happened in the keratoconicornea?

an Bergmanson*, Jessica H. Mathew, John D. Goosey


urpose: Keratoconus (Kc) involves corneal stromal thinning andctasia. The purpose of this study was to determine structuralntegrity and numbers of stromal lamellae.

Method: Five Kc corneal buttons were preserved and processedor transmission electron microscopy using a protocol minimizinghrinkage and distortion. Overlapping digital micrographs of fullpical cone thickness were taken. A montage was created (PanaVuemageAssembler 3 software) and printed (Roland FJ-52) at 5000×.

or Eye 33 (2010) 256–300

The number of lamellae was counted using established criteria foridentifying individual lamellae.

Results: Among the corneas examined, three had distinctly sim-ilar histopathology and were considered ‘typical’ Kc. The other twocases, hydrops (H) and extreme thinning (ET), were consideredindividually. The ‘typical’ Kc cornea had, on average, 372.7 (SD:+15.9) lamellae, while the H and ET corneas showed 308 and 109lamellae respectively. All corneas showed clear ultrastructural evi-dence of lamellar fragmentation into smaller units and a loss ofinterweaving anterior lamellae.

Conclusions: Earlier research demonstrated that Kc leads to anextensive loss of anterior limiting lamina, while the current workshowed that anterior stromal lamellae were also lost, thus explain-ing corneal thinning. Interestingly, the typical Kc had an increasein stromal lamellae compared to normal corneas which contains242. Large numbers of thin (<1 �m) lamellae were encountered inall corneas suggesting that fragmentation of lamellae across thecorneal thickness is a pathophysiological feature of Kc. Anteriortissue loss together with generalized lamellar fragmentation maybe dominant factors in ectasia. Stromal thinning in Kc cannot beexplained by a simple lamellar count.

Keratoconus in the young

Lynne L. Speedwell


Purpose: Numerous papers in the literature investigate keratoconus(KC) in young people and children, and the possible causes. All chil-dren aged up to 16 years attending Moorfields Eye Hospital, London(MEH) are seen in the children’s unit. Of those referred for contactlenses, many have KC. The aim of this study was to look at whetherthe numbers of children with KC was increasing and the possiblecauses, and to consider why there is a high rate of KC in youngpeople with Down’s syndrome.

Method: A literature search was carried out and the diagnosisof all new patients referred to MEH children’s contact lens servicewas audited for 3 months.

Results: The main causes of KC are atopy, vernal keratoconjunc-tivities, ethnic origin and genetic. The incidence of atopy appearsto be increasing in today’s westernised urbanised societies. Atopyincreases eye rubbing and hence the risk of developing KC. Eth-nic origin increases the risk of developing KC earlier. Down’s havethinner, steeper corneas than normals making them more prone todevelop KC from a young age. More than 25% of new contact lensreferrals to MEH were for KC. None had Down’s syndrome. The auditis ongoing.

Conclusions: KC may be affecting more young people in west-ernised urbanised societies due to an increase in causative factors.The effect on the patient during their school life should be consid-ered and contact lens clinics must plan for the extra time that thesepatients may require.

Retardation of myopia in orthokeratology (ROMIO) study: 6-Month results

Pauline Cho


Purpose: To confirm if orthokeratology can retard myopic pro-gression via a randomized, single-masked study. Data from thescheduled 6 month time point will be presented.

Method: Children aged 6–10 years old with spherical equiva-
lent refractive error −1.25 D to −4.50 D (with-the-rule astigmatismless than 1.50 D) were recruited and randomly assigned to wearMenicon Z Night Lens and spectacles. Axial length after cycloplegiawere measured using the IOLMaster. The right eye or the eye whichsatisfied the Rx requirement were selected for analysis.



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Results: Seventy-nine children wearing Night Lens (n = 40) andpectacles (n = 39) have completed the 6-month time line. The axialength of children wearing ortho-k lenses and spectacles were.13 ± 0.12 mm and 0.20 ± 0.11 mm respectively. Progression ofyopia in children wearing spectacles is significantly faster than

hose wearing ortho-k lenses (t-test, p = 0.009) in the first 6 months.Conclusion: Ortho-k significantly slowed the progression of

yopia in children after 6-month lens wear.(Results of 56 children completing the 6-month time point were

resented at the 17th Asia Pacific Optometric Congress held in Hongong in November 2009 as well as at the NCC 2010 in Amsterdam inarch 2010.)

A VINCI LECTURE

he biomechanical principles and potential value of soft contactens orthokeratology

abian Conrad*, Klaus Ehrmann, Jennifer D. Choo, Brien A. Holden


urpose: Orthokeratology (OK) offers a reversible, temporary butffective alternative to surgery for ‘eliminating’ myopia during theay. There is also growing evidence that this method may alsoetard myopia progression through its effects on corneal shapeeducing peripheral hyperopia. Two major factors limiting successf OK are rigid lens discomfort and the limited number of ‘fitters’ ofhese specialised lenses. The purpose of this project was to investi-ate whether custom-made soft contact lenses (SCL) could be usedor OK, enabling a more comfortable and more flexible approacho OK promoting a far wider application of this method of visionorrection.

Methods: Finite element modelling and sophisticated lensesign software were used to create novel and innovative SCLeometries. Open and closed eye clinical performance was assessednd topographical changes of the cornea quantified, using customeveloped software.

Results: Corneal flattening of up to 3.50 D was observed after 6 hf lens wear. Individual lens design parameters controlling pressureistribution, and thereby corneal changes, were identified. A highorrelation was found between finite element model predictionsnd observed topographical changes.

Conclusions: Specially designed OK soft lenses achieved signif-cant programmed changes in corneal shape. One obstacle that iset to be overcome with designs used thus far is the induction ofsmall, central area of corneal steepening observed with all lensesigns. However, this “centre near” effect may offer potential forhe correction of presbyopia.

isual performance in myopia

sieh Ehsaei*, Catharine M. Chisholm, Edward A.H. Mallen, Ian E.acey


urpose: Myopes form a significant proportion of our patients. Theyften achieve better visual performance with contact lenses com-ared to spectacles due to the removal of spectacle minification.he ocular elongation commonly found in myopes may have impli-ations for visual function due to a reduction in sampling densityf retinal neurons. The purpose of this study is to evaluate theentral and peripheral visual performance of myopes compared tommetropes.

Method: 25 myopes (MSE: −5.25 ± 2.21 D, mean axial length
MAL): 25.36 ± 1.06 mm) and 25 emmetropes (MSE: 0.13 ± 0.22 D,
AL: 23.48 ± 0.53 mm) were recruited. All participants (age:2.2 ± 3.6) had a visual acuity of 0.0 logMAR or better. Landolt Cap discrimination thresholds were determined at high and low

or Eye 33 (2010) 256–300 259

contrast, using a 4AFC adaptive staircase paradigm, presented ona high resolution CRT monitor. All measurements were carried outin both horizontal (±30◦, ±20◦, ±10◦, 0◦) and vertical (±25◦, ±20◦,±10◦) meridians.

Results: Repeated measures ANOVA showed that emmetropesmanifest a statistically superior visual performance at low contrastin both horizontal (p = 0.033) and vertical (p = 0.030) meridians atall eccentricities, compared with myopes. A similar trend was seenfor high contrast thresholds but this did not reach statistical signif-icance.

Conclusions: These data indicate that the myopes exhibitreduced low contrast visual performance compared to theemmetropes and suggests that the reduced sampling densityassociated with increased axial length of the myopic eye, has impli-cations for the visual function of many of our patients.

Dual-focus soft lens to reduce childhood myopia progression

John R. Phillips*, Nicola S. Anstice

*E-mail address: [email protected]

Purpose: To test the efficacy of a new soft contact lens designed toslow myopia progression in children.

Method: The dual focus (DF) lens had a central correction zoneand concentric treatment zones creating 2.00 D of simultaneousmyopic retinal defocus during distance and near viewing. A singlevision distance (SVD) lens with the same form (lathe-cut in Hioxifil-con A) but without treatment zones was the control. Forty children,11–14 years old wore a DF lens in one eye and a SVD lens in the fel-low eye for 10 months (Period 1). Lens assignment was swappedbetween eyes for the second 10 months (Period 2). Spherical equiv-alent refraction (SER) and axial eye length were monitored usingcycloplegic autorefraction and partial coherence interferometryevery 5 months. Accommodation was assessed using an open-fieldautorefractor.

Results: Visual acuity and contrast sensitivity with DF lenseswere not significantly different from control. Children accommo-dated normally to near targets. Myopia progression (mean ± SD) in10 months was significantly reduced with DF lens wear; Period 1:DF = −0.44 ± 0.33 D vs SVD = −0.69 ± 0.38 D: p < 0.0001 and Period2: DF = −0.19 ± 0.36 D vs SVD = −0.37 ± 0.38 D: p = 0.003). Eye elon-gation was also significantly reduced with DF lenses; Period 1:DF = 0.11 ± 0.08 mm vs SVD = 0.22 ± 0.09 mm; p < 0.0001 and Period2: DF = 0.03 ± 0.10 mm vs SVD = 0.14 ± 0.10 mm: p < 0.0001).

Conclusions: Axial myopia progression was significantly reducedin eyes wearing DF lenses, without compromising visual function.


Peer Review Group for therapeutics prescribers

Susan Bowers

During the peer review group AS, SP and IP therapeutic drug pre-scribers will each present one interesting case for their peers todiscuss. This will take place in small groups and involve cases takenfrom the Clinical Management Guidelines.

CONFERENCE SESSION 7a

Keratoconus, pathophysiology: What you didn’t know and itsmanagement implications

Cristina Kenney


Keratoconus is a disorder of abnormal central thinning that changesthe cornea from a dome shape to a cone shape. Keratoconus patientshave visual distortion, irregular astigmatism and decreased vision.





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he incidence of keratoconus is approximately 1 in 2000 individ-al and 6–10% of the patients have a family history of the disorder.his presentation will review the signs and methods currently usedo diagnosis keratoconus patients, their clinical symptoms and thepidemiology of this disorder. Keratoconus has been associatedith 10 different chromosomes. A defect in the superoxide dis-utase 1 (SOD1) gene, an antioxidant enzyme, has been reported

n family members with keratoconus. However, it is likely thathe cause of keratoconus is not linked to a single gene defect butas multiple genes involved. Keratoconus corneas have the threeathologic features of corneal thinning, oxidative damage and ante-ior corneal instability which are interrelated to each other. Eacheature will be described in order to understand how they interacto cause the pathological changes to the cornea. The contributionf mitochondria and antioxidant enzymes to the oxidative damageill be evaluated. Potential sites of therapeutic intervention will

e discussed along with helpful recommendations for the kerato-onus patient.

aser ectasia: Man-made keratoconus?

ichael Twa


eratoectasia after LASIK is an ongoing concern for patients androviders of refractive surgery. This presentation will explore theimilarities and differences between this post-surgical ectasia anderatoconus. Several recent studies have identified risk factorsssociated with the occurrence of keratoectasia after LASIK thatnclude surgical parameters and patient factors. The possible mech-nisms of ectasia after refractive surgery will discussed in theontext of these findings. Appropriate screening techniques touard against post-surgical ectasia will be presented.


ellucid dystrophy: The elusive butterfly

avid F. Anderson


rom its naming in 1957 to today, Pellucid Marginal DegenerationPMD) has remained largely an enigma, and a particularly trou-lesome one! The location of the affected area poses significanthallenges to the optometrist, surgeon and patient alike and noreatments to date have demonstrably changed disease progres-ion. Now, using high resolution corneal imaging, coupled withew metrics of corneal function and physiology, both diagnosis andanagement of PMD are entering a new era. We will explore how

arly, accurate diagnosis coupled with improved medical and sur-ical intervention is beginning to re-shape how we approach andopefully capture this elusive butterfly.


he role of RGPs in modern practice

athan Efron


as the 1998 prediction of a well-known contact lens researcher –hat rigid contact lenses will be obsolete by the year 2010 – come toruition? This Eulogy to RGPs will demonstrate why it has. A recenturvey of international contact lens prescribing trends shows that
igid lenses constituted less than 5% of all contact lenses prescribedn 16 out of 27 nations surveyed. This compares with rigid lensesepresenting 100% of all lenses prescribed 1965 and about 40% in990). With the wide range of sophisticated soft lens materialsvailable today, including super-permeable silicone hydrogels, and
or Eye 33 (2010) 256–300

designs capable of correcting astigmatism and presbyopia, thereis now no need to fit cosmetic patients with rigid lenses, withthe associated intractable problems of rigid lens-induced ptosis,3 and 9 o’clock, staining, lens binding, corneal warpage and adap-tation discomfort. Orthokeratology is largely a fringe applicationof marginal efficacy, and the notion that rigid lenses arrest myopiaprogression is flawed. That last bastion of rigid lens practice – fit-ting patients with severely distorted corneas as in keratoconus –is about to crumble in view of a number of demonstrations byindependent research groups of the efficacy of custom-designedwavefront-corrected soft contact lenses for the correction of kera-toconus. It is concluded that rigid contact lenses now have no placein modern contact lens practice.

In practice soft torics: Are they better?

Jonathan Walker


With over 50% of patients entering an ECP’s practice being astig-matic, fitting toric contact lenses has become a major part ofmodern day practice. It was not so long ago when the choice ofsoft toric lenses was very restricted, with thick prism ballasted,truncated lenses made out of low water content materials. Today,lens designers still incorporate the prism ballast but in a waythat reduces the lens mass and improves comfort. Unfortunatelythough, this still leaves a rather chunky inferior to the lens, whichcomprises the physiology of the cornea. With the recent introduc-tion of silicone-hydrogel materials, Si-Hi torics have gone a longway to resolve the issue of hypoxia under the prism ballast area.But recent figures have shown that the majority of toric lenses fittedin the UK are still made from conventional hydrogel materials. It’spresumed the reason for this is, if the patient is asymptomatic thenthe practitioner repeats what the patient are currently wearing.This “wait-until-there-is-problem” approach is thwart with poten-tial problems. Once upon a time, high myopes/astigmats would fallunder the domain of RGPs, that is no longer the case, with the adventof custom made Si-Hi torics almost all astigmats can be fitted ina toric lens. But management of the astigmat also requires solv-ing their visual problems when they become presbyopic. For theECP to become a true “Specialist” they must encompass all lenses,including RGP bifocals. So in 2010, there is a huge choice of silicone-hydrogel torics to choose from, both molded and lathe cut, it is nowfor the practitioners to repay Industries investment and start fittingthem.

CONFERENCE SESSION 8b

New specialist lens solutions and care techniques

Lyndon Jones


Over the past 30 years the development of contact lens solutionshas shown tremendous changes, with products becoming increas-ingly complex and diverse in their composition and performance.To many practitioners and patients, contact lens solutions appearrelatively similar in their composition, resulting in many opting tochange between products on a whim, often driven by cost consid-erations rather than sound clinical acumen. For much of the past 20years, companies concentrated on formulating lens care regimensthat provided maximum disinfection strength, with an aim of pro-viding safe, effective regimens that killed any potential pathogenic
organisms on the lens surface. Recently, more emphasis has beenplaced on producing regimens that assist with improving lenscomfort, with new regimens incorporating a variety of surfactantsand other surface active agents to aid wettability and, hopefully,





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mprove end of day comfort. A variety of unique approaches, typi-ally from lesser well known companies, have been developed thatay provide some benefits to patients. In addition, supplementary

leaning devices and antibacterial cases are also aspects that war-ant some attention. This presentation will provide delegates withn update on these developments.

ew developments in multifocal contact lenses

ric Papas


s demographic trends show that more and more individuals areecoming presbyopic, the need to provide them with an effec-ive correction becomes increasingly important in contemporaryontact lens practice. The problem of positioning multiple focallements so that they deliver effective near vision, without unac-eptably degrading distance performance (or vice versa), remainschallenging one, and lens designers continue to propose inter-

sting ways in which this might be solved. This presentationill consider recent developments in this area and investigateow the assessment of their merits and drawbacks can be aidedy the use of in vitro predictive methods as well as by clinicalvaluation.

ew developments in paediatric lenses

ynne Speedwell


hildren have been fitted with contact lenses for around sixecades. One of the first medical conditions requiring lens fittingas aphakia and in spite of massive strides forward in surgical tech-iques, it is probably still the most common reason for fitting lenseso young children. Other conditions include corneal pathologies,etinal dystrophies, trauma and many more. Were it not for theore recent contact lens developments, it would not be possible

o fit many of these patients. The modern paediatric contact lensractitioner utilises a full range of lenses, from silicone rubber thatas changed little since the 70s to tinted silicone hydrogel lenseshat can be manufactured today. Rigid lenses retain an importantlace in the armamentarium and in some cases, only the availabil-

ty of the current computer lathed designs allows many children tochieve their maximum visual potential.

ew developments in orthokeratology

auline Cho


he popularity of orthokeratology, particularly for myopic controln children is on the increase. The LORIC study (2005) in Hong Kong,nd the CRAYON study (2009) in US, have provided clinical evidencehat orthokeratology has a potential for slowing myopic progres-ion in children. These findings need to be confirmed and currently,number of research studies on myopic control have commenced

n different parts of the world. This presentation will look at ongoingesearch and future possibilities in orthokeratology, particularly inhe area of myopic control in children. The most recent researchndings will also be compared and discussed.

ew developments in specialist lens geometry

eil Cox


omputer controlled lathes have made possible asymmetric lenseometries. Production developments and clinical applications areiscussed.

or Eye 33 (2010) 256–300 261

Developments in wavefront design for asymmetric corneas

Jan P.G. Bergmanson


Distorted corneal optics (e.g., keratoconus) creates aberrations thata gas-permeable lens cannot fully correct. The research team inthe Laboratory of Ray Applegate in the Visual Optics Institute atthe University of Houston College of Optometry is developing asoft contact lens that addresses this visual dilemma. The goal ofthis lens design is to meet three major complaints by patients withaberrated corneal optics – improve retinal image quality, increasecomfort and increase wear time. This soft lens (patent pending)provides wavefront correction tailored to the individual cornea. Toachieve its wavefront correcting objective, the correction containedin the lens has to more carefully counter the optical errors of theeye than currently required for astigmatic corrections. All patientsto date prefer the increased retinal image quality and comfort overtheir current gas-permeable correction. The remaining challenge isto develop and manufacture a lens design that can reliably remainwithin allowable position, movement and rotation errors over time.

New developments in hybrid and semi-scleral designs

Caroline Burnett Hodd


The advent of much higher Dk materials has led to a rebirth ofcorneo-scleral lenses and to a new generation of hybrid lenseswith rigid centres and soft skirts that claim to offer the visionof an RGP lens with the comfort of a soft. Large diameter lensesoffer improved comfort and better centration than smaller corneallenses, whilst giving better and more consistent vision than softlenses. The newest designs have a fitting philosophy based on fit-ting the sagittal depth of the cornea rather than its curvature andcompletely vault the cornea making them ideal for conditions likekeratoconus. However, these lenses are not only aimed at irregularcorneas but also at the astigmat and those requiring a correctionfor presbyopia.


UV danger in the UK? U bet!

Cristina M. Schnider*, Hiroshi Sasaki, Yasuo Sakamoto, NobuyukiFujita, Yoko Yamashiro, Kazuyuki Sasaki


Purpose: Previously, the authors reported on the impact of solarangle and season on ocular-UV-exposure (US-AAO-2009). Thisstudy was performed to better understand the impact of factorssuch as latitude and environs on UV-exposure to the head, eyesand face.

Method: A mannequin system with 12 UV-A/B sensors (embed-ded in cheeks, chin, neck, forehead, crown of head and eyes) wasused to collect UV intensity relative to solar angle in the followinglocations and times: Okinawa (beach, lat. 26.2◦N, July), Kanazawa(roof, lat. 36.6◦N, July and November), Japan and Reykjavik (roof, lat.64.1◦N, August), Iceland. Measurements were taken every secondfrom sunrise to sunset. The data presented here compares expo-sures to top of head and centre of eye.

Results: Though ambient-UV was highest in Okinawa, ocularexposure was significantly higher in Reykjavik in the face-to-suncondition, due to persistently lower angles of the sun in the sky
throughout the day. (Key: O – Okinawa, K – Kanazawa, R – Reyk-javik.). Average annual UVB exposure –kJ/m2 O – 22.5, K – 14.0, R– 5.5; head-crown cumulative UV-AB – J/cm2 O – 84.9, K – 98.2,R – 42.3; center-eye facing-sun cumulative UV-AB – J/cm2 O – 25.8,







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– 22.0, R – 35.5; center-eye back-to-sun cumulative UV-AB –/cm2 O – 23.7, K – 13.9, R – 8.0.

Conclusions: People dwelling in northern latitudes are likely toeceive more total radiation to their eyes in a day than those in moreoutherly latitudes due to the increased time the sun spends belowolar angles of about 40◦. This means that major re-education maye in order to protect the eyes of our patients from damaging effectsf UV.

acterial adhesion to silicone hydrogel lenses

ark D.P. Willcox*, Hua Zhu, Ajay V. Kumar, Jerome Ozkan, Duojiau, Simin Masoudi, Roya N. Borazjani


urpose: Silicone hydrogels have achieved excellent oxygen deliv-ry to the cornea. However, they are associated with adverse eventsuring wear, many of which are produced after bacterial contam-

nation of lenses. This study aimed, for the first time, to examinehe level of bacterial adhesion to the currently available siliconeydrogel lenses.

Method: All the different currently commercially available sil-cone hydrogel lenses were used in the study. Three strains oftaphylococcus aureus and three strains of Pseudomonas aerugi-osa were used. Bacteria were grown overnight in media containingH-uridine and resuspended in PBS to 1 × 107 CFU/mL. Lenses wereashed in PBS and incubated in 1 mL bacterial suspension for

8 h. After being washed in PBS three times, the number of totalradioactive) and viable (CFU) bacteria adhered on lens surfacesere estimated.

Results: Trends for adhesion of test strains within genera to dif-erent lenses were consistent. For S. aureus, total adhesion to lensesanged from log 4.5 to log 5.9 total cells/lens, and viable log 3.5o log 6.0 cells/lens. Highest adhesion was to lotrafilcon A, lowestdhesion was to asmofilcon A (p < 0.05). For P. aeruginosa, totaldhesion to lenses ranged from log 6.0 to log 6.6 total cells/lens, andiable log 5.9 to log 6.5 cells/lens. Highest adhesion was to comfil-on A, lowest adhesion was to balafilcon A (p < 0.05).

Conclusions: P. aeruginosa adhered in higher numbers than. aureus regardless of lens polymer type. Future studies willxamine the effect of lens wear on bacterial adhesion to theseenses.

iurnal variation of matrix metalloproteinase-9 in the tear filmnd its association with clinical signs

aria Markoulli*, Eric Papas, Brien A. Holden


urpose: Matrix metalloproteinases (MMPs) are degradingnzymes which maintain and remodel tissue architecture. Theirncontrolled production could have collagen degrading effects,uch as in recurrent corneal erosions and in the ulcerating cornea.s these conditions are exacerbated upon waking, this study setut to determine the normal diurnal variation of MMP-9 in tearsnd its association to clinical signs.

Method: Bulbar and limbal redness was assessed and tears wereollected from a group of 37 healthy, non-contact lens wearersged between 18 and 46 years of age. Samples were obtained fromoth eyes at midday, before sleep and immediately upon waking.otal protein content (TPC) and total MMP-9 concentration waseasured.Results: TPC was 3.4 ± 0.3 mg/ml, 4.3 ± 2.3 mg/ml and

6.5 ± 1.6 mg/ml for midday, before sleep and upon wakingespectively, the latter being significantly greater (p < 0.0005).MP-9 concentrations at these time points were 12.3 ± 2.5 ng/ml,

.0 ± 1.9 ng/ml and 2485.9 ± 297.7 ng/ml. Again, MMP-9 uponaking was significantly greater than the other visits (p < 0.0005).

or Eye 33 (2010) 256–300

The change in bulbar redness between midday and upon wakingwas not associated with the change in TPC or MMP-9 (r2 = 0.01,p = 0.44 and r2 = 0.00, p = 0.84 respectively). Likewise for limbalredness (r2 = 0.00, p = 0.92 and r2 = 0.02, p = 0.38 respectively).

Conclusions: During sleep, MMP-9 concentration in the tear filmincreases roughly 200-fold, compared with an increase in TPC ofonly about 4 times. These changes are not associated with thechanges in bulbar and limbal redness suggesting that this is notan indicator of up regulated MMP levels.

In vitro analysis of the physical properties of blister pack solu-tions of silicone hydrogel contact lenses

Lyndon W. Jones*, Kara L. Menzies


Purpose: Recently, manufacturers have incorporated various sur-face active agents into the blister packaging solutions (BPS) of softlenses in an attempt to improve initial comfort of the lens on eye.The purpose of this study was to measure and compare the physicalproperties of the BPS for 10 silicone hydrogel lenses, 2 conventionalpolyHEMA-based hydrogel lenses, and 2 saline controls.

Method: The pH, surface tension (ST), viscosity, and osmolal-ity of the BPS was measured for lotrafilcon A, lotrafilcon B, andlotrafilcon A and lotrafilcon B with a “modified BPS” (m-lotrafilconA, m-lotrafilcon B) (CIBA Vision), balafilcon A (B&L), galyfilcon A,senofilcon A and narafilcon A (J&J), and comfilcon A and enfilcon A(CooperVision) and BPS from two conventional polyHEMA-basedmaterials – etafilcon A (J&J) and omafilcon A (CooperVision). Thetwo saline solutions examined were Unisol (Alcon) and SoftWearSaline (CIBA Vision).

Results: The pH results for all BPS remained in the pH range oftears (6.6–7.8). The ST of the modified BPS was significantly lower(p < 0.01) than the original non-modified BPS. Viscosity measure-ments ranged between 0.90 and 1.00 cP for all BPS except for themodified BPS, which had significantly higher viscosities (p < 0.001).Osmolality measurements were not significantly different (p > 0.05)between BPS made by the same manufacturer but were signifi-cantly different comparing BPS made by different manufacturers(p < 0.05).

Conclusions: The incorporation of surface active agents into BPScan alter the physical properties of the BPS of silicone hydrogellenses and warrants investigation into their initial wettability andcomfort of the lens on eye.

Do presbyopes prefer progressive spectacles or multifocal con-tact lenses?

Susan W. Neadle*, Vera Ivanova, Sheila B. Hickson-Curran


Purpose: Practitioners have a range of vision correction optionsto offer presbyopes, none of which are successful for all patientsand all activities. It is therefore important to offer the most appro-priate vision correction option for each presbyope’s lifestyle andvisual demands. Two such options are spectacles with progressiveaddition lenses (PALs) and multifocal contact lenses (MFCLs). Thepurpose of this study was to evaluate task and situational pref-erence for these vision correction options and determine whichmethod was most appropriate from the patient’s point of view.

Method: 27 subjects with near ADDs up to +2.50 D were fit-ted with both PALs (Varilux Comfort) and a MFCL (senofilcon A)and randomly dispensed each for 1 week. Subjects were then dis-
pensed both options to wear as they determined most appropriate,for approximately 2 weeks. Pertinent assessments included patientdiaries and subjective questionnaires.
Results: After trying each vision correction option, 11% subjectschose PALs and 11% MFCL as the best option to meet their vision





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eeds, whereas an overwhelming preference (78%) was for theombination of PALs and MFCLs. PALs were preferred for station-ry and solitary activities requiring precise vision, while MFCL werereferred for social and active activities providing a wider field ofiew and more natural vision experience.

Conclusions: Patients perceived the benefits of PALs and MFCLs complimentary and could choose between modalities based onime, place and activity throughout the day. Practitioners can bet-er satisfy presbyopic patient’s needs by prescribing a combinationf both PALs and MFCLs.

ff-axis refraction before and after treatment in orthokeratol-gy myopic patients

osé M. González-Méijome*, António M. Queirós, César Villa-Collar,amón Gutiérrez-Ortega, Jorge M. Jorge


urpose: The purpose of this study was to characterize the cen-ral and peripheral refraction across the horizontal meridian of theisual field before and after myopic corneal refractive therapy (CRT)ith contact lenses.

Method: Twenty-eight right eyes (mean age ± SD = 24.6 ± 6.3ears) were fitted with Paragon CRT contact lenses to treat myopiaetween −0.88 and −5.25 D of spherical equivalent. Central anderipheral refraction was measured along the horizontal meridianp to 35◦ of eccentricity in 5◦ steps.

Results:Baseline central average spherical equivalent (M) mea-ured by subjective refraction changed from −1.95 ± 1.27 D to0.38 ± 0.67 D. At 25◦ to both sides of the central refraction mea-

urement, peripheral refraction after treatment was not statisti-ally different from baseline values (p > 0.351). Beyond the 25◦ limit,

component changed in the myopic direction up to −1.11 ± 0.88 Dt 35◦ in temporal retina (p < 0.001). Treatment induced was sym-etric between nasal and temporal visual field along the horizontaleridian (p > 0.05 for all eccentricities). Furthermore, the degree

f myopic increase in spherical equivalent for 30◦ (r2 = 0.573,< 0.001) and 35◦ (r2 = 0.645, p < 0.001) eccentric refraction wasighly correlated with axial spherical equivalent at baseline.

Conclusions: CRT inverts the pattern of peripheral refraction inpherical equivalent refraction creating a treatment area of myopiceduction within the central 25◦ of visual field, and a myopic shifteyond the 25◦. In peripheral refraction for 30◦ and 35◦, the amountf myopia induced in terms of spherical equivalent has an almost:1 relationship with the amount of baseline spherical equivalentefraction to be corrected.

onsistency of ocular comfort reporting in contact lens wearers,pectacle wearers and non-wearers

ercy Lazon de la Jara*, Eric Papas, Jennie Diec, BOptom, Brienolden, Mark Willcox


urpose: To determine ocular comfort changes among groups hav-ng various modes of vision correction and evaluate the consistencyf comfort reporting.

Method: Participants (n = 197) rated their ocular comfort uponaking, 9 am, 12 pm, 3 pm, 6 pm and 9 pm using an online question-aire (1–10 Numeric Visual Scale). Five categories were identifiedased on habitual correction modality (full time contact lensearers [FTCLW], full time spectacle wearers [FTSW], spectacle

nd occasional contact lens wearers [SOCLW], part time specta-
le wearers [PTSW] and no correction [NC]). Comfort changes wereomputed as the difference between 9 am and 9 pm ratings andompared using a linear mixed model, after adjusting for age andender. Reporting consistency was determined by observing therequency of similar comfort changes on all 3 days.
or Eye 33 (2010) 256–300 263

Results: Comfort decrements were significantly greater forFTCLW (−1.3 ± 1.8, p = 0.001) and FTSW (−1.0 ± 1.8, p = 0.017) thanfor the NC group (−0.6 ± 1.5). The magnitude of comfort changedecreased with increasing age in the FTSW (r: −0.2, p: 0.01) andSOCLW (r: −0.2, p: 0.023) groups. Other groups showed no signif-icant differences. Consistent comfort decrements of ≥1 point oneach of the 3 days were seen for 35% of FTCLW, 36% of FTSW and27% of NC groups. Similarly 29% of FTCLW, 36% FTSW and 43% ofthe NC groups consistently showed no decrement.

Conclusions: A significant decrease in comfort during the daywas experienced in both full time contact lens and spectacle wear-ers. Approximately 1/3 of participants have a consistent comfortdecrease irrespective of whether they wear contact lenses, specta-cles or no correction.

Longer prescribed replacement intervals leads to more stretch-ing of frequent replacement lenses

Sheila B. Hickson-Curran*, Patricia Chou, Jill Gardere


Purpose: Determining the optimal contact lens replacement fre-quency can be a dilemma for some practitioners who consider manyfactors such as ocular health, patient comfort, patient replacementcompliance and manufacturer recommendation as important inthis decision. One factor that may assist this decision is knowl-edge about the likelihood of patients complying with the prescribedreplacement interval and the degree of overwear (stretching) thatthey report.

Method: 645 frequent replacement contact lens wearersanswered questions relating to lens replacement frequency usingan online, sponsor masked survey. The respondents representedwearers of lens brands (hydrogel and silicone hydrogel) availablein the United States that are prescribed for 2-week (2W) or monthly(4W) replacement.

Results: Wearers of lenses prescribed for 2W replacementreported that they did so as follows: Within 2 weeks 43%, within 3weeks (prescribed +1 week) 65%, within 4 weeks 85%, 8 weeks ormore 4%, 10 weeks or more 2%. 4W lens wearers told by their eyedoctor to replace lenses every month did so as follows: Within 4weeks 36%, within 5 weeks (prescribed +1 week) 55%, 8 weeks ormore 23%, 10 weeks or more 14%.

Conclusions: Patients showed low compliance with the pre-scribed replacement schedule whether this was 2-weekly ormonthly. Lenses prescribed for longer replacement intervals canlead to more extreme overwear (stretching) of frequent replace-ment contact lenses. Prescribers should be aware that the timeinterval they recommend can impact frequency of replacementand should reinforce the value of replacement compliance at eachvisit.

The effect of compliance with replacement frequency on com-fort and vision with silicone hydrogel lenses

Kathy A. Dumbleton*, Craig A. Woods, Lyndon W. Jones, Doris B.Richter, Desmond Fonn


Purpose: The manufacturers recommended replacement frequency(MRRF) for silicone hydrogel (SH) lenses is usually either 2 weeks(2W) or 1 month (1M); however, many patients are non-compliantwith these recommendations. The purpose of this investigation wasto examine the effect of compliance with MRRF on comfort and
vision in SH wearers.
Method: A larger study was conducted to investigate compliancewith MRRF, and, as part of this study, patients were asked to ratetheir comfort and vision with their lenses in the morning (AM), atthe end of the day (EVE), when their lenses were new (NEW) and





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hen their lenses needed replacing (NR). Ratings were made oncales from 0 (very poor) to 10 (excellent).

Results: 741 patients wore 2W replacement modality (2WR) and48 patients wore 1M replacement modality (1MR) SH lenses. TheM and NEW ratings for comfort and vision were significantlyigher than the EVE and NR ratings (p < 0.001). Non-complianceates (with the MRRF) were 29% (95%CI 25.3–32.4) in 1MR wear-rs and 59% (95%CI 55.5–62.7) in 2WR wearers. Patients whoere compliant with the MRRF had significantly higher ratings for

VE (p = 0.002, p = 0.008) and NR (p < 0.001, p < 0.001) comfort andision. After compliance had been accounted for, EVE and NR com-ort and EVE vision ratings were higher for 1MR than 2WR wearersp = 0.015, p = 0.044, p = 0.019).

Conclusions: Patients who were compliant with MRRF hadetter EVE and NR comfort and vision, regardless of replacementodality. Subjective performance with SH lenses appears to beost favourable when replacing lenses as recommended.

ighlights of the BCLA Journal: Contact Lens and Anterior EyeCLAE)

hehzad Naroo


he British Contact Lens Association (BCLA) has grown into theremier contact lens association in the world so it is not surprisinghat its annual conference is a highlight in the diaries of many.or is it surprising that the peer reviewed publication of the BCLA,ontact Lens and Anterior Eye (CLAE) is the journal of choice forcademics, clinicians and industry based personnel involved in theeld. Dr Shehzad Naroo has been Editor-in-Chief since 2005. Inhat time the journal has gone from four issues per year to five andow six. Each issue now contains one clinical review paper thatlso allows one continued education and training (CET) point forK optometrists and opticians. Over the last five years the journalas produced many excellent papers and in this presentation Draroo will give the main highlights of the journal from the last

ew years. These will include the details of the most downloadedapers, the most cited papers and some of the most relevantoo.

ONFERENCE SESSION 10: Irving Fatt Memorial Lecture

orneal confocal microscopy: Research and clinicalpplications—Two studies

anagiotis Kallinikos


tudy 1

urpose: To employ confocal microscopy to investigate the aeti-logy of keratocyte loss after short-term contact lens wear byonitoring quantitative changes in keratocyte density.Methods: Twenty neophyte subjects aged 26 ± 3 years partici-

ated in the study, which was conducted over the course of threexperimental sessions. In the first session, one eye of each subjectas fitted with a silicone hydrogel contact lens, and the other eye

erved as the control. Both corneas were exposed to an anoxic envi-onment for 2 h. Ultrasound pachometry and confocal microscopyere performed on both eyes at baseline, immediately after the

xperiment and 2 h post experiment. This procedure was repeatedfter 72 h, but in this case one eye of each subject was fitted with ayper-Dk rigid contact lens and the fellow eye served again as the
ontrol. In the third experimental session, each subject was askedo periodically rub one eye only. Tear samples collected from theubbed and control eyes were assayed for epidermal growth factorEGF), hepatocyte growth factor (HGF), and interleukin (IL)-8.
or Eye 33 (2010) 256–300

Results: The increase in corneal thickness was similar in theexperimental and control eyes. Both anterior and posterior kerato-cyte densities decreased in the experimental eyes compared withthe control eyes, in all sessions. EGF and IL-8 concentrations wereincreased in the rubbed eyes compared with the control eyes.

Conclusions: It is hypothesised that the mechanical stimulationof the corneal surface, due to the physical presence of a contact lens,induces the release of inflammatory mediators that cause kerato-cyte dysgenesis or apoptosis.

Study 2

Aims/hypothesis: The aim of this study was to define the ability ofcorneal confocal microscopy to quantify the extent of degenerationand regeneration of corneal nerve fibres in diabetic patients withincreasing neuropathic severity.

Methods: Corneal confocal microscopy was performed in 158diabetic patients (stratified into mild, moderate, and severe neuro-pathic groups using conventional clinical measures of neuropathy)and 25 age-matched non-diabetic control subjects, and images ofthe sub-basal nerve plexus were assessed for nerve fibre density(NFD), nerve branch density (NBD), nerve fibre length (NFL) andnerve fibre tortuosity (NFT).

Results: Corneal NFD (F3 = 9.6, p < 0.0001), NBD (F3 = 13.9,p < 0.01), NFL (F3 = 23.8, p < 0.0001) and NFT (F3 = 12.2, p < 0.001)were reduced in diabetic patients compared with control sub-jects, with a tendency for greater reduction in these measures withincreasing severity of neuropathy.

Conclusion/interpretation: Corneal confocal microscopy repre-sents an in vivo clinical examination technique which accuratelydefines the extent of corneal nerve damage and repair and acts asa surrogate measure of somatic neuropathy in diabetic patients. Itcould represent an advance to define the severity of neuropathyand expedite assessment of therapeutic efficacy in clinical trials ofhuman diabetic neuropathy.


Make your staff contact lens experts, the clever way

Sarah Morgan


Have you ever been on the receiving end of an enquiry about con-tact lenses either over the telephone or at the reception desk? Itis probably one of the most challenging scenarios to deal with at atime when the contact lens ‘expert’ is inaccessible behind the con-sulting room door. Having staff outside of the consulting room whocan field questions relating to contact lenses is vital if a practice is tobe seen as providing an excellent contact lens service. Patients tendto judge the expertise of the eye care professional on the interac-tion with the front-line staff – so it matters! Most staff are hungryfor more information about contact lenses, and they are driven bythe myriad of questions they are asked and the frequency of hav-ing to say ‘I’ll have to check. . .’. Whilst staff cannot become expertsovernight, there are many ways to dispel the myths that contactlenses are ‘complicated’ – perhaps the pricing systems seem thatway and that there are too many lens types to think about? Thislecture reviews approaches that can be utilised at practice level todevelop the knowledge of staff so that one day, they will feel suf-ficiently expert to both answer everyday enquiries about contactlenses in addition to creating awareness in those patients who areyet to discover contact lenses.

How to talk so your patients will listen & listen so they will talk

Craig Wilcox






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s highly trained professionals we are all well versed in the lan-uage of Optics but how many of us speak the same language as theeople we take care of? Fact: the number one reason that patientsomplain is that the practitioner or practice did not listen to themr give them the time and respect they deserved. Of course weid. Or did we? We have in our armoury things like instruments,ests, lenses and drugs, so why not the skills to connect with youratients? We are told that we have to be both ‘high tech’ and ‘highouch’ but unlike our highly technical clinical skills our communi-ation skills are hardly given a mention in our education. It is allery well knowing what we need to do, we also need to know howo do it. One short session (will add absolutely nothing at all toour technical skills but) will impart clinical pearls that all success-ul practitioners have in common.


ontact lens compliance with children and teenagers

ruce Evans


he literature on compliance by contact lens wearers in generalill be briefly summarised and the literature on compliance by

ontact lens wearing children and teenagers will be reviewed inore detail. This literature will be contextualised by considering

he research evidence from other healthcare disciplines on com-liance in children and teenagers. This will be used to inform theebate on compliance in young contact lens wearers and in partic-lar to address the question ‘Can young patients be more complianthan older patients?’ The talk will be concluded by a summary of

ethods of improving compliance in young contact lens wearers.

hat your patients don’t tell you!

yndon Jones


atients are notoriously non-compliant, with estimates regard-ng non-compliance with various aspects of lens wear and careunning at between 50% and 90%. In addition, recent work hasuggested that some practitioners encourage non-compliance byroviding poor advice on such matters as when lenses should beeplaced. Practitioners may also routinely miss aspects of non-ompliance by not conducting thorough progress checks. Onexample relates to patients switching to incompatible care reg-mens through cost or convenience concerns. Practitioners whoo not routinely undertake corneal staining evaluations may benaware of such poor compliance. This presentation will reviewome of the more common reasons why patients are somewhatliberal with the truth” at follow-up visits and describe methodso combat these non-compliant behaviours. It will include advicen questioning strategies aimed at determining those patients whoay be exhibiting dangerous non-compliant behaviours.

eally motivating your staff

arah Morgan

-mail address: [email protected] well-designed prac-ice with superb products and state-of-the-art equipment may begreat place to work, but the experience for patients is only a suc-

ess if the people within make the grade. What is the magic thatreates a talented group of staff who enjoy coming to work and are
ocussed on both practice and patient needs? Can a manager makehe unmotivated motivated – or does motivation come only fromhe employee? This lecture provides better understanding of theariety of attitudes present in the work place and how best to helptaff focus on the overall goals. Research has shown that there are
or Eye 33 (2010) 256–300 265

key differences in attitudes to work which stem from generationalinfluence. A person born in the early 1960s will attach importanceto work-life balance compared with those born in the early 1980swho tend to be averse to commitment. Awareness of these differ-ences is helpful when more experienced managers and supervisorsare interacting with more junior members of the practice team. It isvery easy to assume that all members of staff want to be rewardedfinancially, but once a reasonable level of reimbursement has beenmet are there any other drivers for work performance? Understand-ing the range of factors which influence different members of staffand tailoring the supervisory/management interaction accordinglycan help optimise staff output. How to engage with staff to involvethem in practice improvements will be discussed.


Bacterial infections of the cornea; the macro/micro picture

Suzanne Fleiszig


For more than 20 years, we, and others in this field, have workedtowards understanding why contact lens wearers are susceptible tocorneal infection. We have faced a major stumbling block revolv-ing around the fact that it is not possible to determine how lenswear compromises corneal defences against infection without firstknowing what those defences are. Until recently, that topic wasvery difficult to study. Firstly, we didn’t know enough about thebasic biochemistry or cell biology of the ocular surface to prop-erly study its function. Secondly, there were no tools available forsorting out which of the many molecules present were actuallyinvolved in maintaining health leading researchers to use educatedguesses as to which to study. We also lacked in vivo model sys-tems for studying both normal processes and contact lens relatedinfections. Until recently, infection models were limited to one thatrequires scratching the cornea all the way into the stroma to exposeit before adding bacteria, and another in which bacteria are injectedinto the stroma. Clearly neither situation is representative of howcontact lens infections happen. So while these two infection modelshave enabled researchers to learn a plethora of information aboutinfection once it has already been initiated (which is also impor-tant) they are not really suited to studying how contact lenses causeinfection, because critical early events involving the epithelium arecompletely bypassed. Nor are they particularly useful for studyingwhy the cornea is not susceptible to infection when healthy. Due tothis lack of available in vivo models, researchers (including this lab)resorted to studying bacterial interactions with corneal epithelialcells using cells grown in tissue culture dishes. Those attemptingto study those interactions in vivo learned that bacteria would notinteract at all with the healthy cornea in the absence of contact lenswear leaving nothing to study. Basically, research in this field hadbeen “beating around the bush” for more than two decades withresearchers resorting to indirect methods and models using what-ever means were available. We have now entered a new era. Withthe sequencing of the entire genomes of humans, experimentalanimals, and microbes that cause contact lens infection, combinedwith the development of new easily obtained screening tools thathave the capacity to hone in on the actual molecules involved inbiological processes (for example, those critical for defence, andthose impacted during susceptibility), combined with new biolog-ical information that has arisen from use of these tools in otherrelated fields, there has been a recent explosion of new relevant
information and we are now in an excellent position to move thefield forward to finally solve this obstacle to safe contact lens wear.Also of critical importance to that common goal of industry, prac-titioners and patients alike, the contact lens industry has started tomake rodent lenses available to researchers who as a result can now




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irectly attack the problem. In our laboratory, we have developedovel in vivo and in vitro methods for studying defences duringealth, in addition to new imaging technologies that enable us tosee” into the living cornea to observe what bacteria do and howhe cornea responds. This lecture will describe some of these newechnologies and their current and future potential for cornea andontact lens research. The lecture will also discuss early resultssing them and what they have already revealed about barriers to

nfection in the healthy cornea and about how lens wear or bacte-ia compromise them. We will also consider the answers to variousingering questions in the field, and we will attempt to answer themased on what we are learning. Those include:

. Would it help if patients were more compliant?

. Do we need to kill bacteria to keep patients safe? And do we needto stop them binding to contact lenses?

. Why is extended wear a risk factor?

. Does fluorescein staining predict risk of infection?

. Is stagnation under a lens a problem?

. Is hypoxia a risk factor?

. Why Pseudomonas?

. What is the relationship between infection and inflammation?

ontinued research in this area has significance beyond enabling uso understand contact lens infections. The study of how and whyontact lens wear impacts ocular surface homeostasis advances ournderstanding of corneal health and disease in general. It also hasotential for development of novel methods to prevent infection ofhe eye and of other sites.

ontact lens infections: Can they ever be eliminated?

avid Evans


dvances in contact lens design and technology have not yet pre-ented microbial keratitis, the most significant complication of lensear. This talk will outline the normal ocular defences against

nfection, and the potential mechanisms by which lens wear couldompromise those defences. Research and therapeutic strategieshich could eventually lead to the eradication of contact lens-

ssociated microbial keratitis will be discussed.


revention of microbially driven adverse events: To kill or noto kill?

ark DP Willcox*, Ajay K. Vijay, Peter Wu, Fiona Stapleton, Huahu, Padmaja Sankaridurg


ontact lens wear remains an ideal way of correcting many formsf refractive error. Generally contact lens wear is safe and effective.owever, in rare instances wear can be linked to adverse events,any of which are related to microbial contamination of lenses.

ortunately, frank infection of the cornea is rare occurring at a ratef 1/2500 wearers/year if lenses are worn on a daily wear sched-le, rising to 1/500 wearers/year if lenses are worn on an extendedear schedule. Other non-infectious adverse events such as con-

act lens induced acute red eye (CLARE) and contact lens inducederipheral ulceration (CLPU) are more common – around 1/20o 1/50 wearers/year. Many groups have been assessing ways of
educing the incidence of microbially driven adverse events. Micro-ial adhesion to and growth on lenses is believed to be an initiatingactor for the development of the adverse events; the microbes thennter the cornea and grow. Thus preventing these events has beenargeted. Mechanisms that prevent growth of the microbes would
or Eye 33 (2010) 256–300

prevent frank infection, but might still lead to corneal inflamma-tion as microbes may still be retained on a lens surface. Indeed,it is possible that death may lead to greater release of inflamma-tory mediators from the microbes. Dead bacteria can not infect thecornea. Dead Staphylococcus aureus were unable to produce CLPU-like lesions (indeed any inflammatory response) in the corneas ofrabbits; live S. aureus in the presence of a small peripheral lesionproduced CLPU-like lesions. However, high numbers of dead Pseu-domonas aeruginosa are able to produce CLARE-like lesions in thecornea, although there was no increase in the incidence or sever-ity of the inflammation in the presence of the dead comparedto live bacteria. Other researchers have found that application oflarge amounts of the Gram-negative pro-inflammatory moleculelipopolysaccharide (endotoxin) to the cornea can produce inflam-mation. On the other hand, a reduction in numbers of live bacteriaon lenses (even if dead bacteria are present) reduces the incidenceof frank infection. Thus, strategies that only kill bacteria colonisinglenses will likely result in a reduced incidence of infection. In orderto reduce the incidence of inflammation (CLARE, CLPU, etc.) strate-gies that reduce the total number of bacterial cells (live and dead)are likely to be successful.

CONFERENCE SESSION 13: BCLA Medal Address

A new paradigm for dry eye etiology, diagnosis, pathogenesis,prevention, treatment and contact lens success

Donald Korb


Dry eye status: Dry eye is the leading reason for visits to optometristsand ophthalmologists in the US, and for contact lens intoleranceleading to discontinuation of contact lens wearing. Treatment ofdry eye has proven to be less than optimal.

A new direction for dry eye: A change in direction for dry eye eti-ology and treatment is highlighted both from recent research and arecent report by the prestigious International Tear Film and OcularSurface Society: “It is important to note that meibomian gland dys-function may be the leading cause of dry eye syndrome throughoutthe world”. As a result, an International Meibomian Gland Work-shop was organized in 2008 by the Tear Film and Ocular SurfaceSociety, following the model of the 1995 and 2007 InternationalDry Eye Workshops. These lengthy meetings over several yearsled to the 1995 and 2007 DEWS Reports, which established con-temporary standards and recommendations for dry eye diagnosisand treatment. A similar report by the Meibomian Gland Workshopestablishing standards and recommendations for the specific roleof the meibomian glands in dry eye is scheduled for 2010. This dra-matic shift from the traditional aqueous and mucin based modelsfor dry eye to inclusion and emphasis of meibomian gland dysfunc-tion qualifies as a paradigm shift, as defined by the nomenclator ofthe term paradigm shift, Thomas S. Kuhn.

Lecture focus: This lecture will present the evidence basedmedicine (EBM) for supporting this new paradigm of dry eye eti-ology, diagnosis and treatment, including the ever-expanding roleof meibomian gland dysfunction and obstruction, and a new clin-ical entity described by the author and colleagues, non-obviousobstructive meibomian gland dysfunction (NOMGD). NOMGD hasparticular relevance to contact lens practice. The author’s devel-opment of a new diagnostic instrument for meibomian glandevaluation has led to the concept of meibomian gland function-ality, and allowed quantification of meibomian gland functionality
and correlations to ocular symptoms and signs. The relevance ofNOMGD to the tear film and to lid wiper epitheliopathy allows anunderstanding of how this new paradigm relates to dry eye etiol-ogy, pathogenesis, prevention and treatment, and explains manyof the dichotomies and anomalous findings encountered in the



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ultifactoral dry eye conditions and disease encountered in pri-ary, tertiary and contact lens practice.

ONFERENCE SESSION 14

econtamination: The new guidance

oger Buckley

ast September guidance entitled ‘Managing CJD/vCJD risk in oph-halmology’ appeared on the Department of Health’s website. Itndicated a welcome re-thinking of measures imposed 10 yearsarlier in response to the emergence of a new variety of Creutfeldt-akob Disease (vCJD) in 1995, a human disease linked to the epi-emic of ‘mad cow disease’ (BSE) that had begun in 1986. The retinand optic nerve show high levels of infectivity in CJD and vCJD,ut research has consistently failed to show significant infectivity

n the anterior segment. Accordingly, the decontamination of con-act lenses and ophthalmic devices used on more than one patienteed not involve measures intended to eliminate prions, the agentsf these invariably fatal diseases. The new guidance takes as itstarting point the low potential for prion infectivity of the anteriorye and of the surface of the cornea and conjunctiva in particular.eliance is placed on thorough cleaning to remove cellular debrisnd adherent protein, and the concentration of the recommendedisinfecting agent, sodium hypochlorite, is now aimed at inactivat-

ng orthodox infectious agents such as bacteria and viruses.

nfection control—How dentists do it

ichael Martin

ny healthy mouth contains numerous potentially pathogenicacteria, yeasts and viruses, yet there have been few definitive doc-mented cases of cross infection in dentistry. A survey in Scotlandhowed that the majority of dentists had inadequate decontamina-ion procedures, poor handwashing techniques and inadequate usef personal protective equipment. In December 2009 the Depart-ent of Health published definitive guidelines on decontamination

HTM01–05) and this specified two standards, essential and bestractice. Essential practice has to be adopted by all dentists byecember 2010 and by this time there has to advanced plans for the

ntroduction of best practice. These guidelines require that dentistsave uniform infection control procedures. The guidelines have theupport of all the professional bodies, but there are arguments thathey are not necessary and inevitably put financial pressure on den-al practices.

esistance to resistance, community-based MRSA: a new chal-enge for optometrists

onald Cameron

RSA is often thought to be a hospital based issue surroundingajor operations. However with MRSA increasingly being found

o colonise the non-hospitalised population optometrists carry anncreased risk of transmission but also of infection of potentiallyight threatening ocular infections. Donald Cameron will talk abouthe history, prevalence and dangers of MRSA infection with partic-lar reference to the precautions we should all take in our practice.

ands up to hygiene

ane Veys

ractising good hand hygiene is the single most effective way torevent the spread of infection.

Yet effective hand washing compliance can be variable, evenmongst health care professionals! Between September 2009 andarch 2010, data was collected from over 200 UK eye care prac-

itioners attending eye health related courses at the Vision CarenstituteTM on how well they rated their own hand hygiene prac-

or Eye 33 (2010) 256–300 267

tice. Participants used a Bosch interactive voting unit to registertheir responses, which were then displayed to the whole groupwhen everybody had voted. Following participation in practicalworkshops using UV disclosing gel, to demonstrate effectivenessof technique, their rating was reevaluated. Results show a signif-icant shift in self rating scores once awareness for correct handhygiene had been raised. 69%rated themselves excellent or verygood initially, compared to 25% post demonstration (Student’s t-test < 0.0001). This data supports the need for more engagementand ongoing education on this topic. Evidence based, practical tipsto promote hygiene in practice will be reviewed.


Critical oxygen transmissibility to avoid overnight lens inducedcorneal swelling

Desmond Fonn*, Craig Woods, Doris Richter, Amir Moezzi


Purpose: To determine whether the Holden-Mertz criterion of oxy-gen transmission (Dk/t) required to avoid overnight lens inducedcorneal swelling is still appropriate.

Method: 29 neophytes wore each of 12 silicone hydrogel lensesof varying central oxygen Dk/t values (range 31–211 × 10−9)overnight, in random order, and on one eye only. The contra-lateraleye (no lens) served as the control. Central corneal thickness wasmeasured using a digital optical pachometer before lens insertionand immediately after lens removal on waking.

Results: The mean overnight lens induced central cornealswelling significantly exceeded the contralateral control eye meanswelling by 2.3% (p < 0.05). Using a logarithmic function for thebest fit line demonstrated that the line asymptotes towards themean non-lens wear corneal swelling of 4.3%, thus exceeding themaximum Dk/t value of lenses used in this study.

Conclusions: The results of this overnight swelling study sug-gests that the critical oxygen transmission exceeds the highest 211Dk/t value. Even if an arbitrary value of 1.5% is added to the non-lens wearing eye accounting for lens induced swelling that is notcaused by hypoxia (shown previously), the Holden and Mertz crite-ria of 87 × 10−9 grossly underestimates the critical minimum valueto avoid overnight lens induced corneal swelling.

Characterization of patients wearing contact lenses on anextended wear (EW) basis, both in and out of US FDA EW indi-cation

Meredith E. Jansen*, Robin Chalmers, G. Lynn Mitchell, KathrynRichdale, Luigina Sorbara, Dawn Y. Lam


Purpose: To describe differences between patients who report dailywear (DW) and extended wear (EW) and to describe EW use ofDW-only approved lenses (US Food and Drug Administration).

Method: A retrospective chart review of 3211 established softcontact lens (SCL) patients with known overnight wear status(aged 8–33 years, wearing +8.00 to −12.00 D SCLs) recorded datafrom 10,515 clinical visits from 2006 to 2009. Demographic factors(listed below) were analyzed by patient reported EW at each visitby using the Chi-square test (�2). Significant univariate factors forEW were entered into a model to test factors for EW with SCLs notFDA approved for EW.

Results: Compared to DW, patients reporting EW were more2
likely to be male (15.6% vs 12.0%, � = 10.86, p = 0.001), Cau-
casian (�2 = 18.62, p = 0.0009), college students (15.6% vs 12.2%,�2 = 9.2, p = 0.002), smokers (24.0% vs 10.9%, �2 = 11.46, p = 0.0007)and wearing silicone hydrogel lenses (17.2% vs 8.0%, �2 = 111.1,p = 0.0001). Years of CL wear was also significantly associated with



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W (�2 = 68.0, p = 0.0001). Off-indication EW was reported 17.6% ofhe time, 7.0% with 13 hydrogel, and 10.7% with 2 silicone hydrogelrands without FDA EW approval.

Conclusions: Males, Caucasians, college students, smokers andilicone hydrogel lens wearers were significantly more likely toeport EW. Many brands of hydrogel lenses and two brands of sil-cone hydrogels were associated with EW use without FDA EWpproval. This information helps identify groups more likely toear EW CLs, both in and out of EW indication, and facilitates tar-

eting of evidence-based patient education to those groups.

he risk of vision loss in contact lens wear and following LASIK

iona J. Stapleton*, Thomas Naduvilath, Yvonne Wu, Nicole Carnt,Optom, Lisa Keay, Katie Edwards, Arthur Ho


urpose: To estimate the risk of vision loss (VL) following contactens (CL)-related microbial keratitis (MK) and the one-off risk of VLollowing LASIK surgery.

Method: A 12-month national prospective surveillance studydentified new cases of CL-related MK. Controls were generatedsing a population-based survey and incidence of VL of 2“T linesas estimated. The risk of VL at 6 months after LASIK was estimated

rom prospective FDA studies from 2005 (n = 13). A proportioneta-analysis estimated the rate of LASIK VL.Results: There were 286 eligible CL-MK cases, of which 39 lost

ision and 1122 community controls. The incidence of VL forny CL type was 0.6 (95% confidence intervals (CI): 0.5–0.7) per0,000 wearers/year, with a higher rate during the first 6 monthsf wear, 0.8 (CI: 0.8–0.9). VL varied with CL modality; in overnightL use in 4.0 (CI: 2.9–6.6) and daily CL use in 0.4 (CI: 0.4–0.4)er 10,000 wearers/year. VL following LASIK occurred in 57 (CI:3–106) per 10,000 cases. Least-squares fitting of cumulative VLP, /10,000 wearers) over time (t, years) was conducted using anxponential model, to predict years of CL wear to which the risk ofL with LASIK was equivalent. VL following LASIK was equivalent

o 94 years (CI: 34–192) of any CL use, 138 years (CI: 55–257) ofaily CL use and 13 years (CI: 5–25) of overnight CL use.

Conclusions: Daily CL worn for a life-time and overnight CLs wornor over 10 years produce the VL rate equivalent to LASIK.

eographic and temporal aspects of contact lens complicationsn the CLAY study

athryn L. Richdale*, G. Lynn Mitchell, Meredith E. Jansen, Beth T.inoshita, Luigina Sorbara, Heidi Wagner


urpose: The CLAY group was formed to characterize events thatisrupt soft contact lens (SCL) wear in youth versus adulthood. Asreviously reported, SCL replacement schedule, care system andxtended wear were associated with contact lens complications.he purpose of this abstract was to examine the geographic andemporal aspects of these events.

Method: A retrospective chart review of 3549 SCL wearersged 8–33 was conducted at six academic sites in North Amer-ca. Information on visit location, date, patient demographics, SCLarameters, wear schedules, care systems, and slit-lamp findingsere collected on patient visits from 2006 to 2009. Events that

nterrupted contact lens wear were adjudicated. Survival analysesere used to examine events by five geographic regions, season,

nd day of the week.
Results: Of the 14,327 visits, there were 522 events in 426 SCL
earers. Approximately 1/3 were infiltrative events. By univariatenalysis, geographic locale and season were significant risk fac-ors for an event (p < 0.01), but day of the week was not (p = 0.97).n a multivariate model, longer replacement schedule (monthly:

or Eye 33 (2010) 256–300

2.17X, CI = 1.22–3.86, 1–2 weekly: 2.51X, 1.42–4.44, ref: daily dis-posable) and the Autumn season (1.49X, 1.09–2.03, ref: Winter)carried an increased risk, while the Northeast and Midwest regions(NE: 0.50X, 0.31–0.80, MW: 0.64X, 0.44–0.94, ref: Northwest) wereat decreased risk for an event.

Conclusions: These results suggest that geographic locale andseason are related to successful contact lens wear. More informa-tion is needed to determine why such relationships exist and whatcan be done to minimize contact lens-related complications.

DALLOS AWARD

Pilot study of contact lens wearer risk-taking propensity andpractitioner perception of compliance

Nicole Carnt*, Lisa Keay, Yvonne Wu, Fiona Stapleton


Purpose: To determine associations between contact lens wearerrisk-taking propensity and practitioner perceived compliance withlens care hygiene and complication rates.

Method: Ten contact lens practitioners invited up to 10 contactlens wearers to complete a questionnaire on risk taking and lenscare hygiene. Each wearer’s risk taking propensity was estimatedusing Rasch analysis of questionnaire responses. Lens care hygiene(maximum score 40) had 4 components (Lens disinfection, 20;Hand hygiene, 8; Case hygiene, 6; Case replacement, 6). Practition-ers completed wearer’s history surveys, including adverse eventsand the association with non-compliant behaviour, and rankedcompliance on a 1–5 scale. Risk taking propensity and perceivedcompliance were investigated as predictors of hygiene and adverseevents using correlation and t-tests.

Results: Thirty-six wearers completed the questionnaire. Thequestionnaire fit the Rasch model, demonstrating good separationand reliability (Person: 2.44, 0.86; Item: 2.20, 0.83). Risk takingpropensity was associated with poor lens care hygiene (p = 0.03)and inadequate lens disinfection (p = 0.045). There was insuffi-cient power to investigate the association between adverse eventsand risk taking. Perceived compliance was not correlated withrisk taking, lens care hygiene (p > 0.05) or adverse related to non-compliance events (p > 0.05), but was associated with all adverseevents (p = 0.03). Analysis with traditional sum scoring of the risktaking propensity questionnaire yielded similar results.

Conclusion: A risk-taking questionnaire can predict wearerswith poor lens care hygiene. Practitioner’s perceived compliance isrelated to total adverse event rates, rather than only those related tonon-compliance and is not associated with poor lens care hygiene.A risk-taking questionnaire tool may aid practitioners in identify-ing wearers with poor hygiene.

RAPID FIRE SESSION

The impact of tear film components on in vitro lipid uptake tosilicone hydrogel and hydrogel contact lens materials

Holly I. Lorentz, Miriam L. Heynen, Lyndon W. Jones


Purpose: To analyze the influence of additional tear film compo-nents on in vitro deposition of a model lipid (cholesteryl oleate; CO)on silicone hydrogel (SH) and conventional hydrogel (CH) contactlens materials.

Method: Balafilcon A (BA), lotrafilcon B (LB), and etafilcon A(EA) were incubated with three different doping solutions for 1 or
7 days: a CO only solution, a lipid doping solution (LDS) containingfive common lipids, and an artificial tear solution (ATS) containingthe LDS plus lysozyme and mucin, at physiological concentra-tions. Each doping solution contained the same concentration ofradiolabelled 14C-cholesteryl oleate. After soaking, lenses were




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emoved from the doping solution, extracted, and deposition ofO was quantified using a LS6500 Beckman Coulter beta counter.

Results: For each doping solution, CO deposition was greaterfter 7 days than after 1 day (p = 0.007). The lens materialseposited statistically different amounts of CO (p < 0.0001), withhe order of deposition being BA > LB > EA. The doping mediumn which the CO was suspended had a significant impact on themount of CO deposited (p < 0.001), with ATS < LDS < lipid alone.

Conclusions: This in vitro study demonstrates that CO depositions cumulative over time and that SH materials deposit more COhan a CH FDA group IV material. It also clearly demonstrates thateposition of CO is influenced by the composition of the dopingedium and that in vitro models must use more physiologically

elevant incubation solutions that mimic the natural tear film if initro data is to be extrapolated to the in vivo situation.

ens-related dryness symptoms in a cross-section of UK softontact lens wearers

raeme Young*, Robin Chalmers, Leslie Napier, Chris Hunt


urpose: To estimate the prevalence of and factors associated withontact lens-related dryness symptoms in a large population ofoft contact lens patients in the UK.

Method: Soft contact lens (CL) wearers (N = 932) from 12 UK clin-cal sites were queried regarding CL history and wearing experiencey a self-administered questionnaire. A new categorization systemsing Contact Lens Dry Eye Questionnaire (CLDEQ) items was usedhere Dry = Frequency of ‘sometimes’, ‘frequently’, or ‘constantly’

nd Intensity 3–5; Not Dry = Frequency of ‘none’ or ‘rarely’ andntensity 0–2; Marginal Dry = other categories. Data were analyzedcross the categories, with p-values < 0.05 taken as significant.

Results: CL-related dryness prevalences were: Dry = 33%,arginal = 56% and Not Dry = 11%. Wearers with Dry status

ad significantly lower typical comfort scores (Dry = 7.1 ± 1.9;arginal = 8.4 ± 1.9; None = 9.1 ± 1.7, p < 0.001), end-of-day

omfort (Dry = 5.1 ± 2.5; Marginal = 7.3 ± 2.1; None = 8.4 ± 2.4,= < 0.001) and shorter comfortable wearing times

Dry = 9.3 h ± 4.5; Marginal = 11.8 ± 4.9; None = 12.4 ± 5.4,= < 0.001). Dry status was significantly more likely among

oric lens wearers (n = 129) compared to spherical lens wearers43% vs 30%, n = 643, p = 0.004). Lens material class, lens care systemnd gender were not statistically significantly related to drynesstatus in this survey. Of the Dry group, only 38% had previouslyeen diagnosed with dry eye and 47% were self-assessed as dryye.

Conclusions: The survey provided useful data regarding the cur-ent status of UK CL wearers. CL-related dryness score predictsatients’ wearing experience; poorer comfort and shorter comfort-ble wearing time.

odelling the in-eye tear film with Langmuir and Brewsterngle techniques

arc P. Broadbent*, Nadia Rasul, Brian J. Tighe


urpose: Langmuir techniques involve moving barriers that com-ress the surface of a liquid held in a shallow trough, just as theyelids compress the tear film. Brewster Angle Microscopy (BAM)llows the visualisation of surface films. Together they form an idealay of imaging and measuring the spreading capability and homo-

eneity of lipid layers and effects of added components such as careolutions.

Method: Temperature-controlled troughs of different sizes aresed, the smallest being designed to match the palpebral aperture,llowing direct use of ex-vivo tears. In larger troughs the target

or Eye 33 (2010) 256–300 269

components are deposited onto a water subphase. Surface pres-sure is measured during compression and expansion (mimickingblinking action). A p-polarized light beam incident at the Brewsterangle (53.40◦) is reflected from surface adsorbed monolayers, butnot water, forming high contrast images of the lateral morphologyof the deposited film.

Results: Isotherms of fresh human lipid show high collapse pres-sures (ðc > 50 mN/m) and highly reflective BAM images suggestingthat human lipid is spread readily and very surface active at theair–water interface. Added care solution components produce dis-tinctive isotherm features and collapse pressures. Additionally, thelipid film morphology is altered; darker patches indicating caresolution interaction with the lipid layer. Lipid-free artificial tearshave low collapse pressures (e.g. Systane®, 8 mN/m; HypoTears®,unpreserved 9 mN/m; preserved 22 mN/m).

Conclusions: These techniques give valuable insight into tear filmbehaviour, including: the high surface activity of fresh lipid, therelative effect of care solution components, low surface activity ofartificial tears and the effects of wear-induced lipid degradation.

Palpebral conjunctival epithelium in a dry eye mouse model

Jan PG Bergmanson*, Johanna Tukler Henriksson, Cintia S. De Paiva,Stephen C. Pflugfelder


Purpose: Moderately dry eye diagnosis is difficult, because it is notknown what microscopic surface changes have occurred causingassociated symptomology. The mouse model was used to definetissue changes provoked by dryness.

Method: Twelve C57BL/6 mice, 6 normal and in 6 with ocu-lar dryness – scopolamine hydrobromide (0.5 mg/0.2 ml) QID andexposure to a dry environment for 5 (n = 3) and 10 (n = 3) days. Thelids were fixed in 2% glutaraldehyde. Thick sections with palpe-bral conjunctiva were stained (1% toluidine blue) and viewed withan Olympus IX70 microscope. Palpebral epithelial measurementswere obtained using NIH Image 1.63 and the number of goblet cellsassessed.

Results: The epithelium near the lid margin was stratified andlacked goblet cells. Over the next 411.1 ± 73.3 �m the epitheliumtapered down from 8 to 3–4 layers of cells with goblet cells present.In this region, the control epithelium averaged 23.2 ± 3.4 �m andwas significantly (p < 0.05) thicker than the 5 day (17.0 ± 3.4 �m)and the 10 day (17.8 ± 2.6 �m). Control averaged 19.3 ± 8.5 gobletcells versus 28.3 ± 18.9 and 25.0 ± 4.4 for 5 and 10 day respectively(p > 0.05). However, in the normal, 36% of the goblet cells had anepithelial coverage, compared to 54% for the 5 day and 56% for the10 day (p < 0.05).

Conclusions: The dry eye palpebral conjunctival epitheliumbecame thinner in but the goblet cell density did not change. How-ever, the ocular surface access for goblet cells appeared inhibited bysurrounding epithelial cells, which may in this manner slow downthe progress of goblet cells towards the surface.


Training day for medics: Contact lens fitting for ophthalmolo-gists

Ursula Vogt, Sarah Janikoun, Vinod Kumar

This day will be dedicated to teaching and promoting the latestdevelopments in medical contact lens practice. We shall start with
Dr Ursula Vogt and a ‘Mini guide to contact lenses’, which takesa look at medical contact lens treatments. The Immediate Past-President of the BCLA, Sarah Janikoun will then discuss: ‘Is theproblem the solution?’ and we will then examine the challenge of‘Fitting irregular corneas’ with contact lenses. During the workshop



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ou will have the opportunity to handle lenses, and learn whichenses to use, when and for whom. Consultant ophthalmologist Mrinod Kumar will talk you through the very important subject of

Therapeutic contact lenses’. The morning session will conclude withn examination of ‘Coloured contact lenses’. This course gives youhe opportunity to exchange views and engage in discussion in ariendly atmosphere with other ophthalmologists.


yopia: The current state of play

rien Holden


yopia affects a quarter of the world’s population (1.6 billion peo-le). It is estimated that around 200 million are blind (less than 3/60

n the best eye) or significantly visually impaired (visual acuity inhe best eye less than 6/18 for adults and less than 6/12 for children)ue to uncorrected refractive error (URE). Studies conducted inhina estimate that 44% of 15 years old children were significantlyisually impaired due to URE with 85% not having any spectacleorrection. The prevalence of myopia is a rapidly increasing in Asia.he increase in Eastern Asia, in particular, is so severe that it war-ants the term epidemic. By 2020, it is estimated that the number ofeople with myopia will grow to one third of the world’s population2.5 billion). Data from Taiwan shows that the prevalence of myopian 12 years old children increased 3–4 times over a decade. High

yopia brings with it higher risks of cataract, glaucoma and retinaletachment. Studies show that both genetics and environment playrole the prevalence of myopia. Where both the parents are myopicchild has an 80% chance of being myopic. Anti-myopia products,

argeting both child and adult-onset myopia, would slow the pro-ression of myopia, lower the number of highly myopic people andlleviate the significant burden of visual impairment worldwide.his presentation reviews the available data on the prevalence andorbidity of myopia and examines the current scientific basis for

he development of myopia. Options available for slowing or pre-enting the progression of myopia are discussed and strategies thatight be able to optically control myopia are presented.

yopia control

admaja Sankaridurg

yopia (short-sightedness) is a significant health problem affect-ng at least 25% of the population in Europe and at a much higherercentage for population in parts of Asia. Whilst environmentalnd genetic factors are considered to play a role in the develop-ent of the condition; the individual contribution of these factors

as not yet been elucidated. One of the theories for ‘myopiagene-is’ suggests that peripheral retina may also play a role in regulatingye growth and that the development and progression of refractiverrors in humans could be retarded or controlled by optically alter-ng the characteristics of off-axis image curvature. This presenta-ion discusses the current state of myopia control with optical prod-cts. On-axis and off-axis refractive power/aberrations obtainedrom eyes of children with various refractive errors and the influ-nce of optical interventions on the on-axis and off-axis refractiveower will be presented and potential significance discussed.


iology of myopia—The latest

arl Smith III


n order to develop effective optical treatment strategies foryopia, it is important to understand how visual experience influ-

or Eye 33 (2010) 256–300

ences refractive development. Beginning with the discovery of thephenomenon of form deprivation myopia, research involving manyanimal species has demonstrated that ocular growth and refractivedevelopment are regulated by visual feedback associated with theeye’s refractive state. Because of the prominence of central vision inprimates, it has generally been assumed that signals from the foveadominate the effects of vision on refractive development. How-ever, our experiments in monkeys demonstrate that eye shape andemmetropization are mediated by local retinal mechanisms andthat foveal vision is not essential for many of the vision-dependentaspects of refractive development. On the other hand, the periph-eral retina, in isolation, can effectively regulate emmetropizationand mediate many of the effects of vision on the eye’s refractivestatus. Moreover, when there are conflicting visual signals betweenthe fovea and the periphery, refractive development is dominatedby peripheral vision. The overall pattern of results suggests thatoptical treatment strategies for myopia that are directed at theperiphery may be more successful than strategies that effectivelymanipulate only central vision.

CONFERENCE SESSION 17c

Myopia control technology and contact lens design

John R. Phillips


Purpose: To report the design, efficacy and clinical potential of adual focus contact lens for slowing childhood myopia progression.

Methods: A dual-focus (DF) soft lens was designed with a cen-tral correction zone and concentric treatment zones which created2.00 D of simultaneous myopic retinal defocus during distance andnear viewing. Efficacy in slowing myopia progression was tested ina paired-eye comparison clinical trial. Forty children, 11–14 yearsold wore a DF lens in one randomly assigned eye and a singlevision distance (SVD) lens in the fellow eye for 10 months (Period1). Lens assignment was swapped between eyes for the second 10months (Period 2). Spherical Equivalent Refraction (SER) and axialeye length were monitored using cycloplegic autorefraction andpartial coherence interferometry every 5 months.

Results: Myopia progression in the control (SVD) eyes variedbetween −1.58 D in 10 months to +0.15 D in 10 months. To assessefficacy over these widely different progression rates, linear regres-sion analyses of progression (change in SER) in the eye wearing theDF lens vs that in the eye wearing the SVD lens were conducted.In Period 1, the slope of the regression indicated that progressionwith DF lenses was reduced to approximately 0.57 dioptres perdioptre (D/D) of progression with SVD lenses. Eye elongation wasreduced to a similar degree (0.54 mm/mm). Overall the data indi-cated that DF lenses reduced myopia progression by approximately45%. Visual acuity (VA) and contrast sensitivity (CS) were not sig-nificantly different in eyes wearing DF lenses compared with eyeswearing SVD lenses (p = 0.63 and p = 0.21 respectively).

Conclusions: Myopia progression can be slowed significantlyusing a new dual focus technology based on soft contact lenseswhich are a safe and familiar option for refractive correction. Theavailability of this technology will allow development of clinicaltreatment options. For example, a practitioner could set a progres-sion target, apply treatment and then monitor myopia progressionin a similar manner to current glaucoma protocols which employtreatment targets for intra-ocular pressure.

Patient management aspects of myopia control

Richard Weisbarth






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stimates are that the number of individuals with myopia willeach an astonishing 2.5 billion by 2020. As a public health concern,yopia may lead to a significant risk of retinal problems and visual

oss. This presentation will cover some of the past, present anduture therapies for myopia control including contact lenses spe-ially designed to slow or control the progression of myopia. Properatient selection, education and practice management tips andechniques for these “myopia control” contact lenses will be dis-ussed. Major emphasis will be placed on fitting children at an earlyge and the implications and patient management aspects that thisarries with it for the contact lens practitioner. The significance ofppropriate parent education and communication techniques willlso be highlighted.


f I wore contact lenses would I sleep in them?

uzanne Fleiszig


xtended wear is an established risk factor for infection. The adventf silicone hydrogel lenses has not reduced that incidence, show-ng that hypoxia is not required for infection to occur. For the sameeason that hydrogels were not appropriate for extended wear, sili-one hydrogels are not appropriate. The reason that extended wearredisposes to infection is likely to include that bacteria have moreime to form a biofilm on the contact lens in the eye, adapt to then vivo environment, and eventually acquire the capacity to invadehe cornea. It could also relate to the fact that contact lens wear cannhibit important defenses of the corneal epithelium (e.g. antimi-robial peptide expression) and that this can take up to 72 h of lensear. If inflammation precedes infection as part of the pathogene-

is, then it is likely the process will take time to unfold. Increasedisk during extended wear might also relate to the fact that the lenss worn during eye closure, if it impacts special defenses that arective only in that situation.

OTION: WITH MODERN SILICONE HYDROGEL LENSES CONTIN-OUS WEAR IS NOT A CRAZY IDEA

or the motion: With modern silicone hydrogel lenses continu-us wear is not a crazy idea

rien Holden


his presentation will examine the physiological requirements ofhe eye for successful continuous contact lens wear and indicatehy silicone hydrogel lenses can meet these requirements.

or the motion: With modern silicone hydrogel lenses continu-us wear is not a crazy idea

hilip Morgan


ilicone hydrogels were introduced in 1999 as a new form of con-inuous wear contact lens correction. There was some uptake ofsage of the lenses on this basis although more recently, less than0% of fits in the UK are on a continuous wear basis; at the sameime, there has been a great surge in the use of silicone hydro-el materials for daily wear. Given the apparent lack of interest inontinuous wear with silicone hydrogels in the UK, this presenta-ion will review the history of this form of vision correction and
ttempt to explain the reasons for the popularity of the modalityn markets such as Norway and whether this wide uptake coulde transferred to other markets. In general, the rate of corneal
nflammatory events is higher with continuous wear lenses, andhis presentation will consider if there is evidence of any clinical

or Eye 33 (2010) 256–300 271

benefit arising from the introduction of silicone hydrogels for con-tinuous wear compared with predecessor materials.

Against the motion: With modern silicone hydrogel lenses con-tinuous wear is not a crazy idea

Lyndon Jones


Patients continue to seek an alternative to spectacles for the correc-tion of their refractive error. While some opt for refractive surgeryor overnight orthokeratology, the majority choose soft contactlenses. While most wear their lenses on a daily basis, this modal-ity does not offer the ultimate convenience afforded by wearinglenses on an overnight basis. Patients still sleep in lenses even whentold not to do so, with an estimated 40% of patients occasionallyor frequently sleeping in their lenses. Throughout the 1970s andearly 1980s manufacturers released a variety of materials that wereintended for overnight wear. These early materials were often wornfor up to a month at a time without being removed and achievedgreat commercial success. As a result of positive acceptance andreportedly low complication rates, extended wear for cosmetic usefor up to 30 days was approved by the FDA in 1981, sparking anexplosion in the number of patients being fitted with lenses forovernight wear. Very soon afterwards reports of corneal ulceration,with significant vision loss, began appearing in journals, and thesafety of overnight wear was questioned. The results from well con-trolled studies in the US were published in 1989 and these clearlydemonstrated that overnight wear of lenses carried with it a sig-nificantly increased risk of corneal infection. As a result, the FDAimmediately reduced the approved length of time for overnightwear without removal from 30 to 7 days. In the mid 1980s it washypothesized that using lenses on a disposable or frequent replace-ment basis, in which the lenses were inserted once only and thendiscarded upon removal, would likely have an impact on the infec-tion rates reported. Such a concept became a clinical reality with theintroduction of disposable extended wear lenses to the US in 1987.However, by the late 1990s a study from Holland clearly demon-strated that disposability had not reduced the rate of ulcerationwith soft lenses worn overnight. The introduction of silicone hydro-gel materials – worn for up to 30 nights – in the late 1990s broughtwith it much promise in terms of safer overnight lens wear. How-ever, while hypoxic complications were markedly reduced, ratesof microbial keratitis have recently been shown to be unaffectedby such materials, in studies conducted in the US, Australia andUK. This short review will summarize the data on infections withovernight soft lenses and demonstrate that such lens wear bringswith it an increased risk of infection.

Against the motion: With modern silicone hydrogel lenses con-tinuous wear is not a crazy idea

Mark DP Willcox*, Jerome Ozkan, Hua Zhu, John McNally, PravinKrishna, Brien A. Holden


Silicone hydrogel lenses have become the lens of first choice for fit-ting for daily wear and extended wear. Recently, silicone hydrogelshave been released for use on a daily disposable basis. Whilst theirincreased oxygen transmissibility leads to improved corneal andconjunctival health during wear, epidemiological evidence showsthere has been no reduction in the incidence of microbial kerati-tis or non-infectious inflammatory events with these lenses. Even
though epidemiological evidence suggests that even one night ofsleep in contact lenses (1N EW) leads to an increased risk of micro-bial keratitis, the evidence also suggests that more nights of sleepin lenses are associated with increasing risk. Thus, we sought todetermine what the impact of daily replacement of silicone hydro-





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el lenses, but allowing people to sleep in those lenses, had on theate of contact lens related ocular adverse events. Subjects wereispensed with silicone hydrogel lenses on a EW schedule, buteplacing lenses daily. In Stage 1, lenses were replaced nightly, prioro sleep. In Stage 2, lenses were replaced each morning followingaking with concomitant instillation of saline drops prior to inser-

ion of the new lens. In Stage 3, lenses were replaced each morningithout saline instillation. Scheduled clinic visits were conducted

t 1 week and 1 month. Neophytes were also required to completeweek of daily wear prior to commencing lens wear. Adverse event

ates with monthly lens replacement was used as an historical con-rol. Overall adverse event (inflammatory and mechanical events)ates were lower with morning lens replacement (3.4%) comparedo both monthly (9.4%, p = 0.026) and nightly (10.0%, p = 0.018)eplacement. There was a reduced incidence of CIEs with morn-ng replacement (1.7%) compared to nightly replacement (6.7%,= 0.025), which was driven largely by a reduction in CLPU. Daily

eplacement of lenses in the morning followed by EW leads to aeduction in mechanical events (mainly corneal erosions) but doesot lead to reduction in CIE rate compared to monthly replacementf lenses during CW. The increased handling with daily replace-ent, and consequent likelihood of ocular and lens contaminationay overwhelm the benefit offered.


ptake-release: what is it and will managing it be enough toeep patients safe?

rthur B. Epstein


opic outline: ISO-FDA mandated disinfection efficacy testing forPS/MPDS contact lens care systems has been predicated on disin-

ectant levels remaining constant throughout the disinfection cyclend during storage of lenses. Consequently, the concept of disinfec-ant uptake into the contact lens and lens case during storage andubsequent release into the tear film upon insertion has remainedither unrecognized or overlooked. The recent global recalls of twoajor lens care products have focused attention on uptake-release

nd made it very much a hot topic. This brief discussion examineshe consequences of disinfectant uptake yielding sublethal levelsuring the disinfection cycle. It also explores the potential conse-uences of higher than anticipated levels of disinfectant released

nto the pre-corneal tear film. Unintended consequences caused byther components used in modern lens care products will be con-idered. Relevant scientific and clinical data will be presented asvidence supporting the need for enhanced uptake-release stan-ards in all future regulatory test protocols for contact lens careroducts in addition to relevant clinical, microbiology and toxicol-gy studies.

ow to stop SICS!

achael C. Peterson*, Desmond Fonn, Craig A. Woods, Lyndon Jones


opic outline: The debate into the causes and relevance of solutionnduced corneal staining

SICS) still rages due to our limited understanding of the nature ofhis epithelial reaction. Research conducted at the Centre for Con-act Lens Research has recently determined that SICS induced by
he combination of balafilcon A and ReNu MultiPlus can be sub-tantially reduced by a simple rub and rinse technique, prior tovernight disinfection. This presentation will describe the studynd its outcomes, to ensure that practitioners have the latestnowledge in this hot topic: 20 participants were recruited for a
or Eye 33 (2010) 256–300

study where balafilcon-A lenses were worn bilaterally during twovisits. The ‘control’ lens was not rubbed or rinsed prior to overnightstorage in ReNu MultiPlus. The contra-lateral ‘test’ lens was rubbedand simultaneously rinsed using the same care-solution, for either60 s (visit 1), or 20 s (visit 2). Lenses were soaked overnight, thenworn for 2 h, after which corneal staining was graded. For both vis-its and all participants without exception, SICS was reduced in theeye exposed to the test lens. In 80% of participants the non-rubbedlens induced clinically relevant corneal staining, compared to < 15%with rubbed and rinsed lenses. This is the first time that a rub stephas been shown to impact SICS. This finding may offer new insightsinto the mechanisms behind the SICS reaction. However furtherwork is required to establish the longevity of this effect over themonthly wearing cycle.

Fighting Acanthamoeba from the inside

Fiona L. Henriquez*, Sara J. Campbell, Bharath K. Sundararaj, CraigW. Roberts


Topic outlineObjective: Acanthamoeba species can cause severe disease in

the eye (Acanthamoeba keratitis) and in the central nervous sys-tem (Granulomatous Amoebic Encephalitis). Current treatmentsfor AK are limited and not completely effective Herein, we examinethe potential of a number of potential antimicrobial agent targets,including tubulin polymerization and depolymerization, alterna-tive oxidase and a number of amino acid biosynthesis pathways,including the histidine biosynthesis and shikimate pathway.

Method: a “pharmaphylogenetic” approach was used in com-bination with EST and genomic information to inform potentialnew antimicrobial targets and thus inhibitors of Acanthamoeba.Potential targets were confirmed through PCR assisted amplifica-tion of their genes. Known inhibitors of those targets confirmedwere tested for their ability to arrest Acanthamoeba growth withthe use of a colorimetric assay.

Results: Sequence analysis verified the presence of a numberof target genes in the Acanthamoeba genome and expression inthe trophozoite stage. We cloned a number of genes responsiblefor amino acid biosynthesis and demonstrate that inhibition of theassociated pathways can restrict the growth of Acanthamoeba.

Conclusions: Acanthamoeba possess a number of biochemicalpathways that are not present in the human host and thereforeprovide a rationale for novel therapies against Acanthamoeba infec-tion. This work is highly significant and critical in the identificationof new treatments against this opportunistic pathogen.

Lensless metrology of lenses

Ian L. Pykett*, Martin Humphry, Andrew C. Hurst, Andrew M.Maiden, John M. Rodenburg


Topic outline: Good delivery of oxygen to the cornea is an imper-ative in contact lens design and fabrication. However, oxygentransmissibility (Dk/t) is particularly difficult to determine forlenses that have inherently complex thickness profiles, especiallysoft torics. Current Dk/t data can be substantially misleadingbecause they are typically reported using only nominal centrethickness information. There is therefore an unmet need for awidely-available technique that can measure lens thickness pro-files along multiple meridians. The Virtual Lens is a new method for
microscopy that transfers the task of image formation from physicalcomponents (lenses) to a software algorithm. The method providesa quantitative measure of the wavefront phase retardation thatis introduced as an illuminating beam is transmitted through thespecimen. Consequently it can provide, within practicable imag-




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ng times, non-contact and fully automated measurement of theptical thickness of hydrated contact lenses with both high lateralnd depth resolution. The acquired data also can reveal other lensefects such as inclusions and variations in transparency. Exam-les will demonstrate how this new method can be used routinelyo obtain contact lens thickness profiles from both localised regionsnd on a whole-lens basis. The technology can be added to a con-entional optical microscope platform, or may be used as the basisor an instrument dedicated to contact lens metrology. It could alsoe incorporated as a process inspection tool.

novel technique for assessing contact lens wettability in vivo

era Haddad*, Carole Maldonado-Codina, Philip B. Morgan


opic outline: This presentation will describe a novel On-eye Wet-ability Analyser (NOWA) which has been developed to measuren vivo contact lens contact angle and to assess the rate of liquidpreading (RLS) across a lens surface. The NOWA instrumentationonsists of a manual syringe unit mounted on a custom-made XYZanipulator. A 1.5 �l drop of the probe liquid (0.4%hyaluronic acidixed with 2%fluorescein) was formed at the tip of a Teflon dos-

ng tube which was lowered until the drop made contact with theens surface. A two-camera set-up allowed the contact angle (sideamera) and the RLS (top camera) to be imaged. On-eye wettabilityas assessed for four lenses (etafilcon A, lotrafilcon A, balafilconand senofilcon A) which were worn by 10 contact lens-adapted

ubjects under two conditions: direct from blister and after soak-ng in buffered saline (both 30 min and 6 h after application). Theverall subjective comfort was assessed for each of the four lensessing a 0–100 analogue scale.

An important finding in this work is the significant correlationetween subjective comfort and the RLS (p = 0.02) i.e. fasterpreading of the liquid across the lens surface was associated withmproved subjective comfort. This work also showed a significantifference in contact angle and RLS between the different lenses

nvestigated (p = 0.006 and p = 0.02, respectively).

yopia control with orthokeratology contact lenses in SpainMCOS): Design, baseline findings and 18-month refractive andiometric data

acinto Santodomingo-Rubido*, Cesar Villa-Collar, Bernardilmartin, RamónGutierrez-Ortega


opic outlinePurpose: To compare axial length growth between white myopic

hildren wearing orthokeratology contact lenses (OK) and distanceingle-vision spectacles (SV) over a 2-year period. We outline theethodology adopted, baseline data and preliminary refractive and

iometric observations following the first 18-month trial duration.Methods: Subjects 6–12 years of age and with myopia of −0.75 to

4.00 DS and astigmatism ≤1.00 DC were prospectively allocatedK or SV correction. Measurements of axial length (Zeiss IOL-aster), anterior chamber depth, corneal topography, cycloplegic

efraction and visual acuity were taken at 6-month intervals.Results: Thirty-one children were fitted with OK and 30 with

V. Baseline refractive errors and biometric parameters were nottatistically different between groups (p > 0.05). Over the first 18-onth trial period, axial length increased significantly over time

n both study groups (p < 0.0001), but the SV group experienced a
reater axial elongation in comparison with the OK group (p = 0.01).oth groups showed a small, but statistically significant change innterior chamber depth over time (p < 0.05), which was greater inhe SV group in comparison to the OK group (p = 0.03). Significantifferences in refraction were found over time, between groups
or Eye 33 (2010) 256–300 273

and for the time:group interaction with regard to the spherical(p < 0.01), but not cylindrical components (p > 0.05). As expected,the OK group experienced a significant corneal flattening in com-parison to the SV group evidenced by the change in the flatterand steeper corneal powers (p < 0.0001) and corneal shape factor(p < 0.003).

Conclusion: Orthokeratology lens wear attenuates axial elonga-tion in comparison to distance single-vision spectacles in children.

UV umbrella and crosslinking: Do not BQ the limbal stem cells!!!

Christina N. Grupcheva*, Svilena S. Peeva


Topic outline: The crosslinking has become very popular in the last5 years not only for treatment of keratoconus, but other cornealpathology such as bullous keratopathy and keratomalacia. Theadverse effect of UV radiation on the limbal stem cells is wellknown. The most common clinical presentation of stem cell dam-age is epithelial defects within 6 months following the treatment.The purpose is to develop and prove effective a simple methodfor UV protection of the limbal stem cells, during crosslinkingprocedure.

Riboflavin is applied following the standard protocol.Pachymetry proves the corneal thickness and then a special“treatment protection lens” is placed over the cornea. The lens isprepared with 8.5 Barron recipient trephine. ACUVUE® OASYSTwith UV protection class I – blocking 96% UV-A and 100% UV-Bis preferred. The handmade 3.5 mm ring-protector is placed overthe cornea with primary goal to protect limbal area and secondarygoal to create a pool for the riboflavin. Six cases will be presentedand commented. In brief all treated eyes demonstrated quick andstabile epithelialisation at 16 h (range 14–18). Subjectively patientsreported less irritation than in the previously treated fellow eye,using the classic protocol. During the follow up period no epithelialcomplications such as erosions, epithelial hyperplasia, etc., wereobserved.

Protection of the limbal epithelium during crosslinking proce-dure provides quicker epithelialisation and more comfort duringshortened recovery period.

Healthy contact lens wear and the future of silicone hydrogels

Brian Pall


Silicone hydrogels have brought great gains not only in terms ofcomfort, but also in terms of an improvement in oxygen relatedphysiological measures when compared to hydrogel lenses. More-over, material developments within specific silicone hydrogelshave also reduced non-oxygen related physiological measures, likeCPLC and SEALs when compared to first generation silicone hydro-gel materials. That said, the one area where these materials have notseemingly yielded any improvement is in the reduction of microbialkeratitis and inflammatory related infiltrates. Global studies showmuch work still to do in improving patient care and compliance,as a way to address the situation. However, advances in solutions,and indeed in contact lens technologies themselves, also repre-sent important opportunities to reduce adverse events. The field ofantimicrobials in particular is a key focus area in the developmentof new contact lens technologies, and some initial work on identi-fying an antimicrobial lens has already been published. However,there are many pertinent questions for the future of antimicrobial
contact lenses, specifically: what are the requisites for a well per-forming antimicrobial contact lens. In this presentation, we willdiscuss the critical choices when developing antimicrobial tech-nologies including the optimal antimicrobial agent in terms ofefficacy.




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standardised method for the quantified determination of con-act lens disinfectant efficacy against Acanthamoeba

imon Kilvington*, Anthony Lam, James Lonnen, Wayne Heasel-rave


urpose: Although standards exist for determining the efficacy ofontact lens care solutions (CLCS) against bacteria and fungi (ISO4729) none exist for Acanthamoeba. As such, conflicting find-

ngs on the effectiveness of CLCS against the organism have beeneported. Here we describe a quantifiable and reproducible methodor assessing Acanthamoeba disinfection.

Method: A. castellanii (ATCC 50370) trophozoites were main-ained in an axenic broth medium. Cysts were prepared using Neff’sncystment medium. Solutions were challenged with trophozoitesr cysts and, at timed intervals, aliquots removed and 10-fold dilu-ions made across a microtitre plate. E. coli was added as a foodource and the plates incubated. Surviving amoebae were enumer-ted by the presence or absence of growth in the wells using a mostrobable number approach. CLCS studied were: MPS-1, MPS-2,PS-3 (1 ppm PHMB), MPS-4 (PQ1 and MAPD), MPS-5 (experimen-

al formulation of PQ1 and alexidine) and PER-1 (1-step hydrogeneroxide).

Results: After a 6 h contact time, the log reduction in trophozoiteiability for the solutions were: MPS-1 (2.5 ± 0.2), MPS-2 (1.8 ± 0.2),PS-3 (0.1 ± 0.1), MPS-4 (2.7 ± 0.2), MPS-5 (4.0 ± 0.2) and PER-1

3.8 ± 0.2). For the cysts the values were: MPS-1 (2.9 ± 0.3), MPS-(2.5 ± 0.2), MPS-3 (0.7 ± 0.1), MPS-4 (0.2 ± 0.1), MPS-5 (3.8 ± 0.3)

nd PER-1 (2.7 ± 0.3).Conclusions: The method is relatively simple to perform and

nables the reproducible and quantifiable determination of CLCSfficacy against Acanthamoeba trophozoites and cysts. This willacilitate the introduction of a standardised and universal approacho Acanthamoeba disinfection testing in line with that prescribed bySO 14729 for bacteria and fungi.

valuation of silver impregnated contact lens storage cases inivo

aya Dantam*, Fiona Stapleton, Hua Zhu, Jerome Ozkan, Thomasaduvilath, Mark Willcox


urpose: To evaluate the frequency and level of microbial con-amination of silver-impregnated contact lens (CL) storage casesompared with regular cases and to establish the effect of wet andry case storage on contamination

Method: Two non-contemporaneous prospective, single group,ilateral, open label clinical studies were designed to evaluate stor-ge case contamination with silver-impregnated (MicroblockTM,IBA Vision; n = 41) and regular storage cases (CIBA VISION; n = 34).ubjects were fitted with balafilcon A CLs (Bausch & Lomb) on daily-ear basis and used Aquify MPS. Cases were replaced monthly and

ollected at 1, 3 and 4 (silver cases only) months. Regular casesnd the 4th month silver cases were maintained ‘dry’; and thether silver cases were maintained ‘wet’ between uses. The rightell of each storage case was sampled for microbial procedures.

isher’s exact test and linear mixed model were used for statisticalnalysis.

Results: The differences in overall rate of contamination between
ilver and regular cases (71% and 82% respectively) were nottatistically different. However, the maximum recovery of microor-anisms was significantly lower (p < 0.005) from silver cases (750FU per well) than regular cases (510,000 CFU/well). The silverases showed significantly lower rates of recovery of fungi (p < 0.05,
or Eye 33 (2010) 256–300

4%), Gram-negative bacteria (p < 0.05, 11%), and Gram-positivebacilli (p < 0.05, 33%). Silver cases maintained ‘wet’ have lower con-tamination (p < 0.05) than the storage cases maintained ‘dry’.

Conclusions: Overall, the silver-impregnated cases maintained‘wet’ resulted in lower microbial recovery, which may limit CLadverse responses associated with microbial contamination.

Langerhans cells in the cornea of diabetic patients: Relevance todiabetic neuropathy

Mitra Tavakoli*, Nathan Efron, Rayaz A. Malik


Purpose: The presence of a lymphocytic infiltration in autonomicganglia and an increased prevalence of autoantibodies and iritisin diabetic patients with autonomic neuropathy suggests a rolefor autoimmune mechanisms in the development of diabetic andperhaps somatic neuropathy. Corneal Langerhans cells are antigen-presenting cells which can be identified in corneal immunologicconditions using in-vivo confocal microscopy. The aim of this studywas to assess the presence and density of Langerhans cells (LCs)in Bowman’s layer of the cornea in diabetic patients with varyingdegrees of neuropathy compared to healthy control subjects.

Method: 128 diabetic patients aged 58 ± 1 years with differingseverity of neuropathy (NDS – 4.7 ± 0.28) and 26 control subjectsaged 53 ± 3 years were examined with in-vivo corneal confocalmicroscopy to quantify the density of “Langerhans cells” (LCs).

Results: LCs were observed more often in diabetic patients(73.8%) compared to control subjects (46.1%), P = 0.001. The LC den-sity (number/mm2) was also significantly increased in diabeticpatients (17.73 ± 1.45) compared to control subjects (6.94 ± 1.58,P = 0.001). There was a significant correlation between the den-sity of LCs with age (r = 0.162, P = 0.047) and severity of neuropathyassessed by NDS (r = −0.202, P = 0.02).

Conclusions: In vivo corneal confocal microscopy enables quan-tification of Langerhans cells in Bowman’s layer of the cornea. Thereis a relationship between density of LCs and the degree of nervedamage. Corneal confocal microscopy could be a valuable tool toestablish the role of immune mediated corneal nerve damage andprovide insights into the pathogenesis of diabetic neuropathy.

Mechanical property evaluation of current IOL materials vs newproposed injectable IOL materials

Jane H. Bramhill*, Brian J. Tighe, James S.W. Wolffsohn


Purpose: Intraocular lenses (IOLs) are widely used in cataract treat-ment. The mechanical properties of the IOL material dictate itsmethod of insertion and thus the size of surgical incision. This workinvestigates the rheological properties of current IOL materials andnew experimental materials in comparison to the natural lens.

Method: A range of IOL hydrophilic and hydrophobic materialswas sourced and their rheological behaviour characterised usinga Bohlin CVO Rheometer. A new experimental IOL material (forinjection and polymerisation in situ) has been synthesised whichincorporates the viscoelastic used during surgery. The mechani-cal behaviour of this was compared to current materials and thenatural lens.

Results: The modulus of the human lens and variations in bothstiffness and stiffness gradient with age have been widely reported;values obtained depend upon method of determination but for theyoung healthy lens are reported to be well below 10 kPa. Current
commercially available IOLs have moduli ranging between 10 and100 kPa depending on the nature of the material. This is greater thanthe natural lens explaining the inability of the eye to accommodatewith conventional IOLs. The new injectable material has a modulusof ca. 5 kPa (modulated by crosslink density and initiation method)




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oupled with a refractive index of approximately 1.5, dependingpon water content.

Conclusions: A new injectable material incorporating the vis-oelastic used during cataract surgery has greater mechanicalimilarity to the natural lens than conventional IOLs. Viscousnd elastic components of IOL moduli have not been previouslyeported and may influence ease of surgical manipulation.


hy fit contact lenses?

athan Efron


ontrary to what many practitioners believe, current generationontact lenses are easy to fit, are well tolerated, provide supe-ior vision, are physiologically compatible with the anterior oculartructures, cause few serious complications and are cost effective.hese factors will be explored with examples of advancements thatave occurred in contact lens practice over the past two decades.onsideration will also be given to the role of optometrists, the con-act lens industry and educational institutions in promoting contactenses as an alternative form of vision correction.

hat’s fashionable to recommend in 2010

arah Morgan


he eye examination is complete and the patient is interested inrying contact lenses. From the wide choices of replacement fre-uencies and materials, which one is going to be the best for theatient? This lecture will provide an overview of the key optionsvailable to patients and the popular lens types available in 2010.

onfidence with RGP and specialist fittings

arco van Beusekom

ver the past years RGP lenses seem to have become specialtyroducts. Knowledge and experience about fitting RGP lenses haseclined and by this the Demise of the RGP seems to become aelf fulfilling prophecy. Still RGP lenses can and do offer patientsany advantages and need to be in the toolbox of every serious eye

are practitioner. In this lecture we’ll try to show you some clinicalearl’s for successful fitting of RGP lenses. Besides some basic ele-ents also toric RGP lenses will be highlighted and explained. Theutch experience.

atest thinking and advice on lens care products

ick Atkins


o you think you know everything about lens care? This lectureill review the latest data on contact lens solutions with regards to

heir efficacy and interaction with contact lens materials. Advice toelp avoid potential for lens/solution combination hypersensitivityill be given.

ne day disposable contact lenses—What are the differences?

arole Maldonado-Codina


his lecture will consider recent developments in daily disposable
ontact lens material technology (for example, macromolecularntrapment and/or release) and how these developments impactn contact lens practice. After an overview on the potential clinicalenefits of this modality of lens wear, the presentation will pro-ide an outline of the main daily disposable contact lenses currently
or Eye 33 (2010) 256–300 275

available, with particular emphasis on their material characteristicsand how the ‘enhanced’ versions of some of the lenses differ fromthe ‘original’ versions of the same lens. The lecture will also dis-cuss the recent emergence of a silicone hydrogel daily disposablelens onto the market and consider what this lens can offer clini-cally. The lecture will also consider the epidemiological evidenceoutlining the risk of complications (in particular, infection) in dailydisposable wearers compared with other soft lens modalities.

POSTERS

DRY EYES

1

Assessment of dry eye treatment effectiveness using the tearlabosmolarity system

Timothy G. Albert, Umberto Benelli, Marco Nardi, Chiara Posarelli


Purpose: To evaluate the efficacy of three tear eye drops for thetreatment of mild, dry, irritated eyes using a new tear osmolaritydiagnostic device.

Method: Randomized, investigator-masked evaluation of 60patients in which 20 patients used carboxymethylcellulose sodium(CMC), 0.5% {Cellufresh, Allergan, Irvine, CA} (Group 1); 20 patientsused a drop containing polyethylene glycol 400, 0,25% and SodiumHyaluronate {Blink Intensive Tears, Abbott Medical Optics, SantaAna, CA} (Group 2); and 20 patients used HP Guar 0.18% {Systane,Alcon Laboratories, Ft. Worth, TX} (Group 3). Study visits were atbaseline and 1 month. Tests performed at both visits included: Tearosmolarity before and after 5 minutes of instillation, Schirmer, tear-film break-up time (TBUT), visual acuity, fluorescein staining andwavefront aberrometry.

Results: After 30 days using the drops, osmolarity resultsshowed a mean reduction after instillation (improvement) of5.6 ± 2.3 mOsm/L in Group 1, 9.9 ± 2.8 mOsm/L in Group 2 and4.5 ± 1.8 mOsm/L in Group 3. The difference was statistically sig-nificant. LogMAR BCVA results showed an improvement in Group2 compared to baseline with no change in BCVA in groups 1 and 3.There was no statistically significant change from day 1 to 1 monthin TBUT, while the Schirmer test showed an improvement in allgroups at 1 month.

Conclusions: Assessment of tear osmolarity provides the mostobjective, measurable test for determining improvement in dry eyepatients. The results found that Blink Intensive Tears significantlyimproved tear osmolarity compared to Cellufresh and Systane.

2

New methodology for the objective evaluation of the tear filmlipid layer by tearscope plus®

Carlos García-Resúa*, David Calvo Romero, Antonio Mosquera,Manuel González Penedo, Maria J. Giraldez, Eva Yebra-Pimentel


Purpose: Observation of interference lipid layer pattern by thetearscope® supposes a valuable non-invasive technique to assesstear film quality. However, that technique is affected by a highsubjective component. So, the aim of this study is to develop anobjective method to characterize these patterns.

Method: The proposed methodology consists of three steps:
acquisition of the digital image of lipid tear film; extraction ofthe region of interest and the analysis of the texture. Tearscopeplus® attached to a Topcon® SL-D slit lamp together with TopconDV-3 camera was used for the acquisition process. An opponentcolor space is chosen to simulate the primate retinal color process-






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ng technique. Texture features are extracted using a Difference ofaussian rotational invariant bank filter. A wide range of frequen-ies were studied.

Results: The classification step has been done with 91 digital tearmages including 22 color fringe images, 14 wave images, 27 open

eshwork images and 28 closed meshwork images. The classifica-ion process has been done with the nearest neighbour techniquesing the euclidean distance as measure. The results confirm thatach of the types present higher responses in very limited and dif-erent frequency bands, allowing to focus our future research inhose bands. The accuracy of the classification step is over 90% forach film type in its higher response band frequency.

Conclusions: This pilot study offers a new technique that obtainsbjectively the type of the tear film lipid pattern with the tearscopelus®.

uantitative analysis of corneal staining after a PEG400 eye dropnstillation in mild dry eye patients

iancarlo Montani*, Francesco Romano


urpose: The study aims to evaluate the effect of PEG4000.25%) + HA (0.20%) and low osmolarity eye drops on modificationf corneal staining in dry eye patients.

Method: In this contralateral, single blind study, the effect ofEG400 (0.25%) + HA (0.20%) and low osmolarity eye drops wastudied on 20 patients (21–52 years) affected by dry eye (>level, DEWS grading) and presenting corneal staining (>type 1, CCLRUcale). The corneal staining was assessed before and after 21 days,uring which the patients applied three times a day 2 drops of eyerops in the right eye and 2 drops of saline solution in the left eye.he digital images were taken using a slit lamp (Topcon SLD7-DV3)nd a yellow filter “Wratten#12” one minute after sodium fluo-escein instillation. The analysis was performed by a new imagerocessing software realised by Innovative Solutions for Eyes (ISE).he software allows the quantitative analysis of corneal stainingnd applies a new classification considering the exact staining areain mm2).

Results: The corneal staining in right eye was 2.473 (SD = 0.586)efore and 0.226 (SD = 0.452) after the eye drops use (significantifference, p < 0.0001). The corneal staining in left eye was 2.27SD = 0.752) before and 2.1 (SD = 0.614) after the saline solution usenot significant difference, p = 0.331).

Conclusions: This study indicates the effectiveness of PEG 400ye drops to reduce corneal staining. These results could bexplained by the properties of this formulation: 1) tear film osmo-arity reduction; 2) tear film break-up time increase (PEG400); 3)pithelial cells migration and regeneration (hyaluronic acid).

odification of the tear film osmolarity with the use of contactens in Omafilcon A and Methafilcon A materials

iancarlo Montani


urpose: To investigate the tear-film osmolarity in contact lensearer before and after seven hours of use of contact lenses inifferent materials.

Method: 50 patients between 18 and 48 year, no diseasef anterior segment. No use of contact lenses and drugs.o contraindication to use Contact lenses. Tear film osmolar-

ty > 310 mOsm/L in both eyes. After measuring the refractive errornd the examination the anterior segment we measured the tear

or Eye 33 (2010) 256–300

film osmolarity using the TearLAb (Ocusense San Diego CA). After-ward we fitted the right eye of all patients with a lens in OmafilconA (Hema + PC) hydration 62% material and in the left eye a lens inMethafilcon A (Hema + MMA/EGDMA) hydration 55%. After 7 h ofuse, before remove the lenses, we measured again the tear filmosmolarity in both eyes

Results: The tear film osmolarity in right eyes was332,93 mOsm/L (SD = 8.18) before contact lens fitting and337,86 mOsm/L (SD = 0.452) after the use of Omafilcon A con-tact lens (the difference was not significant p = 0.114). The tearfilm osmolarity in left eyes was 332,46 mOsm/L (SD = 6.54) beforecontact lens fitting and 352,4 mOsm/L (SD = 11.63) after the use ofMethafilcon A contact lens (the difference was significant p < 0.001)

Conclusions: This study show that the lenses in Methafilcon Ahave significant increase of the tear film osmolarity than lenses inOmafilcon A. The measure of tear film osmolarity can help to pre-vent the effect of soft contact lens material on tear film and can helpthe practitioner to identify the material that introduces its lowermodification.

5

The nature and fate of tear film lipids in contact lens wear

Amandeep Panaser*, Brian J. Tighe


Purpose: The purpose is to examine links between contact lens wearand lipid oxidation. Lipid deposition on lenses is well researched,but their degradation is not. Unsaturated lipids are potentially sus-ceptible to oxidation; oxidative end products of polyunsaturatedlipids include malondialdehyde (MDA), which has been linked withcontact lens intolerance.

Method: Several techniques including thin layer chromatog-raphy (TLC), high pressure liquid chromatography (HPLC), gaschromatography mass spectroscopy (GCMS) and the thiobarbituricacid reactive substances (TBARS) assay were used to determinelipid profiles, individual fatty acid profiles and oxidative fatty acidbreakdown products on patient-worn lenses from various clinicallyorganised and monitored studies.

Results: Extensive technique optimisation enabled analysis oflipid extracted from single lenses. Significantly, oxidation of theprincipal unsaturated fatty acid (oleic acid 18:1) was found byGCMS to increase with extended wear time whereas the princi-pal saturated fatty acid (palmitic acid 16:0) remained unchanged.At short (< 5 day) wear times both saturated and unsaturated fattyacids were present. In the eyes of long term wearers the TBARSassay showed the presence of reactive species typified by MDA,both in the absence of a lens and (but at slightly elevated level) inlens-wearing tears.

Conclusions: Lipids are stable in the non-contact lens wearingeye and in short term wear, but oxidation on the elevated anteriorlens surface causes unsaturated lipid degradation. The presence ofMDA implies the degradation on the lens surface of polyunsatu-rated lipids not present in normal meibomium secretion, possiblyarising from cellular debris.

6

The phenol red test and the questionnaires for dry eye: is thereany relationship?

Giorgio Parisotto*, Fabrizio Zeri


Purpose: To evaluate the relationship between the McMonniesQuestionnaire (MQ), the Ocular Surface Disease Index (OSDI) andthe phenol red cotton thread test (PRT).





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Method: Participants were enrolled in the experiment duringisual screening. Sixty-four individuals (23 males and 41 females)ere assessed with the PRT and completed the MQ and OSDI ques-

ionnaires in random order.Results: The mean (±SD) score was 8.9 ± 4 and 14.2 ± 14 for

Q and OSDI respectively. The PRT mean was 17.5 mm ± 6.he questionnaire scores were significantly higher in womenMann-Whitney test; p < 0.001). There was a significant correlationr = 0.66; p < 0.05) between MQ and OSDI but no significant correla-ion either between PRT and MQ (r = −0.18; p = n.s.) or between PRTnd OSDI (r = −0.17; p = n.s.). When the relationship was evaluatedetween the PRT scores within the marginal dry eye range (7 to6 mm) and the questionnaire scores, a significant correlation waseen with MQ (r = −0.45; p < 0.05) but this was not the case withSDI (r = −0.15; p = n.s.).

Conclusions: The findings indicate a strong correlation betweenuestionnaires, but no relation between the questionnaires andRT. This result should be viewed in the light of the subjectsxamined in the study, which included a considerable number ofndividuals with marginal dry eye, although with no pathologyresent. It is thus possible to state that within a normal population,o significant correlation was found between PRT and question-aires, although this correlation becomes significant with the MQhen considering those with marginal dry eyes.

lide-index: a novel method to diagnose and measure contactens induced dry eye

eiko Pult*, Paul J. Murphy, Christine Purslow


urpose: To investigate, whether a combination of objective andubjective evaluation is able to improve diagnoses of contact lensnduced dry eye (CLIDE), and if this combination is able to monitorhe CLIDE status.

Method: Ninety-eight (37 M, 61F; mean age 31.8 yrs;ange = 18–55) experienced soft contact lens wearers werelassified as CLIDE+ or CLIDE- (n = 40/n = 58), using the Contactens Dry Eye Questionnaire (CLDEQ). Pre-lens break up timePLBUT), limbal and bulbar hyperaemia, corneal staining, lid wiperpitheliopathy and lid parallel conjunctival folds (LIPCOF) weressessed in the right eyes only. The last 37 subjects were observedwice to assess repeatability of the resultant combination using5% limits of agreement.

Results: LWE and LIPCOF severity scores were significantlyncreased in CLIDE+ (ROC, p < 0.045), while no significant differ-nces were found between groups for PLBUT, corneal stainingr hyperaemia (0.29 < p < 0.78). Temporal LIPCOF showed an areander the ROC (AUC) of 68.5%, of nasal LIPCOF 70.1%, of LIPCOFum, and of LWE 65.4%. Best test combination was temporal plusasal LIPCOF, plus symptoms of dryness and grittiness with an AUCf 93.1%, named here the CLIDE-Index. The CLIDE-Index was notignificant different in repeated observations and showed a 95%imit of agreement of 5.5.

Conclusions: A combination of the questions ‘dryness’ and ‘grit-iness’ plus ‘LIPCOF Sum’, named here the CLIDE-Index, seems to bepromising method to measure and diagnose CLIDE in experienced

ens wearers. Any change in score of ≥ 5.5 units may be consideredbnormal.

iosurfactants: towards a bio-mimetic artificial tear

adia Rasul*, Brian J. Tighe


or Eye 33 (2010) 256–300 277

Purpose: To develop a novel biosurface treatment to manage dryeye, based from synthetic protein-lipid complexes. At Aston, wehave designed biosurfactants from hyaluronan (HA), synthetic sur-factant protein analogues and polar phospholipids.

Method: The Langmuir trough technique and the static surfacetension measurement via the du Nûoy ring method were usedto explore the association behaviour both at the interface and inthe bulk. Brewster Angle Microscopy (BAM) in conjunction with atemperature controlled Langmuir trough was utilised to visualisethe synthetic protein-lipid complexes at the air-water interface.Nuclear Magnetic Resonance (NMR) spectroscopy was used tounderstand the structure property relationships. The coefficient offriction was measured to assess lubricity.

Results: Although HA solutions lack boundary lubricating capa-bility at the air-water interface (imparting a dynamic surfacetension of 65 mN/m), the inclusion of HA into ocular lubricants isbeneficial due to its unique properties. We have sought copolymerswith structures (confirmed by NMR) that mimic the function ofnative apoproteins in solubilising lipids (e.g., 2-dilauryl-sn-glycero-3-phosphocholine), without the usage of solvents. The solutionsexhibit remarkable surface properties; a dynamic surface tensionof 22 mN/m and a maximum surface pressure of 50 mN/m. This sur-face behaviour approaches that of native lipoidal films. The staticsurface tension measurements attained concur well (26 mN/m).

Conclusions: Experimental evidence supports belief that thecombined HA and synthetic protein-lipid complexes provide abalance of rheological, biotribological and surface properties thatare composition dependent and show competitive advantage.Moreover, further investigation is necessary to optimise the bio-surfactants and to explore potential for commercialisation.

9

Albumin as a diagnostic marker in tears

Gunilla Runstrom, Aisling M. Mann, Jonathan Walker, Brian J. Tighe


Purpose: Serum albumin has been identified as a useful marker forassessment of the blood-tear barrier and plasma leakage into thetear film. However, the controlling factors and rationale for albumininflux into tears remains unclear; albumin in tears may signify anadverse inflammatory response, alternately it may indicate a ben-eficial protective host response. This study assessed the usefulnessof existing clinical point of care serum and urine-based analyticalkits for the determination of albumin levels in optometric practice,in relation to contact lens wear.

Method: Tear and tear envelope samples albumin levels wereassessed in contact lens wearers and controls exploiting numer-ous assays. Laboratory based enzyme-linked immunosorbentassay (ELISA), microfluidic Bioanalyzer assays and 4 establishedmicroalbuminuria diagnostic kits (QuikRead, Hemocue, Afinion andNycoCard) were employed.

Results: Albumin is present ‘normally’ in serum at approximately40 mg/ml, in urine below 22 ug/ml and in non-stimulated tearsat approximately 50 ug/ml. Sensitivity of the microalbuminuriakits are reported as follows: QuikRead (5–150 ug/ml), Hemocue(7–150 ug/ml), Afinion (5–200 ug/ml) and NycoCard (5–200 ug/ml).ELISA is in the nanogram sensitivity range. In the case of themicroalbuminuria kits, the ability to transfer the measuring tech-nique from urine to tears was determined and each were evaluatedfor their suitability and cost effectiveness.

Conclusions: The influence of specific lens materials on albuminleakage into the tear film and at the interfacial tear was apparent.Its influx in association with other protein species in lens wear pre-sented an interesting insight into the, as yet, undetermined role ofalbumin in the ocular environment.




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evelopment and realisation of a non-invasive method for tearlm assessment by using a corneal topographer

oreen Wiedemann*, Wolfgang Sickenberger, Martina Michel


urpose: Primary objective was to develop a non-invasive methodor qualitative and quantitative tear film assessment using a cornealopographer.

Method: Prior to the measurements new program-modificationsor the corneal topographer were developed in order to determinehe tear meniscus height (NIC-TMH) and the tear film break-upime (NIC-BUT). To illuminate the tear meniscus, four verticalrranged IR-Diodes were used. The NIC-BUT measurement is basedn the projection of a Placido-disc and its reflection from theear film. To compare the new method with established tech-iques the tear meniscus was measured by slitlamp (TMH) andhe non invasive tear film break-up time (NIBUT) by using theearscope (Keeler). One eye of 34 subjects (n = 34, mean age8.32 ± 7.17 years, 47% female, 53% male) was examined with bothethods.Results: Tear meniscus height: A normal distribution (Shapiro-

ilk-Test) was found for the reference- and also for the newethod. For both, the NIC-TMH and TMH, the mean was

.18 ± 0.03 mm with a low correlation due to a broad distribu-ion of the single values. Tear film break-up time: Within both

ethods no normal distribution was found (n = 34; p = 0.000;hapiro-Wilk-Test). The determination and evaluation of three NIC-UT measurements was possible for 17 of 34 subjects. The medianf the NIC-BUT was 11.33 s (mean 12.75 ± 5.24 s) and the median ofhe NIBUT was 8.8 s (10.0 ± 5.0 s). There was a significant differenceetween both techniques (p = 0,049, Wilcoxon).

Conclusions: The corneal topographer represents an advancedlternative for the qualitative and quantitative tear film analysis.

AS PERMEABLE

1

study to evaluate surface roughness of rigid gas permeableontact lenses with and without plasma treatment

elicity R. Gill*, Paul J. Murphy, Christine Purslow


urpose: Plasma surface treatment of gas permeable contact lensess designed to improve on-eye comfort and performance by reduc-ng surface deposition and degradation over time. This studyompared lens surface topography (roughness) in untreated andlasma-treated, worn lens samples.

Method: Twelve volunteers were recruited and randomly fittedith either plasma-treated (n = 6) or untreated (n = 6) QuasarTM

spheric lenses (No.7 Contact Lens Laboratory, Hastings, UK.),oston EO material (Polymer technologies, Boston, US), using theame care regimen. Lenses were worn for 3 months on a full timeasis and then harvested. The surface topography of the anteriorurface of samples from lenses were evaluated with atomic forceicroscopy (AFM Nanoscope IIIa DimersionTM 3100, Digital Instru-ents, Santa Barbara, CA, US) in tapping mode at five randomised

ocations over 100 �m2 area. Median values of average roughnessRa) and root mean square of roughness (Rms) values were obtained
or each sample.
Results: Median Ra values were significantly higher in untreatedenses [13.84 nm (11.83–26.59)] than plasma-treated lenses10.35 nm (7.68–15.97)]; p < 0.05 Mann Whitney U test. Mean Rmscores were also higher in untreated, worn samples [20.18 nm

or Eye 33 (2010) 256–300

(16.02–32.94)] than plasma-treated, worn samples [14.65 nm(11.24–20.99)]; (p < 0.05).

Conclusions: After 3 months wear, plasma-treated lenses havesmoother surface topographies than untreated lenses, suggesting aclinical benefit of treatment, since increased surface roughness hasbeen found to increase bacterial adhesion and may adversely affectcontact lens comfort.

12

Keratoconus GP fitting study: effect of lens diameter on lensperformance and initial comfort

Luigina Sorbara*, Katrin Mueller*E-mail address: [email protected]

Purpose: The purpose of this fitting study was to determine theeffect of varying lens diameter of two types of keratoconic lenses onlens performance and initial comfort with participants with eithercentered and oval cones.

Method: Sixteen keratoconic participants were fitted with lensesof three diameters ie 8.7/9.0, 9.6 and 10.1/10.4 diameters and twolens types (Rose K (RK) and Centra Cone (CC) according to themanufacturers’ instructions. Lens movement, centration and initialcomfort were assessed.

Results: Ten subjects (2 female and 8 male) participated in thestudy, the mean age was 40.4 ± 14.33 years. Six subjects were inthe central early group, five in the oval early and five in the ovallate group. The lenses with the 9.6 lens diameter (LD) decenteredthe least for all lenses (p = 0.001). The 8.7/9.0 were more decentredfor the oval late and central late cones (p = 0.009). Movement ofsmaller RK was greater than CC for centred early cones (p=0.001)and movement decreased for larger CC lenses for all cone types butnot significantly (p > 0.05). The RK lenses were more significantlycomfortable than the CC lenses for the centred cones (p=0.003). Thelarger diameter CC lenses were more comfortable for all cone types,but, not significantly (p > 0.05).

Conclusions: Cone type is an important factor in relating lensperformance of the two brands used. Lens diameter affects com-fort and centration especially for the 8.7/9.0 for centred cones and10.4/10.1 diameters for oval cones. Movement was not correlatedwith comfort.

MULTIFOCALS

13

Influence of required spectacle ADD on success with a multifo-cal contact lens

Peter D. Bergenske*, Joseph M. Rappon


Purpose: Success rates for fitting presbyopic patients with contactlenses have typically been considered to drop off as the patient ADDdemand increases. Having multiple levels of ADD power availablein a multifocal contact lens (MfCL) might be expected to increasesuccess rates and should help to level out differences due to higheradd requirements.

Method: 294 US eye care practitioners (ECPs) who were active infitting presbyopic contact lenses participated in a pre-market eval-uation of the lotrafilcon B MfCL which has 3 levels of ADD power.Lenses were to be prescribed according to the manufacturer’s fittingguide.

Results: In total 2455 patients were fit with lenses. 214 ECPs fitat least 9 patients and reported spectacle ADD and final lenses forsuccessful fits. Nearly 60% of patients fit had spectacle ADDs of 2.00or greater. Despite this relatively challenging group of patients, anoverall success rate of 76% was achieved. Success rate varied slightly





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y ADD group: <1.00 79%, 1.25–1.50 79%, 1.75–2.00 79%, 2.25–2.502%. Successful patients with ADD less 1.50 were most often fit withwo low ADD lenses. Successful patients with ADD greater than 2.00ere most often fit with two high ADD lenses.

Conclusions: The three levels of ADD power in the lotrafilconMfCL provided ECPs with consistent success across the range of

resbyopic correction. Lens ADD power utilized in successful fitsorresponds well with spectacle ADD requirements and the man-facturer’s fitting guide.

4

ontact Lens Dry Eye Questionnaire-8 (CLDEQ-8) reflects statusf and responds to change in overall opinion of CL performance

obin L Chalmers*, Kurt Moody, Graeme Young, Sheila Hickson-urran, Chris Hunt


urpose: To test the Contact Lens Dry Eye Questionnaire 8 (CLDEQ-) for ability to reflect status of and change in Overall Opinion ofontact lenses (CLs).

Method: Subjects with complete data-sets (n = 309) in an IRB-pproved randomized treatment trial completed the short formLDEQ-8 (Frequency plus pm intensity of Dryness, Discomfort and

Blurry vision’; plus frequency of ‘Closing eyes to rest them’ andRemoving CLs to relieve discomfort’) and an anchoring questionn Overall Opinion (‘Opinion’) of CLs at baseline and 2 weeks afterandomization to silicone hydrogel lenses, senofilcon A, or lotrafil-on B. Healthy current CL wearers were enrolled. Sum CLDEQ-8cores (possible 0 to 35) were tested for correlation with ‘Opin-on of habitual lenses’ (Spearman’s) and then for responsiveness tohange in Opinion after randomization by ANOVA.

Results: The CLDEQ-8 scores were highly correlated with habit-al lens Opinion at baseline (−0.44, p < 0.0001) and responsive tohange in Opinion status after randomization (−0.58, p < 0.0001).aseline Opinion scores were: Fair 17.4 ± 9.2, Good 13.7 ± 6.4,ery Good 9.1 ± 4.8, and Excellent 6.4 ± 3.6 (ANOVA, F = 291.1< 0.0001). After 2 weeks, change in CLDEQ-8 scores ranged from:uch Improved: −16.7 ± 10.0, Unchanged: −2.3 ± 5.0, to Muchorse 8.5 ± 5.8; (ANOVA, F = 16.5, p < 0.001).Conclusions: CL clinical practice is hampered by unresponsive

nd unrepeatable clinical tests, hindering assessment of changes inatients’ CL experience. The CLDEQ-8 score significantly reflectedaseline status and change in Opinion after refitting with two typesf silicone hydrogel lens. The CLDEQ-8 could be an efficient out-ome measure in CL clinical trials.

5

he science behind a new multifocal contact lens fittingpproach

heila B. Hickson-Curran*, Susan W. Neadle, Thomas R. Karkkainen


urpose: Fitting multifocal contact lenses involves relying on trialnd error in order to determine what lens combination is success-ul for each patient. The average success rate of multifocal contactens fitting is only 53%, and takes an average of 3.5 visits. As partf the development of a new multifocal lens, the fitting approach,erived scientifically from a series of clinical Design of ExperimentsDOE’s), was determined through evaluation of subjects across a
ange of ADDs, resulting in the development of a predictive suc-ess algorithm where the first lens selected was associated withhe highest level of probable success.
Method: 233 myopic presbyopes participated in bilateral,rospective, augmented factorial DOE’s. Lenses were worn for one

or Eye 33 (2010) 256–300 279

week and clinical measures and subjective responses were col-lected. A total of 46 lens pair/ADD combinations were evaluated.Each lens pair was modelled by fitting a regression model to lensperformance factors.

Results: Analysis resulted in a “Probability of Success” functionthat was plotted against ADD power. The function combines factors,such as the probability for an improvement in subjective distanceand near vision, the probability of maintaining distance vision andthe probability of purchase. Lens pairs were ranked from highestpercentage to lowest percentage for each by ADD.

Conclusions: The method predicts initial lens combinations thatresult in patient success. Incorporated into fit recommendations,this method substantially reduces the time and effort required tofit a new multifocal contact lens.

ORTHOKERATOLOGY

16

Effect of ambient illumination on best corrected visual acuity inovernight hyperopic orthokeratology

Paul Gifford


Purpose: To investigate effects of ambient illumination on bestcorrected visual acuity (BCVA) in short-term overnight hyperopicorthokeratology (HOK) lens wear.

Method: Fourteen subjects (20–37 years) were fitted with bi-aspheric rigid lenses for HOK, in one eye only. Lenses were wornovernight only over 4 nights and changes in subjective refraction,high and low contrast best corrected visual acuity (HCVA, LCVA)and corneal topography (Medmont E-300) were measured on Days1 and 4 on lens removal after overnight wear. Repeated-measuresANOVA with post-hoc paired Student t-tests were employed tocompare changes from baseline, with a critical p-value of 0.05.

Results: Significant refractive and corneal topographic effectswere found at both visits, reaching −1.35 ± 0.68D refractive changeand 1.27 ± 0.54D central corneal steepening on Day 4 (p < 0.001).Relative to baseline, HCVA decreased by logMAR 0.13 ± 0.08 at Day1 and 0.16 ± 0.10 at Day 4 (p < 0.05). Reducing room illumination ledto greater reduction in HCVA (0.16 ± 0.10 at Day 1 and 0.20 ± 0.09at Day 4; p < 0.05). LCVA decreased by 0.18 ± 0.14 at Day 1 and0.30 ± 0.20 at Day 4 (p < 0.01). Reducing room illumination led togreater reduction in LCVA (0.26 ± 0.19 at Day 1 and 0.42 ± 0.24 atDay 4, p < 0.05).

Conclusions: Reducing ambient illumination decreased high andlow contrast BCVA at morning visits compared to normal lightingconditions. This supports the current hypothesis that larger treat-ment zone diameters are needed to improve visual outcomes inHOK.

17

Refractive indicators for stability of myopia in paediatricovernight orthokeratology

Kate L. Johnson


Purpose: To evaluate the long term efficacy of overnight orthok-eratology in myopic children through case record analysis forrefractive indicators of myopic progression.

Method: Case records of 62 paediatric patients, wearingovernight OK for at least twelve months and returning for reviewin the past six months, were analysed to extract age at commence-ment, initial spectacle refraction (best vision sphere); cornealtopography (Medmont E-300) and date of most recent review.





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yopic progression was defined as a reduction in uncorrectedisual acuity and an objective refraction of −0.50D or greater inither eye. Corneal topography maps were compared to the pre-ious consultation to eliminate loss of OK treatment as a factorowards any change in refraction.

Results: At commencement of lens wear average age was2.7 ± 2.7 years (range 6.8 to 18.0; 45 Caucasian, 14 Asian, 3 Indian).he mean initial spectacle refraction was OD: −2.19 ± 1.20D, OS:2.16 ± 1.09D. The study group averaged 1052 ± 485 days total

ens wear. Thirteen children (21%, all Caucasian) demonstratedne incidence of myopic progression over an average 755 ± 377ays of OK lens wear (OD: −0.65 ± 0.40D; OS: −0.73 ± 0.38D). Fourhildren (6.5%) demonstrated a second progression over an average66 ± 243 days from the first progression (OD: −0.94D ± 0.31D;S: −0.88 ± 0.43D). One child demonstrated a third progressionf myopic change 678 days after the second (OD: −1.25D; OS:1.00D).

Conclusions: Clinical case record analysis indicates thatvernight OK offers a potentially viable modality for stabilisingyopia in the majority of myopic children over a period of 12 to 60onths.

ATHOLOGY

8

ge and other risk factors for serious and significant events withontact lens wear in youth: Contact Lens Assessment in YouthCLAY) Study Group

obin L. Chalmers*, Lynn G. Mitchell, Meredith E. Jansen, Bethinoshita, Kathryn L. Richdale, Luigina Sorbara


urpose: To describe risk factors for significant and serious eventsS&SE, CCLRU grid) in soft contact lens (SCL) wearers and to findower and upper ages where increased risk abates.

Method: A retrospective chart review of 3,549 SCL patients agedto 33 years with SCL powers +8.00 to −12.00D (over-sampling < 17rs), documented events from January 2006 to fall 2009. Potentialisk factors (listed below) were noted for all visits. All potential&SE were adjudicated to consensus by an expert panel (maskedo name, age, CL brand, power). Significant univariate risk factorsere tested via multivariate survival analysis model.

Results: Data from 14,327 visits over 4,642 years yielded 187&SE in 159 wearers (8 MK, 41 CLPU, 27 CLARE, 110 IK and 1 Iri-is). Unadjusted risk peaked between age 15–25 years with 1.9%&SE visits, with lower risk <15 years 0.9% and >25 years 1.1%Chi-square 16.3, p < 0.001). By univariate analysis, EW, CL mate-ial, replacement schedule (daily disposable protective) and use ofulti-purpose solutions (MPS) were significant (all p < 0.004). Byultivariate analysis, EW (2.5X, 1.6, 3.7), and MPS use (2.9X, 1.1,

.8), were significantly associated with S&SE.Conclusions: Extended wear and use of MPS play a critical role in

he development of serious and significant events with SCL wear.ge 8 through 14 years was associated with low risk of serious andignificant events compared to teens and young adults. Soft CLsppear acceptable to deliver optics designed to manage the devel-pment of refractive error in children.

9

x vivo and in vitro investigation of diagnostic dyes fluorescein
nd lissamine green on human corneal epithelial cells
aniel J. Cira*, Rachael C. Peterson, Christopher Amos, Craig A.oods, Desmond Fonn, Maud B. Gorbet


or Eye 33 (2010) 256–300

Purpose: Investigate the impact of sodium fluorescein (NaFl)and lissamine green (LG) dyes on cells collected non-invasivelyusing the ocular surface cell collection apparatus (OSCCA) andon a confluent monolayer of human corneal epithelial cells(HCEC).

Method: Five participants underwent a contra-lateral combi-nation of 0, 1 or 6 instillations with 1% NaFl or 0.5% LG onseparate occasions. After 2 h, cells collected using the OSCCA werestained with Hoechst and PI dyes and counted. Dilutions of NaFl(0.5% and 1%) and LG (0.5%) were added to a confluent mono-layer of HCEC that had been cultured in a keratinocyte serum-freemedium. After a-2 h incubation, a cellular viability MTT assay wasperformed.

Results: Ex vivo: for 0, 1, and 6 instillations, 421 ± 220, 517 ± 342and 386 ± 262 Hoechst-stained epithelial cells were counted withNaFl, and 440 ± 226, 646 ± 252 and 608 ± 283 with LG. Therewas no significant difference (p > 0.05) between the number ofcells collected per instillation treatment with NaFl or LG dyesand the controls (0 instillation). Following fluorescein instilla-tion, 38 ± 29 collected cells stained brightly with both NaFl andHoechst. In vitro: after 2 h, no significant differences in viabil-ity between NaFl and control cells were observed. Residual LGmay have inhibited the MTT assay. Microscopy revealed that cellsexposed to NaFl were rounder and smaller compared to controlsand LG.

Conclusions: Neither NaFl nor LG instillations appear to signifi-cantly increase cell shedding in vivo or cell death in vitro after 2 h.These findings suggest that the OSCCA and HCEC model are bothsufficiently sensitive enough methods to study corneal staining.

20

Mimicking the eye: comparative micro-tribological measure-ments of contact lenses

Elizabeth G. Duncan*, Samuele GP Tosatti, Stefan Zürcher


Purpose: It has been suggested that contact lenses (CL) displayinglower Coefficient of Friction (CoF) against the eyelid during wearprovide improved comfort performance. However, the quantitativemeasurement of a lens’ tribological properties under relevant con-ditions, in the eye, is not standard practice. Challenges with thiskind of investigation include the use of an appropriate model formimicking the eyelid and determination of suitable investigativemethods to deal with the lens material’s softness. The purpose ofthis study was to modify the setup of a commercial microtribometerand establish a protocol capable of comparing the CoF of differentCL under biologically relevant conditions.

Method: The CL were mounted on a spherical support andimmersed in a buffered solution containing lysozyme and dilutedfull human serum. A mucine coated glass plate was used as counter-surface. The resulting lateral force (Ft) was determined for differentapplied normal forces (Fn). The CoF was determined as slope of thelinear regression Ft/Fn. CL were measured using the biologicallyrelevant set-up with a model for the eyelid (mucine-tip) and tears(packing solution with lysozyme and serum). Ageing of lenses wasalso assessed by increasing the number of measurement cycles.

Results: The CoF results varied from 0.02 to 0.4 depending onmaterial and number of cycles. No difference (95% 2-sided, CI−0.1970, 0.05671) was found between lotrafilcon B with and with-out copolymer 845 in the packing solution after 100 measurement
cycles.
Conclusions: The eye was successfully modelled and allowed formeaningful comparative tribological measurements for differenttypes of CL.




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bjective measurement of contact lens induced conjunctivaltaining

ichel L. Guillon*, Cécile A. Maissa, Renee J. Garofalo, Nick T. Cock-hott, Barry A. Hanna


urpose: The objective of the investigation was to measure the cir-umlimbal conjunctiva staining associated with contact lens wear.

Method: Twenty-seven successful daily contact lens wearersonstituted the study population. The investigation was a dou-le masked, randomised, cross over bilateral investigation. Fiveontact lenses with different lens edge designs were tested: fourilicone hydrogel lenses (Acuvue Oasys, Biofinity, AirOptix, PureVi-ion) and one conventional hydrogel lens (Acuvue 2). Each contactens was worn for a period of 10 (±2) days. At baseline prior toontact lens insertion and at follow-up immediately post contactens removal lissamine green staining was photographed in eachuadrant. The photographs were analysed to quantify the extentf staining present. At the follow-up visits, the lens edge was alsohotographed and classified based upon appearance.

Results: The results revealed a significant increase (p < 0.001)n circumlimbal conjunctival staining with contact lens wear. Thencrease was contact lens type dependant. The differential stain-ng was dependent upon both the edge design and the material

echanical properties. Staining post contact lens wear was alsoocation dependent with significantly lower staining in the supe-ior quadrant (p < 0.001) than in any other. Measured circumlimbaltaining was not related to subjective comfort.

Conclusions: Contact lens induced circumlimbal staining is lensdge and lens material dependent, most marked in the nasal quad-ant and least in the superior. Circumlimbal staining and lensomfort were not associated in this study.

2

ntimicrobial efficacy of contact lens care solutions and a newxperimental multipurpose formulation against bacteria, fungind Acanthamoeba

imon Kilvington*, Marina Nikolic, Anthony Lam, Nancy Brady,ames Lonnen, Wayne Heaselgrave


urpose: To compare the relative antimicrobial efficacy of com-ercial contact lens care solutions and a new experimentalultipurpose formulation against bacteria, fungi and Acan-

hamoeba castellanii trophozoites.Method: Test solutions comprised 18 multipurpose solutions

MPS) based on PHMB or PQ1-MAPD, 2 hydrogen peroxide (1-tep) and a new experimental MPS containing PQ1 and alexidine.est organisms were: Pseudomonas aeruginosa (ATCC 9027), Serra-ia marcescens (ATCC 13880), Staphylococcus aureus (ATCC 6538),andida albicans (ATCC 10231), Fusarium solani (ATCC 36031) and. castellanii (ATCC 50370). Biocidal assays were performed accord-

ng to ISO 14729. Acanthamoeba viability was determined by a mostrobable number approach.

Results: After 6 h exposure, all MPS showed >3.0 log kill of bac-eria with the exception of the PQ1-MAPD which gave only a 2.3og kill with S. aureus. Fungal efficacy varied from 1.0 – 3.0 log. Both-step peroxide systems gave ≥3.0 log kill for bacteria and fungi.
canthamoeba trophozoite efficacy varied from 0.2 - >3.0 log forHMB based MPS, 3.0 log for PQ1-MAPD and ≥3.0 log for the 1-tep peroxides. The new experimental MPS showed ≥3.0 log kill ofll bacteria, fungi and Acanthamoeba trophozoites.
or Eye 33 (2010) 256–300 281

Conclusions: Although the MPS exhibited good antibacterialactivity, significant variation was observed in efficacy against fungiand Acanthamoeba trophozoites. A new experimental MPS, utilizingthe dual disinfectant activity of PQ1 and alexidine, exhibited broadantimicrobial efficacy which was comparable to that obtained with1-step hydrogen peroxide systems.

23

Triggered delivery of anti allergy drugs from contact lenses

Anisa Mahomed*, Brian J. Tighe


Purpose: This poster addresses the growing interest in extendingoptometric practice into the therapeutics field, by the effective useof contact lenses as a controlled drug delivery device.

Method: In order to identify appropriate drug/lens matrix com-binations and to predict achievable loading and release durationfor different drug structures, factors affecting uptake and release ofa range of marker molecules (e.g. fluorescein sodium (FlNa)) fromvarious lens materials was investigated.

Results: Marker molecules provide valuable structural insightinto the uptake and release potential of drugs such as olopatadine(OLP), ketotifen fumarate and nedocromil. Using a combinationof marker molecules with similar properties to the drugs it wasdemonstrated that solute sorbtion from buffered saline into ahydrogel and passive diffusion into fresh buffered saline aregoverned by: solute molecular weight and pKa; partition and dis-tribution (LogD) coefficient of both solute and hydrogel; watercontent and anionicity of the hydrogel. Various techniques wereidentified to achieve “triggered” in-eye release, thus overcomingthe limitation of simple passive diffusion. One example is the pHshift in distribution coefficient (FlNa LogD: 3.41 at pH4, 0.14 at pH7;OLP LogD: 2.19 at pH4, 0.08 at pH7).

Conclusions: Although factors influencing diffusion of drugs inhydrogels is well recognised, their relative magnitude and impor-tance are not. In order to enable a lens, packing solution/drugcombination to achieve effective triggered release into the ocularenvironment, factors such as the mechanical action of the eyelidtogether with the effect of tear proteins and pH on drug distribu-tion coefficient become important.

24

The temporal relationship between solution induced cornealstaining and cells of the human corneal epithelium

Rachael C. Peterson*, Craig CA Woods, Maud MB Gorbet, DesmondD. Fonn


Purpose: This study aimed to investigate the relationship betweensolution induced corneal staining (SICS) and human corneal epithe-lial cell sloughing.

Method: A randomised contra-lateral double masked studydesign was applied to determine cell sloughing responses to SICSover time. Five subjects were screened and assessed for baselinecorneal staining (CS) and epithelial sloughing with the ocular sur-face cell collection apparatus (OSCCA). Balafilcon A (BA) lenses weresoaked overnight in either PHMB-based solution (MPS) to induceSICS, or peroxide-based solution (HPB). Lenses were worn contra-laterally for 2, 4 or 6 h. At each visit contact lens cytology, CS grading
and cell collection with OSCCA were performed. Using the samestudy design, the repeatability of the optimal sloughing time deter-mined (above) was investigated over 3 further visits. Thirty sampleswere examined in total.




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Results: CS observed with BA and MPS was maximal at 2 h,ecreasing significantly by 4 h (p < 0.01) and further still by the 6 hime point. Conversely, cell yield with BA and MPS was minimal ath with no difference to the contra-lateral control, but increased byh where it was found to be significantly greater than the other col-

ections (p < 0.01, p = 0.04). Mean ± SD cell yields with BA + MPS andA + HPB were of 810 ± 346 and 455 ± 218 respectively which wereepeatable at 4 h, although varied widely between participants

Conclusions: There is a relationship between SICS and sloughingf cells from the human corneal epithelium. At 2 h SICS-affectedells take up fluorescein but remain on the eye until sloughingetween 4 to 6 h after lens insertion.

5

he relationship between corneal fluorescein staining andorneal infiltrates with a change in care system in North Amer-can soft CL wearers

uigina G. Sorbara*, Lynn G. Mitchell, Meredith E. Jansen, Beth T.inoshita, Dawn Y. Lam, Kathryn L. Richdale


urpose: The CLAY study characterized events that disrupt softontact lens (SCL) wear in youth versus adulthood, in a large obser-ational study. This is a secondary analysis from that dataset. Theurpose was to describe the relationship between corneal fluores-ein staining and subsequent corneal infiltrates and to determinehether they are related to a subsequent change in care system.

Method: A retrospective chart review of SCL patients aged 8 to3 yrs (+8.00 to −12.00D CL powers and over-sampling < 17 yrs)as performed where all clinical visits were recorded from Jan-ary 2006 to fall 2009. Age, health history, CL power, brand, yearsf wear, replacement, extended wear (EW), care system (LCP) andlit lamp findings were noted for all visits Patients with and with-ut staining were observed for the presence or absence of cornealnfiltrates and subsequent change in care system.

Results: Review of the records of 1,472 patients having 12,466isits (daily disposables were excluded) yielded 36.2% with and3.8% without staining (p = 0.0001). A change in care system waseported by 54.2% of the stainers and 55.5% of the non-stainersp = 0.64). Patients with staining were significantly more likely toevelop corneal infiltrates compared with those with no staining4.9% vs. 1.7%, p = 0.0001).

Conclusions: In this post-market observational study, it wasound that infiltrates were more likely to be preceded by cornealuorescein staining. The presence of corneal staining was not asso-iated with a subsequent change in care system.

6

omparative efficacies of a novel contact lens care systemontaining povidone-iodine and other care solutions againsturface-attached pseudomonas aeruginosa

atsuhide Yamasaki, Fumio Saitoh


urpose: To clarify if bacterial biofilms formed on lens storage casesan be a risk factor in contact lens-related keratitis, and the eval-ation of the disinfection efficacies of a Povidone-iodine (PVP-I)isinfection system and multipurpose solutions (MPS) on plank-onic and biofilm bacteria.

Method: Biofilms of Pseudomonas aeruginosa and Staphylococ-us epidermidis were formed in the multi-well plates using anxperimental model. The planktonic types and biofilms for eachacteria were exposed to a PVP-I system and 4 MPS and viable bac-erial counts were assessed. To estimate the amount of bacterial

or Eye 33 (2010) 256–300

transmission from biofilms onto the contact lenses, the balafil-con A lenses, which showed the highest transmission rates ofP.aeruginosa biofilms in saline solution were soaked in the testsolutions. The amount of transmitted bacteria on the lenses wasevaluated.

Results: The PVP-I system demonstrated a high efficacy againstbiofilms, as well as against planktonic bacteria, despite an expo-sure time of 5 minutes. In contrast, all the MPS showed disinfectionefficacies against planktonic bacteria, whereas the biofilms wereresistant to the MPS, even after an exposure time of 4 h. Further-more, the amount of transmitted P.aeruginosa biofilm onto thebalafilcon A lenses was significantly lower for the PVP-I systemwhen compared with the MPS.

Conclusions: These result demonstrate that a PVP-I system isefficient against biofilms. The results also suggest that due to theinsufficient disinfection efficacy of MPS on biofilms, MPS users maybe exposed to an increased risk of being infected with microbialkeratitis if the lens storage cases are contaminated with bacterialbiofilms.

SILICONE HYDROGELS

27

Surface characterisation of silicone hydrogel contact lenses byFourier transform infra red spectroscopy

David Austin*, Trevor Emmett, Sheila Rae, Shahina Pardhan


Purpose: A number of studies have utilised Fourier TransformInfrared (FT-IR) Spectroscopy to analyze either the water compo-nent or the surfaces of a limited number of silicone containingcontact lenses. The objective of this current FT-IR study was to pro-vide a comparison of the surfaces of six different available siliconehydrogels, which feature a range polymer composition, equilibriumwater contents and different methods to shield the silicone com-ponent. In addition a comparison with the surface components ofpolymacon was also undertaken.

Method: The FT-IR spectra were obtained using a Perkin-Elmer100 series spectrometer with the front surface of the lens placedonto an attenuated reflectance attachment. Three different lenssamples of each of the seven different lens materials were recorded,galyfilcon A, senofilcon A, balafilcon A, lotrafilcon A and B, comfil-con A and polymacon with a labelled power of −1.00D. Spectrawere exported to Origin 8.1 (Silverdale Scientific UK) for plottingand peak analysis.

Results: The surfaces of the silicone hydrogels displayed a num-ber of different silicone components including, SiCH2R, Si-CH = CH2,Si(CH3)3 which were not present in the polymacon spectra. Aninteresting feature was the similarity of the surface spectra siliconecomponents for the six silicone hydrogels in this study. There washowever differences in peak height potentially indicating differentquantities of silicone component.

Conclusions: FT-IR spectroscopy provided a rapid method of sur-face analysis of hydrated and dehydrating lenses and indicated thatall the silicone hydrogel lenses under test displayed silicone com-ponents near the surface.

28

A clinical comparison of three contact lens care systems used
in conjunction with senofilcon A and lotrafilcon B daily wearlenses
Lee A. Hall*, Renée Garofalo, Graeme Young






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urpose: To compare the clinical performance of three contact lensare systems when used with two silicone hydrogel lenses.

Method: This was a 6-week, single-masked (investigator), bilat-ral, randomised, three-part cross-over study comparing three lensare systems: Alcon® Opti-Free® RepleniSH® (OFR), Bausch & LombeNu MultiPlus® (RNM) and Ciba Vision Clear Care® (CC). In therst phase, subjects wore senofilcon A lenses and in the second,

otrafilcon B. A range of clinical variables was evaluated at each-week follow-up visit. Lenses were also measured for changes inodulus.Results: There were no significant differences in subjective com-

ort on insertion, however end-of-day comfort was rated higherith OFR compared with RNM for the senofilcon A lens (p = 0.02).

ignificantly higher levels of dryness symptoms were also reportedor this lens when using RNM compared with OFR (p = 0.03). Non-nvasive break-up time was significantly greater (p = 0.004), andower palpebral roughness significantly less (p = 0.001), when usingFR compared to RNM for lotrafilcon B. With senofilcon A, higher

evels of film deposit were noted while using RNM and CC comparedith OFR (p < 0.05). Significantly more corneal staining was notedith RNM compared to the two other care systems (p < 0.03). In

ach case, lens modulus was higher at the end of the 2-week period,here were however no significant differences among care systems.enses showing deposits had a small but significantly higher mod-lus (p = 0.04).

Conclusions: The study has highlighted clinically significant dif-erences in silicone hydrogel lens performance after 2 weeks use ofhree care systems.

9

ens-wearing experience with silicone hydrogel and PVA-basedaily disposable lenses

oachim Nick*, Mary S. Fahmy, Timothy A. Giles, Wilson W. Movic


urpose: Patients and practitioners have an unprecedented arrayf contact lens options. Among those are lenses designed foraily disposable use. The daily disposable modality has numer-us advantages, including decreased potential for deposit- andolution-related complications and increased compliance. Withinhis category, various material options exist, including, moreecently, silicone hydrogel daily disposable lenses. A clinical trialas conducted which evaluated patient experiences with a siliconeydrogel and a PVA-based daily disposable lens.

Method: 178 subjects were enrolled in a randomized, subject-asked bilateral crossover trial comparing narafilcon A and

omfort-enhanced nelfilcon A lenses, each worn for 1 week. All sub-ects were current wearers of daily disposable lenses. Subjects weresked to rate their experiences regarding the subjective perfor-ance of the lenses. In addition, lens fit and surface characteristics

f the lenses were evaluated.Results: The overall performance of both lenses was similar in

erms of overall comfort (non-inferiority test, p = 0.008), overallision quality (non-inferiority test, p < 0.001), and overall satis-action (non-inferiority test, p = 0.032). There were no significantifferences between the two lenses for comfortable wearing timep = 0.452) or for purchase intent (p > 0.999). Investigators ratedheir overall impression of the surface wettability of nelfilcon lensesignificantly higher than that of the narafilcon lenses (p = 0.002). Noignificant differences were found in investigator preference for
verall lens fit (p = 0.053).
Conclusions: The results of this trial indicate that PVA-basedelfilcon A lenses provide a subjective wearing experience that isomparable to narafilcon A silicone hydrogel lenses among dailyisposable lens wearers.

or Eye 33 (2010) 256–300 283

30

Vital stains and silicone hydrogels: absorption characteristics ofdifferent silicone hydrogels to fluorescein, fluorexon, lissaminegreen and rose bengal

Sonja J. Tetzlaff*, Stefan Bandlitz


Purpose: To determine the characteristics of different SiHy mate-rials in regard to absorption of the vital dyes flourescein (FS),fluorexon (FX), lissamine green (LG) and rose Bengal (RB).

Method: At baseline transmission curves of 6 SiHy materi-als were determined by a spectrophotometer (Humphrey LensAnalyzer 360). Then the lenses were stored 10 minutes in 0.90%saline solution intermixed with FS, FX, LG or RB. Washing outof the dyes was obtained by rinsing and storing the lenses foranother 10 minutes in a fresh saline solution. A second transmis-sion curve was taken to detect the remaining dye by comparingthis curve with the baseline transmission. For subjective evalu-ation of the discolouration the lenses were compared with newlenses.

Results: SiHy materials showed a statistically significant absorp-tion of FS, LG and RB (p < 0.05). No discolouration was found with FX(p = 0.317). With FS and LG the most intensive discolouration wasfound with balafilcon A and comfilcon A, while with RB senofilconA and comfilcon A discoloured most. The least discolouration for alldyes was found in lotrafilcon A. Similar observations were analyzedin subjective scoring.

Conclusions: All used vital dyes were absorbed by SiHy, exceptflourexon. The degree of absorption varied between the differentlenses and dyes. Absorptions characteristics might be related tothe molecular structure of the silicone component. We recommendrinsing the patients’ eye immediately after the use of all vital exceptfluorexon or not to insert lenses immediately after the use of thesedyes.

31

Clinical evaluation of a new contact lens solution when usedin conjunction with two silicone hydrogel lenses during shortterm wear

Daniel Tilia*, Percy Lazon de la Jara, Rebecca Weng, Thomas Naduvi-lath, Mark Willcox, Brien Holden


Purpose: To evaluate and compare short-term clinical performanceof a new multipurpose solution (MPS) and a commercial MPS whenused in conjunction with two silicone hydrogel lenses.

Method: Galyfilcon A and balafilcon A contact lenses were ran-domly allocated to each eye and worn contralaterally. Lenses werepre-soaked overnight in either new MPS (New Sol (NS): containingPolyquat and Alexidine, Abbott Medical Optics) or a commercialMPS (OPTI-FREE RepleniSH (OFR): containing Polyquat and MAPDA,Alcon). Lenses were worn daily wear for 4 days and disinfected withthe same solution. Solution use was crossover, with randomisedorder and solution identity was double-masked. Subjects wereassessed 2 h after initial insertion and after 2 h of wear on day 4.Subjective ratings were also collected after 6 h of wear on each day.Preference for solution with either lens type was collected at studycompletion. Logistic regression and mixed linear models were usedfor statistical analysis.

Results: NS had a significantly lower rate of SICS compared toOFR (2.8%v9.7%, p = 0.016). OFR/balafilcon A had the highest rate(16.7%) while NS/galyfilcon A had the lowest (0.0%). NS was ratedsignificantly better than OFR for burning/stinging (p = 0.025) andsubjective redness (p = 0.03) on initial insertion with pre-soaked




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Conclusions: These results suggest the new solution contain-ng Alexidine and Polyquat produced lower levels of SICS and wasuperior in certain other aspects than the commercial solution thatontains Polyquat and MAPDA during short term wear.

2

ebound tonometry over hydrogel and silicone hydrogel con-act lenses

abrizio Zeri*, Paolo Calcatelli, Bernardo Donini, Luigi Lupelli,uciana Zarrilli, Peter G Swann

Corresponding author: [email protected]

urpose: To assess the accuracy of intraocular pressure (IOP) mea-urements using rebound tonometry over disposable Hydrogeletafilcon A) and Silicone Hydrogel (senofilcon A) contact lensesCLs) of different powers.

Method: The experimental group comprised 36 subjects, (19ale, 17 female). IOP measurements were undertaken on the sub-

ect’s right eyes in random order using a Rebound TonometeriCare). The CLs had powers of +2.00D, −2.00D and −6.00D. Six mea-urements were taken over each contact lens and also before andfter the CLs had been worn.

Results: A linear regression analysis showed good correlationetween IOP measurements with and without CLs, (all r≥0.80;< 0.05). Bland Altman plots didn’t show any significant trend in

he difference in IOP reading with and without CLs as a function ofOP value. A two-way ANOVA showed a significant effect of mate-ial and power (p < 0.01) but no interaction. All the comparisonsetween the measurements without CLs and with Hydrogel CLsere significant (p < 0.01). The comparisons with Silicone HydrogelLs were not significant.

Conclusions: Rebound tonometry can be reliably performed overilicone Hydrogel CLs. With Hydrogel CLs, the measurements wereower than those without CLs. However, despite the fact that theseifferences were statistically significant, their clinical significanceas minimal.

OFT CONTACTS

3

itting neophytes in two daily disposable contact lenses

orman Becker*, Mary S. Fahmy, Sebastian Marx, Martina M.ichels


urpose: The choice of wear modality and lens material may haven impact on the initial experience and success when fitting neo-hytes into contact lenses. A clinical trial was conducted to evaluatehe performance of comfort-enhanced nelfilcon A and narafilcon Aenses in neophytes when worn for one week in daily wear dailyisposable modality.

Method: 326 subjects divided into two groups were enrolledn a prospective, randomized, sponsor-masked (to subject) clini-al trial conducted in Germany, England and Denmark. One groupas fit with nelfilcon A lenses and a second group with narafilconlenses. Subjects must have had no previous contact lens experi-

nce and must have been interested in contact lens wear. Subjectsere asked to rate the subjective performance of the study lenses.

nvestigators were asked to rate lens fit and surface performance.Results: Subjects in each group were equally satisfied and the

ajority would purchase their respective study lens. The nelfil-on A lenses performed comparably or better than the narafilconlenses for the variables of ‘overall comfort’, ‘overall vision’, and

or Eye 33 (2010) 256–300

‘overall satisfaction’. Investigators rated their satisfaction with lensfit and impression of surface wettability significantly higher withthe nelfilcon A lens.

Conclusions: The daily disposable modality and both lens mate-rials were well received among neophytes, which could be shownby high satisfaction ratings and purchase intent results. Eyecarepractitioners can use these results to approach the fitting of neo-phytes with the daily disposable modality, and either of these lensmaterials, with a high level of confidence.

34

Evaluation of a UV filter, benzotriazole, in a silicone hydrogelsoft lens (75%), with different concentrations: 1.25 and 1.50%

Mercedes Burgos-Martínez*, Anna Werno, Simon Alderson,Andrew Courtis, Steve Wright


Purpose: The efficiency of UV blocking is not always highlighted insoft contact lenses, while the eye, aside from the skin- is the organmost susceptible to sunlight-induced damage. Commercial prod-ucts with UV filters do not present all the same protection. ANSI[American National Standard Institute] Z80.20 Class 1 Class 2.

UVA 10% 30%UVB 1% 5%The purpose of this study is to evaluate the blocking capabil-

ity of a UV filter, benzotriazole, in two different concentrations,before and after autoclave and the swelling properties in a siliconehydrogel lens (75% WC).

Method: Benzotriazole (- (3 -(2H -Benzotriazol-2-yl)-4-hydroxyphenyl) -ethyl methacrylate), a commonly used UV filter,was added to a polymer matrix of a silicone hydrogel soft contactlens (75% WC) with 2 different concentrations: 1.25 and 1.50%. 12spherical lenses were lathed with powers +23.00D, −23.00D and−3.00D. Half of the sample was autoclaved (Matachana 21ED).Light transmission measurements were conducted using dualbeam spectrometer (Perkin Elmer Lambda2).

Results: ANSI standards were achieved with 1.50% concentrationfor Class 1. UV transmission increased after autoclaving the lenses.Water content and swell factors decreased.

Conclusions: By proper adjustment of UV-blocker contact lensescan meet the ANSI standards. Autoclaving the lenses decreasesslightly the UV blocker effect. Different concentrations of UV-blocker benzotriazole slightly affect the WC and swell factors ofthe silicone hydrogel studied. Material thickness is an importantsource of variations in UV-blocking capability. It is essential to pro-vide enough protection for the whole range of powers.

35

Another angle on contact lens surface analysis

Darren Campbell*, Sarah M. Carnell, Gareth M. Ross, Brian J. Tighe


Purpose: Dynamic contact angle (DCA) methods have advantagesover other contact angle methodologies, not least that they canprovide more than single contact angle values. Here we illustratethe use of DCA analysis to provide “fingerprint” characterisation ofcontact lens surfaces, and the way that different materials changein the early stages of wear.

Method: The DCA method involves attaching to a microbal-
ance weighted strips cut from a lens. The strips are then cyclicallyinserted into and removed from an aqueous solution. Convention-ally, readings of force taken from linear portions of the resultantdipping curves are translated into advancing (CAa) and reced-ing contact (CAr) angles. Additionally, analysis of the force versus



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mmersion profile provides a “fingerprint” characterisation of thetate of the lens surface.

Results: CAa and CAr values from DCA traces provide a usefuleans of differentiating gross differences in hydrophilicity andolecular mobility of surfaces under particular immersion and

mersion conditions, such as dipping rate and dwell times. Typ-cal values for etafilcon A (CAa:63.1; CAr:37) and balafilcon BCAa:118.4; CAr:36.4) illustrate this. Surface modifications inducedn lens manufacture are observed to produce not only changesn these value, which may be small, but also changes in the DCAfingerprint” (slope, undulations, length of plateau). Interestingly,imilar changes are induced in the first few hours of lens wear withome lens-patient combinations.

Conclusions: Although single parameter contact angles are use-ul for material characterisation, information of potential clinicalnterest can be obtained from more detailed analysis of DCA traces.

6

in situ” corneal and contact lens thickness changes with highesolution OCT

osé M. González-Méijome*, Alejandro Cervino, Sofia C. Peixoto deatos, Jorge J. Martins Jorge, Teresa Ferrer-Blasco, Robert Montés-icó


urpose: To evidence the utility of high resolution spectral domainptical coherence tomography (HR SOCT) in evaluating epithelial,tromal and contact lens thickness changes under closed-eye con-itions in situ without lens removal.

Method: Eight young healthy patients wore a thick soft contactens during 90 minutes under closed-eye conditions and measuresf epithelial and stromal corneal thickness were obtained at regularntervals with a HR SOCT

Results: Minimal changes in epithelial thickness were detectedith a transient statistically significant increase in epithelial thick-ess in the fellow control eye 30 minutes after insertion (p = 0.028).significant and progressive increase in stromal thickness up to

% of edema after 90 minutes of lens wear was observed at a con-tant rate of 2.5% every 30 minutes, being statistically significant inll observations (p < 0.001). Fellow control eye also showed a sig-ificant increase in stromal thickness at a much lower rate of 0.5%very 30 minutes. Lens thickness decreased significantly by 2% after0 minutes of lens wear under closed eye conditions (p < 0.001).

ndividual analysis showed that all eyes displayed stromal swelling,hile only half of them showed epithelial swelling.

Conclusions: Increase in stromal thickness and a slight decreasen lens thickness were observed in response to a hypoxic stimulusnder closed eye conditions. Lens changes cannot be attributed toehydration and might reflect the adaptation of the material tohe physiological conditions of the ocular surface. High resolutionpectral domain HR SOCT is a powerful tool to investigate in vivohe physiological interactions between cornea and contact lenses.

7

n vitro versus in vivo contact angles of hydrogel contact lenses

era Haddad*, Carole Maldonado-Codina, Philip B. Morgan


urpose: Compare contact angles of hydrogel lenses obtained in the
aboratory to those obtained on-eye.
Method: Sessile drop and captive bubble contact angles wereeasured in the laboratory (in vitro) for four lens materials (etafil-

on A, balfilcon A, lotrafilcon A and senofilcon A) using an OCA0 instrument. All lenses were soaked in buffered saline prior to

or Eye 33 (2010) 256–300 285

measurement and water was used as the probe liquid. The on-eye(in vivo) contact angles of the same (soaked) lenses, which wereworn by 10 subjects, were measured using Novel On-eye Wetta-bility Analyser (NOWA) 30 minutes and 6 h after lens application.The NOWA delivers a drop of 0.4% sodium hyaluronate mixed withsodium fluorescein onto the lens surface whilst a two-camera sys-tem records the resulting contact angles.

Results: Contact angles using the four different methods were(mean ± standard error): sessile drop (60.7 ± 4.8◦), captive bub-ble (26.6 ± 0.5◦), NOWA 30 minutes (17.8 ± 0.9◦) and NOWA 6 h(17.9 ± 0.9◦). Contact angles obtained at the two times points usingthe NOWA were similar whilst those obtained with the sessiledrop and captive bubble were significantly different to each other(p < 0.0001) and also to those found with the NOWA (p < 0.0001).

Conclusions: Significant differences are observed in contactangle when lenses are measured in the laboratory compared withthe in vivo situation, presumably due to the coating of lens surfaceswith tear film components. These findings bring into question theutility of laboratory contact angles for predicting a lens behaviouron the eye.

38

Multi-centre clinical evaluation of two daily disposable contactlenses

Lee L. Hall*, Clare C. Topic, Terri T. Henderson, Graeme G. Young,Chris C. Hunt, Kurt K. Moody


Purpose: To evaluate and compare the performance of a siliconehydrogel daily disposable lens (DD) with a conventional hydrogelDD

Method: This was a 248 subject, 1-week, subject-masked, paral-lel group study. Subjects were randomised to wear one of two DDs:narafilcon A or nelfilcon A. Subjects were existing soft contact lenswearers. A mixed model analysis was used to estimate means foreach lens and find the 97.47% confidence interval (CI) for the differ-ence; a non inferiority bound of 0.5 (5-point scale) was used witheach variable. The primary hypotheses related to overall comfortand limbal hyperemia; secondary variables were overall handling,end-of-day comfort, initial comfort and inferior corneal staining.

Results: 21 sites enrolled 248 subjects (75% female, 42% existingDD wearers). All subjects were successfully fitted and 98% com-pleted the study. The difference in overall comfort between lenseswas +0.43 (1–5 scale, CI: +0.10 to +0.76) where a positive differenceindicated better comfort with narafilcon A. Since the lower boundof CI was greater than zero, narafilcon A was superior to nelfilconA. For limbal hyperemia, the difference between lenses was −0.17(CI: 0.24 to 0.10); since the upper bound of CI was less than zero,narafilcon A was superior to nelfilcon A. Narafilcon A was also supe-rior to nelfilcon A for the secondary hypotheses, apart from initialcomfort which was non-inferior to nelfilcon A.

Conclusions: Narafilcon A DDs gave superior clinical perfor-mance compared to nelfilcon A DDs with respect to overall comfort,limbal hyperemia, overall handling, end-of-day comfort and infe-rior corneal staining.

39

Development of a patient-reported outcomes instrument forsoft disposable contact lenses

*
Michael L. Henderson , Colleen M. Riley, Kurt Moody

Purpose: To develop a patient-reported outcomes (PRO) instrumentfor the evaluation of soft disposable contact lenses.





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Method: Develop a scale designed to assess patient experienceith soft disposable contact lenses using modern psychometricethods such as factor analysis (FA) and item response theory (IRT).

he Food and Drug Administration (FDA) guidance for patient-eported outcomes and the National Institutes of Health roadmapnitiative Patient-Reported Outcomes Measurement Informationystem (PROMIS) was used as a template for development.

Results: Relevant PRO domains of comfort, vision and handlingere identified based on patient interviews and an initial bank

f items created. Items were pre-tested by patients for clarity,nderstanding and interpretation. An initial validation study wasonducted of the domains and items consisting of 461 subjects at5 sites. Psychometric analyses (FA and IRT) were performed on theriginal item bank and refinements were made to the domains andtems. A second round of data was collected to provide further evi-ence about the validity of the refined version. The second roundtudy consisted of 525 subjects at 15 sites.

Conclusions: The PRO instrument was rigorously developed andalidated for existing soft disposable contact lens users and pro-ides a blueprint for scale development using the best availablesychometric techniques. The final item bank contained 128 itemsor comfort, 194 for vision and 54 for handling. The validity of thenstrument is strongly supported by clinical results and provides

repeatable and reliable measurement. The instrument detectshange as gains and losses as well as differences between clini-ally distinct groups.

0

hort-term optical performance of soft contact lenses

arco A. Miranda*, Clare O’Donnell, Hema Radhakrishnan


urpose: To investigate the optical changes in the eye during andfter short-term soft contact lens wear.

Method: In a prospective paired-eye study, 9 subjects weretted with commercially available lotrafilcon A, sifilcon A, balafil-on A, vifilcon A, as well as lotrafilcon A and sifilcon A lenses inwo experimental designs each (based on and with 1x and 2x thehickness of the vifilcon A design). All lenses were either plano-owered or ± 3.00D for the lotrafilcon A lenses. At each session,easurements of low- and higher-order ocular aberrations (HOA)ere performed at baseline, immediately after lens insertion and

t intervals of 15 mins, 30 mins, 1 h, 3 h, 5 h and 7 h. Measurementsere performed with lenses on eye, except for the baseline session

nd final measurement at each session.Results: Significant differences were found between baseline

easures and measurements with lenses, for spherical equivalentSE) (p = 0.00), fourth-order spherical aberrations (p = 0.00), RMSf HOA (p = 0.00), and vertical coma (p = 0.01; RMANOVA). Differ-nces in SE were due to experimental lotrafilcon A lenses (p < 0.01),ifilcon A (p = 0.03) and ±3.00D lotrafilcon A lenses (p = 0.00). Thebserved changes in ocular higher-order aberrations were depen-ent on the lens material and design. At each session, differencesere only detected for RMS of HOA between the initial visit

nd 30 mins later (p = 0.04). For most lenses, measurements hadeturned to baseline values 2 h after lens removal.

Conclusions: Our data showed that although some contact lensesignificantly altered some of the ocular aberrations, they thenemained stable throughout the 5 h test period and returned toaseline values soon after lens removal.

1

linical comparison of three daily disposable lenses

oachim Nick*, Mary S. Fahmy, Norman Becker


or Eye 33 (2010) 256–300

Purpose: The popularity of the daily disposable modality has led tothe introduction of newer technologies, including silicone hydro-gel materials and comfort additives. A clinical trial was conductedto compare a new silicone hydrogel daily disposable lens made ofFilcon II 3 with both nelfilcon A and comfort-enhanced nelfilcon Alenses.

Method: Twenty-eight subjects were enrolled in a randomized,bilateral crossover trial comparing Filcon II 3 and comfort-enhanced nelfilcon lenses for 1 week each. All of the subjects werehabitual wearers of nelfilcon lenses. Subjects were asked to rate thesubjective performance of the two study lenses. Additionally, thesubjects at one site (n = 19) were asked to rate their habitual lenseson several attributes and a comparison of the first brand of studylenses dispensed vs. habitual was made.

Results: After 1 week, the group randomized to wear comfort-enhanced nelfilcon lenses first rated them higher for comfort,vision, handling, and overall satisfaction than the group wear-ing Filcon II 3 lenses first. For most variables, the group wearingcomfort-enhanced nelfilcon lenses first rated them higher thanhabitual nelfilcon lenses, while the group wearing Filcon II 3lenses first rated them similar or lower than habitual. In thecrossover analysis, at 1-week, comfort-enhanced nelfilcon lenseswere rated significantly better than Filcon II 3 for overall com-fort (p = 0.007), overall vision (p < 0.001), and overall satisfaction(p < 0.038). No significant difference was found for overall handling(p = 0.603).

Conclusions: In subjects who are successfully wearing nelfilconlenses, comfort-enhanced nelfilcon provides a better wearing expe-rience than Filcon II 3.

SOFT CONTACTS AND DRY EYES

42

Uptake and release of ciprofloxacin by soft contact lens materi-als loaded with hyaluronic acid

Lyndon W. Jones*, Dareen Nguyen, Andrea Weeks, Miriam Heynen,Elizabeth Joyce, Heather Sheardown


Purpose: The purpose of this study was to determine the effectof hyaluronic acid (HA) in model conventional hydrogel andsilicone hydrogel (SH) materials on the uptake and releaseof the fluoroquinolone antibiotic ciprofloxacin, and to evalu-ate the potential of these materials as ocular drug deliverydevices.

Method: A 3 mg/ml ciprofloxacin solution (0.3%) was prepared inborate buffered saline. Three hydrogel material samples (pHEMA;pHEMA TRIS; DMAA TRIS) were prepared with and without HAof molecular weight (MW) 35 or 132 kDa. Hydrogel discs werepunched out from a sheet of material with a uniform diameterof 5 mm. Uptake kinetics were evaluated at room temperature bysoaking the discs in 0.3% ciprofloxacin for 24 h. Release kineticswere evaluated by placing the drug-loaded discs in saline at 34 ◦C ina shaking water bath. At various time points over 6 days, aliquots ofthe releasate were removed and ciprofloxacin amounts determinedby fluorescence spectroscopy.

Results: All materials released sufficient drug to meet the MIC 90for most common bacterial isolates (0.00025 to 0.032 mg/ml). Over-all, the silicone-based hydrogels (pHEMA TRIS and DMAA TRIS),released lower concentrations of ciprofloxacin than the conven-

more ciprofloxacin compared to materials with HA MW35 andlenses without HA (p < 0.02). HA-based materials were still releas-ing the drug after 6 days.




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Conclusions: HA-containing hydrogel biomaterials show muchromise as antibiotic drug delivery devices, for periods up to 1eek.

3

hallenges in assessing in vivo front surface contact lens wetta-ility

ancy J. Keir*, Doris Richter, Craig A. Woods, Desmond Fonn


urpose: Contralateral study designs are often used to assess dif-erences in wettability between lens materials. To better interpretesults, this analysis was conducted to investigate differences in inivo wettability between subjects and between eyes.

Method: Retrospective analysis was completed for two ran-omized, double-masked, clinical trials. Eighteen subjects eachore two silicone hydrogel lens materials (senofilcon A and

omfilcon A) contralaterally for 20 minutes. Lenses were thenwitched between eyes and worn for an additional 20 minutes.his trial was repeated on another day, using the same ran-omization schedule and subjects. In vivo wettability was graded0–4; 0 = excellent) prior to lens removal. Descriptive statisticsere calculated for the average of all measurements for each

ens type. Average between-eye difference was estimated for eachepeated trial, and the coefficient of repeatability was determinedCOR) ± 95%CI.

Results: The mean ± standard deviation (SD) (range) was.91 ± 0.79 (0 to 2.81) and 0.97 ± 0.85 (0 to 2.88) for senofilcon And comfilcon A, respectively. Mean ± SD of the absolute value ofetween-eye differences were 0.41 ± 0.56 and 0.40 ± 0.39 for tri-ls 1 and 2, respectively. The COR for the between-eye differenceas 1.07. One subject had a substantial (> grade 1.5), repeatable,

etween-eye difference in wettability.Conclusions: There was a moderate range in in vivo wettability

rades between subjects. Additionally, these results suggest thatetween-eye differences exist and should be considered. Whenhoosing a study design, contralateral studies including a cross-ver are recommended.

4

he influence of wear on contact lens surface wetting charac-eristics

ichael L. Read*, Carole Maldonado-Codina, Phillip B. Morgan


urpose: To investigate changes in contact lens surface wetta-ility following wear using an ex vivo dynamic contact angleechnique.

Method: Three existing soft contact lens wearers were fitted withtafilcon A contact lenses over a range of wearing periods (5, 10, 20,0, 60, 120 and 360 min) with three repeats for each wearing period.he lenses were removed and contact angles were measured threeimes using a dynamic captive bubble technique. A linear regression

odel was used to analyse the data.Results: Measurement run was found to be a significant factor

n the analysis (p = 0.001), therefore subsequent analysis used therst measurement only. Receding contact angles did not changeignificantly following wear (p = 0.2). Advancing contact angles andontact angle hysteresis reduced with wear (p = 0.006 and p = 0.005
espectively), although the rate and extent was patient dependantp = 0.005). Mean values for contact angle hysteresis reduced from9.0◦±2.6◦ prior to wear to 34.0◦±7.8◦, 26.2◦±3.1◦, 19.6◦±9.8◦,9.1◦±11.6◦,21.3◦±8.7◦, 20.6◦±5.2◦, 16.4◦±6.3◦ for 5, 10, 20, 30, 60,20 and 360 min, respectively.
or Eye 33 (2010) 256–300 287

Conclusions: This study highlights the ability of a dynamiccaptive bubble technique to monitor changes in hydrogel lens wet-tability associated with wear. The improved surface wetting isrelated to a reducing advancing contact angle which occurs rapidlyafter lens insertion, although this appears highly patient depen-dant. This enhanced wettability following wear is likely to be dueto deposition of tear film components onto the lens surface. Fur-ther work will investigate how ex vivo lens surface wettability isinfluenced by lens material and tear chemistry.

45

The extrinsic modification of contact lenses with poly (vinylpyrrolidone) and related copolymers

Gareth M. Ross*, Sarah M. Carnell, Marc P. Broadbent, Brian J. Tighe


Purpose: Polyvinyl pyrrolidone (PVP) is extensively used in oph-thalmic solutions (especially comfort and care drops). PVP andPVP-based copolymers, introduced into packing solutions prior toautoclaving, are now used for extrinsic modification of lens sur-faces. This work examines the effectiveness and persistence of thistechnology as exemplified by two commercial products: etafilconA and lotrafilcon B, in unmodified (etA & loB) and modified (etAM)and loBM) form respectively.

Method: Subjective assessment of comfort is notoriously diffi-cult. A range of in-vitro techniques has been developed to assessthe nature and duration of these lens modifications. They includecolorimetric PVP assay, friction coefficient (CoF), surface energyand surface activity (static, dynamic and Langmuir compression)in conjunction with an extraction system designed to mimic in-eyeelution.

Results: The anionic Group IV material, etA, binds PVP effec-tively resulting in a 55% reduction in steady state and start-up CoF,no significant polymer elution from the surface of etAM and littlefree PVP in the packing solution (colorimetry). The uncharged loBplasma surface coating binds the modifying PVP copolymer weaklyresulting in elution within 1 h and only 5% reduction in steady stateCoF. Conversely, loBM packing solution contains significant (ca 1%)PVP copolymer reducing the start-up friction “spike” by some 20%,even during > 90% dilution, suggesting that loB modification willprimarily affect initial (insertion) comfort.

Conclusions: PVP and its copolymers are effective in lens surfacemodification. The nature and duration of effects depends upon thenature of the lens surface and the concentration employed.

SOLUTIONS

46

Physical properties of contact lens disinfecting solutions

Vicki L. Barniak*, Krista M. Fridman, Catherine A. Scheuer, Susan E.Burke

*E-mail address: Vicki L [email protected]

Purpose: Contact lens disinfecting solutions (CLDS) should be for-mulated in such a way as to minimize physiological impact on tearsand ocular tissues. One factor influencing biocompatibility is phys-ical attributes of CLDS. The purpose of this study was to investigatephysical properties of CLDS in comparison to healthy human tears.

Method: The pH, osmolality, viscosity, and surface tension of
eight disinfecting solutions were measured. CLDS1, 2, 6, 7 containpolyaminopropyl biguanide; CLDS3, 4 contain polyquaternium-1and myristamidopropyl dimethylamine; CLDS5 contains polyhex-amethylene biguanide and polyquaternium-1; CLDS8 containshydrogen peroxide.




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Results: The pH range for the CLDS systems was 6.7 to 7.8. ThreeLDS were within the pH range generally reported for tears. SixLDS examined were isotonic relative to tears. One CLDS was hypo-onic compared to healthy tears (220 mOsm/kg). Most solutionsested had a surface tension similar to tears (43–46 nN/m). TwoLDS had surface tensions below that of tears (38 and 40 nN/m)nd one had a surface tension of 49 nN/m. The viscosity of all MPSested was within the range of tears (1–10 mPa s).

Conclusions: The physical properties of eight CLDS systems wereested. The pH, osmolality, surface tension, and viscosity of threeolutions fell within the range reported for tears. CLDS1 and CLDS8ere outside the pH range for healthy tears. CLDS2 and CLDS3 devi-

ted from the pH and surface tension of healthy tears. CLDS4 wasutside the range of healthy tears for pH, osmolality, and surfaceension. Further study is needed to understand the clinical signifi-ance.

7

mobicidal effects of multipurpose solutions determined by anutomated counter

aureen V. Boost*, Sindy S.Y. Lai, Pauline Cho


urpose: The effects of multipurpose solutions (MPS) on Acan-hamoeba have been reported by several studies but results remainnconclusive partly due to difficulties of current methods in assess-ng viability and accurately assessing surviving numbers. Theres no requirement for manufacturers to report efficacy againstcanthamoeba, but recently it has been recommended amoe-icidal testing should be included and the requirements suchest discussed. We describe concurrent enumeration and viabilityetermination of Acanthamoeba using a rapid, automated counterVi-Cell) and effects of the presence of organic soil on Acan-hamoeba disinfection.

Method: The disinfectant capacity against Acanthamoeba of fourPS was assessed using a Vi-Cell automated counter which deter-ines viability by trypan blue exclusion. The effects of the presence

f organic soil in the form of bacterial cells and bovine serum albu-in (BSA) were determined.Results: None of the MPS tested met the 1-log reduction in

iability recently suggested, the most effective solution achievingnly a 0.5 log reduction. Other MPS had minimal activity againstcanthamoeba. The presence of Pseudomonas aeruginosa did notignificantly affect disinfecting capacity of the active solution, butSA seriously reduced trophozoicidal activity.

Conclusions: The Vi-cell counter offers a rapid, simple and repro-ucible method for enumeration of viable trophozoites allowingvaluation of disinfectant capacity of MPS. Only one MPS demon-trated trophozoiticidal activity and even this limited activityas inhibited in the presence of BSA. Inability of MPS to killcanthamoeba requires practitioners to educate their patients toegularly disinfect lens cases with hot water to reduce risk of infec-ion.

8

luronics and care solutions: does size matter?

arah M. Carnell*, Gareth M. Ross, Val J. Franklin, Brian J. Tighe


urpose: An increasing range of surfactants, known trivially asPluronics”, is found in lens care solutions. Product data sheets con-ain names such as poloxamer, poloxamine, Pluronic and Tetronicoupled with of numerical descriptors such as 87, 127, 237, 407,04, 1107, 1304 and 17R4. This poster provides a simple interpre-

or Eye 33 (2010) 256–300

tation of this confusing nomenclature and addresses the question“does the number make a difference”?

Method: Surfactant-influenced aspects of MPS performanceinclude cleaning capability and comfort enhancement - bothrelated to the surface activity of the surfactant and its persis-tence at the lens surface. Comparative behaviour of surfactants,including critical aggregation concentration (cac) was assessedby: static and dynamic surface tension (du Noüy, bubble pres-sure and Langmuir techniques). Surface persistence was assessedby controlled extraction followed by measurement of wettability,lubricity and surface energy of the lens and surface activity of theextract.

Results: Surface activity decreased in all cases with increasein solution agitation. The behaviour of the more hydrophilic“Pluronics” - designatory numbers ending in “7” - is typified byPluronic F127 (static surface tension ca 40 mN/m above cac, ris-ing to ca 60 mN/m under dynamic conditions; persistence onuncharged lenses under simulated in-eye conditions ca 1 h). Themore hydrophobic surfactants, designatory numbers ending in “4”,show higher surface activity under agitation (dynamic surface ten-sion ca 50 mN/m) and are longer retained, especially on siliconehydrogel lenses.

Conclusions: Surfactant-lens interaction was found to be influ-enced by the hydrophobic content and molecular weight of thesurfactant and both charge and lens surface hydrophobicity.

49

The use of the ISO 14729 standard for bacteria and fungi in theevaluation of the disinfection efficacy of multipurpose solutionsagainst acanthamoeba

Brien C. David*, Patricia A. Walsh, Susan E. Norton

*E-mail address: Brien C [email protected]

Purpose: To evaluate the use of the ISO 14729 Standard for mea-suring the disinfection efficacy of several multi-purpose solutions(MPS), against Acanthamoeba spp.

Method: ISO 14729 was used as a guideline to evaluate the dis-infection efficacy of various MPS against challenges of two speciesof Acanthamoeba (Acanthamoeba castellanii and Acanthamoebapolyphaga), and two life forms (trophozoites and cysts). Disin-fection efficacy testing was performed on several MPS, followingmethodology outlined in ISO 14729, modified to allow for Acan-thamoeba propagation. Trophozoites and cysts were prepared atconcentrations of approximately 2 × 106 amoeba/ml in Dulbecco’sPhosphate Buffered Saline with 0.05% Tween. Three lots of eachformulation were evaluated.

Results: Using the ISO 14729 Standard, results demonstratedlog reductions against Acanthamoeba trophozoites ranging from0.34 to ¡Y a 4.00 for the solutions tested. Differences in responsemagnitude to the trophozoite challenge, was also species-specific.The most substantial differences in disinfection efficacy of the MPSwere observed with the Acanthamoeba cysts. Notably, when mea-sured at or beyond the manufacturer’s labeled disinfection soaktime, some solutions showed minimal disinfection activity againstAcanthamoeba cysts.

Conclusions: The current ISO 14729 bacterial/fungal test stan-dards, can clearly distinguish performance differences among MPSas measured by log reductions for evaluating disinfection efficacyagainst Acanthamoeba. Results indicate differences were depen-dent on species of Acanthamoeba as well as the life form used as
the challenge. The results indicate the disinfectant(s) used in a MPSsystem may affect that solution”s efficacy against Acanthamoeba.Further study is needed to determine clinical significance of thesein vitro results.



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n evaluation of the rate of disinfection of various multipur-ose solutions and a hydrogen peroxide solution using the ISO4729 standard

rien C. David*, Patricia A. Walsh, Denise Callahan, Julie Strassburg,iffany Hilfiker Susan E. Norton

E-mail address: Brien C [email protected]

urpose: To evaluate disinfection rate of several multi-purposeolutions (MPS) and a hydrogen peroxide (H2O2) system using theSO 14729 standard, but use shorter disinfection times.

Method: ISO 14729 was used to evaluate disinfection effi-acy of several MPS and a H2O2, against separate challenges of5 × 105 of Staphylococcus aureus, Pseudomonas aeruginosa, Ser-

atia marscescens, Candida albicans, and Fusarium solani, butodifying exposure times to 10, 20, 30 or 60 min. To test the H2O2,

ases were filled with 10 ml of H2O2, approximately 5 × 105 CFUas inoculated into the solution, and cap with neutralizing disk was

mmediately applied. Three lots were evaluated for each solution.Results: Differences in the magnitude of disinfection efficacy

ere observed at the exposure times studied. Each solution showedxcellent efficacy against P. aeruginosa while C. albicans proved toe more difficult (two of five solutions did not achieve minimum

SO 14729 acceptance criteria (i.e., minimum 3.0 log reduction foracteria, 1.0 log reduction for fungi) in any time point measured.olutions showed time dependency for biocidal effect over the timeoints measured in this study. Only two solutions achieved the ISO4729 Standard for all five organisms within the measured time-oints.

Conclusions: The results indicate the rate of disinfection of aiven MPS or H2O2 solution can vary, with the challenge organism.ome solutions showed an improvement in disinfection efficacyver time, while others did not. These results do not suggest a ben-fit for reducing the current disinfection regimen recommended byhe manufacturer’s instructions.

1

olution induced corneal staining and its effect on ocular com-ort

ennie Diec*, Vicki E. Evans, Thomas Naduvilath, Varghese Thomas,rien A. Holden


urpose: Solution induced corneal staining (SICS) is generallyeported as asymptomatic. Patient (Px) comfort ratings (CR) withnd without SICS were examined to test this view.

Method: Px (n ≈ 40) wore either lotrafilcon A, lotrafilcon B, galy-lcon A, senofilcon A, balafilcon A or comfilcon A with 3% H2O2,HMB, Polyquad/Aldox or Polyquad/Aldox/Tearglyde for 3 months.ICS was defined as diffuse punctate staining in minimum 4/5 areasf the cornea. SICS and CR were collected at scheduled 2 week, 1onth and 3 month visits. Average CR (1 = poor, 10 = excellent) in

x with (n = 110) and without (n = 941) SICS were compared (at timef SICS and other visits) using linear mixed models, adjusting forepeat participation. Post hoc multiple comparisons were adjustedsing Bonferroni correction.

Results: Px with first event SICS rated significantly lower com-ort during the day (7.8 vs 8.5 p < 0.001), comfort at end of day6.5 vs 7.5 p < 0.001), absence of dryness at end of day (6.5 vs 7.5
< 0.001), absence of burning and stinging (8.1 vs 8.9 p < 0.001),bsence of itching (8.1 vs 8.8 p = 0.013) and absence of overallens awareness (7.6 vs 8.4 p < 0.001). Of Px with SICS, CR at visit
ith SICS were compared to their visits without SICS. At visit withICS, Px had significantly lower ratings for overall comfort (7.5

or Eye 33 (2010) 256–300 289

vs 7.8 p = 0.041) and absence of burning and stinging (8.1 vs 8.6p = 0.002).

Conclusions: Px with SICS have less comfort than Px without SICS.It is important to assess for SICS and change Px to an appropriatelens/solution combination that minimise SICS.

52

In vitro assessment of cleaning effectiveness of care solution-lens combinations

Val J. Franklin, Brian J. Tighe


Purpose: Cleaning efficiencies of care solutions are difficult to assessdue to the multi-factorial nature of the problem, including patienttear chemistry, wear schedule, compliance and complexity of solu-tion compositions. A series of artificial tear models and assaytechniques has been developed to address this problem.

Method: We have developed a range of serum-based tear mod-els that reflect the different wear modalities and spoilation profilesof both soft and RGP lenses. The use of combined non destruc-tive techniques such a fluorescence spectrophotofluorimetry anddestructive techniques for assessing individual deposition speciesenables quantification of both the effect of factors that affect depo-sition (patient variables, material, time, etc.) and the effect of caresystems in removing deposition

Results: The calculated relative cleaning efficiency indicates theproportion of surfactant-removable spoilation that is attainableunder the study protocol. Saline gives a relative cleaning effi-ciency of 20–30% whereas most surfactant-based commercial lensproducts produce values around 80% removal of total depositedmaterial. The efficacies are most dependent upon: (a) lens material,(b) extent and photo-oxidation of deposited layer and (c) natureand level of surfactant present.

Conclusions: All care solutions show greater cleaning capabil-ity than saline; the performance of these solutions has continuedto evolve since ‘simple’ single purpose cleaners were first intro-duced. Current solutions contain a range of components designedto enhance cleaning and show retained interaction with the lensin an attempt to aid comfort. Cleaning capability of these solutionsis not simply related to surfactant CMC (critical micelle concentra-tion) as with low molecular weight surfactants.

53

In vitro biocompatibility assessment of contact lens multi-purpose solutions with silicone hydrogel lenses

Ling C. Huang*, Amit Agarwal, Lauren Crawford


Purpose: To evaluate contact lens multipurpose solutions (MPS)cytotoxicity and assess MPS biocompatibility with silicone hydro-gel (SiHy) contact lenses (CLs) on human corneal epithelial cells(HCEC) and L929 mouse fibroblasts.

Method: SV40-transformed HCEC were exposed to six MPS[Complete MPS Easy Rub formula (CER), Optifree Express (OFE),Optifree RepleniSH (OFR), AQuify (AQF), Renu Multiplus (RMP) andan investigational MPS comprising polyquaternium-1/alexidine]
for 5–30 min. Media, phosphate buffer saline, and benzalkoniumchloride served as controls. Cell viability was determined by MTTassay. Four SiHy CLs (senofilcon A, balafilcon A, lotrafilcon A, comfil-con A) were cycled (24 h) in MPS (20 ml, n = 3), for 7 days. L929 and




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CEC were exposed to cycled-CLs for 24 h and scored for reactivityccording to USP Direct Contact Test criteria.

Results: Viability of HCEC with CER, AQF, RMP, and investi-ational MPS were comparable to media and saline. OFX andFR decreased HCEC viability (n = 3, p < 0.05). L929 showed low

eactivity to CER, AQF, RMP and investigational MPS-cycled CLs;nvestigational MPS-cycled comfilcon A CLs was non-cytotoxic.FX and OFR-cycled CLs demonstrated moderate to severe cyto-

oxicity (grade 3–4). HCEC showed no reactivity to CER, AQF, andnvestigational MPS-cycled CLs. RMP-cycled senofilcon/comfilconLs demonstrated moderate cytotoxicity; RMP-cycled balafil-on/lotrafilcon CLs were non-cytotoxic. OFX or OFR-cycled CLsisplayed moderate to severe cytotoxicity.

Conclusions: Direct exposure of CER, AQF, RMP, and investiga-ional MPS maintained HCEC viability. Biocompatibility analysishowed consensus between mouse fibroblasts and HCEC. SiHy CLsere compatible with CER, AQF, and investigational MPS, moder-

tely compatible with RMP, and less compatible with OFX and OFR.

4

comparison of multipurpose contact lens care solutions inelation to their disinfecting efficacy using stand alone and reg-men testing

iikka L. Järvinen*, Jarkko M. Holopainen, Kirsi M. Koskinen


urpose: Multipurpose care solutions (MPS) were investigated forisinfecting efficacy against yeast (C. albicans) and bacteria (S.ureus) using stand alone (ST) and against yeast using regimenRR) testing. Efficacies were also evaluated in product specific lensontainers, some produced of antimicrobial materials. In additiono multinational products, some European products were investi-ated of which detailed information is rarely available.

Method: ST and RR tests were performed according to ISO 14729ethodologies. 10 mL (test tube) and 3 mL (lens container) of MPSas incubated with the challenge organisms (105–107 CFU/mL)

or 4 h (bacteria) or 4 + 24 h (yeast). “Rub&rinse” regimen proto-ol was chosen regardless of the manufacturer’s recommendations.hallenge inoculums for RR were prepared in organic soil (killed. cerevisiae in inactivated FBS) and lenses incubated for 10 minefore treating them by rub, rinse and soak (for 4 h). Tested MPSesere Aqua Balance (Lapis Lazuli), Optifree RepleniSH (Alcon),

iiloset BioTwin (Finnsusp), Regard (Vita Research), ReNu MultiPlusBausch&Lomb), Solo Care Aqua (CibaVision), and Synergi (Sauflon).

Results: Generally, S. aureus was killed nearly 100% withhe majority of MPSes, but C. albicans disinfecting efficaciesiffered significantly. For yeast, the efficacy order was RenuultiPlus > Piiloset BioTwin ≈ Solo Care Aqua ≈ Optifree Replen-

SH ≈ Aqua Balance > Synergi > Regard. The difference in efficacyhen test was performed in product specific lens container instead

f standardized test tube was up to 30%. RR protocol with yeastesulted <10 CFU/lens with FDAIV-group (Methafilcon A) lensesor each MPS, but results for silicon hydrogels (Lotrafilcon B)ere <10 CFU/lens for Renu MultiPlus, the other MPS resulting in

0–40 CFU/lens.Conclusions: MPS products were found to differ in their efficacy

owards yeast and bacteria. Not all of the MPS products exceededhe ST criteria of ISO 14729.The less effect, the more variation was
ound between parallel samples. RR protocol cleaned the lensesell; however most of the MPS products left subsequent amounts
f surviving organisms in the soaking solution. Antimicrobial lensontainers did not have much effect on the performance in thistudy, but may provide additional benefits in real life use.

or Eye 33 (2010) 256–300

55

Utility of a contact lens case pulsator to aid lysozyme removalfrom etafilcon a hydrogel lenses soaked in a no rub MPS regi-men

Lyndon W. Jones*, Elizabeth Joyce, Miriam L. Heynen


Purpose: To investigate the use of an external contact lens casevibrating device (“JitterBug”) for enhancing lysozyme removal fromFDA group IV lenses soaked in a no rub multipurpose solution(MPS).

Method: Etafilcon A lenses were incubated in Hen Egg Lysozyme(HEL) (3 mg/mL) solution for 16 h at 37 ◦C (n = 12). Six lenses wereplaced into standard lens cases, that were magnetically secured tothe JitterBug pulsating platform and 6 lenses were placed into iden-tical control cases. The microprocessor controlled JitterBug deviceinitially pulsed for 16 s then pulsed 1 s every 15 min over 6 h. Allcases contained Opti-Free Express. After 8 h, all lenses were placedinto fresh HEL solutions and shaken for another 16 h at 37 ◦C. Thedoping, cleaning and rinsing cycles were repeated for 28 days. MPSsolutions were collected each day and pooled into 7 day aliquots. Atthe end of 28 days, protein from the lenses was extracted. Proteinin solution and from the lenses was quantified using a modifiedBradford assay.

Results: Significantly more protein was removed from the lensesusing the JitterBug device in the first 7-day concentrates, as com-pared to the static cleaning (941 �g vs 812 �g; p = 0.008).

The remaining 7-day concentrates and lens extracts exhibitedno significant difference (p > 0.05).

Conclusions: Vibrating enhanced cases may be potentially usefulas cleaning adjuncts when patients use no rub care regimens.

56

Monitoring of anionic and cationic species in multipurposesolution (MPS) formulations using ion chromatography (IC) andcapillary electrophoresis (CE)

Aisling M. Mann*, Anisa Mahomed, Brian J. Tighe


Purpose: Recently the range of disinfecting agents and importanceof anionic species in multipurpose formulations has increased.Analytical methodologies enable available concentrations, changesduring disinfection and selective adsorption to lenses to bemonitored. IC and CE have been developed to assay sodiumchlorite, PQ42 in addition to the more widely used PHMB andPQ1.

Method: Suppressed IC separates and quantifies anions orcations using aqueous chromatography and was used to monitorthe chlorite anion and associated components in commercial MPS.CE, which separates species by charge and size, was used to evaluatePHMB, PQ42 and PQ1 on a 50 um bare fused silica capillary.

Results: The chlorite anion was quantified using IC in avail-able commercial products. Commercially available “pure” samplesof sodium chlorite were shown to contain chloride and chlo-rate peaks which were also detected in the MPS. Anions used
to buffer pH and control osmolarity (phosphate, tetrahydrobo-rate and chloride) were also detected, although on some columns(e.g. AS11) chloride and borate co-elute. Concentration limits usingconductivity detection were similar for all anions (ca. 5 ppm). CEdetection limits for PHMB, PQ42 and PQ1 were in the region of



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0, 10 and 10 ppm respectively. PHMB has a unique distributionf molecular weights resulting in a separation profile exhibiting6 peaks.

Conclusions: Disinfectant concentration is an important aspect ofolution efficacy. IC and CE combining anionic and cationic detec-ion are useful tools in MPS evaluation and enable the effects ofhelf life, containers and lenses on the available concentrations ofhe active species to be monitored.

7

urvival and growth of stenotrophomonas maltophilia in mul-ipurpose contact lens solutions

arina Nikolic*, Simon Kilvington, Simon Cheung, Nancy Brady,tan Huth, Wayne Haeselgrave


urpose: Stenotrophomonas maltophilia is a Gram-negative envi-onmental bacterium. The organism can cause keratitis and haseen isolated from the lens storage cases of symptomatic andsymptomatic persons. Here, the efficacy of multipurpose solutionsMPS) against S. maltophilia and its ability to support the growthf Acanthamoeba was investigated.

Method: S. maltophilia was tested against MPS containing: poly-examethylene biguanide (PHMB), polyquarternium-1 (PQ1), PQ1ith myristamidopropyl dimethylamine (MAPD) and EDTA (PQ1-APD-EDTA), PQ1-MAPD and nonanoyl ethylenediaminetriacetic

cid (PQ1-MAPD-C9ED3A) and an experimental formulation basedn PQ1 and alexidine (PQ1-ALEX). The ability of the bacterium toupport the excystment and replication of Acanthamoeba spp. waslso studied.

Results: All 13 PHMB formulations and the experimental formu-ation PQ1-ALEX resulted in a ≥3.0 log reduction in S. maltophiliafter 1–2 h contact time. No regrowth of the bacterium occurredver 14 days for 9 of the solutions in which culturing was under-aken. Solutions based solely on PQ showed <1.0 log kill after4 h. The PQ-MAPD-C9ED3A and PQ-MAPD-EDTA formulationshowed <1.0 log kill at 6 h and 3.0–4.0 log kill at 24 h. A 2 loge-growth of the bacterium was observed in the PQ and PQ-MAPD-9ED3A solutions but not PQ-MAPD-EDTA or PQ1-ALEX after 6ays. S. maltophilia readily supported Acanthamoeba excystmentnd trophozoite replication.

Conclusions: S. maltophilia is resistant to MPS composed of PQnd PQ-MAPD but not PHMB or PQ1-ALEX. The ability of S. mal-ophilia to survive and replicate in certain MPS may provide a foodource in storage cases for the growth of Acanthamoeba.

8

ynamic contour tonometry over a thin daily disposable hydro-el contact lens

aniela S. Nosch*, Armin Duddek, Dider Herrmann, Oliver M.tuhrmann


urpose: Dynamic Contour Tonometry (DCT) has been shown toeliver accurate and repeatable results for intraocular pressureIOP) measurement, independent of corneal physical properties
uch as thickness, curvature and rigidity. The aim of this study waso find out if DCT remains accurate when it is applied on regu-arly shaped corneas while a thin, daily hydrogel contact lens (CL)s worn.
or Eye 33 (2010) 256–300 291

Method: This was a prospective, randomised study and included46 patients (46 right eyes), with 26 females and 20 males. Theage varied from 22 to 66 years (mean: 43.04 ± 12.69 years). IOPand ocular pulse amplitude (OPA) measurements were taken withand without a daily disposable hydrogel CL (−0.50D, Filcon IV,Sauflon) in situ (using the DCT), while the order of measurementwas randomised in order to prevent any possible effect of repeatedmeasurements.

Results: The average value for the IOP measurements with-out CL was 16.51 ± 3.20 mmHg, and with CL in situ it was16.10 ± 3.10 mmHg. The mean difference was 0.41 mmHg and notfound to be statistically significant (p = 0.074). The average valuefor the OPA measurement without CL was 2.20 ± 0.79 mmHg. WithCL in situ it was 2.08 ± 0.81 mmHg. This gave a mean difference of0.11 mmHg and was statistically significant (p = 0.025). The Bland-Altman-Plot showed a maximum difference in IOP of +2.44 and−2.00 mmHg (CI 0.95). Regarding OPA, the maximum differencewas +0.81 and −0.60 mmHg (CI 0.95).

Conclusions: It can be concluded that the presence of a thinhydrogel CL does not affect the accuracy of IOP measurements whenDCT is used.

59

Evaporation effects on the efficacy of contact lens multipurposesolutions

Charles H. Powell*, Hoong Lisa, Simon Kilvington, Anthony Lam,James Lonnen


Purpose: Non-compliance is a significant factor in contact lensrelated microbial keratitis. This may include reuse and “topping off”of solutions and also failure to cap a lens case during soak, resultingin evaporation effects. Here, the impact of partial evaporation onthe antimicrobial efficacy of contact lens multipurpose solutionsagainst fungi and Acanthamoeba was investigated.

Method: MPS-1 (hydroxyalkylphosphonate, poloxamine, PHMB,boric acid, EDTA); MPS-2 (sodium citrate, sodium borate, propy-lene glycol, tetronic 1304, nonanoyl ethylenediaminetriacetic acid,PQ-1, Aldox); MPS-3 (alexidine, hydranate, polyquarternium-10,poloxamine/poloxamer); and MPS-4, an experimental MPS con-taining PQ-1 and alexidine. Solutions were evaporated under astream of air to 2× and 4× by weight, challenged with Candida albi-cans, Fusarium solani or A. castellanii trophozoites and assessed forrate of kill over 6 h.

Results: MPS-1 showed no efficacy changes when evaporated to2× but lost >50% efficacy for C. albicans and F. solani at 4×. MPS-2showed reductions in activity of 60%-80% for C. albicans and 40%-60% for F. solani at 2×/4×. MPS-3 lost 98–100% of its efficacy forC. albicans and F. solani even at 2×. MPS-4 did not lose efficacy ateither 2× or 4×. Acanthamoeba testing continues but no efficacyloss with MPS-4 was seen even at 4×.

Conclusions: MPS-3 was withdrawn from the market followingan association with Fusarium keratitis. This study indicates that lossof antifungal efficacy on evaporation may have been a key causativefactor. In contrast, the experimental formulation MPS-4, also con-taining alexidine, showed no loss in antimicrobial efficacy on partialevaporation.

60

A clinical safety and acceptability evaluation of a novel multi-purpose disinfecting solution

Nicholas Tarantino*, Eugenia Y. Kao, Ling C. Huang, Dave A. Ziegler






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urpose: To evaluate and compare the clinical safety and accept-bility of an investigational multi-purpose solution (MPS) and aommercial MPS with multiple lens materials.

Method: An investigational MPS containing Alexidine andolyquaternium-1 (New MPS) was compared to Opti-Free Replen-

SH MPS (OFR) in a parallel-group study over 90 days. Subjectsn = 274) were randomized in a 2:1 ratio, such that 180 subjectssed New MPS, and 94 used OFR across five representative lensaterials: galyfilcon A, lotrafilcon B, balafilcon A, comfilcon A, and

ny Group IV material. Ocular physiology and subjective comfortere assessed through 90 days of regimen use. Additionally, lens

leanliness was assessed by measuring total reflectance on theorn study lenses.

Results: There were no statistically significant differences foundetween New MPS and OFR in any safety or subjective acceptabil-

ty measures after 90 days, including corneal staining change fromaseline (p = 0.257) and overall lens comfort change from baselinep = 0.652) across all lenses. Corneal staining results were strati-ed by lens wear time (1, 2, 3–4 h and 5+ h), but there was noifference between New MPS and OFR at any time point, withhe greatest change observed at 3–4 h (p = 0.165). Lens cleanli-ess results also indicated no difference among all lenses testedp = 0.411). Though balafilcon A lenses were found to be statisti-ally cleaner with OFR (p = 0.043), the difference was not clinicallyignificant.

Conclusions: This study showed New MPS to be comparable toFR with soft contact lenses, including silicone hydrogel lenses.

1

mpact of a novel multipurpose solution on the structural andunctional integrity of tear proteins

lli A. Wright*, Philip B. Morgan, Carole Maldonado-Codina, Thomasowitt, Curtis B. Dobson


urpose: Contact lenses accumulate tear proteins, includingysozyme and lactoferrin, during routine wear. Denatured proteineposits on contact lenses can cause reduced vision, discomfort andlinical complications. Additionally, the antimicrobial properties ofear proteins may be lost following denaturation. This in vitro studynvestigated the ability of a novel multi-purpose solution (MPS) to

aintain the functional and structural integrity of lysozyme andactoferrin.

Method: Human lactoferrin and lysozyme, formulated in eitherhosphate buffered saline or an artificial tear solution, were mixedith novel MPS and challenged with a denaturant. The struc-

ural integrity of the tear proteins was assessed using differentialcanning calorimetry (DSC) and native polyacrylamide gel elec-rophoresis (PAGE). The functional integrity of the tear proteinsas investigated by adding the test solution to a suspension of

ither Pseudomonas aeruginosa (ATCC 9027) or Staphylococcusureus (ATCC 6538), and assessing the turbidity of the solution,sing either a short term bacteriolysis protocol or conventional MICssessment after overnight incubation.

Results: The novel MPS prevented the loss of the denaturationeak detected in the denatured protein samples during DSC anal-sis. The MPS reversed the shift in the position of the denaturedrotein bands detected on the native gels during PAGE. Further-
ore, the novel MPS counteracted the SDS-induced abolition of the
ytic properties of lysozyme, and reversed the increased turbidityfter SDS treatment of lactoferrin.

Conclusions: These data indicate that the novel MPS maintainedhe structural and functional integrity of lysozyme and lactoferrin.

or Eye 33 (2010) 256–300

Further work may elucidate how MPS can impact on tear proteinstructure and function.

62

Pre-disposing factors for solution induced corneal staining(SICS)

Graeme Young*, Kristy Canavan, Susanna Jones, Rosemary Stewart


Purpose: To evaluate predisposing factors in subjects susceptible tosolution induced corneal staining (SICS).

Method: 446 existing soft contact lens wearers were refit withone of two study lenses (lotrafilcon B, omafilcon A) and used ahydrogen peroxide care system (AOSept®) for a 4 week period.Each subject was then challenged with similar lenses pre-soakedin a multi-purpose solution (ReNu MultiPlus®) and assessed afterapproximately 2-h to be categorized as either ‘stainers’ or ‘non-stainers’ based on whether they showed a classic SICS pattern.

Results: Overall, 36% (155/425) of eligible subjects were clas-sified as ‘stainers’ and included a higher proportion of omafilconwearer as ‘stainers’; 44% (91/205) vs. 29% (64/550). After usingthe peroxide system, the ‘stainers’ showed poorer lens wetting(p < 0.02) and higher levels of film deposit (p = 0.03); 45% of ‘stain-ers’ showed some film deposit compared with 37% of ‘non-stainers’.Furthermore, on slit lamp examination, the ‘stainers’ showedsignificantly higher levels of upper and lower palpebral hyper-emia (p = 0.03, p = 0.01), tarsal roughness (p = 0.01), corneal staining(p < 0.0001) and conjunctival staining (p = 0.004). Even though notexposed to preservatives, twice as many eyes in the ‘stainers’ grouphad some level of corneal staining: 51% vs. 25% (p < 0.0001). Therewere no significant differences between the ‘stainer’ and ‘non-stainer’ groups with respect to: age, sex, refraction or keratometry.

Conclusions: This study highlighted some notable trends inpatients susceptible to SICS. The findings suggest poor tear qual-ity as a pre-disposing factor for SICS.

63

Evaluation of antimicrobial efficacy of multipurpose solutionsagainst clinical microbial isolates

Hua Zhu*, Rani Bandara, Simin Masoudi, Duojia Wu, Mark Willcox


Purpose: Keratitis during contact lens wear is associated withmicrobial contamination of lenses. Recent recalls of lens care solu-tions with an increased risk of infection highlight the need forbroad spectrum antimicrobial activity. This study evaluated theantimicrobial efficacy of two multipurpose solutions against clini-cal isolates.

Method: A commercially available multipurpose solution(MPS-A) containing polyquad-aldox and an investigational MPScontaining polyquad and alexidine (PQ-ALEX) were used. MPSswere challenged with ISO panel organisms and sixteen clinicalisolates including Staphylococcus aureus (2), Acinetobacter sp (1),Delftia acidovorans (1), Pseudomonas aeruginosa (2), P. fluorescens(1), Serratia marcescens (2), Stenotrophomonas maltophilia (1), Can-dida albicans (2), Fusarium solani (2), Acanthamoeba castellanii (1),
and A. polyphaga (1). After 0, 6 and 24 h of disinfection, sampleswere neutralized and numbers of survivors estimated by quantita-tive culturing.
Results: Both MPSs showed good activity against ISO panel S.aureus, P. aeruginosa and C. albicans. Activity of PQ-ALEX was higher




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han MPS-A (p < 0.05) against ISO strains of S. marcescens (6.4 ± 0.1s 3.9 ± 1.0 log reduction respectively) and F. solani (3.0 ± 0.2 vs.8 ± 0.1). PQ-ALEX was superior to MPS-A (p < 0.01) against clin-

cal isolates, including a methicillin-resistant S. aureus (6.3 ± 0.0s 3.1 ± 0.2), S. marcescens (4.7 ± 0.5 vs 2.2 ± 0.9), D. acidovorans5.9 ± 0.7 vs 0.1 ± 0.2), S. maltophilia (6.5 ± 0.0 vs 0.8 ± 0.4), and C.lbicans (4.0 ± 0.8 vs 0.2 ± 0.2) after 6 h disinfection. MPS-A and PQ-LEX showed similar activities against clinical isolates of F. solanind Acanthamoeba sp (≥1-log).

Conclusions: Clinical isolates are more resistant to disinfection.solution containing alexidine and polyquad has demonstrated a

road and superior antimicrobial spectrum against clinical isolates.

ORICS

4

itting soft toric customized silicone hydrogel lenses in irregu-ar corneas

esús Carballo-Álvarez*, Mercedes Burgos-Martínez, Laura Batres-alderas, Leticia Santamaría-García, Steve Wright


urpose: The latest generation of Silicone hydrogel (SiHy) materi-ls with high DK, 75% WC and low elasticity modulus are suitableor custom fitting to diverse corneal topographies. They allow anncrease in thickness without significantly compromising cornealxygenation. The fitting of these lenses maintains a well centeredptical zone and not decentered as can be the case with RGPs. Theurpose of this study is to evaluate the fitting of soft toric lensesith special parameters and of SiHy material in patients with irreg-lar corneas.

Method: The following cases were fitted:4 eyes with keratoconus grade II - 4 eyes with keratoconus and

ntrastromal rings - 1 eye after corneal graft - 1 eye after traumatismOptical quality, corneal integrity and subjective comfort by

he patients were evaluated. Visual acuity was measured withDTRS test. Tear quality was analysed with BUT and Schirmer tests.opography and aberrometry analysis were undertaken by Oculusentacam. Back curve (BC), total diameter and thicknesses wereodified until the best and most stable fitting was obtained.Results: Fittings were stable with BCs of 8.00 and 8.30, as well as

igh cylinders, which are common in these cases. VA was equal tor better than spectacles.

Corneal integrity was not significantly affected after threeonths with wearing times of between 6 and 15 h. Subjective com-

ort and handling were scored as good.Conclusions: The latest generation of soft toric SiHy lenses are a

iable option for fitting irregular corneas, giving satisfactory resultsor both patient and fitter.

5

oric design reverse geometry lenses for myopic astigmatism,linical performance and preliminary results

onnie Chen, Sin Wan Cheung, Pauline Cho


urpose: To evaluate the effectiveness of the Menicon Z Night Toricrthokeratology (ortho-k) Lens for correcting myopia and astigma-ism.

Method: Forty-four children aged 6–12 year old with myopiaore than −0.50D, with-the-rule astigmatism of −1.25D or above

or Eye 33 (2010) 256–300 293

and unremarkable ocular and general conditions were fitted withthe Menicon Z Night Toric Lens (NKL Contact lenzen B.V., Emmen,The Netherlands). Visual acuity, subjective and objective refrac-tion, corneal topography and biomicroscopy examination wereperformed at baseline, the first overnight, first week, first monthaftercare visits (and every 3 monthly thereafter for a duration of 2years). The results from the right eyes or the astigmatic left eyes (ifthe right eye did not satisfy the refraction criteria) were reported.

Results: Forty-four subjects had worn the toric ortho-k lensesfor 1 month. Ninety-six percent were successfully fitted with thefirst pair of lenses. Toric ortho-k significantly reduced the manifestmyopia from −2.64 ± 1.33 D to −0.36 ± 0.43 D and refractive astig-matism from −1.80 ± 0.47 D to −0.41 ± 0.42 D (p < 0.001, paired ttest) after lens wear for one month. After one-month lens wear, theunaided logMAR VA was 0.11 ± 0.14.

Conclusions: Menicon Z Night Toric Lens is effective in correct-ing astigmatism and myopia in high astigmatic and low-moderatemyopic children with no significant corneal staining and lens bind-ing.

66

Aberrations in soft toric contact lenses and the effects of decen-tration

Sheila M. Rae*, David T. Austin, Shahina Pardhan


Purpose: Visual performance of soft toric contact lenses will dependon lens stability, position on eye and the wavefront aberrations,which may vary with the lens optics and stabilization method.Aberrations of toric lenses were assessed in centred and decentredpositions.

Method: Wavefront aberrations were measured in a wet cellusing the AMO Clearwave aberrometer. Three lens designs weretested in a range of sphere and cylinder powers and axis directions.Lens A was stabilized by dual thin zones, lens B was an acceler-ated stabilization design and lens C by prism ballast and also hadaspheric optics to control spherical aberration. Aberrations weremeasured with lenses centred, decentred downwards by 0.5 mmand rotated nasally by 5 degrees.

Results: Vertical prism (Z1,-1) was significantly higher for lens Cthan A or B (p < 0.001). Vertical coma (Z3,-1) was positive and signif-icantly higher in lens C than A or B (p < 0.001). Simulated downwarddecentration caused a significant increase in a negative direction ofZ3,-1 for lenses A and B (p < 0.001) but a significant reduction in thepositive magnitude of Z3,-1 for lens C (p < 0.001). Root mean squarehigher-order aberrations increased with downward decentrationfor lens B (p = 0.028) but decreased for lens C (p < 0.001).

Conclusions: The prism ballast design was associated with pos-itive vertical coma. Downward decentration of all three lens typesinduced negative vertical coma due to the inherent spherical aber-ration in the lens designs and this offset the inherent coma in theprism ballast design. The effects were independent of lens powerand axis direction.

MISCALLANEOUS

67

Global incidence and perceptions on eye examinations

Louis Dias*, Sule Sencer, Anna Sulley, Ian Davies






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urpose: To understand the incidence and perceptions of eye exam-nations (EE) globally in the general population

Method: A survey was conducted in 13 countries in 2008; inter-iews were conducted with 500 adults per country (aged 18–4).

Results: The majority report having had some form of EE,lthough for only 54% has this been comprehensive, comparedo 82% and 91% having general health and dental examinationsespectively. Lack of knowledge and insufficient attention onye health is responsible; nearly half are not sure what an EEnvolves, but 62% are willing to pay more for a better examina-ion. The ideal age to start EE was 5.6 years old, compared to6.9 years when they first take place. The global frequency ofE is 0.74 times per year, with Korea having the highest aver-ge (0.95). Large numbers recognize the benefits of improvedision and contact lens wear, with widespread agreement on lifenjoyment, self image and performance in school and at work.atients rely heavily on practitioners’ advice on vision correc-ion, although this varies by country with a low of 56% in Japano a high of 91% in France. Finally, while EE are believed to bemportant, the intent to have one in the next year is significantlyower.

Conclusions: The diversity of perceptions and beliefs glob-lly presents challenges for practitioners. Although many peopleeglect primary eye care, they value their sight and are willingo pay for eye examinations - they just don’t realize they needhem.

8

nderstanding patient’s needs, wants, desires and habits

imothy A. Giles*, Inma Perez


urpose: Just as there are many choices in recommendingontact lenses, our patients also come with many choices.atients wear contact lenses only (full-time wear), or con-act lenses on a part-time basis, or may experience challengesut will never wear glasses. This analysis was designed to

dentify common characteristics of contact lens wearers and pro-le patients according to desires, wants, needs, and wearingabits.

Method: Through a international mailing in July 2009, 5,528 softontact lens wearers aged 12 and over were identified and sent a2 page legal booklet and questionnaire. The questionnaire askeduestions on contact lens wearing habits, perceived vision correc-ion needs, purchase habits, lens care habits and practices, level ofommitment to wearing contact lenses, and any challenges theyay encounter.Results: A total of 2,987 responses were received and processed,

,461 by mail and 1,526 on-line. Based on the responses to theuestionnaire, five main patient profiles were identified; patientsredominately happy and compliant (28%US, 17%EU), those withhallenges but are committed to wearing SCL’s (22%US, 28%EU),atients wearing SCL’s from breakfast to bed time without signifi-ant problems (37%US, 34%EU), those wearing them for sports andocial activities (7%US, 14%EU), and finally those who wear cos-etic lenses (6%US, 7%EU).Conclusions: The results indicate based on specific desires

nd wearing habits, patients can be categorized into specificrofiles that are distinct and unique. This will assist the Eyeare Practitioner in selecting the appropriate contact lens mate-ial and modality for each patient based on their specificeeds.

or Eye 33 (2010) 256–300

69

Adolescent and parent attitudes towards contact lenses:behaviours and management

Joan Gispets*, Fernando Hidalgo, Juan J Durban


Purpose: The study aimed to identify different approaches throughwhich adolescents and their parents could gain confidence in thefitting of contact lenses (CL) among the teen population.

Method: A survey was conducted amongst adolescents and theirparents in Spain and Portugal to determine their attitudes towardsCL. The Health Belief Model was applied to the survey results toidentify different management approaches to increase adolescents’and their parents’ confidence in the use of CL among the youngerpopulation.

Results: The majority of adolescents (77.5%, n = 223) expressedan interest in wearing CL, considering them effective, safe and com-fortable. Parents (n = 230), considered CL less safe for adolescentsthan for the general population. In addition, mothers had signifi-cant concerns regarding adolescents’ ability to follow CL use andcare instructions and potential eye damage. Parentsı own expe-rience with CL was also an important factor in determining theirattitude towards adolescent CL wear. Applying the Health BeliefModel to the data, it is possible to conclude that mothers perceiveCL to cause eye damage and adolescents are more vulnerable to thisrisk. In addition, they consider CL to offer mostly aesthetic benefits;consequently avoiding their use does not have a negative impact.These beliefs are not based on scientifically contrasted evidence.

Conclusions: Eye care specialists should adequately inform par-ents about the benefits of CL. It is crucial to improve their trainingwith special emphasis to be placed on improving communicationskills to ensure that these messages are correctly and coherentlydelivered.

70

Design optimisation of portable sensor technology for on-lensassay

Daniel P. Harvey*, Neil Hayes, Brian J. Tighe


Purpose: Optometric practise is increasingly demanding in terms ofthe diagnosis of ocular disease. The objective of this sensor technol-ogy development is to provide information at the point of routineoptometric examination which would provide supportive evidenceof tear abnormality.

Method: The first stage was the design of diagnostic fibre-optichardware enabling rapid assay of lens-borne tear components uponimmediate removal from the eye. The next stage of design is theoptimisation of probe configuration and comparative validationwith an increasing range of electrolytes before moving to a morecomprehensive range of (e.g. protein-based) tear components.

Results: We have evaluated three configurations of the lens-contacting sensor probe: (a) a loop of approx 5 mm diameter, (b) afibre optic tip 0.5 mm diameter, and (c) a 10 mm diameter quartzsensor head. The relative advantages and disadvantages of theseconfigurations is based on the balance of cost, convenience and
efficiency. The quartz head is more expensive to produce, but itsability to make contact with almost the entire lens surface con-veys greatest sensitivity. This is of great potential advantage withlow concentration protein-based analytes. For routine electrolyte(sodium, potassium, calcium) assay adequate sensitivity and repro-



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ucibility (<1.5 ± 0.8 mg/dl), and lowest cost is achievable with theimple 0.5 mm fibre end, which is also conveniently used as a lowerear meniscus probe, in the presence or absence of a contact lens.

Conclusions: Potential advantages of this methodology includepeed and accuracy of diagnosis and greater confidence in caseshere referral is involved.

1

lemental analysis of hydrogel contact lenses using Laser-nduced Breakdown Spectroscopy (LIBS)

yndon W Jones*, Esperanza Rodriguez-Celis, Martine Tourigny,ndre Blain


urpose: To determine the feasibility of using Laser-Induced Break-own Spectroscopy (LIBS) for rapid elemental characterization ofydrogel contact lenses.

Method: Seven different polyHEMA-based and silicone hydrogelSH) lens materials (nelfilcon A, etafilcon A, galyfilcon A, senofil-on A, lotrafilcon A, lotrafilcon B, and balafilcon A) were analyzedy LIBS (PharmaLIBSTM250). No sample preparation was required,nd the laser was directly focused onto the surface of the materi-ls. Each lens was analyzed at 121 sites, requiring less than 2 miner lens. The Si emission line at 390.6 nm was monitored for allaterials to determine its presence or absence, surface uniformity

nd its variation with respect of drying time. Si uniformity in theenses was assessed by reporting the %RSD (relative standard devi-tion = [SD/average Si intensity] × 100) and 2D plots.

Results: No Si signal was detected for the polyHEMA-basedaterials nelfilcon A and etafilcon A. All SH materials exhibited a

trong Si signal, with a high signal to noise ratio. For the non-surfacereated lenses, galyfilcon A and senofilcon A, an increase in the Siignal was observed with drying time (up to 12 h). This behaviouras not observed in the plasma-coated lotrafilcon A and lotrafilconmaterials.

Conclusions: This is the first study to report on the use of LIBSo provide direct elemental analysis of hydrogel contact lenses. Iness than two minutes and with no sample preparation, materials

ere analyzed for the presence of Si, surface changes over time,nd homogeneity of Si across the lens surface.

2

valuation of different methods for determining ocular domi-ance

homas R. Karkkainen*, Arkady Selenow, George A. Zikos, Saman-ha Slotnick, Megan Fumerton


urpose: Ocular dominance is an important measurement whenroviding presbyopic correction with contact lenses as well as prioro refractive and intraocular lens surgery. Several methods are usedlthough to date there is no “gold standard” that exists. This studyas to compare the inter-test agreement between various domi-ance tests and evaluate the agreement between an optometristnd technician performing one of the tests.

Method: Thirty-one presbyopic subjects had their ocular dom-
nance determined using the following tests: (1) instrumentighting; (2) sighting dominance; (3) fixation disparity; (4) stereo-revalence; (5) stereopsis with increasing blur; (6) stereopsis withecreasing blur; (7) through focus stereopsis assessment; (8) binoc-lar rivalry; (9) sensory dominance by a technician; (10) sensory
or Eye 33 (2010) 256–300 295

dominance by an optometrist. The inter-test agreement was calcu-lated and compared.

Results: The strongest level of agreement occurred betweenthe following tests: (1) stereo-dominance with increasing blurand stereo-dominance with decreasing blur; (2) stereo-dominancewith increasing blur and stereo-prevalence; (3) stereo-prevalenceand the through-focus stereo assessment; (4) instrument sight-ing and sighting dominance; (5) stereo-dominance with increasingblur & the through-focus stereo assessment. The highest level ofagreement reached 86%. The agreement for the sensory blur testsbetween optometrist and technician were surprisingly modest at65%.

Conclusions: The highest correlation occurred between testswith similar methodologies such as stereo-dominance withincreasing and decreasing levels of blur. Clinicians should be awareof the variability between tests and that results may not be repeat-able especially if multiple individuals are administering the test, asthey consider dominance testing for contact lens fitting or refrac-tive surgery.

73

The economic impact of contact lens drop out in Europe

Jami R. Kern*, John Rumpakis


Purpose: The economic impact of contact lens dropouts on eye carebusinesses is seldom reported and may be greater than perceived.This study identified the dropout rate, the associated reasons, andthe economic impact on European eye care businesses.

Method: A web-based local language survey of eye careproviders was implemented in 27 countries between January 1and June 30, 2009. An a-priori rule to omit outliers greater thanthree standard deviations from the mean was applied to all vari-ables to minimize the impact of extreme values. The hypothesisthat the dropout rate is higher than the historically reported rate(10%) was statistically assessed.

Results: The 56 EU respondents reported seeing an average of 23gas permeable and 130 soft contact lens patients per month. Themean EU dropout rate was 30.5%, statistically significantly higherthan the historically reported rate (p < 0.05). Reasons for dropoutincluded discomfort (45%), poor vision (18%) and expense (18%).The median lifetime lost revenue to a business due to a dropoutwas D34,674.

Conclusions: Greater attention should be paid to contact lenswearers who are at risk for dropping out, as the economic impact issignificant to an eye care business. Well informed businesses shouldbe aware of the underlying causes and address them proactivelyto improve patient experience and reduce the potential economiceffect of contact lens drop out in their practices.

74

A novel method to assess the impact of surface wetting and opti-cal quality of contact lenses

Shizuka Koh*, Ritsuko Higashiura, Mutsumi Fuchihata, TomoyukiInoue, Fujikado Takashi, Naoyuki Maeda


Purpose: With new material technologies entering the market, an
objective way to assess the clinical impact of such advances andthe patients for whom they are best suited would be useful. Thisinvestigation used higher-order-aberrations (HOAs) as objectivemeasures to quantify the quality and stability of the pre-lens tear




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lm, with a subjective measure of ocular dryness to compare aydrogel (etafilcon-A) (HG) and silicone-hydrogel with internaletting agent (senofilcon-A) (SiH).

Method: Ocular HOAs were measured over a period of 60-econds with 10-sec blink intervals in 15 non-contact-lens-wearingormal controls and 17 symptomatic current CL wearers. Up to 6thrder Zernike polynomials were analyzed over the central 4 mm.otal HOAs, fluctuation index (FI) and stability index (SI) were sta-istically analyzed. Subjective ocular dryness ratings (0–3) werelso collected.

Results: Total HOAs for HG/SiH for the control groupere 0.134 ± 0.034/0.129 ± 0.033 �m and 0.153 ± 0.067/

.137 ± 0.046 �m for the symptomatic wearers. Though totalOAs were not statistically different between the 2 lens types inither group, the SiH-lens yielded a significantly lower FI in theymptomatic wearers (p = 0.006) and was better for SI in bothroups. (p < 0.001, p = 0.045). Subjective ocular dryness ratings wereot statistically different between the 2 lens types in either group.

Conclusions: Wavefront technology provides insights into theerformance of new contact lens materials by objectively measur-

ng the anterior surface tear film quality and stability, which is vitalo both sustained clear vision and ocular comfort.

5

he ability of subjective rating scales of visual performance toiscriminate and quantify changes in dioptric blur

ete S. Kollbaum*, Meredith E. Jansen


urpose: Patient-reported subjective responses have becomencreasingly popular in describing and discriminating contact lensisual performance. The ability of many of these measures to dis-riminate and quantify changes in dioptric blur, however, has noteen investigated.

Method: Ten young (18–35 years) subjects rated their subjec-ive visual performance monocularly on 3 scales following wearf their optimal monocular distance refraction and nine differentlurring lenses (−0.50 to +1.50 in 0.25 D steps) in a trial frame.he three scales used were an analog 0–100 scale, a 100 mm visualnalog scale (VAS), and a 5 point Likert scale (“Excellent”, “Good”,Average”, “Fair”, “Poor”). The blurring lens power was double-asked and randomized to include 5 repeated measures for each

ens power on each scale.Results: The correlation between the 100 point scale and the

AS was 0.97, while the correlation of both 100 point scales withhe 5 point Likert scale was 0.90. There were no significant dif-erences between ratings on any of the scales due to eye (L/R) orominance. Repeatability of all scales was quite good (Cronbach’slpha 0.94 for 2 repetitions and increasing to 0.97 for 5). All scalesould detect increasing levels and changes in blur of under 0.25 Dith 1 repetition.

Conclusions: All three scales evaluated were highly correlatedith each other, indicating that they are all measuring similar visual

ttributes and some comparisons could be made between scales.dditionally, all scales successfully discriminated changes in blurmaller than 0.25 D with only a single measurement.

6

epeatability of confocal microscopy measurements on the cen-
ral and peripheral cornea
imitra I Makrynioti*, Philip B. Morgan, Nathan Efron


or Eye 33 (2010) 256–300

Purpose: To assess confocal microscopy repeatability (ConfoScan3,Nidek, Italy) when assessing the morphology of the limbus, mid-peripheral and central cornea.

Method: The central, mid-peripheral and limbal cornea (tempo-ral and nasal) of the right eye of 8 subjects were examined witha ConfoScan3 in two different visits, at least six months apart.Bland-Altman repeatability was measured for 29 parameters: basalcell density and size, anterior and posterior keratocyte densities(AKD/PKD), endothelial cell density, polymegethism, pleomor-phism, mean area and sides of endothelial cells - in the five differentcorneal areas examined.

Results: As a percentage of the mean absolute values, repeata-bility of 0–10% was classified as “excellent”, between 10–30% as“acceptable” and over 30% as “poor”. Repeatability was excellentfor 14% of parameters and acceptable for 52% of parameters. Thenumber of endothelial cell sides in the central cornea demonstratedthe best repeatability (2.0%) whilst mid-temporal PKD showed thepoorest repeatability (53.7%).

Conclusions: Confocal microscopy is at least an adequatelyrepeatable method of evaluating the various corneal layers at differ-ent locations. Our dataset supports the ongoing use of the techniquein research and clinical practice.

77

Fabry’s disease: the unique role of optometrists

Langis Michaud


Purpose: To explain the unique role of optometrists in the detectionand the follow-up of patients affected by Fabry’s disease and otherlysosomal storage disorders.

Method: Literature review of ocular complications related toFabry’s disease and other lysosomal storage disorders. Highlightson the importance of slit lamp findings.

Results: A simple slit lamp exam, associated with systemicsymptoms, could lead to the accurate and on-time diagnosis of life-threatening diseases. Patients affected spend in average > 7 yearsbefore getting an appropriate medical diagnosis. Optometrists canplay a crucial role by referring the patient way before this to occurand could contribute to save lives.

Conclusions: Fabry’s disease and other lysosomal storage dis-order affect 1/100 000 in general population. Undiagnosed, thesediseases lead to the death of the patients before age of 50–60years old. Optometrists could play a major role in the diagnosisand follow-up of patients.

78

Effects of topical anaesthetic agents on corneal sensitivity

Clare O’Donnell*, Ioannis Chatzidiakou


Purpose: To compare the magnitude and duration of effect of topicalproxymetacaine hydrochloride 0.5% and lignocaine hydrochloride4% (Chauvin Pharmaceuticals, France) on corneal sensitivity usingmechanical and thermal stimuli. A secondary aim was to deter-mine whether corneal nerve structure differed in participants with
different coloured irides.
Method: 27 healthy subjects participated in this prospectivestudy. Central corneal sensitivity was assessed using a Cochet-Bonnet aesthesiometer (Luneau Ophthalmologie, France) and anon-contact corneal aesthesiometer (NCCA) at baseline and for





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p to 90 min following the contralateral instillation of the twonaesthetics. Corneal nerve structure was assessed using an in vivoorneal confocal microscope (Confoscan 3, Nidek Technologies Srl.,igonza, Italy).

Results: Proxymetacaine caused a greater reduction in sensitiv-ty than lignocaine at 2 min and 10 min after instillation for theochet-Bonnet measurements (p = 0.028, p = 0.001 respectively).he duration of action of both anaesthetics was prolonged whenorneal sensitivity was assessed with the NCCA compared to theochet-Bonnet instrument. The effect of anaesthesia was greater

or blue versus brown irides at 2, 5 and 10 min after instillation,hen examined with the NCCA instrument (p < 0.05). The analysis

f corneal nerve images revealed differences in nerve orientationp < 0.001) and sub-basal nerve density (p = 0.008) in participantsith blue/green versus brown irides.

Conclusions: Differences between anaesthetics in the effect ofction can vary, depending on the type of aesthesiometer used tossess corneal sensitivity. Further work is needed to elucidate pos-ible relationships between iris colour and corneal nerve structurend function.

9

ffect of cholesterol deposition on numbers of bacteria adher-nt to contact lenses

ark DP Willcox*, Negar B. Omali, Hua Zhu, Roya N. Borazjani


urpose: Contact lens surfaces can attract tear film compo-ents during wear. Protein depositions on lens surfaces haveeen previously shown to modulate bacterial adhesion buthere have been few studies on the effects of adsorbed lipids.his study was designed to determine whether surface boundholesterol could alter the number of bacteria adhering to aens.

Method: Unworn lenses were washed then soaked in solutionsf cholesterol at the concentrations ranging from 2.5 to 20 �g/mLo achieve the same cholesterol loadings as are found ex vivo. Tri-iated Pseudomonas aeruginosa 6294 or Staphylococcus aureus1, at 7 log cells/mL in phosphate buffered saline, were addedo the soaked lenses and incubated for 24 h. Numbers of bacteriadherent to lenses were counted by estimating radioactivity of theens.

Results: In vitro adsorption of cholesterol to either balafil-on A and senofilcon A was dose dependent. The adhesion of. aureus to cholesterol soaked lenses was slightly but not sig-ificantly increased compared to adhesion to un-soaked lenses5.25 log cells/lens vs 5.38 log cells/lens for balafilcon A; 5.11og cells/lens vs 5.38 log cells/lens for senofilcon A). For P.eruginosa, there was also slight but not significant increasen numbers of cells on lenses soaked with cholesterol (6.6 vs.8 log cells/lens for balafilcon A; 6.4 vs 6.7 log cells/lens forenofilcon A).

Conclusions: Whilst cholesterol has been shown to adsorb toontact lenses during wear, this lipid does not appear to modu-ate bacterial adhesion to a lens surface.

0

orneal oxygen consumption differences between soft contactens daily wear

ames S. Wolffsohn*, Martin Cardall, Shehzad A. Naroo


or Eye 33 (2010) 256–300 297

Purpose: To determine how current commercially available hydro-gel and silicone-hydrogel contact lenses affect oxygen consumptionof the natural eye during open-eye daily wear.

Method: An oxygen sensitive material was mounted within anair-sealed goggle positioned over the left cornea (open, regularlyblinking eye) of 15 healthy young subjects (mean age 22.8 ± 4.1years).The materials luminescence was assessed in real-time usinga fibre optic and a temperature probe inside the goggle wasmonitored for compensation of the oxygen output reading. Thetemperature compensated luminescence of the oxygen sensitivematerial indicates the concentration of oxygen in the goggle, withthe rate of depletion taken as a direct measure of oxygen consump-tion. The average of three, thirty second assessments of the rate ofoxygen depletion within the goggle were immediately after lensinsertion and after 1 hour and 8 h of daily wear. Subjects worebilaterally Etafilcon (1-Day Acuvue Moist-Dk/t = 33), Narafilcon A(1-Day Acuvue TruEye-Dk/t = 118), Senofilcon A (Acuvue Oasys-Dk/t = 147), Lotrafilcon A (Focus Night and Day-Dk/t = 175) or nolens, of their normal prescription power (range −0.50D to −3.00D)in randomized order.

Results: Oxygen consumption was on average 0.39 ± 0.15%/minO2 without contact lenses. Oxygen consumption increasedfrom morning to afternoon (0.38 ± 0.12%/min O2 versus0.43 ± 0.14%/min O2, F = 9.16, p = 0.002), but did not differ betweenthe lenses (F = 2.83, p = 0.14).

Conclusions: Taking into account natural blinking, lens mate-rial transmissibility, lens thickness profile and lens movementon the open-eye, all the soft contact lenses examined caused nochange in oxygen consumption on lens insertion and open-eyewear.

81

The impact of air-drying lens storage cases in various locationsand positions

Yvonne T. Wu*, Hua Zhu, Mark Willcox, Fiona Stapleton


Purpose: To determine the rate and type of microbial contaminationwhen lens storage cases are air-dried in two different positions andin four different locations

Method: Unused contact lens storage cases (n = 97) were rinsedwith PBS, and then placed on tissue paper in different locations:humid (toilet and bathroom) and non-humid (office and bedroom);air-dried face up and down in room temperature. After 24 h, thecases sampled for microbial investigation. The microbial profile andthe rate of contamination between different locations and positionswere compared.

Results: Irrespective of the air-drying location, lens cases posi-tioned face-up had a significantly higher contamination rate (34/48,71%) compared to lens cases air-dried face-down (6/49, 12%).(p < 0.001) For lens cases air-dried face-up, there was more contam-ination when placed in humid environments (toilet and bathroom)than in the non-humid environments (office and bedroom).(p = 0.01) However, the lens case contamination rate amongst var-ious locations was similar when lens cases were air-dried facedown. Total microorganisms recovered from lens cases rangedfrom 0–275 CFU/well. The most frequently recovered micro-organisms from the contaminated cases were coagulase-negative
staphylococci (CNS), fungi and Bacillus spp. Thirty-three percent(13/40) of lens cases were contaminated with multiple micro-organisms.
Conclusions: Small numbers of micro-organisms may contam-inate lens cases from the environment while cases are air-dried




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ace up. Cases air-dried in humid environments have higher lev-ls of microbial contamination; this is particularly true when lensases are positioned face up.

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ASE REPORTS

ate onset keratectasia after lasik

ndreas Berke


lthough Lasik is supposed to be a safe procedure for correctingefractive errors, it is not free from complications. The most severend even sight threatening complication after Lasik is the iatrogeniceratectasia. The iatrogenic keratectasia has been reported as earlys 1 week and as late as 2 years postoperatively. This case reportresents a case of iatrogenic keratectasia diagnosed 8 years aftersuccessful Lasik operation. In 2000 the patient had Laser oper-

tions on both eyes. The baseline refraction of her right eye wasph −3.75 D cyl −1.75 D 85◦. Initially the patient was satisfied withhe outcome of her Lasik operations, but in 2005 she complainedor the first time about a progressive worsening of her right eyeision In 2008 a keratectasia was diagnosed. Her right eye has anstigmatism of nearly 14 D. The central corneal thickness is lesshan 340 �m including the flap. The patient is expecting penetrat-ng keratoplasty.

orneo-scleral gas-permeable contact lenses after intacsmplants in keratoconus: cases

uan Carlos Montalt*, Enrique Espana, Cristina Peris, Cristina Gómez


urpose: To describe a series of cases of intacs with keratoconusho had a residual ametropia and were fitted with corneo-scleral

as-permeable (GP) lenses.Method: Five eyes from 3 young patients were fitted with a

ew GP contact lens corneo-scleral (data design: multiaspheri-al, material: polymer: fluorosilicone acrylate, technology HDS,k: 58 (Iso/Fatt method) and diameter: 12.60 mm). The prelim-

nary study included Pentacam, biomicroscopy, ocular responsenalyzer (ORA), endothelial cell count and refraction. We evaluatedisual acuity and comfort with contact lenses, and the status of theornea.

Results: The values of spherical equivalent, average keratometrynd corneal astigmatism were −4.15 D (range: −0.87,−9.0), 47.62(range: 40.90,56.10) and 5.46 D (range: 3.70,10.0), respectively.ean best corrected visual acuity (BCVA) with glasses and contact

enses was 20/32 (r: 20/40,20/25) and 20/20 (r: 20/25,20/16),espectively. All cases improved the BCVA with corneo-scleralenses; 2 eyes gained 4 lines, 2 eyes improved 3 lines, and 1 eyemproved 2 lines. Pentacam, ORA and endothelial cell count didot show any significant change. After 6 months there weren’tdverse effects on the cornea. The average daily use time was
1.20 h (range: 7,12).
Conclusions: Patients implanted with intacs in keratoconusithout good vision with glasses may require wear GP contact

enses. In the cases presented the corneo-scleral GP lens haseen a good treatment option for myopia and irregular astigma-

or Eye 33 (2010) 256–300

tism. Our results with the contact lenses indicate a significantimprovement in vision compare to glasses in patients with intacsimplants.

3

Scleral contact lens management of ocular complications in acase of toxic epidermal necrolysis

Sophie J. Harper*, Cindy Tromans, Fiona Carley


A 36 year old female patient suffered a severe reaction to systemicuse of the NSAID Ibuprofen. She initially presented to casualty butwas transferred to a burns unit. Severe ocular involvement includedentire loss of eyelid skin and complete epithelial loss over theentire ocular surface, involving both cornea and conjunctiva. Ini-tial treatment was removal of extensive pseudomembranes withintensive topical lubrication and topical antibiotics but with lit-tle or no improvement over 3–4 days. Amniotic membrane graftssecured with symblepharon rings were subsequently employed.The corneas epithelialised but stromal haze and significant vascu-larisation remained, with marked keratinisation of areas of bulbarand tarsal conjunctiva. Subsequently both corneas had 360 degreeprogressive vascularisation and stromal thinning with areas ofoverlying defects. After one year, VA was very poor at worse than1.60logMAR RE and LE. Scleral contact lens fitting was undertakento offer corneal protection and vision rehabilitation. A fenestrated9.17 20 mm +2.00D PMMA scleral lens was fitted to the RE andsubsequently the LE also. Post-fitting, the patient achieved a wear-ing time of 12 h with improved VA to 0.46 logMAR RE and 0.70logMAR LE, with subjectively improved comfort and decreaseduse of ocular lubricants. At review the patient showed numer-ous tiny intra- and sub-epithelial cystic changes, known to beassociated with stem deficiency and conjunctivalisation. Severetoxic reactions to NSAIDs are rare and this case shows how scle-ral lenses have a role to play in the management of toxic epidermalnecrolysis.

4

Management of anisometropia and pellucid marginal degener-ation with semi-scleral lenses

Nathalie Trottier*, Léo Breton, Langis Michaud

*E-mail address: nat [email protected]

This presentation reports a case of a 66 year old male patientdiagnosed with a Pellucid Marginal Degeneration (PMD) whowas referred to the University of Montréal optometry clinic forfurther assessment. He presented with corneal ectasia, severe ani-sometropia with limited vision, aphakia and retinal detachment(OS) several years prior (in 2004). Since contact lenses (CL) wouldlimit the image size difference between the two eyes, severaloptions were discussed with the patient to address the cornealwarpage and the anisometropia. Scleral lenses (Maxim 4, Accu-lens) were prescribed for this challenging case. The custom designof this lens allows the cornea to be vaulted and to correct highamounts of irregular astigmatism, improving the vision and thequality of life of the patient. The reverse geometry of the lens
permits an increase in the sagittal height so as to reduce inferiorbearing, without allowing bubbles under the lens. This lens designhas already been shown to be effective with other cases of PMD.The patient was very pleased with his new lenses, which improvedhis BCVA from 20/50 OD and 20/40 OS to 20/25 OD and 20/30 OS.




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isual rehabilition with scleral lenses in two cases of cornealctasia following refractive surgery

ennifer A. McMahon*, Shima R. Shah


ackground: Two patients (A and B) with gross corneal ectasiaollowing refractive surgery presented for scleral lens fitting assess-

ent. Both patients had previously been seen in the HES contactens service and could not be successfully fitted with other lensypes due to intolerance (patient A)/unacceptable fit (patient B).urther corneal surgery was not appropriate in either case.

Methods: Patient A was fitted with a non ventilated 23 mm diam-ter scleral lens in one eye, the fellow eye remaining unaided.atient B was fitted with non ventilated 23 mm diameter scleralenses in both eyes. All 3 lenses were fitted from a preformed fittinget.

Results: Scleral lenses provided an improvement in visual acuityn the affected eye(s) which could not be achieved in any otherolerable manner. Patient A was able to achieve an average wearingime of 10 h per day compared to a maximum of 1 hour per day withhe best fitting corneal lens. Visual acuity was 6/9 and there was auantifiable improvement in binocular status. Patient B achieved aatisfactory fit with good visual acuity of 6/9 right eye and 6/12 leftye, which is comparable with the best recorded in other lens typesnd compares to 2/60 and 3/60 unaided respectively. The wearingime is currently 15 h per day.

Conclusions: Preformed scleral lenses are a viable option foratients with post operative corneal ectasia particularly whenther lens types give an unsatisfactory result and surgery is notppropriate.

igid gas permeable fenestrated scleral contact lens fitted to aewborn infant presenting with a congenital limbal dermoid asreventative treatment for refractive amblyopia

van Hare*, Eli Savyon, Judith Raz, Fanny Segev


urpose: Treatment of high irregular astigmatism caused by a con-enital limbal dermoid was initiated in a one month old infant, asrevention of Amblyopia development

Method: A scleral contact lens with a hole corresponding to theize and position of the dermoid was fitted to the infant’s eye. Theother inserted the lens with the dermoid protruding through the

ole, on a daily basis. Patch therapy of the other eye for half thehild’s wake hours was implemented.

Results: Resultant over-refraction was +1.00D. The infant suc-essfully wore the lens for all the mothers waking hours from thege of 2 to 17 months. Partial lamellar keratoplasty was thereaftererformed, resolving most of the astigmatism. Post-op spectaclesere prescribed enabling 6/6 J1 acuity.

Conclusions: A scleral contact lens may be used as an effective
ethod of treatment in infants with congenital limbal dermoid,
or prevention of refractive amblyopia. This method of treatmentrovides the ophthalmologic team with as much time necessary toait for the child to grow and reach an age more suitable for ker-

toplasty.

or Eye 33 (2010) 256–300 299

7

Fitting strategy and case examples of prosthetic contact lensesfor irregular astigmatism, iris coloboma and zavalia syndrome

Lefteris Karageorgiadis, Nikos Vasileiou, Nikos Karageorgiadis


Purpose: To describe the basic fitting principles and show rela-tive case examples, in cases that combine irregular astigmatism(due to trauma or penetrating keratoplasty) and pupil mydriasis orcoloboma. Hydrogel hand painted prosthetic lenses with thickeroptical zone that incorporate toric correction is the solution ofchoice to offer increased visual acuity, elimination of photophobiaand improved cosmesis when fitted and manufactured properly.

Method: The initial fitting is described in order to decide the pos-sibility of correcting these cases with thicker hydrogel hand paintedlenses. Furthermore the issues that contribute to the success of eachcase (Corneal topography, aberrometry, refraction and endothelialevaluation). Three cases are described who suffered from low visualacuity, photofobia and poor cosmesis.

Results: Basic steps and principles were employed to fit the eyeswith irregular topography. Using modern contact lens designs forpost transplant and irregular astigmatism, corneal physiology isnot compromised. These hand painted lenses with the appropriatetechnique restored normal visual function of these patients.

Conclusions: All cases that present abnormally increased pupildiameter or loss and irregular astigmatism, can be successfullyfitted with hand painted prosthetic lenses that combine the advan-tages of the design and correction of lenses used for keratoconus,post transplant and irregular astigmatism and the cosmesis of theprosthetic lenses.

8

Herpes simplex ocular infection: a case of keratouveitis

De Gaulle I. Chigbu


Purpose: Herpes simplex viral (HSV) infection of the anterior eye isa major cause of visual impairment in the world. The purpose ofthis case report is to present a case of keratouveitis associated withHSV that was initially diagnosed as herpetic epithelial keratitis.

Method: A 66-year-old female presented with tearing, photo-phobia and foreign body sensation in the right eye, which wasdiagnosed as a herpetic dendritic ulcer. Prior to transferring hercare to me, her eye care professional placed her on topical virop-tic (trifluorothymidine) 1.0%. Her medical history was remarkablefor chickenpox but when questioned she denied any previous her-pes simplex viral infection. Serological test for HSV antibody wasordered to aid in screening for previous exposure to HSV whereasa serological test for varicella zoster virus (VZV) was ordered toconfirm immunity status to VZV. The diagnosis was re-evaluatedas Herpes simplex viral keratouveitis.

Results: Serological test for HSV antibody was positive. TheHSV keratouveitis resolved within 30 days with topical and oralantivirals, topical corticosteroid, topical prophylactic antibioticand cycloplegic agent. Prophylaxis with valacyclovir hydrochloride1000 mg tablet by mouth once a day was initiated to prevent viralreplication and reactivation of the latent herpes virus.

Conclusions: HSV keratouveitis is a sight-threatening ocular dis-
ease characterized by recurrent chronic inflammation and highfrequency of complications such as corneal scarring, secondarycataract, and visual impairment. Prompt diagnosis and appropri-ate treatment is imperative to prevent the development of ocularcomplications of HSV keratouveitis.




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Method: Slightly adapted conventional orthokeratology.


itting hydrophilic lenses with special optical zones afterorneal traumatisms, synechia and physiological large pupils:our case studies

ercedes Burgos-Martínez*, Mónica Álvarez, Laura Berasategui,antiago Jeremías, Ramón García, Pedro Rubio, Mónica Monzón,teve Wright


urpose: In some instances standard contact lenses do not providehe right solution for special cases. In these cases special parametersre needed. Four clinical cases are presented where larger opticalones are needed due to physical reasons to avoid reflections, halosnd obtain appropriate vision.

Method: Patient A presented with a displaced and deformedupil due to an impact of a tennis ball and the absence of arystalline lens. Contact lens (CL) prescription (Rx) was +10.50 D.atient B showed a torn iris due to an explosion of a grenade dur-ng military service and the absence of a crystalline lens. CL Rx was11.00 −1.25 40◦. Patient C suffered from a complication of IOLmplant and synechia. CL Rx needed was +15.50 D. Patient D hasphysiological pupil of 9.50 mm. Slit lamp and topographer weresed to determine the size of the pupil diameter. Hioxifilcon B (49%)as employed to manufacture special front optical zones of 10.00,

.00, 8.00 and 11.00 mm respectively. Lenses were bicurve, backurface toric with prism ballast.

Results: All patients achieved satisfactory vision with visual acu-ty equal to or better than spectacles and reflections disappeared.hysical fitting was correct, and the toric lens stable. Comfort wasood all day.

Conclusions: Special custom contact lenses are a viable optionor special cases with deformed or very large pupils that can beommonly found in the high street practice. Suitable contact lensesmprove the quality of life for these patients.

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ontact lenses improve quality of vision and quality of life inatient with nystagmus and cone dystrophy

raeme G. Stevenson*, Lauren L. Gardiner, Mercedes M. Burgos,eatriz B. Fernández


urpose: Many patients with complex conditions are oftenenied contact lenses for reasons which are difficult to jus-

or Eye 33 (2010) 256–300

tify. This case report describes the successful contact lensfitting of a patient who suffers from progressive cone dystro-phy, nystagmus, achromatopsia and a high hyperopic-astigmaticprescription.

Methods: The patient was fitted initially with partial correctioncontact lenses which were worn only rarely. It was anticipatedthat more frequent use would be possible when lenses becameavailable to the full prescription. The patient was fitted eventu-ally with specialist small diameter lenses (Hioxifilcon B and 13 mmDiameter).

Results: The results showed a standard of VA better than that ofspectacles for near vision and this surprised all involved. Near VAimproved from N12 to N8 with the contact lenses. Other advan-tages which were immeasurable include a greater feeling of wellbeing and less dependence on spectacles and 3rd party help. Asuccessful fitting which achieved a standard of vision favourableto that of spectacles using small diameter soft toric lenses isdemonstrated.

Conclusion: An improvement in vision and cosmesis has beenachieved in this complex case by using specialist small diametersoft toric contact lenses. An immediate and obvious improve-ment in this young patient’s quality of life demonstrates theimportant part Eye Care Practitioner’s play in the overall welfareof our patients. This also demonstrates that complex condi-tions and prescriptions can be fitted successfully in the highstreet practice to the benefit of the patient and practitioneralike.

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Vision enhancement by orthokeratology on patients with nys-tagmus

Imre IK Kovats


Purpose: Because nystagmus is not active during sleep and thecircumstance that every additional optical correction on or infront of the eyes increase the movement of the seen picture,make orthokeratology to the ideal method of correction of nystag-mus. Additionally other effects of orthokeratology can be used toimprove vision quality like optimizing the centration of the opticaltreatment to the optical axis.

Results: The result is an enhancement of vision acuity and reduc-tion of uncontrolled eye movement.

Conclusions: Orthokeratology can be helpful in cases ofnystagmus.




abstracts of the 34th bcla annual clinical conference, birmingham, 2010

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