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JOURNAL OF

THE COLLEGE OF

OPHTHALMOLOGISTS

OF SRI LANKA

VOLUME 22 No. 1 2016

• THE ROLE OF ANTERIOR SEGMENT OCT IN GLAUCOMA

• LAMELLAR DISSECTION TECHNIQUE IN

DEEP ANTERIOR LAMELLAR

KERATOPLASTY (DALK) • EFFECT OF AXIAL LENGTH ON ACCURACY

OF DIFFERENT TYPES OF BIOMETRY IN PHACOEMULSIFICATION SURGERY

College of Ophthalmologists of Sri Lanka Annual ISSN 2345-9115

Journal of

The College of Ophthalmologists

of Sri Lanka

Editors

Dr. Mangala Gamage, DO, MS, FRCS

Consultant Eye Surgeon

Dr. Binara Amarasinghe, DO, MS, FRCS

Consultant Eye Surgeon

Published by

College of Ophthalmologists of Sri Lanka National Eye Hospital, Colombo 10, Sri Lanka.

Email: [email protected] Telephone: 94+11-2693924

Fax: 94+11-2693924

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Ananda Press 82/5, Sir Ratnajothi Saravanamuttu Mawatha,

Colombo 13, Sri Lanka.

Tel: +94 11 2435975 E-

mail: [email protected]

Journal of the College of Ophthalmologists of Sri Lanka is published annually in two volumes. It is clinically oriented, designed to keep ophthal-mologists up to date. It contains peer reviewed articles, current research, case presentations and clinical challenges.

9 7 7 2 3 4 5 9 1 1 0 0 6

JOURNAL OF THE COLLEGE OF OPHTHALMOLOGISTS OF SRI LANKA

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Journal Articles 1. Smith JD. Ophthalmology and the medical community.

Surv Ophthalmol 1996; 41: 1-30. 2. Smith JD, Jones TS. Ophthalmology and society. Surv

Ophthalmol 1997; 42: 65-78.

Books 3. Smith JD, Jones TS. Public JQ, et al. Ophthalmology

and the World. Boston. Bayside Press, 1997, pp 1-9.

Chapters 4. Stevens JT. A transcendentalist’s view of optics, in Smith

JD (ed): Ophthalmology and the Universe, Vol. 6. Part 3. Boston, Bayside Press, 1997. ed 2, pp 230-245.

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JOURNAL OF THE COLLEGE

OF OPHTHALMOLOGISTS

OF SRI LANKA

VOL. 22 2016 NO. 1

CONTENTS

Page

Editorial

Research and access priorities in eye health 1

Presidential address – 2015

Minimizing barriers for ophthalmic teams in achieving our mission

Baminiwatta Damayantha 2

Refraction planning in cataract: Avoid creating an unhappy patient

Robert H Taylor, Roger B Ellingham 11

Dr. P. Sivasubramanium Oration – 2015

Vascular endothelial growth factor (VEGF): Its role in ocular neovascularization

Saliya Pathirana 17

The role of anterior segment OCT in glaucoma

J. K. Dilruwani Aryasingha 37

Lamellar dissection technique in deep anterior lamellar keratoplasty (DALK)

– does it matter in postoperative progression

K. H. Wickramasinghe, S. K. G. S. Kurera, C. J. Kumarage, W. M. C. M. Andradi,

D. H. H. Wariyapola 40

The effect of preservatives on the ocular surface and success of glaucoma

(Continued)

College of Ophthalmologists of Sri Lanka Annual ISSN 2345-9115

Page

filtration surgery

Nuwan Niyadurupola 41

Knowledge, attitudes and practices of pre-intern doctors on the management

of emergency ophthalmological conditions

M. M. Dissanayake, S. Vithoosan, S. A. A. Senevirathne, N. Wickramasekara,

P. H. Dissanayake 45

Effect of axial length on accuracy of different types of biometry in

phacoemulsification surgery

H. P. M. K Gunewardena, N. G. I. R. De Silva, M. T. K. Perera, W. M. C. M. Andradi,


Astigmatic change following suture manipulation after deep

anterior lamellar keratoplasty (DALK)

S. K. G. S. Kurera, K. H. Wickramasinghe, C. J. Kumarage, W. M. C. M. Andradi,


Conjuctival intraepithelial neoplasia – a case study

G. J. N. Widanage, I. K. Devasurendra, B. Amarasinghe, S. Nanayakkara 52

1

Editorial

Research and access priorities in eye health The Journal of the College of Ophthalmologists of Sri Lanka 2016; 22: 1

Patients, clinicians, clinicians-scientists play a valuable role in shaping the future of vision research.

Limited funding demands targeted research initiatives that ultimately affect health policy and

practice to secure progress in improving patients outcome in eye health.

Top priorities for eye research have been identified as part of a national collaborative initiative

in most of the countries.

It has been identified that a series of unanswered questions considered as great importance to patients, carers and eye health professionals.

The aim would be to inform funders, researchers, clinicians, and the public about the key

areas as to where they believe the research money should be spent. For example in cataract

surgery research questions include the potential for improvement in cataract surgery

outcomes and the efficacy and the safety of the method used.

WHO global eye health action plan for 2014 to 2019 targets universal eye health coverage

through the provision of comprehensive eye care services integrated into national health system at all levels.

In the area of health research WHO highlights two principle activities.

1. Biomedical research for the development of more cost effective interventions for major causes of visual impairment.

2. Operational research for overcoming barriers in service provision and uptake and

improvement of public health approaches and strategies.

Guidance for public eye health research from WHO includes eye health research priorities,

information on causes and magnitude of visual impairment, guidance on stakeholder analysis

for the development of national eye health plans, data collection and monitoring.

Provision of effective and accessible eye care services is the key for effectively controlling

visual impairment and blindness.

Joint Editors

2

Presidential Address 2015

Minimizing barriers for ophthalmic teams in achieving our mission

Baminiwatta Damayantha1

The Journal of the College of Ophthalmologists of Sri Lanka 2016; 22: 2-10

This year’s theme was “minimizing barriers for the visually impaired.” At today’s presentation I have chosen to

elaborate on “Minimizing barriers for the ophthalmic teams in a high output setting.”

Global figures include 285 million people are visually impaired. Out of them 39 million are blind and 246 million

having low vision.

Preventable causes account for 80% of the total global visual impairment burden.

About 90% of the world’s visually impaired people are living in the developing countries. This is actually the

challenge in our developing country having one of the fastest aging populations in the region.

65% of visually impaired and 82% blind

people are over 50 years of age, although

this age group comprises only 20% of world

population.

Globally uncorrected refractive errors are

the main cause of visual impairment. The

cataract is the leading cause of blindness.

Glaucoma, childhood blindness and age related macular degeneration are the other diseases gaining prominence

in our setting.

The regional situation in comparison to

other regions of the world we pose a large

number of persons who require services for

visual impairment.

1President, College of Ophthalmologists of Sri Lanka, 2015.

The Journal of the College of Ophthalmologists of Sri Lanka

Minimizing barriers for ophthalmic teams in achieving our mission 3

The millennium development goals are a much talked about amongst public health professionals. It has now been

shown that out of eight, seven Millennium development goals cannot be reached without sight.

It is estimated that 90% of visually im-

paired children in developing countries

are not in school.

Women suffer from the greatest

burden of blindness globally and they

typically have much poorer access to

treatment and care.

One child becomes blind every minute

of every day.

Vol. 22, No. 1, 2016

4

The learning’s from eye health programs

can serve many other global health

partnerships.

This illustrates the important role “sight”

plays in the global arena.

Prevention of blindness and vision loss brings a range of benefits to society. It ranges from bringing benefits to

economy, like increased employment, increased productivity and reduced welfare cost, in health, improved

quality of life, reduced comorbidities and reduced hospitalization. Socially, reduces extreme poverty and hunger, increased independence and increased community participation is

affected by reduced vision.

Multisectoral approaches benefit from

political leadership and accountability In developing countries a successful prevention of

blindness program, must always have strong

political backing. Success worldwide has been

demonstrated when there is coordinated and well

formulated program which includes: i . Informed and committed political leadership ii. National eye health plans iii. National eye health committees iv. Clear, time-linked targets and indicators v. and very importantly, deliberate investment

in an eye health work force.



It is interesting to note that the

absolute number. of blind people

in the world has not changed over

the period of 20 years. However

the age standardized prevalence

rate has declined as depicted by

the consolidated data from the

global vision data base. This

indicates that preven-table causes

of blindness are being taken care

of successfully throughout the

globe.

In consideration of the large demand in eye care a

global action plan has been developed by IAPB and

clearly defines the targets and goals.

The target now is to reduce preventable blindness by

25%.

To achieve this, it needs collection of data, a well-trained

and adequate work force and equity in eye care.

A major contributor is the National Eye Health programs of the country like V2020.

The situation in our country, indicates

• 1.1% of people over 40 years are blind. Of which 79% are due to cataract.

• This accounts for approximately 60,000 people blind due to cataract.

Based on 2014 data, • There are 45 General Ophthalmic surgeons islandwide. • If each surgeon does 1500 cataract surgeries per year (30/week). • Considering the lack of data in private practice, • Annually approximately 80,000 cataract surgeries would be carried out.

But, Is this enough?

Vol. 22, No. 1, 2016

6

There are many methods of projections to derive the number of cataract surgeries to be done in a country.

Reference to the model developed by Thulsiraj et al.

Working the numbers, currently we have a need to do 156,000 more cataract surgeries in addition to the 80,000

being carried out per year.

This brings us to the daunting tasks of 236,000 per year.

There is a wealth of data on developing countries, and looking at Sub Saharan African countries where ophthalmic

services are still young we find a number of strategies in place where the service provision for cataract has been

improved to 3 per million populations, developing cadres specific for the needs. In Sri Lanka we remain at 2 per million having established services long before. The projected norms for developing countries by WHO is one ophthalmologist per 150,000 people. If these were applied to Sri Lanka we would need 133 General Ophthalmologists.

Considering the other requirements of the country this is more a dream than a reality.

The bottle necks in the system are naturally infrastructure,

workforce and resources. The Journal of the College of Ophthalmologists of Sri Lanka


Resource allocation, infrastructure is definitely in the hands of the administrators. There should be a well

structured plan to increase our outputs as a professional body.

The methods are many and much debated but it should be emphasized that an interim plan must be put in place

to avoid preventable blindness to the masses in our country.

In this scenario as the debate continues I believe it is time to

increase our service delivery by better utilization of our

work force with the cooperation of all the members to meet

the growing needs.

I quote,

“Human potential is the same for all. Your feeling, “I am of no

value”, is wrong. Absolutely wrong. You are deceiving yourself. We all have the power of thought – so what are you lacking? If you have willpower, then you can change anything. It is

usually said that you are your own master.” – Dalai Lama

I firmly believe in this and would like you to follow the thoughts of these great philosophers.

I quote,

“Pay no attention to the faults of others, things done or left undone.

Consider only what by oneself is done or left undone.” – Lord Buddha

Vol. 22, No. 1, 2016

8

Having this in mind, I wish to present my

view of getting the maximum output from

the available human resources by ensuring a

happy and healthy working environment.

It is my view that, if the worker is happy

and contented, the atmosphere will be

invariably healthy.

Always consider a happy person as a

healthy person and a healthy person could

be motivated to travel the extra distance.

The happiest people Do not necessarily have the best of everything. They just make the best of everything they have. In relation to creating a happy and healthy working atmosphere, I would like to present my views on the

following aspects.

1. Attitudes 2. Knowledge 3. Unity 4. Healthy Workforce 5. View points 6. Leader’s attitude 7. Relaxing environment

Attitudes I consider this aspect, a very significant feature in our day-to-day working environment.

A renowned musician Stevie Wonder has said, “Just because a man lacks the use of his eyes, does not mean he lacks

vision”.

Every one of us needs a VISION to be successful in our life endeavours. It is this vision on which our attitudes are

built on.

This attitude if not nurtured in the proper direction affects the team spirit which in turn adversely affects the

output.

Teams with highest spirits and coordination attain success with the least amount of stress. The importance of

emphasizing the team member’s contribution should not be forgotten.

Thus, each member should consider himself an important

link of the team and contribute in the best manner possible

to achieve the team’s goal.

Another aspect which needs to be highlighted is the

attitudes of being conscious of the thought that “this is our

workplace”, if so, one would always be willing to “run the

extra mile”.



The supreme being Lord Buddha has declared that caring for patients is equal to caring for the Lord Buddha

himself. Thus, with correct attitude one can improve the teams productivity and contribute to this meritorious

deed. Knowledge Knowledge is power. Sufficient knowledge is essential in reaching a goal successfully. When you’re working in a

team, each member should have the competency for the duties and activities to be performed. Also, each team

member should be aware of the duties entitled to him.

I can not emphasize how important communication skills are amongst our professionals. Especially with those

who are blind or having low vision.

It is best to be aware that the ‘PATIENT’ is under severe stress, disorganized, and long waits at the clinic would

increase their non-cooperative actions. A smile would, I am sure, ease the tensions and develop relationships.

Knowledge can come in many forms. Workshops, seminars, experience, observation, listening and dialogues to

name a few. Sharing the knowledge is also an important factor especially with the team.

A knowledgeable leader would always plan the day’s work in advance and complete the assignments prior to

leaving the work site.

In this way knowledge would contribute positively to a happy environment.

Unity

It is my belief that there is no team work without

unity. Workplace friendships make working more

enjoyable and create a great sense of calmness among

workers. In such an atmosphere, workplace-related

misunderstandings are less likely to occur.

One may argue or view that unity sometimes would

be misused by the subordinates developing into a

state of disrespect to the employment grades. However, my contention is that one could maintain teamwork, attitudes and unity at worksite while upholding

discipline among the staff.

In order to enhance unity among co-workers various activities can be organized. For instance, arranging religious

ceremonies, annual fellowships, a fairwell for a staff member, quiz competitions and concerts can be arranged.

I have found organizing outreach camps with the participation of the entire team develops good interpersonal

relationships.

This unity brings about an environment of “Team Spirit” which is vital for any group of persons with common

goals.

Healthy workforce As we have limited human resources, the absence of even a single worker can paralyze the whole system.

Therefore, to have a healthy workforce arranging regular health check-ups for the staff and directing them to

obtain relevant treatment would be beneficial. This facility could also be extended to the families of the staff.

Vol. 22, No. 1, 2016

10

A good team leader should be aware of each members concerns and deal with empathy especially with regard to

health issues. This would enhance productivity in the long run.

Viewpoints Regular management meetings and review sessions are essential to achieve the goals at the working stations. The

participation of officers representing every category should be encouraged for these sessions. Suggestions on

further improvements and overcoming obstacles should be obtained from them. I am reminded of my teachers at

Centre for Sight, Kandy who had mastered the art of productivity having their monthly meetings, where each

representative from a category was encouraged to voice their views and concerns. This not only exposed areas of weakness, it illustrated the role and importance of each category. I believe this held

the key to their success.

Leader’s attitude My view is that a leader leads from the front. His/her role extends far beyond the boundaries of expertise but also

into the roles of managers. My experience is that delegation of activities hold a vital role.

I am again reminded of my teachers who had the juniors appointed and responsible for various parts of the Centre

For Sight. My colleagues will fondly remember their role as in charge of the toilets, in charge of the library etc.

This shows clearly their management skills of our esteemed teachers. Of course, these appointments were of no

avail if not followed up by regular monitoring, which some of us remember so well.

Hence a leader’s role is no easy task and must be truly backed by the correct attitude.

Relaxing environment The human mind can be relaxed by pleasing the senses especially eyes and ears. An atmosphere pleasing to the

eyes can be created by having a clean, organized, environment with appropriately coloured curtains and walls.

Adding a natural element to the environment by using flowers and plants would enhance the relaxation. This

peaceful setting can be further improved by adding soft music in the background. This would in turn boost our

productivity for the desired results. I presume I have covered most of the requisites for creating a happy and healthy working atmosphere. My belief is

that creating such an atmosphere makes the staff want to come to work, want to work their hardest and at the end

of the day feel good about what they have done, in a place which they never want to leave. I hope my suggestions would encourage you in your role as the “Team leader”, “Team member” and “Team

manager” to fulfill the enormous work load ahead of us. I wish you all the very best in your endeavors.


Refraction planning in cataract: Avoid creating an unhappy patient 11


Robert H Taylor1, Roger B Ellingham1


Introduction The focus of this paper is the prevention of an unhappy

patient following cataract surgery. Such patients often

have a technically perfect cataract operation but are

unhappy with their result. There may be other reasons

but commonly this is because of the refractive outcome.

Information, which might have prevented such a disaster

is accessible pre operatively. These include taking a

careful history of prior refractive correction, (contact

lenses/glasses/refractive surgery), age, lifestyle and the

characteristics of the pre-operative refraction

(hypermetropia, myopia, astigmatism, anisometropia).

Information from the biometry measurements (axial

lengths and keratometry) should be factored in. Lastly the

patient should be consulted about their preferred

refractive outcome, and the consequences of their choice.

This article is a personal perspective from the authors.

The diagnosis of cataract is not difficult and the decision

whether to operate is not usually complex, although there

are important factors to consider in determining the

risk/benefit ratio for each individual. These become more

important if the pre-operative visual acuity is still quite

good. The general assumption made in this article is that

the biometry is performed correctly, the correct lens is

selected with the correct formula and the error rate is of

the of the order of 30% of cases having 0.5 dioptre error

from aim. This may be greater in patients with high

ammetropia. This article uses a variety of clinical examples loosely

based on fact, but the details are all made up. The tables

are presented in a manner that is consistent, with the

intraocular lens power on the left in dioptres (D) and the

predicted spherical equivalent (SE) on the right.

There may be many alternatives to the solutions given,

which may include toric lenses, multifocal lenses and

top up laser. The solutions given is aimed at making

the reader think about what might be achieved if these

more complex and expensive options are unavailable.

Case 1 An 81 year old male presents with reduced vision. He

drives. He wears glasses only for close work.

Refraction and best corrected acuity: Right +0.25/+0.25x90 6/9 Left +0.25/+0.25x90 6/12 It is agreed to operate on the left eye.

Calculated lens implant choices: Left eye

22.5 -1.20

22.0 -0.81

21.5 -0.45

21.0 -0.11

20.5 -0.25

Refractive planning The question here relates to picking a 21.0 or 21.5

dioptre lens. Let us assume he wishes distance vision

(as he has now) and is happy with reading glasses. In

a third of cases the error in biometry is in the order of

0.5 dioptre sphere. A 21.0 D lens will result in a

spherical equivalent in the range +0.39 to -0.61 in two

thirds of cases. A 21.5 D lens might leave him almost -

1.00 with which he might easily read, at least large

print or in good light. If such a patient is able to understand these risks, this

can be discussed. If his lifestyle avoids reading then

perhaps the 21D lens is the correct decision. Either

would probably be a good result.

Message: in general operate on the eye with the worst

visual acuity first, although be careful about pre-

existing amblyopia, particularly if patients have prior

history of strabismus, anisometropia or high hyper-

metropia (see later). If acuity is equal, it is acceptable

to operate on the eye the patients prefer.

For the otherwise uncomplicated patient aim for about

-0.3 DS. If their historic refraction (prior to cataract)

was hypermetropic, pick slightly more plus, if myopic,

slightly more minus.

1Consultant Ophthalmologist, York Hospital, England.

Vol. 22, No. 1, 2016

12

Case 2 A 61 year old female presents with reduced vision in

the left eye. She rarely wears glasses for near or

distance and has never had contact lenses. She drives.

Refraction and best corrected acuity: Right -0.75/+0.50x180 6/9 Left -1.25/+0.50x180 6/18 A decision is made to operate on the left eye cataract. Calculated lens implant choices:

Assuming there is no particular demand from the

patient to have both eyes the same, then using the

same dioptre lens for each eye is attractive, probably a

20.0 D lens implant in this example. This philosophy

rarely leads to post operative intolerance as the result

reflects the pre operative anisometropia, to which the

patient has often adapted in their current spectacles.

Case 3 A 73 year old man presents with difficulty driving at

night. He has required frequent changes in glasses

over the last 2 years. His first glasses were for reading

when 45 years old. Right

21.0 -0.81

20.5 -0.52

20.0 -0.12

19.5 +0.2

Refractive planning

Left

20.5 -1.20

20.0 -0.81

19.5 -0.45

19.0 -0.14

Current refraction and best corrected acuity: Right -3.00/+0.50x180 6/12 Left -3.00/+0.50x175 6/18


24.5 -2.0

24.0 -1.9

23.5 -1.58 The pre operative spherical equivalent in the left eye is -1.00 and the right is -0.50 which explains how she manages for some near vision activities without glasses. She also has a small amount of astigmatism, which will increase her depth of focus – which may or may not be reflected in the keratometry (see later). The pre-existing anisometropia is important and should influence the post operative aim. If the aniso-metropia is historic (and not just a consequence of the cataract) it might lead to the decision to preserve this patient’s pre existing anisometropia and aim for -1.00 spherical equivalent in the left eye (and -0.3 in the right). In this scenario, warnings need to be given to ensure she understands that distance vision may appear blurred post operatively. In addition the pre-existing glasses-independence may not be recreated – particularly if the keratometry does not reflect the astigmatism. Patients are often under the impression that they will

be glasses independent after cataract surgery. This

may be the case, but is not guaranteed. The biometry calculation reflects the pre-existing anisometropia with a smaller dioptre lens for emme-tropia in the left eye. It is worth checking the axial lengths are consistent with this as well (the more myopic eye should be longer). Index myopia may create or neutralise a pre existing anisometropia, which might influence your refractive aim.

23.0 -1.23

22.5 -0.81

22.0 -0.52

21.5 -0.12

21.0 +0.23 The history is important, as the first glasses used were for reading, suggesting the myopia is secondary to cataract formation (index myopia). This is a good example where looking at the biometry measurements before the calculations is worth while. Although not displayed, the history would imply index myopic change. The lens implant calculations seem to suggest a normal axial length. This patient dislikes having to wear distance glasses and is usually relieved to find that you can aim for unaided distance focus post-operatively. In this scenario, patients have to be warned that they will need reading glasses. In the experience of the authors such patients rarely read unaided pre-operatively but it is worth checking. If it is agreed to aim for unaided distance focus, the readings again fall between choosing a 22.0 or 21.5 D lens. Some patient will guide you as to which of the two choices is preferred.



If both eyes are similar, one option is to operate on the

dominant eye first and aim for nearer zero, leaving the

non dominant eye to be a fraction more myopic, but

this all depends on the exact biometry calculations and

patient preference.

Case 4 A 65 year old librarian presents with difficulty seeing

small print. She has worn glasses since she was a

teenager. She reads unaided. Best corrected acuity: -3.00/+0.50x180 6/12 -

3.00/+0.50x175 6/12

13

to respect this. If patients are undecided, the fall back

position is to leave them myopic enough to read

without glasses, so in this example 20.5 D for -2.10

spherical equivalent. Note it is rarely necessary to

leave them -3.00, particularly if there is a small amount

of corneal astigmatism. If the cataract is unilateral this raises a different problem.

If the patient prefers to aim for emmetropia this might

create a problem post operatively with binocular balance.

There are a number of options, which include correcting

the myopia in the unoperated eye with a contact lense, or

proceeding to cataract extraction in the second eye (or

clear lens extraction). Warning the patient of these

difficulties is essential.

Calculated lens implant choices: Right eye

20.5 -2.10

20.0 -1.83

19.0 -1.55

18.5 -1.28

18.0 -0.83

17.5 -0.51

17.0 -0.32

16.5 +0.15

Case 5 A 66 year old female presents with reduced vision in

both eyes. She gives a history of wearing glasses as a

child but no surgery or patching. Refraction and best corrected acuity

+5.00/+0.50x180 6/18 right

+5.00/+0.50x180 6/12 left

This patient presents a number of potential problems that need careful consideration. The patient has a lot to gain from cataract surgery including eliminating her

undesirable hypermetropia. In theory there is a magnification benefit of hypermetropia that may be beneficial if there is co-existing macular disease. Warning patients of lack of magnification is prudent, even if this is rarely a problem.

Refractive planning It is impossible to predict what sort of post operative refraction this patient might choose. A discussion is required. An obvious option is to aim for a degree of myopia so that the patient will again read without glasses. If this is the aim it may not be necessary to aim for a similar spherical equivalent as usually about -2.00 spherical equivalent is sufficient for comfortable reading. If a patient reads without glasses, then chooses to aim for an emmetropic end result, it is important to have them understand that they are unlikely to read without glasses. Some patients struggle to comprehend this as they have always read easily without glasses in the past.

Patients often have a slight underlying anisometropia,

which may be masked by index changes. This is

another example where it is important to check the

axial lengths and keratometry readings. If there is

aniso-metropia, the lenses chosen should be selected

Enquiry should be made about amblyopia (sometimes

termed lazy eye). Patients may give a good history of this,

although some patients are unaware of its presence. If the

cataract is not too severe confirmation of normal

binocular vision is helpful. However binocular tests

become unreliable if cataract is advanced or unilateral.

The second potential is the presence of a manifest strabismus. This may not be obvious from initial ins-

pection and again a history of strabismus is sometimes not present. Confirmation of aligned eyes with a cover test is reassuring. Further workup, for example assess-ment of suppression, binocular vision and ocular alignment would be encompassed by an orthoptic

report. Cataract surgery in the presence of binocular vision

abnormalities can lead to large angle strabismus or

intractable double vision. As a general rule, operate on

the better potential eye and warn patients of these

risks.

Vol. 22, No. 1, 2016

14

Calculated lens implant choices: Right eye

Hoffer Q AL 21.5

31.0 -1.50

30.5 -1.20

30.0 -0.81

29.5 -0.45

29.0 -0.11

28.5 +0.23

28.0 +0.59

Refractive planning This patient gives no history of strabismus surgery or

patching so probably has normal binocular vision. In

addition her refraction is equal (axial lengths should

be checked to exclude axial anisometropia masked by

index myopic shift).

In the absence of a large corneal astigmatism, the

choice of a 29.0 D lens would seem to be appropriate.

Note the use of Hoffer Q formula because of the short

axial length (1).

Case 6 65 year old female complains of reduced vision in the

left eye. She gives a history of reduced vision in the

left eye all her life. She has had no strabismus surgery.

Refraction and best corrected acuity:

-0.25/+0.75x180 6/18 +4.00/+2.00x180 6/60

Biometry Right eye: Biometry Left eye:

SRK-T Hoffer Q

Axial length 22mm Axial length 20mm

24.0 -1.2 29.5 -1.2

23.5 -0.81 29.0 -0.81

23.0 -0.52 28.5 -0.52

22.5 -0.12 28.0 -0.12

22.0 +0.35 27.5 +0.35

21.5 +0.72 27.0 +0.72

21.0 +1.1 26.5 +1.1

In this case the suggestion is that the left eye is amblyo-

pic. If so it should have a shorter axial length, which is

confirmed. As outlined above, the risk of proceeding to

cataract surgery in the left eye first would be intractable

double vision. This is less of a problem if the eyes are

aligned with binocular functions. Any manifest de-

viation would be a contraindication to proceeding to

cataract surgery in the left eye first. This is because

improving the acuity in the left eye to a level superior to

the right eye could anti-suppress the left eye leading to

intractable double vision, i.e. double vision that persists

even after subsequent cataract surgery to the right eye.

The right eye has reduced vision. If we assume this is due

to cataract, the recommendation would be to proceed to

cataract surgery for the right eye first. Refractive planning The right eye is planned first, as outlined above, and the aim would be emmetropia. The K readings are not presented, but the spectacle astigmatism power is low so let us assume that the K readings reveal less than 1 dioptre of corneal astigmatism. As the patient is likely to have been hypermetropic until the onset of cataract, a lens choice of 22.5 might be reasonable. For planning the left eye, the pre-existing anisometropia should be respected and the fact that the left eye is probably amblyopic makes the choice less critical. A 27.5 or 27 power lens could be chosen to maintain the direction of the pre-existing anisometropia, if not its magnitude. Although it is tempting to push up the myopic end result in some patients if they wish for a reading vision outcome, it is often not tolerated well in patients who have always been hypermetropic.

Case 7 A 54 year old female presents with worsening vision in the left eye. She has worn single vision glasses for driving since early adulthood, and more recently changed to full time varifocal glasses wear. She wishes to have uncorrected distance vision. Refraction and best corrected acuity

-2.00/+2.00x85 6/6 -1.75/+2.00x95

6/12

K1 42.00 D K2 44.00 @95 left eye


22.5 -1.20

22.0 -0.81

21.5 -0.45

21.0 -0.1



Refractive planning This case is similar to Case 2, although there is more

astigmatism which is reflected in the K readings. The

patient’s preference is for good uncorrected distance

vision but this is unlikely to be achieved with 2 D of

corneal astigmatism. While on-axis incisions or toric

lens implants are options, let us assume that these are

unavailable.

This patient’s most positive meridian is +0.25 D in the

left eye, zero in the right eye. The initial lens to choose

might appear to be 21.5 D for a post operative

spherical equivalent of -0.45 D. However, given her

degree of astigmatism, this would create a

hypermetropic meridian. Therefore selecting a 22.0 D

lens would be more logical.

This same principle applies if the overall myopia is

greater. See next case.

Case 8 A 60 year old patient presents with reducing vision as

a result of cataract. He has worn contact lenses for

many years and reading glasses over the top. He

requests good unaided visual acuity at distance in the

operated eye and understands that he will need

reading glasses, which he will use while continuing

with his contact lens in the un-operated eye. Refraction and best corrected acuity Right -10.00/+2.00x90 6/18 Left -10.00/+2.00x90 6/9 K1 42.00 D K2 44.00 @90 each eye

Refractive planning Aim for a myopic spherical equivalent of half the

corneal astigmatism power which, in this case, is -

(+2.00/2) = -1.00. Remember that biometry is less

accurate in higher axial lengths so it is wise to leave

more room for error and counsel the patient

accordingly.

This case is uncommon and most myopes have a degree

of anisometropia. By reflecting this in the refractive

planning, a useful all round uncorrected acuity can be

achieved, assuming the degree of astigmatism is not

large. Some patients prefer to continue in glasses and

have used their myopia on occasion to see close up

(perhaps unlikely if -10 but always worth asking). If this

is the case aiming for a spherical equivalent of between -

1.0 and -2.0 (depending on corneal astig-matism and

anisometropia) may be a better option. A set of varifocals

is usually well tolerated.

15

Some moderately myopic presbyopic patients (around

-4.00 D), have adapted to enjoy the unaided near

magnification that their refractive error enables. It is

worth checking that they would not miss this

magnified near vision if given an emmetropic outcome

with cataract surgery. A clue to this pitfall is to

observe whether they look over the top of their glasses

when they are given fine detail to examine.

Case 9 A 64 year old man presents with reduced vision as a

result of cataracts. He has worn glasses since age 7

years and currently wears varifocals. He has no strong

preference about glasses post operatively.

Refraction and best corrected acuity -10.00/+1.00x180 6/12 -

6.00/+1.50x160 6/9

Right Left

Axial length 26.5mm Axial length 24.50mm

17.0 -3.19

19.5 -3.19

16.5 -2.84

19.0 -2.84

16.0 -2.51

18.5 -2.51

15.5 -2.22

18.0 -2.22

15.0 -1.9

17.5 -1.9

14.5 -1.58

17.0 -1.58

14.0 -1.23

16.5 -1.23

13.5 -0.81

16.0 -0.81

13.0 -0.52

15.5 -0.52

12.5 -0.12

15.0 -0.12

Refractive planning The pre-existing refraction is reflected in the different

axial lengths of the two eyes. An option is to aim to

preserve this difference in the planning and aim for

approximately -2.5 in the right eye and -0.3 in the left

eye. With these measurements a 15.5 D lens in each

eye would probably be ideal. Note the symmetry in

the intraocular lens choice.

In this case, one danger is in doing the right eye first

and leaving the spherical equivalent at zero or

minimally myopic. This leaves no room for maneuver

for the left eye as a hypermetropic error on the left is Vol. 22, No. 1, 2016

16

undesirable, and leaving the same degree of low

myopia or emmetropia as on the right may lead to

binocular intolerance, as the pre-existing anisome-

tropia is eliminated.

Case 10 A 55 year old lady presents with symptomatic early

cataract. She does not wear glasses or contact lenses at

all and prior to the cataract developing was happy

with her unaided vision.

Refraction and best corrected acuity -0.5/+0.25x90 6/9

-0.75DS 6/12 Left eye K1 38.0 D K2 39.0 D@90

24.5 -2.0

24.0 -1.9

23.5 -1.58

23.0 -1.23

22.5 -0.81

22.0 -0.52

21.5 -0.12

21.0 +0.23

Beware in this case because the patient is young and

very symptomatic and expects not to be needing any

refractive aids. She has not told you that she had laser

refractive surgery for low myopia 10 years ago. A clue

is available as the K readings (in diopters) are low.

Her presbyopia has developed coincident with the

small and asymmetric index myopic change that has

been preserving her unaided near vision on the left

and distance vision on the right remains well

preserved. Her left eye now has sufficient nuclear

cataract to interfere with her reading and interfere

with the clarity of vision in the right eye for distance.

The assumptions in the lens implant calculations are

invalidated with prior refractive surgery and adjust-

ments must be made (which we are not within the

remit of this paper) (2). Following the calculations

without adjusting for the prior surgery is likely to lead

to a hypermetropic outcome and an unhappy patient.

Counselling the patient about the increased chance of

a refractive surprise is crucial prior to surgery. The

patient should be prepared for the possibility that a

second procedure might be needed to correct any

postoperative refractive error once the refraction has

stabilized. Multiple postoperative visits will also be

necessary.

Conclusion This article has aimed to point out some of the

common scenarios that lead to a patient unhappy with

the refractive outcome after cataract surgery. The cases

are not exhaustive, and sometimes multiple factors are

present in one patient. We have chosen not to discuss

toric lens implants or multifocals, as it would

overcomplicate the discussion and there are many

circumstances where such premium lenses are

unavailable. We aim to assist surgeons in their early

careers rather than experienced refractive cataract

surgeons. In any cataract surgical plan, always

consider the patient and their preferences as a whole,

and the way in which both eyes function together.

Recognise for each individual their needs and desired

outcome. Often small adjustments to lens power

choices, combined with the multifocality of low

astigmatism and preservation of small amounts of

anisometropia, can lead to very happy patients free

from refractive aids. Managing expectations is

extremely important as even the best plan may not

produce the desired outcome.

Follow the acynom RACkUP

Refractive history Myope, hypemetropia,

Anisometropia astig, presbypia, contacts,

Corneal astigmatism laser old refractions/axial

lengths power, axis (k’s)

And their significance, eg Understand the

loss of near sight in myopes patients wishes

double check for amblyopia,

Plan Lens choice primary position tropia, low

myopia or myopic astigma-

tism, anisometropia, glasses

dependence, and reading

aids

References 1. RCOphth guidelineshttps://www.rcophth.ac.uk/wp-

content/uploads/2014/12/2010-SCI-069-Cataract-

Surgery-Guidelines-2010-SEPTEMBER-2010.pdf accessed

25/5/2016. 2. Kalyani SD, Kim A, Ladas JG. Intraocular lens power

calculation after corneal refractive surgery. Curr Opin

Ophthalmol. 2008; 19(4): 357-62. doi: 10.1097/ICU.0b013e3282fec43e.


17

Dr. P. Sivasubramanium Oration – 2015

Vascular endothelial growth factor (VEGF): Its role in ocular

neovascularization

Saliya Pathirana1


Dr. P. Sivasubramaniam DO, MS, FRCS, FRCOphth, FCS (SL, HON)

Dr. Ponniah Sivasubramaniam was the most respected Ophthalmologist

who lived in Sri Lanka. He passed away at the age of 86 years on 3rd

December 2002.

He was born on the 31st of August in 1916 in Kandegamuwa. He had his

early education in Jaffna and later at St. Josephs College, Colombo and

graduated at Ceylon Medical College with a 1st class at the final

examination.

From the day he returned to Ceylon in 1950 after the postgraduate

training in Britain he began to work in Jaffna as a consultant

Ophthalmologist. He was posted to Victoria Memorial Eye Hospital in

1955 and continued working until his retirement. He was the 1st Sri

Lankan to pass the final FRCS Ophthalmology examination in 1950.

His biography indicates that he carried a good record during his undergraduate period that he carried away all

the prizes at the London Matriculation at St. Patrick College in Jaffna and won the exhibition prize for Botany and

Zoology.

He held many positions in various professional organizations and was the founder member of the

Ophthalmological Society in Ceylon in 1957. He was also the President of the Sri Lanka Association of

Advancement of Science in 1957, President of the Ophthalmological Society Ceylon in 1962, President of SLMA in

1976, President of 5’ congress of the Asia Pacific Academy of Ophthalmology and founder President of College of

Ophthalmologists of Sri Lanka in 1992.

He was awarded Jose Rizal award 1974 for a outstanding contribution to Ophthalmology in the Asia Pacific

region. He completed his 50 years of service on 30th November 1993. He was a member of the board of study,

examiner for DO, MS examinations. He had numerous publications in national and international journals mainly American Journal of Ophthalmology, Archives of Ophthalmology, British Journal of Ophthalmology, Oriental Archives of

Ophthalmology, Transactions of Asia Pacific Ophthalmology, Ceylon Medical Journal and Transactions of Ophthalmological

Society. His book “text book in Ophthalmology” written in 1960 was the book for medical students.

He also took leadership in preparing national plan for the prevention of blindness in 1990 and to establish eye care

in Sri Lanka and carried out a landmark survey of blindness.

In considering the clinical work half a century ago in addition to cataract surgery he performed DCR, glaucoma

Surgery, and squint surgery.

His variety of interest within the chosen field affected almost every facet of Ophthalmology as he contributed

greatly to important clinical and lab advances in disease areas. He had incredible wisdom and ability to stimulate

his colleagues and students to do the right thing and to follow the accepted norms. The Journal of the College of Ophthalmologists of Sri Lanka

Vascular endothelial growth factor (VEGF): Its role in ocular neovascularization 18 Neovascularization and edema in retinal disorders Leading causes of blindness in the world are, in people aged over 50 years-age-related macular degeneration

(AMD), diabetic retinopathy.

Major cause of blindness in both disorders is related to neovascularization and edema. VEGF is implicated in

pathologic neovascularization.

Central vision loss with neovascular AMD

Milestones in VEGF research

1948-1958 Michaelson, Ashton, and Wise contribute to “factor X” hypothesis 1971

Folkman publishes “tumor angiogenesis factor” hypothesis

1983 Dvorak demonstrates tumor secretion of vascular permeability factor (VPF)

1989 Ferrara clones VPF and identifies it as an angiogenesis factor; VPF is rechristened VEGF 1997

First clinical trials of anti-angiogenic therapy in cancer patients initiated

1999 First anti-VEGF therapy tested in humans with AMD

2003 VEGF164 (165) found to be required for pathologic, but not physiologic, retinal neovascularization

2003 Optimal methods of long-term controlled delivery of an anti-VEGF agent evaluated in

animal studies

2004 First FDA-approved anti-VEGF therapy for colorectal cancer

Vol. 22, No. 1, 2016

19

Properties of VEGF

1. Stimulator of angiogenesis

2. Potent inducer of vascular permeability

3. Vessel survival factor

4. Fenestration factor

5. Proinflammatory effects

6. Neuroprotective effects

VEGF stimulates angiogenesis Triggers degradation of basement membrane of endothelial cells. Endothelial cells then change shape and invade

surrounding stroma, proliferate and form migrating column. Then cease proliferation, change shape, and adhere

to each other and form new capillary tube. Sprouting tubes fuse into loops, creating circulation.

VEGF is a potent inducer of vascular permeability 50,000 times more potent than histamine in inducing vascular permeability. Induces vessel leakage via multiple

mechanisms. Causes leukocyte-mediated injury of endothelial cells, formation of fenestrae, dissolution of tight

junctions, transcellular bulk flow. Vascular permeability may be antecedent and necessary step for

neovascularization.

Proinflammatory effects of VEGF VEGF receptors present on inflammatory cells. Inflammatory cells make and release VEGF, participate in blood-

retinal barrier breakdown and neovascularization.

VEGF in normal physiology Essential for normal embryonic development. Role in female reproductive cycle. Expressed in tissues in the brain,

kidney, and gastrointestinal mucosa. Corrective role in wound healing and bone repair. Promotes new vessel

growth following myocardial ischemia.

VEGF is present in the healthy eye VEGF receptors primarily located on vascular endothelial cells. High concentrations of VEGF found in retinal

pigment epithelium (RPE). VEGF may play a protective role in maintaining adequate blood flow to RPE and

photoreceptors. It’s trophic for choriocapillaries. Also required for maintenance of choriocapillaries fenestrae.

VEGF in pathologic ocular neovascularization VEGF is implicated in neovascular AMD, diabetic retinopathy, retinal vein occlusion, retinopathy of prematurity,

corneal neovascularization, and iris neovascularization.

Preclinical evidence of VEGF in pathologic ocular neovascularization VEGF and neovascularization are linked in experimental models (cornea, iris, retina, choroid), is necessary and

sufficient to produce pathologic neovascularization. Selective VEGF inhibition suppresses vessel growth in these

models.

Pathophysiology of neovascular AMD Evidence for role of VEGF

VEGF present in surgically excised neovascular choroid membranes of patients with neovascular AMD. Also

present in CNV membranes of autopsied eyes of patients with neovascular AMD. Other growth-stimulating and

growth-inhibiting factors may be implicated in neovascular AMD, but their roles are not as well understood.


Vascular endothelial growth factor (VEGF): Its role in ocular neovascularization 20

VEGF – the common denominator in AMD CNV membranes have demonstrated expression of both VEGF and VEGF receptors

Predominantly classic neovascularization

Occult neovascularization

Left: FAs of choroidal neovascularization Right: Immunohistochemistry for VEGF expression

VEGF in diabetic retinopathy Retinal VEGF levels elevated in experimental diabetes. Blocking VEGF prevents pathology.

VEGF injected in primates induced vascular leakage and produced conditions similar to diabetic retinopathy.

VEGF levels elevated in vitreous of eyes with diabetic macular edema and with proliferative diabetic retinopathy. Vol. 22, No. 1, 2016

21

Pathologic VEGF activates CNV cascade

VEGF is an important target for therapeutic intervention. It is secreted, diffusible, and mitogenic for endothelial

cells. Multiple retinal cell types produce VEGF; retinal endothelial cells have receptors for VEGF. Blood-retinal

barrier breakdown is both prevented and reversed through VEGF inhibition. Extensive data support role of VEGF

in ocular neovascularization and vascular permeability.



Blocking VEGF does not affect underlying stimuli In neovascular AMD, blockade of pathologic VEGF does not block stimuli underlying VEGF cascade sustained

blockade of pathologic VEGF may be required.

VEGF164(165) preferentially elevated in pathologic neovascularization In murine model, VEGF levels were higher in pathologic versus physiologic processes. Expression ratio of

VEGF164/ VEGF120 was ~12 higher in pathologic neovascularization

Expression VEGF164/ VEGF120 in retinal neovascularization

Pathologic 25.3 8.7

Physiologic 2.2 1.1

VEGF164(165) blockade preferentially inhibits VEGF164(165) blockade has no significant effect on

pathologic retinal neovascularization physiologic retinal vascularization

Pathologic neovascularization Revascularization

Murine VEGF 164

equivalent to human VEGF Murine VEGF164 equivalent to human VEGF165 165

Control

VEGF164 selective blockade

Non selective VEGF blockade

Evidence suggests VEGF164(165) is not required for normal retinal vessel growth and function

Retinal vessels in normal mouse Retinal vessels in VEGF164 knockout mouse

Vol. 22, No. 1, 2016

23

Summary VEGF and neovascularization are linked in experimental models (cornea, iris, retina, choroid). VEGF is necessary and sufficient to produce pathologic neovascularization. Based on animal models preferential role of VEGF164(165)

suggested in pathologic neovascularization and blocking VEGF164(165) inhibits abnormal vessel growth while sparing normal vessels.

What is wet AMD? No. 1 cause of non-reversible blindness worldwide! Aging is the most important triggering factor. VEGF is the

most important factor for its development. Who is affected 1. >65 years – Age most important factor 2. Smoking 3. Whites and Chinese more commonly affected 4. Runs in families

The pathology is in – RPE & Bruch's membrane at macula

It presents as painless loss of central vision. Loss can be gradual or acute depending on type. Dry AMD – Gradual loss (5-10 years or more) Wet AMD – Sudden loss of vision (day or days)



Dry AMD Accumulation of yellow extracellular deposits adjacent to retinal pigment epithelium – drusens.

Wet AMD Generally develops in people with Dry AMD. New blood vessels grow below macula. Leads to sudden loss of

vision. Can see sub retinal hemorrhage or sub retinal fluid or both at the macula.

How is it diagnosed ? Dry type – Detected on routine testing by opticians/ ophthalmologists on ophthalmoscopic examination to look

for drusens. Does not need any further investigations.

Wet type needs further tests to confirm diagnosis such as optical coherence tomography (oct), fluorescein

angiography (confirm diagnosis) and amser grid is useful to detect the distortion of the figures with affected eye.

Amsler grid

Vol. 22, No. 1, 2016

25

Optical coherence tomography (OCT)

Treatment of AMD So far no drug to completely cure AMD. Anti VEGF drugs – ranibizumab, bevacizumab, aflibercept (Wet AMD only stops progression) Injected intravitreally works well to achieve relatively quick resolution of exudative signs in most patients. This

will stop the growth of CNV and improve the vision up to a certain extent. Other treatment methods include photodynamic therapy and laser photocoagulation for non central lesions.

Reassure the patient and inform him that he will not go completely blind, and also his peripheral vision is going to

be normal. Affected patients can be helped with magnifying lenses and large prints for reading.

Vitamins and green leafy vegetables to supply anti oxidants.

Currently used Anti VEGF agents



Bevacizumab Alibercept Ranibizumab RTH 258

Baseline lesion characteristics Size of CNV > 5DA poor prognostic indicator Classic CNV or minimal classic CNV are poor prognostic indicators. Occult CNV – untreated show slow decline of VA Persistent active lesions Less responsive to treatment Presence of RAP Presence of GA Any PED – height and width Drying of the exudative or “wet” macula in neovascular AMD can usually be accomplished safely, effectively and relatively quick with an initial series of frequent, continuous therapy with one of these drugs in the so-called INDUCTION PHASE. In most patients, the signs of exudation are brought under good control within 3-4 injections in this phase. It is what to do thereafter, how to keep the macula dry and obtain the best visual outcome in the long run -THE

MAINTENANCE PHASE, that is the challenge and where clinicians practices can vary considerably.

Compartments fluid Sub retinal fluid Intraretinal fluid

Various clinical trials done to compare and to find best treatment methods

MARINA (Clinical trial one)

ANCHOR STUDY (Clinical trial two)

HORIZON extension study

PIER study

EXCITE study

PrONTO

SAILOR

SUSTAIN

CATT

Vol. 22, No. 1, 2016

27

Anti-VEGF induction methods Fixed and variable regimens There are three basic approaches to maintenance dosing regimens.

1. The first is a fixed continuous, monthly or bi-monthly injection schedule.

2. The second is an individualized discontinuous variable approach, also called as - needed or pro re nata

(PRN) dosing. 3. The third is an individualized continuous variable approach commonly known as treat – and - extend

(TAE) strategy.

Ocular and systemic adverse effects of anti-VEGF’s Ocular adverse effects

• Enodophthalmitis • Cataract, raised IOP, glaucoma • Vitreous hemorrhage, retinal detachment • Systemic adverse effects • CVA • Cardiovascular events • GIT and renal disorders

Determining disease activity Functional and morphologic features, improvement of vision. disappearance or appearance of haemorrhages.

OCT morphology

• SRF – sub-retinal fluid • IRF – intra-retinal fluid • PED – pigment epithelial detachment • Sub-retinal hyper-reflective material: SRHM

Any sub/ intra retinal fluid indicates inadequate treatment.

TREAT UNTIL DRY Impact of sub-retinal fluid

1. SRF at baseline no impact on outcome

2. Persistence of SRF compatible with good outcome

3. Recurrence of SRF negative impact on outcome

Impact of intra-retinal fluid

1. Associated baseline worse VA

2. Predictor of worse VA outcomes



Treatment refractory CNV the “Non responder” Revisited diagnosis, consider PCV, check ICG and allow time for recovery if not other alterative are laser, PDT,

steroids.

Patient treated with anti-VEGF for ARMD R/EYE L/EYE

CNV treated with Anti-VEGF

Vol. 22, No. 1, 2016

29

Conclusions 1. Wet AMD causes irreversible damage to the macula and permanent visual impairment if treatment is delayed

and/or not provided adequately or stopped prematurely. 2. However, macula scar and macular atrophy may occur despite timely treatment and regression of CNV based

on baseline characteristics.

Diabetic retinopathy ETDRS classification of diabetic retinopathy

• None

• Non- proliferative (NPDR) +/- Clinically significant macula edema (CSME)

Mild

Moderate

Severe

Very severe

• Proliferative (PDR)

Without high risk characteristics (HRC)

With HRC

Focal DME Localize retinal thickening often surrounded by exudates usually with cluster of microaneurysms.



Diffuse DME Generalized thickening of the central macula with no obvious source of leakage.

Ischemic maculopathy Normal FAZ

Vol. 22, No. 1, 2016

31

The pathogenesis of DME

OCT classification of DME



VEGF Concentration in nAMD, BRVO, CRVO & DME Vol. 22, No. 1, 2016

33

Treatment of DME

1. Laser photocoagulation

2. ANTI-VEGF intra vitreal injections

3. Dexamethazone intra vitreal injections

Many patients lose vision despite laser

year data 2‐line loss with laser 3‐line loss with laser

DRCR.net: grid laser vs. IVTA 17% 13%

DRCR.net: mod. macular grid 13% 7 – 10%

DRCR.net: ranibizumab vs. prompt/deferred 13% 8%

laser/IVTA

DRCR.net: ranibizumab vs. prompt/deferred 13% 8%

laser/IVTA

RESTORE 13% 8%

BOLT: Bivacizumba vs. laser Not reported 26%

Laser helps to reduce severe visual loss in 50% of DME patients. Progressive visual loss experienced in 19% of

DME in spite of laser treatment.

Various anti-VEGF agents have been investigated for the treatment of DME The Journal of the College of Ophthalmologists of Sri Lanka


Studies conducted to investigate anti-VEGF treatment for DME The study conducted by DRCR.net showed the patients treated with 0.5mg ranibizumab plus prompt or deferred

laser had better VA outcomes at 1 year than patients who received sham injections plus prompt laser treatments. Two year primary outcomes of the RISE and RIDE studies clearly demonstrated monthly injections ranibizumab

significantly improved VA. 40 – 45% of patients gained 3-more line of vision. In the READ 3 study patients treated with 0.5mg or 2mg ranibizumab. Increasing VA was 8.7 letters for the 0.5mg

group and 7.5 letters for 2mg group. In 2011 RESTORE study demonstrated superior gain in VA with ranibizumab with or without laser.

Patient treated with anti-VEGF for DME

Exam. date: 2 8/4/20 1 5

Exam. date: 18/5/2 0 1 5

Exam. date: 2 0/6/2 0 1 5

No improvement with anti VEGF Improvement with anti VGEF

OD OS

Vol. 22, No. 1, 2016

35

Non-center involved DME treated with laser only

RETINAL VEIN OCCLUSION

CRVO BRVO

FFA in BRVO and CRVO

Treatment of RVO BRVO study showed that macula photocoagulation is superior in improving VA compared with observation.

CRVO study demonstrated grid laser treatment of macula edema of no visual benefit

Intravitreal anti-VEGF agents for RVO In the BRAVO and CRUISE studies published in 2010 evaluated the effect of ranibizumab for macula edema

secondary to CRVO and BRVO.



In six months both ranibizumab groups showed significant different in improvement of BCVA (+18.3 letters for

the 0.5mg group, +16.6 letters for the 0.3mg group, +7.3 letters for the sham group p<0.5)

It appears that some eyes stabilize after a few consecutive monthly injection and require few injections thereafter.

Findings from SD-OCT is used to predict VA. Anti-VEGF treatment for CME following BRVO

Exam. date: 0 4/0 8/2015

Exam. date: 11/09/2015

Exam. date: 17/06/2015

Exam. date: 07/08/2015

Exam. date: 11/09/2015

My experience during the past 8 years using anti VEGF therapy for wAMD, DME, RVO has proved that anti

VEGF therapy is very effective in managing macula edema in these vascular-retinal diseases. Vol. 22, No. 1, 2016

37


J. K. Dilruwani Aryasingha1


Introduction A comprehensive evaluation of the drainage angle is critical for accurate diagnosis and appropriate therapeutic intervention in glaucoma. There is a wide spectrum of anatomical variations in the drainage angle in normal and affected eyes. Furthermore, forces at different anatomic levels in the eye may be responsible for the pathogenesis of angle closure, the iris (pupillary block), the ciliary body (plateau iris), the lens (phacomorphic glaucoma) and posterior to the lens (malignant glaucoma). Therefore, assessing anterior chamber angle anatomy and surrounding structures with anterior segment imaging is of tremendous importance for identifying individuals in the early stages of the disease and guiding therapeutic decisions.

Gonioscopy Gonioscopy remains the reference standard for assessing anterior chamber angle in the eye. It is inexpensive and can be rapidly performed at the slit-lamp. Gonioscopy permits dynamic visualization of the entire angle quadrant and allows indentation differentiating between appositional and synaechial angle closure. As this is a subjective technique, this can be affected by patient’s cooperation, examiner's skill, type of lens used, direction of gaze, inadvertent pressure on the cornea and environmental illumination. Different classification systems may also cause variability in angle assessment. Furthermore, it does not provide quantitative evaluation of the angle and is also limited in visualizing structures posterior to the iris.

Imaging of the anterior segment Imaging of the anterior segment offers an objective

method for visualizing the angle and adjacent anatomical

structures. In addition to qualitative analyses, some

imaging modalities permit quantitative analyses that can

be used to monitor change or progression over time.

Several imaging devices are available such as ultrasound

biomicroscopy (UBM), scheimpflug photography, eye

cam and anterior segment optical coherence tomography

(AS-OCT).

Anterior segment OCT Anterior segment OCT is a non-contact method

providing high resolution tomographic cross-sectional

imaging of anterior segment structures. AS-OCT uses

the principle of low-coherence interferometry instead

of ultrasound. The technique measures the delay and

intensity of the light reflected from the tissue structure

being analyzed and compares it with the light

reflected by a reference mirror. The combination of

these two signals results in interference phenomenon.

The signal intensity depends on the optical properties

of the tissues and the device uses these signals to

construct a sagittal cross-section image of the structure

being analyzed. OCT technology was initially used to

produce images of the posterior segment of the eye by

using a wavelength of 820nm. In 2001, the wavelength

was altered to 1310nm to allow better penetration

through light-retaining tissues such as the sclera and

limbus and to improve visualization of the anterior

segment.

Figure 1.

Compared with UBM, AS-OCT provides a higher axial

resolution (18um versus 25um in 50 MHz UBM) and

faster sampling rate (2.0 kHz versus 0.8kHz). Another

main clinical advantage over UBM is its ability to

provide noncontact scanning in a seated, upright

position (Figure 1). But in AS-OCT lack of a coupling

medium may affect the image quality due to abnor-

malities in the anterior surface of the eye. The major

drawback for AS-OCT is its inability to visualize

structures posterior to the iris due to blockage of

1Consultant Ophthalmologist, Golden Key Eye & Ent Hospital, Rajagiriya, Sri Lanka.



wavelength by pigment. This limits its application in

discerning several secondary causes of angle closure,

such as plateau iris, ciliary body cyst or tumor, lens

subluxation or ciliary effusions (Figure2).

38

the ARA is defined as the triangular area with boun-daries including the angle recess (apex), iris surface and the inner corneoscleral wall (sides) and AOD (base). The anterior chamber angle is defined in degrees, in which the angle recess forms the apex and the two sides of the angle are formed by drawing the lines through the points defining the AOD 500.

Figure 2.

AS-OCT can be used as an adjunct to gonioscopy as

well as a substitute when gonioscopy is not feasible

due to corneal pathology or lack of patient co-

operation. It is extremely useful as a patient education

tool, especially when laser peripheral iridotomy is

being recommended. Being a non-contact technique

and can be performed under dark conditions, it allows

angle assessment during physiological mydriasis.

OCT-Goniometry Anterior segment OCT plays an important role not only

in identifying the angle structures qualitatively, but also

in providing quantitative measurements by using special

software to determine the extent of apposition in cases of

angle closure. OCT-Goniometry is the new term given for

objective measurement tools obtained by the AS-OCT to

quantify angle opening. After the scleral spur is located

by the technician, several parameters can be measured.

Anterior chamber depth is defined as the axial distance

between the posterior surface of the cornea and anterior

lens surface. One important parameter for angle anatomy

is the angle opening distance (AOD): the length of line

drawn perpendicular from a point on the corneal

endothelial surface (either 500 or 750um anterior to the

scleral spur) to the iris surface. Theoretically, a distance of

500um from the scleral spur approximates the location of

the trabecular meshwork and a longer distance of 750um,

covering a more extensive region, may be less affected by

local iris surface irregularities.

Because AOD measurements are made in the iris plane,

they can be influenced by the presence of peripheral

anterior synechiae or other irregularities of iris contour

and curvature. To overcome these limitations and to

account for the whole contour of the iris surface, Ishikawa

et al. devised the angle recess area (ARA), which borders

the anterior iris surface, corneal endothelium, and AOD

500 or AOD 750. Therefore,

AOD750

Scleral

AOD50 Spur Angle (SSA)

TISA75

TISA500

Figure 3.

Because of poor visualization of the angle recess near the

scleral spur and inability to measure the ARA properly

with AS-OCT, Radhakrishnan et al, proposed calculating

the trabecular-iris space area (TISA), which does not

require clear visualization of the angle recess (Figure 3).

The researchers described this parameter to be a better

indicator than ARA for actual filtering area and a more

sensitive identifier of narrow angles in eyes with deep

angle recesses. The TISA excludes the nonfiltering area

via its posterior border outlined by a line drawn from the

scleral spur to the opposing iris perpendicular to the

plane of the inner scleral wall. Therefore, the TISA is the

trapezoidal area with AOD anteriorly, inner scleral wall

posteriorly, inner corneos-cleral wall superiorly, and iris

surface inferiorly. Clinical applications of AS-OCT Anatomically narrow angles can be diagnosed with AS-OCT both qualitatively and quantitatively. Widening of the angles after laser iridotomy in eyes with narrow angles or pupillary block glaucoma has been demonstrated with both UBM and AS-OCT. Serial monitoring of the angle since approximate alignment with ocular landmarks (such as iridotomies, iris naevi, conjunctival blood vessels etc.) can be performed with AS-OCT by utilizing the video image during OCT scan acquisition. Although AS-OCT is limited due to blockage of infrared

light by iris pigment with incomplete visualization of the

ciliary body, it can visualize iris cyst, iris melanoma or

ciliary effusions in some cases. AS-OCT has been

described to differentiate cystic and solid lesions of the

iris. However, these pathologies and others including

plateau iris, phacomorphic glaucoma, or malignant

glaucoma are better detected with UBM. In

Vol. 22, No. 1, 2016

39

contrast to AS-OCT, UBM better demonstrates the

anterior rotation of the ciliary body with loss of ciliary

sulcus in plateau iris syndrome.

AS-OCT can be used to assess the iris contour in

pigment dispersion syndrome (PDS). In this condition,

pigment liberation is secondary to rubbing between

the iris pigment epithelium and lens zonules because

of increased iridolenticular contact.

AS-OCT is a useful tool to evaluate filtering blebs or

glaucoma drainage devices in the postoperative

period. Clinically, blebs can be described as diffuse,

cystic, encapsulated or flat. However, these

descriptions are subjective and there may be cases in

which clinical appearance does not correlate with bleb

function. Therefore, visualizing intrableb morphology

with anterior segment imaging may enhance our

under-standing of different surgical outcomes and

wound healing. Encapsulated blebs have a thick wall,

high reflectivity because of dense collagenous

connective tissue present in the bleb wall and an

enclosed fluid-filled space. Flat blebs demonstrated

high scleral reflectivity with no bleb elevation. AS-

OCT allows visualization of the glaucoma drainage

devices in the anterior chamber to assess their position

or potential occlusion.

The noncontact nature of AS-OCT makes it a valuable

tool in identifying angle pathology in posttraumatic

eyes. Angle recession or cyclodialysis cleft may be

documented.

Summary Anterior segment imaging is an important facet of glaucoma care. The various devices have their own advantages and disadvantages and the decision to use these modalities depends on their cost, technicians’ expertise, and medical professionals’ clinical pre-ferences. References 1. Ritch R, Liebmann J, Tello C. “A construct for unders-

tanding angle-closure glaucoma: the role of ultrasound

biomicroscopy”. 2. Dandona L, Dandona R, Mandal P, et al. “Angle-closure

glaucoma in an urban population in Southern India. The

Andhra Pradesh Eye Disease Study. Ophthalmology 2000;

107: 1710-16. 3. Radhakrishnan S, Rollins AM, Roth JE, et al. Real-time optical

coherence tomography of the anterior segment at 1310 nm.

Arch Ophthalmol 2001; 119: 1179-85.

4. Radhakrishnan S, Goldsmith J, Westphal V, et al.

Comparison of coherence tomography and ultrasound

biomicroscopy for detection of narrow anterior chamber

angles. Arch Ophthalmol 2005; 128: 1053-9. 5. Fukuda S, Kawana K, Yasuno Y, et al. Repeatability and

reproducibility of anterior ocular biometric

measurements with 2-D and 3-D optical coherence

tomography. J Cataract Refract Surg 2010; 36: 1867-73. 6. Tan AN, Sauren LD, de Brabander J, et al. Reproducibility of

anterior chamber angle measurements with anterior segment

OCT. Invest Ophthalmol Vis Sci 2011; 52: 2095-9.


Lamellar dissection technique in deep anterior lamellar keratoplasty (DALK) – does it matter in postoperative progression 40

Lamellar dissection technique in deep anterior lamellar keratoplasty

(DALK) – does it matter in postoperative progression K. H. Wickramasinghe1, S. K. G. S. Kurera2, C. J. Kumarage3, W. M. C. M. Andradi4, D. H. H. Wariyapola5

The Journal of the College of Ophthalmologists of Sri Lanka 2016; 22: 49

Introduction Success of DALK depends on postoperative graft

behavior. Factors that might influence this are graft

size, lamellar dissection and suturing techniques.

Method DALK done from 2009 December to 2014 October

were enrolled. 90 eyes were included in the analysis.

Topography and refractive data were collected at 3

monthly intervals starting at postoperative 3rd month.

Data was analyzed using SPSS.

Results Average age of the patients was 25 years. 52.9% were

females. Preoperative average keratometry (Avrg-K)

in the operated eye was 57. Preoperative best corrected

visual acuity(BCVA) in 4.3% was 6/9 or better and

91.4% had 6/18 or less. 72.4% of surgeries used

Anwar’s big bubble technique (ABB) and 26.7% were

layer by layer dissections (LL). Postoperatively pooled

data showed 6/9 or better vision in 46.5% at

postoperative 3rd month. It increased to 67.2% at 6th

month, 78.1% at 9th month and 77.8% at 12th month.

Postoperative Avrg-K was 43.

In patients who had ABB, preoperative BCVA in 4.9%

was 6/9 or better. 85.4% had 6/18 or less BCVA. Avrg-

K in the operated eye was 57. Postoperatively BCVA

was 6/9 or better in 42.9% at 3 months, 65.5% at 6

months, 79.3% at 9 months and 88.8% at 12 months.

Postoperative Avrg-K was 43.

In patients who had LL, Preoperative BCVA was less

than 6/18 in all patients (n=15). Avrg-K in the

operated eye was 62. Postoperatively BCVA was 6/9

or better in 45.5% at 3 months, 57.1% at 6 months, 75%

at 9 months and 66.7% at 12 months. Postoperative

Avrg-K was 43. There was no statistically significant

correlation between the lamellar dissection technique

and post operative progression of Average

Keratometry and BCVA parameters.

Discussion There was improvement in BCVA in both methods

until 1 year of post op follow up. Average keratometry

was corrected by DALK. In our setting there was no

difference in post operative progression until one year

follow up between the two lamellar dissection

techniques.

1Registrar in Ophthalmology, 2Post Graduate Trainee in Ophthalmology, 3Senior Registrar in Ophthalmology, 4Research Assistant, 5Consultant Ophthalmologist, Sri Jayawardenapura General Hospital, Kotte, Sri Lanka.

Vol. 22, No. 1, 2016

41

The effect of preservatives on the ocular surface and success of glaucoma

filtration surgery Nuwan Niyadurupola1


Abstract The preservatives in topical glaucoma medication can have a

detrimental effect on the ocular surface. The use of preserved

antiglaucoma drops has been shown to lead to poor

trabeculectomy outcomes. Reducing the amount of preser-

vatives and switching patients to preservative-free eye drops

improves comfort and tolerability of topical medication.

Introduction Preservatives are everywhere these days; from the food that we eat, to the paints on our walls and the varnish on our floors. They are principally used to kill microbes and extend the shelf life of the product. The majority of topical antiglaucoma eye drops contain preservatives. The role of the preservatives in topical medication is also to kill microbes and extend the shelf life of the drops. There is some controversy that the preservatives in topical medication may help enhance drug penetration into the eye, but this appears not to be the case since non-preserved varieties of the medication have been shown to have the same efficacy as the preserved variety. The most common preservative used in topical antiglaucoma medication is benzalkonium chloride (BAK). Other preservatives used in topical anti-glaucoma medication include polyquaternium-1 (Polyquad), Purite and sofZia. Benzalkonium chloride is a cationic detergent and a highly effective anti-microbial. The mechanism of action of BAK as an anti-microbial is to cause dissolution of bacterial cell walls, disruption to cellular junctions and dissociation of lipid bilayers. The problem, however, is that the effect of BAK on cells is non-selective and healthy host tissue can also be damaged. The BAK content of commonly used topical anti-

glaucoma eye drops are shown in Table 1. The highest

concentrations of BAK (0.02%) are contained in

bimatoprost, latanoprost and fixed combination

latanoprost/timolol. The available generic varieties of

latanoprost contain the same concentration of BAK

(0.02%). Travaprost and fixed combination travaprost/

timolol contain polyquaternium-1 (Polyquad) rather than

BAK. In some countries travaprost is available

preserved with sofZia and brimonidine is available

preserved with Purite.

The effect of BAK on the ocular surface Benzalkonium chloride from topical medication has been shown to accumulate in the corneal and conjunctival epithelium (1,2). Benzalkonium chloride can be retained in the epithelium for up to 1 week, with a half-life of 20 hours (1). From the corneal and conjunctival epithelium, BAK can penetrate into the deeper structures within the eye. Following topical instillation, BAK has been found in the trabecular meshwork, iris, lens capsule, retina, choroid and the optic nerve of rabbit eyes (2,3). Topical BAK (0.01%) has been shown to halve the tear break-up time (a measure of dry eye) within minutes of application in healthy volunteers (4). The detergent action of BAK is thought to dissolve the superficial oily lipid layer of the tear film leading to dry eyes (4). Benzalkonium chloride has been shown to reduce the number and function of conjunctival goblet cells compromising the tear film further (5). Dissolution of the lipid layer of the tear film causes excessive evaporation of the aqueous layer of the tear film and mucin precipitation. This can then lead to corneal epithelial defects and risk of ulceration.

Benzalkonium chloride is detrimental to the cornea. Low

concentrations of BAK have been shown to inhibit corneal

epithelial cell pseudopod growth and impair corneal

epithelial regeneration (6). Keratectomies performed in rabbit

cornea have failed to heal in the presence of 0.02% BAK (7).

In patients, the density of superficial corneal epithelial cells

was found to be reduced in those receiving preserved

antiglaucoma eye drops in comparison to those receiving

non-preserved antiglaucoma eye drops and control subjects

on no topical treatment (8). Patients receiving preserved anti-

glaucoma eye drops also had decreased corneal sensi-tivity

compared to those receiving unpreserved antiglaucoma eye

drops or control subjects (8,9). The num-bers of sub-basal

corneal nerves was lower in patients taking preserved

antiglaucoma eye drops than those taking preservative-free

antiglaucoma eye drops (8).

1Consultant Ophthalmic Surgeon, Department of Ophthalmology, Norfolk and Norwich University Hospital, United Kingdom.


The effect of preservatives on the ocular surface and success of glaucoma filtration surgery 42

Table 1. Concentration of benzalkonium chloride (BAK) in antiglaucoma eye drops

Antiglaucoma eye drop BAK content (%)

apraclonidine 0.01

betaxolol 0.01

bimatoprost 0.02

brimonidine 0.005

brinzolamide 0.01

carteolol 0.005

dorzolamide 0.0075

metipranolol 0.004

latanoprost 0.02

levobunolol 0.005

pilocarpine 0.01

timolol 0.01

Fixed combination bimatoprost/timolol 0.005

Fixed combination brimonidine/timolol 0.005

Fixed combination brinzolamide/brimonidine 0.003

Fixed combination brinzolamide/timolol 0.01

Fixed combination brinzolamide/timolol 0.01

Fixed combination dorzolamide/timolol 0.0075

Fixed combination latanoprost/timolol 0.02

Fixed combination pilocarpine/timolol 0.01

In the conjunctiva, BAK has been shown to cause a dose-

dependent loss of epithelial cells. Low concen-trations of

BAK (0.0001% to 0.01%) have been shown to cause

apoptosis of conjunctival cells in culture (10). Higher

concentrations of BAK (0.05% to 0.1%), however, caused

immediate conjunctival cell lysis (10). Chang conjunctival

cells in vitro have shown immediate cell lysis following

addition of 0.01% BAK (11). In a study of conjunctival

histology, patients using multiple topical medication

showed more inflammatory changes and fibroblastic cells

within the conjunctiva compared to control subjects (12).

Benzalkonium chloride was found to be the cause of this

inflammatory infiltrate since topically applied preserved

0.5% timolol (containing 0.01% BAK) and topically

applied 0.01% BAK alone caused an increase in

inflammatory cell counts in the conjunctiva of rat eyes

compared to controls (12). The conjunctival cell profile of

rats treated with topical preservative-free 0.5% timolol,

however, was similar to controls (12). Long-term

antiglaucoma

therapy with at least two agents for a mean of 7.7 years

has been shown to significantly increase the number of

fibroblasts and inflammatory cells in the conjunctiva. (5). The inflammatory and fibroblastic infiltrate of the

conjunctiva may be the cause of significant fore-

shortening of the inferior fornix that has been found in

patients using topical anti-glaucoma therapy

containing preservatives for three or more years (13).

The effect of preservatives on trabeculectomy

outcomes A pivotal study published in 1994 by Broadway D. C. and

co-workers (14), examined the conjunctival cell profile of

topically treated and untreated glaucoma patients and

compared the success rates of trabeculectomy in these

groups. The control patients were patients undergoing

primary trabeculectomy who had not had any previous

surgery and had minimal previous topical therapy. The

study group were

Vol. 22, No. 1, 2016

43

patients on topical antiglaucoma therapy with preserved

eye drops for at least 6 months prior to undergoing

trabeculectomy and were divided into three groups;

those taking beta-blockers alone, those taking a beta-

blocker and a miotic and those taking a beta-blocker, a

miotic and a sympathomimetic. The success rate of

trabeculectomy in patients taking a beta-blocker alone

(90%) was similar to that of controls (93%) (14). However,

the success rates of trabeculectomy were lower in those

on multiple topical medication, and therefore those that

had more exposure to preser-vatives. Those on two

medication (beta-blocker and miotic) had a lower

trabeculectomy success rate of 75% compared to controls

and those on triple therapy had a markedly lower success

rate of only 45% (14). The triple therapy group, that fared

the worst, had increased numbers of fibroblasts,

macrophages, lymphocytes, mast cells and Langerhan’s

presenting cells within the conjunctiva compared to

control eyes (14,15). The increased inflammatory infiltrate

in the conjunctiva of treated triple therapy patients was

presumed to be the cause of trabeculectomy failure in

this group. The triple therapy group also had lower

numbers of goblet cells within the conjunctival epi-

thelium compared to controls (15). The prior duration of

treatment with preserved antiglaucoma drops was also

found to be important for trabeculectomy success. A

duration of antiglaucoma treatment of greater than three

years and hence a greater than three year expo-sure to

preservatives was found to significantly reduce

the success of trabeculectomy surgery in patients

compared to those treated for less than three years or

controls (14).

The effect of preservatives on patients A large study of 4107 patients by Pisella P. J. and co-

workers (16), showed that symptoms of discomfort upon

instillation, foreign body sensation, stinging or burning,

dry eye sensation, tearing and eye lid itching and signs of

dry eye disease were significantly higher in the patients

taking preserved antiglaucoma eye drops compared to

those taking preservative-free eye drops. The prevalence

of symptoms and signs of dry eye disease increased with

the number of preserved eye drops used and switching

patients to preservative-free antiglaucoma eye drops

reduced both symptoms and signs of dry eye disease (16).

Quality of life has been shown to be reduced in those

suffering from burning, itchy eyes, dry eyes and redness

as a result of topical medication (17). It is not surprising

that the patients who reported worse quality of life and

were unsatisfied with their treatment were the ones who

often missed doses of their medication and had poor

adherence (17). Those patients who reported a good

quality of life and were satisfied with their eye drops had

good adherence (17). Furthermore, patients who reported

that they were unsatisfied with their treatment had

significantly more visits to the eye clinics than patients

who reported being ‘rather satisfied’ with their

Table 2. Preservative-free topical antiglaucoma medication

Antiglaucoma eye drop Class

betaxolol β-blocker

levobunolol β-blocker

metipranolol β-blocker

timolol β-blocker

dorzolamide carbonic anhydrase inhibitor

pilocarpine miotic

bimatoprost prostaglandin analogue

latanoprost prostaglandin analogue

tafluprost prostaglandin analogue

Fixed combination dorzolamide/timolol carbonic anhydrase inhibitor/β-blocker

Fixed combination bimatoprost/timolol prostaglandin analogue/β-blocker

Fixed combination latanoprost/timolol prostaglandin analogue/β-blocker

Fixed combination tafluprost/timolol prostaglandin analogue/β-blocker


The effect of preservatives on the ocular surface and success of glaucoma filtration surgery 44

treatment (17). Therefore, reducing the amount of

preservative load on the ocular surface of patients is

beneficial to reducing adverse symptoms and signs,

improving adherence and reducing unnecessary visits

to eye clinics.

Preservative-free antiglaucoma medication There are a number of preservative-free topical

medications available for treatment of glaucoma (Table

2). All preservative-free topical antiglaucoma medi-

cations have been shown to be non-inferior to the

preserved varieties, suggesting that the preservative is

not required for drug penetration into the eye.

Preservative-free antiglaucoma medications have also

been shown to be better tolerated than the preserved

varieties (16). The increasing use of preservative-free

antiglaucoma therapy will hopefully help improve

patient adherence by improving tolerability of the

medication. The improved adherence to antiglaucoma

medication is important to achieve effective intraocular

pressure lowering and reduce glaucoma progression for

our glaucoma patients.

6. Hendrix DV, Ward DA, Barnhill MA. Effects of anti-

inflammatory drugs and preservatives on morphologic

characteristics and migration of canine corneal epithelial

cells in tissue culture. Vet Ophthalmol 2002; 5: 127-35. 7. Collin HB, Grabsch BE. The effect of ophthalmic preservatives on

the healing rate of the rabbit corneal epithelium after

keratectomy. Am J Optom Physiol Opt 1982; 59: 215-22. 8. Martone G, Frezzotti P, Tosi GM, et al. An in vivo confocal

microscopy analysis of effects of topical antiglaucoma

therapy with preservative on corneal innervation and

morphology. Am J Ophthalmol 2009; 147: 725-35. 9. Van Went C, Alalwani H, Brasnu E, et al. [Corneal

sensitivity in patients treated medically for glaucoma or

ocular hypertension]. J Fr Ophtalmol 2011; 34: 684-90. 10. De Saint Jean M, Brignole F, Bringuier AF, Bauchet A,

Feldmann G, Baudouin C. Effects of benzalkonium

chloride on growth and survival of Chang conjunctival

cells. Invest Ophthalmol Vis Sci 1999; 40: 619-30. 11. Debbasch C, Brignole F, Pisella PJ, Warnet JM, Rat P,

Baudouin C. Quaternary ammoniums and other preser-

vatives’ contribution in oxidative stress and apoptosis on

Chang conjunctival cells. Invest Ophthalmol Vis Sci 2001;

42: 642-652. References 1. Champeau E, Edelhauser H. Effect of ophthalmic

preservatives on the ocular surface: conjunctival and corneal

uptake and distribution of benzalkonium chloride and

chlorhexidinedigluconate. In: Holly, F (Ed), The preocular

tear film Dry Eye Institute, Inc, Lubbock, TX 1986; 292-302. 2. Brignole-Baudouin F, Desbenoit N, Hamm G, et al. A

new safety concern for glaucoma treatment

demonstrated by mass spectrometry imaging of

benzalkonium chloride distribution in the eye, an

experimental study in rabbits. PloS One 2012; 7: e50180. 3. Desbenoit N, Schmitz-Afonso I, Baudouin C, et al.

Localisation and quantification of benzalkonium chloride in

eye tissue by TOF-SIMS imaging and liquid chromatography

mass spectrometry. Anal Bioanal Chem 2013; 405: 4039-49. 4. Wilson WS, Duncan AJ, Jay JL. Effect of benzalkonium

chloride on the stability of the precorneal tear film in

rabbit and man. Br J Ophthalmol 1975; 59: 667-9. 5. Sherwood MB, Grierson I, Millar L, Hitchings RA. Long-

term morphologic effects of antiglaucoma drugs on the

conjunctiva and Tenon’s capsule in glaucomatous patients.

Ophthalmology 1989; 96: 327-35.

12. Baudouin C, Pisella PJ, Fillacier K, et al. Ocular surface

inflammatory changes induced by topical antiglaucoma

drugs: human and animal studies. Ophthalmology 1999;

106: 556-563. 13. Schwab IR, Linberg JV, Gioia VM, Benson WH, Chao

GM. Foreshortening of the inferior conjunctival fornix

associated with chronic glaucoma medications.

Ophthalmology 1992; 99: 197-202. 14. Broadway DC, Grierson I, O’Brien C, Hitchings RA. Adverse

effects of topical antiglaucoma medication. II. The outcome

of filtration surgery. Arch Ophthalmol 1994; 112: 1446-54. 15. Broadway DC, Grierson I, O'Brien C, Hitchings RA.

Adverse effects of topical antiglaucoma medication. I.

The conjunctival cell profile. Arch Ophthalmol 1994; 112:

1437-45. 16. Pisella PJ, Pouliquen P, Baudouin C. Prevalence of ocular

symptoms and signs with preserved and preservative free

glaucoma medication. Br J Ophthalmol 2002; 86: 418-23. 17. Nordmann JP, Auzanneau N, Ricard S, Berdeaux G. Vision

related quality of life and topical glaucoma treatment side

effects. Health Qual Life Outcomes 2003; 1: 75.

Vol. 22, No. 1, 2016

45

Knowledge, attitudes and practices of pre-intern doctors on the

management of emergency ophthalmological conditions M. M. Dissanayake1, S. Vithoosan2, S. A. A. Senevirathne2, N. Wickramasekara2, P. H. Dissanayake2


Abstract Objectives: To assess the knowledge, attitudes and practice

regarding ophthalmological emergencies among pre intern

doctors. Methods: One hundred (n=100) pre intern doctors who

have completed their final MBBS were studied using a self-

administered questionnaire which contained questions on

knowledge, attitudes and practices regarding ophthalmo-

logical emergencies. Data were analyzed using SPSSv20.0. Results: Mean age was 25.96±0.7236 (mean±SD) years

(n=100, males=60; females=40). Assessment of knowledge

revealed that mean knowledge on the diagnosis of ocular

trauma, acute loss of vision, red eye were 4.100±0.8103,

3.44±1.258, 3.28±1.0257 (mean±SD) out of five res-

pectively. Knowledge on the management of above

conditions were 3.82±0.9361, 3.26±1.0211, 3.26±1.1687

out of five respectively. 46% of the students haven't

encountered acute angle closure glaucoma during their

clinical practice. Similarly 56% and 42% haven’t

encountered retinal detachment and corneal foreign bodies.

50% were not confident regarding management of acute

angle closure glaucoma and 22% were not confident

regarding corneal foreign bodies management. 55% felt that

the current duration of 2 weeks for clinical appointment in

Ophthalmology is not adequate. 72% suggested that

increasing clinical exposure is the most suitable way to

improve the knowledge and confidence regarding

management of ophthalmological emergencies. Conclusions: Even though most pre intern doctors have

adequate theoretical knowledge regarding diagnosis and

management of common ophthalmological emergencies,

majority were not confident regarding management of the

emergencies as first contact doctors. Most suggested that

increasing the clinical exposure as the ideal way to improve

their confidence in managing ophthalmological emergencies.

Introduction Ophthalmological emergencies are among the

commonest presentations encountered by primary care

doctors. A sound knowledge of these conditions is essential for doctors to manage them appropriately. Diagnosis and treatment or referral to a center with better facilities will significantly affect the visual prognosis of the patient. However in the present day medical curriculum with so much of content for the undergraduate to cover there were discussions on reducing the time allocated for Ophthalmology. Studies done in various parts of the world regarding the knowledge of medical practitioners regarding ophthalmological emergencies showed that most medical undergraduates and first contact care doctors lack a sound knowledge regarding the diagnosis and management of ophthalmological emergencies.

Objective To assess the knowledge, attitudes and practices

regarding ophthalmological emergencies among pre

intern doctors

Methodology One hundred (n=100) pre intern doctors who have completed their final MBBS at a Sri Lankan medical school were studied using a self-administered questionnaire which contained questions on general information, knowledge on emergency ophthal-mological conditions and attitudes and practices regarding ophthalmological emergencies. Ethical clearance was obtained from the Ethics Review Committee of Faculty of Medicine, University of Colombo. Data were analyzed using SPSS v 20.0.

Results Sample size was 100 with 60% males. Mean age was

25.96±0.7236 years. All participants had undergone

two weeks of clinical training in ophthalmology. Data analysis was carried out to obtain a mean score

giving an assessment of each of the ophthalmological

emergencies.

1Senior Lecturer and Consultant Ophthalmologist, Faculty of Medicine, University of Colombo, 2Research Assistant,

Faculty of Medicine, University of Colombo, 3Senior Lecturer, Faculty of Medical Sciences, University of Sri Jayewardenepura, Sri Lanka.


Knowledge, attitudes and practices of pre-intern doctors on the management of emergency ophthalmological conditions 46

Assessment of knowledge regarding ophthalmological

emergencies revealed mean scores of 4.100±0.8103,

3.44±1.258, 3.28±1.0257 (mean±SD) out of five for ocular

trauma, acute loss of vision, red eye respectively.

Figure 1.

Assessing the knowledge on management of ophthal-

mological emergencies revealed that mean knowledge

on management of ocular trauma was acute loss of

vision, red eye were 3.82±0.9361, 3.26±1.0211,

3.26±1.1687out of five respectively.

Figure 2.

Regarding the familiarity with emergency eye con-ditions

46% of the students have not gained adequate knowledge

on acute angle closure glaucoma during their clinical

appointment. Similarly 56% and 42% have not had

adequate exposure on practical manage-ment on retinal

detachment and corneal foreign bodies.

With regard to confidence in managing emergency eye

conditions, 50% were not confident regarding manage-

ment of acute angle closure glaucoma and 22% were

not confident regarding corneal foreign bodies

management.

Even though all have agreed ophthalmological training

should be a part of undergraduate curriculum 55% felt

that the current duration of 2 weeks for clinical

appointment in Ophthalmology is not adequate. 72% suggested that increasing clinical exposure is the

most suitable way to improve the quality of

knowledge regarding ophthalmological emergencies

Discussion Though the pre interns have satisfactory theoretical

knowledge most of them have not had adequate exposure

to most of the emergencies in clinical practice during their

student days. Most were not confident about their ability

to manage the emergencies themselves as first contact

doctors. This could also result from the recent changes in

the medical curriculum trying to incorporate more of core

clinical areas during the undergraduate period. Most of

the participants suggested that increasing the clinical

exposure as to improve the knowledge and skills on

diagnosis and management of ophthalmological

emergencies. At the same time it is the duty of the

ophthalmogist to act proactively assisting the curriculum

development committees to incorporate inputs from

ophthalmology in to core curricular material as they

make an essential component of the work of primary care

doctors. The International Council of Ophthalmology also

provides guidance to increase ophthalmology training in

medical schools. It recommends 40-60 hours of

ophthalmology exposure during undergraduate medical

education which is barely covered in most medical

schools.

Acknowledgements We would like to acknowledge Professor Rohan W

Jayasekara, Emeritus Professor and Former Dean,

Faculty of Medicine, University of Colombo for the

support and guidance.

References 1. Quillen DA, Harper RA, Haik BG. Medical student

education in ophthalmology: crisis and opportunity

Ophthalmology 2005; 112(11): 1867-8. 2. Jacobs DS. Teaching doctors about the eye: trends in the

education of medical students and primary care residents.

Surv Ophthalmol. 1998; 42(4): 383-9. 3. Manolopoulos J. Emergency primary eye care. Tips for

diagnosis and acute management. Aust Fam Physician

2002; 31(3):233-7. 4. Tong, Lili et al. Eye Day for medical students: delivering

ophthalmic undergraduate education through inter-

professional collaboration. Canadian Journal of Ophthal-

mology 2016; 51(4): 242-3.

Vol. 22, No. 1, 2016

47

Effect of axial length on accuracy of different types of biometry in

phacoemulsification surgery H. P. M. K. Gunewardena1, N.G. I. R. De Silva1, M. T. K. Perera2, W. M. C. M. Andradi3, D. H. H. Wariyapola4


Abstract Introduction: The target of cataract surgery is an ultimate

good vision with minimal refractive errors. Final outcome

will depend mainly on the accuracy of the biometry. Both

immersion and optical biometry are in use for biometry

world wide. Some studies have shown advantages and

disadvantages of each other. This study was done to find the

accuracy of final refractive outcome between IOL master

(OPT) and Immersion A scan in hypermetropes, myopes

and emmetropes and analyse which of the two biometry

methods would be better for each instance. Methodology: A retrospective longitudinal study was

carried out from March 2013 to September 2015 in Sri

Jayawardenapura General Hospital (SJGH) on 490 eyes-

which was conveniently selected. IOL Master biometry and

Immersion A biometry was performed randomly in these

patients before cataract surgery. Post-operative data was collected after one month and spherical

equivalent and the difference between the predicted refraction

and spherical equivalent was calculated. Finally comparison of

error in prediction was done in all groups. Results: In 490 eyes, IOL master, measurement was done

in 363 eyes which resulted in 331 emmetropes, 13 myopes

and 19 hypermetropes. In 127 eyes, measurement was done

by Immersion A scan which resulted in 106 emmetropes, 04

myopes and 17 hypermetropes. No statistically significant difference was seen in all three

groups, for the prediction of final refractive outcome (Paired

t test was done). Conclusion: Our study suggests that optical biometry [IOL

master] and immersion biometry are both clinically acceptable

in patients with hypermetropes, myopes and emmetropes.

Introduction A patient hopes for the best vision at the end of a

cataract surgery. Ultimate good vision depends on the

accuracy of biometry. Both immersion (IMM) and optical biometry (OPT, IOL

master) have been shown to have comparable

predictive ability in emmetropic eyes.

However this is often different with axial myopic and

hyperopic eyes, requiring greater refractive corrections

post operatively. There are some benefits of Immersion A scan over IOL

Master. Immersion A scan is useful in dense ocular

media with mature cataract, a patient who is unable to

sit on a table and those who are having fixation

disorders. There are some benefits of IOL master over Immersion

A scan too. IOL master is not dependant on the user. It

is extremely useful in patients with macular disorders

and extreme myopics.

Objectives

• To analyze the accuracy of final refractive outcome between IOL master (OPT) and Immersion A scan in hypermetropes, myopes and emmetropes.

• To analyse which of the two biometry

methods would be better for each instance.

Methodology A retrospective longitudinal study was carried out from

March 2013 to September 2015 in Sri Jayawardenapura

General Hospital (SJGH) on 490 eyes. Convenient

sampling method was carried out and axial length was

calculated randomly by IOL master or Immersion A scan

in groups of emmetropes, myopes and hyper-metropes

pre operatively and predicted refraction was calculated

by SRK/T formula.

All the cataract surgeries were done by a single

surgeon using 2.2mm incision. A single piece IOL was

implan-ted and complicated surgeries were excluded.

All the patients had an uneventful post-operative

period and after one month spherical equivalent and

1Post Graduate Trainee, 2Registrar, 3Research Assistant, 4Consultant Ophthalmologist, Sri Jayewardenepura General Hospital, Kotte, Sri Lanka.


Effect of axial length on accuracy of different types of biometry in phacoemulsification surgery 48

the difference between the predicted refraction and spherical equivalent was calculated. Finally com-parison of

error in prediction was done in all groups.

Results In 490 eyes, IOL Master, measurement was done in 363 eyes which resulted in 331 emmetropes, 13 myopes and

19 hypermetropes. In 127 eyes, measurement was done by Immersion A scan which resulted in 106 emmetropes,

04 myopes and 17 hypermetropes.

Hypermetropes Myopes Emmetropes

IOLM IMM IOLM IMM IOLM IMM

PE 0.68D 0.54D 0.32D 0.20D 0.37D 0.52D

(+/-0.75) (+/- 0.44) (+/- 0.24) (+/- 0.19) (+/- 0.38) (+/- 0.46)

Axial length range PE

26-27mm -0.30

27-28mm -0.31

28-29mm -0.34

29-30mm -0.29

Conclusion This study suggests that optical biometry [IOL master] and immersion biometry are both clinically acceptable in

patients with hypermetropes, myopes and emmetropes.

Vol. 22, No. 1, 2016

49

Astigmatic change following suture manipulation after deep anterior

lamellar keratoplasty (DALK) S. K. G. S. Kurera1, K. H. Wickramasinghe2, C. J. Kumarage3, W. M. C. M. Andradi4, D. H. H. Wariyapola5

The Journal of the College of Ophthalmologists of Sri Lanka 2016; 22: 58-60 Abstract Introduction: A successful DALK requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Therefore post DALK suture manipulation is mandatory to minimize postoperative astigmatism. Method: Post DALK suture manipulations done from July 2010 to August 2015 were included. 87 patients were followed up. Patients had undergone removal of sutures (ROS) depending on astigmatism, starting from 3rd month post DALK. Before ROS and month after ROS, keratometry was checked. Results: 20.5% of single suture removals were done at 3 months and resulted in a surgically induced astigmatic change (SIAC) ranging between 0.29 -19.43. 10.3% were at 6 months and SIAC ranged between 0.13-2.76, 7.7% were at 9 months and SIAC ranged between 0.83-1.51, 12.8% were at 12 months and SIAC ranged between 0.50 -2.92, 10.3% were at 15 months and SIAC ranged between 0.28-1.50, 10.3% were at 18 months and SIAC ranged between 0.57-4.81, 15.4% were at 21 months and SIAC ranged between 0.50 - 8.66, and 5.1% were at 24 months and SIAC was 0.69. 7.6% were after 24 months. 13.9% of double suture removals were done at 3 months and

resulted in a SIAC ranging between 0.57-9.25. 32.5% were at

6 months and SIAC ranged between 0.39-10.69, 15.1% were at



15 months and SIAC ranged between 0.77-14.17, 10.2% were

at 18 months and SIAC ranged between 0.69-16.44, 3.6% were

at 21 months and SIAC ranged between 1.95 -5.97, 2.4% were

at 24 months and SIAC ranged between 1.33-1.86. 2.4% were

after 24 months. Conclusion: Astigmatic change per single ROS stabilises

after 6 months. For double ROS astigmatic change is higher

after 6 months than single ROS.

Methodology DALK was first introduced to SJGH in December 2009. It

is a single surgeon station where the same surgeon

performed all DALK and the decision to offer DALK was

taken by him. The patient’s pre-operative data was

collected and included with demographic data, preoperative refraction, BCVA, topography and pachymetry. Post DALK suture manipulations done from July 2010 to August 2015 were included in the study. 87 patients were followed up who had under-gone removal of sutures (ROS) depending on astig-matism, starting from 3rd month post DALK. Before ROS and a month after ROS, average keratometry was checked and surgically induced astigmatic change was calculated (SIAC) using internet based SIA calculator. Data was collected from clinical records and investigations and a data collection form was used to record the data. The patients included in the study had a routine post-operative review at 1 month. At this review data on refraction, BCVA and topography were collected. Data collection was done by ophthalmology trainees and data was analysed using SPSS. Loose suture removals and broken suture removals were not included in the study.

Results Of the removal of sutures 14.8% were done at 03 months, 27.4% were done at 06 months, 13.9% were done at 09 months, 15.3% were done at 12 months, 5.6% were done at 15 months, 9.7% were done at 18 months, 5.6% were done at 21 months, 2.8% were done at 24 months, and 4.9% were done after 24 months.

Figure 1. Distribution of ROS at each encounter

by percentage.

1Post Graduate Trainee in Ophthalmology, 2Registrar in Ophthalmology, 3Senior Registrar in Ophthalmology, 4Research Assistant, 5Consultant Ophthalmologist, Sri Jayawardenapura General Hospital, Kotte, Sri Lanka.


Astigmatic change following suture manipulation after deep anterior lamellar keratoplasty (DALK) 50

For single suture removals, 20.5% of single ROS were

done at 3 months and SIAC ranged between 0.29-19.43

with a mean of 3.8, 10.3% were at 6 months and SIAC

ranged between 0.13-2.76 with a mean of 1.7, 7.7%

were at 9 months and SIAC ranged between 0.83-1.51

with a mean of 1.2, 12.8% were at 12 months and SIAC

ranged between 0.50-2.92 with a mean of 1.8, 10.3%

were at 15 months and SIAC ranged between 0.28 -

1.50 with a mean of 0.8, 10.3% were at 18 months and

SIAC ranged between 0.57-4.81 with a mean of 3.3,

15.4% were at 21 months and SIAC ranged between

0.50-8.66 with a mean of 4.2 and 5.1% were at 24

months and SIAC was 0.69. 7.6% were after 24 months.

Figure 2. Mean SIAC following single suture removals.

For double suture removals, 13.9% of double ROS

were done at 3 months and SIAC ranged between 0.57-


SIAC ranged between 0.39-10.69 with a mean of 4.4,

15.1% were at 9 months and SIAC ranged between

0.63 - 7.59 with a mean of 3.6, 15.7% were at 12 months

and SIAC ranged between 0.51-14.50 with a mean of

3.9, 4.2% were at 15 months and SIAC ranged between

0.77- 14.17 with a mean of 5.3, 10.2% were at 18

months and SIAC ranged between 0.69-16.44 with a

mean of 5.1, 3.6% were at 21 months and SIAC ranged

between 1.95-5.97 with a mean of 3.9 and 2.4% were at

24 months and SIAC ranged between 1.33-1.86 with a

mean of 1.5. 2.4% were after 24 months.

For quadruple suture removals, 11.1% of quadruple ROS

were done at 3 months and resulted in a SIAC of 6.76,

22.2% were at 6 months and SIAC ranged between 5.28-


SIAC ranged between 0.72-9.14 with a mean of 4.9 and

22.2% were at 12 months and SIAC ranged between 2.57-

6.45 with a mean of 4.5. 22.3% were after 12 months. Data

for quadruple suture removals were few after 12 months

and the data was scattered.

Figure 3. Mean SIAC following double suture removals.

Figure 4. Mean SIAC following quadruple

suture removals. Discussion The decision to offer DALK to patients, who cannot be

adequately treated with glasses and contact lenses, is

based on clinical judgement. Postoperative clinical

parameters may be influenced by the lamellar dissection

technique and suture tension and patient corneal

characteristics like central corneal thickness. It is

important to understand that a clear corneal graft may be

an optical failure if high astigmatism limits visual acuity

and post DALK suture manipulation is useful to

minimize postoperative astigmatism. In this study the

majority who had DALK are young patients with

keratoconus and had an average patient age of 26 years. It

is the most productive part of their lives in terms of

education and career development. Therefore the

decision to offer timely surgery becomes imperative. It

Vol. 22, No. 1, 2016

51

is still the patients’ visual requirement and tolerability

of eyewear that is considered when managing the

patient postoperatively. At the time when these

patients required surgery, majority had moderate to

severe keratoconus.

Of the single ROS, mean SIAC was minimal between 6

and 15 months, but significantly high between 18 and

21 months (3-4D). In double ROS group, the mean

astigmatic change was about the same from 6 to 21

months, but the variability is significant. In quadruple

ROS, the difference is not significant between 3 to 12

months.

Conclusion We were unable to see a definite pattern between early

ROS and late ROS. It is generally believed that early

ROS cause more change in astigmatism than late ROS.

Some believe that late ROS (> 2 years) would not have

much effect. In our study, we noted that at 3 months

the mean SIAC was only 3.8D, but there was a wide

range with a maximum of 19.43D. This would agree

with the commonly held beliefs that early ROS cause a

high astigmatic change. At least in the initial stages

(up to about 9 to 12 months), the astigmatic change is

higher in quadruple ROS than double and single and

higher in double than single.


Conjuctival intraepithelial neoplasia 52

Conjuctival intraepithelial neoplasia – a case study G. J. N. Widanage, I. K. Devasurendra, B. Amarasinghe, S. Nanayakkara The Journal of the College of Ophthalmologists of Sri Lanka 2016; 22: 61-63

Introduction Ocular surface squamous neoplasia (OSSN) encompasses a wide and varied spectrum of disease involving

abnormal growth of dysplastic squamous epithelial cells on the surface of the eye (3).

Figure 1.1 Figure 1.2 Figure 1.3 Figure 1.4 Figure 1. Schematic representation of the progression of OSSN. The figure 1.1 represents normal epithelium with basement

membrane (pink line). In conjunctival intraepithelial neoplasia (CIN), a portion of the epithelium is replaced with dysplastic

cells. Carcinoma in situ is the complete replacement of epithelium by dysplastic cells, with the basement membrane still

intact. In invasive squamous cell carcinoma, note the invasion through the basement into the stroma (3).

Conjunctival intraepithelial neoplasia (CIN) is non-invasive by definition. The basement membrane and the

underlying substantia propria remain intact (1,2). It is a slow-growing tumour that arises from a single mutated

cell on the ocular surface (1). CIN is known by other names including Bowen’s disease, conjunctival squamous

dysplasia, intraepithelial epithelioma, and epithelial dyskeratosis (1). Case report A forty three years old male presented to the outpatient department at National Eye Hospital, Colombo with the

history of slow growing reddish fleshy growth over lateral aspect of left eye of 1 year duration. It was not painful

and did not affect his vision. He was a known diabetic patient on oral hypoglycemic drugs. No significant surgical

or ocular history noted. His visual acuity of left eye was 6/9. He had fleshy well circumscribed conjunctival lesion which was extending

from 11 o’clock to 7 o’clock position around the limbus spreading onto the peripheral cornea. The surface

appeared gelatinous with a prominent “corkscrew” vascular pattern. The adjacent conjunctiva appears injected

with prominent “feeder vessels” leading to the lesion. Rest of the anterior segment and fundus of left eye

appeared normal except for mild non proliferative diabetic retinopathy. There was no palpable lymph nodes or

evidence of distant metastases.

Vol. 22, No. 1, 2016

53

Investigations showed; FBC: WBC 6600, N-64, L-32, E-04, ESR 28mm in 1st hour, RBS-282mg/dl, Blood picure-

normal, CXR-normal, ANA-negative. Wide conjuctival excision with 4 mm margin and corneal epithelium excision with 3mm margin with complete

lamellar dissection was done. The edges of the excised conjuctival margins were treated with cryotherapy (-45°C

or 45 seconds). Amniotic membane graft was applied over the surface. Histology showed intraepithelial dysplasia

amounting to focal severe dysplasia suggesting close follow up.

Figure 2.

Figure 3.

The patient was explained about the condition with the importance of close follow up. As the excised tissue

margins were not involved with dysplasia patient is being following up 6 monthly after the surgery. No

recurrences noted upto now.

Discussion Conjunctival neoplasia is showed to make up 14% of all primary ocular and orbital tumors due to sun exposure (4). UV-B exposure in male gender with light complexion is known to be main risk factors and the prevalence is

higher in equatorial regions around the world (4). UV associated mutations in tumour suppressor genes such as


Conjuctival intraepithelial neoplasia

p53 and hereditary deficiency of DNA repair such as in Xeroderma pigmantosa increases the risk of CIN. It is also associated with human papilloma virus infection subtypes 16 and 18 as well as HIV infection. Non HIV related immunosuppression, old age and smoking are other risk factors (3). Typically, patients present with a gelatinous or plaque like interpalpebral conjunctival gray or white lesion nasaly or temporaly (6). Approximately 95% of CIN lesions occur at the limbus, where the most actively mitotic cells reside (1). There are three major clinical variants of CIN: papilliform, gelatinous, or leukoplakic (1). The adjacent conjunctiva appears injected, with prominent “feeder vessels” leading to the lesion (3). The surface appears gelatinous or leucoplakia and a prominant “corkscrew” vascular pattern (3). Histologically, the epithelium exhibits hyperplasia, loss of

goblet cells, loss of normal cell polarity, nuclear

hyperchromasia, pleomophism, mitotic figures and mild

to moderate increase in nuclear to cytoplasm ratio (3). The most important assessment is whether the neoplasia contained by basement membrane or neoplastic cells have traversed the epithelial basement membrane and invaded the stroma (3). For lesions contained by basement membrane, the term con-junctival intraepithelial neoplasia (CIN) may be used. The neoplasia can be graded as mild, moderate or severe according to degree of cellular atypia. In cases with most severe atypia, full thickness involvement of the epithelium is seen, ofen with squamous eddies or keratin pearls/whorls which was noted in our patient (3). CIN that involves the entire epithelium is referred to

as carcinoma-in-situ (5). On pathology, there is a

characteristic sharp demarcation line between normal

and abnormal epithelium (5). Due to a barrier provided

by Bowman’s membrane, subepithelial cellular invasion

is almost exclusively limited to the conjunctiva (1). Surface keratinization and dyskeratosis can be seen oftenly (3). A chronic inflammatory response is often present in substantia propria. Excision margin at the time of surgery is the most important factor in predicting recurrences. The slow growth of the recurrent lesions with malignant potential leads to suggest that all patients with history of CIN warrant annual follow up for the remainder of their lives. Intraocular spread of squamous conjunctival neoplasia is

rare in developed countries (< 5% of cases). When

intraocular penetration occurs it is typically through the

limbus. Signs include neovascularization of the

54

iris and cornea as well as glaucoma, peripheral

anterior synechiae, thickening of the ciliary body, uvea

and blunting of the iridocorneal angle. High frequency

ultrasound is particularly helpful in these cases. Intra-

ocular penetration is typically treated by enucleation

of the eye or eye-wall resection (4).

The use of topical chemotherapeutic agents, including

Interferon- 2b, mitomycin C, and 5-fluorouracil have

the advantage of treating the entire ocular surface and

avoiding surgical complications such as positive

margins, scarring, and limbal stem cell deficiency (5).

Prognosis The recurrence rate of OSSN after surgical excision can

occur in over half of the cases and may occur years

later (7). The rate of recurrence is substantially higher

in the setting of positive surgical margins. Even if the

surgical margins are negative, up to one third of eyes

may experience a recurrence within 10 years (7). A recurrent OSSN can grow rapidly and be more

invasive, and thus needs to be treated with aggressive

medical, surgical or combination therapy (1). The

conjunctival lesions involving over half of the limbal stem

cells have very poor pronosis such as in our patient

highlighting the importance of long term follow up (1).

Overall, SCC is generally associated with local invasion

rather than widespread systemic metastases.

References 1. Krachmer JH, Mannis MJ, Holland EJ. Cornea:

Fundamentals, diagnosis and management. 2005. 2. Reidy JJ, Bouchard CS, Florakis GJ, et al. Basic and

Clinical Science Course 2011-2012; 2011: 226-33. 3. American Academy of Opthalmology – opthalmic

pathology and intra ocular tumors (Volume 2014-2015). 4. Squamous carcinoma and intraepithelial neoplasia of the

conjunctiva by Paul T. Finger, MD. https://eyecancer.com/

eye-cancer/conditions/conjunctival-tumors/squamous-

carcinoma-intraepithelial-neoplasia-conjunctiva/ 5. Ocular surface squamous neoplasia. http://eyewiki.

aao.org/Ocular_Surface_Squamous_neoplasia 6. Kiire CA, Srinivasan S, Karp CL. Ocular Surface

Squamous Neoplasia. International Ophthalmology Clinics

2010; 50: 35-46. 7. Tabin G, Levin S, Snibson G, et al. Late Recurrences and

the Necessity for Long-term Follow-up in Corneal and

Conjunctival Intraepithelial Neoplasia. Ophthalmology

1997; 104: 485-92.

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