the best refractive surgery aao 2008

$: The Best Refractive Surgery AAO 2008$
A S U P P L E M E N T T O E Y E N E T M A G A Z I N EEyeNet

S E L E C T I O N S

The Best of CATARACT SURGERY

The Best ofThe Best of CATARACTCATARACT& REFRACTIVE SURGERY REFRACTIVE SURGERY

The Best of REFRACTIVE SURGERY

The Best of RETINA

The Best of PRACTICEMANAGEMENT

e y e n e t s e l e c t i o n s 3

Dear Subspecialty Day Attendee, Cataract and refractive surgeons find

themselves at a crossroads at this year’sJoint Meeting. The technologies availablefor improving refraction on both cornealand lenticular planes are the best we’veever had, and yet the small fraction ofpatients dissatisfied with the results oftheir ablation or lens implant has gar-nered much public attention.

How can you avoid the pitfalls andgather the pearls of cataract and refrac-

tive medicine? Start by reviewing whatsome of the top experts in your field hadto say in the stories compiled for youhere in EyeNet Selections. Then enjoyyour Atlanta Meeting to the fullest.

L e t t e r F r o m t h e E d i t o r

EyeNetSUBSPECIALTY DAY

ATLANTA 2008

S E L E C T I O N S

New Pupil Expansion Ring for Floppy Iris

A new expansion ring could help surgeons facing a tamsulosin-affected iris.

5Capsular Tension Rings: Innovation and DebateSurgeons discuss new approaches to zonular weakness, but differ on the criteria for using a tension ring.

7The Value and Vagaries of Sterile Technique

What is the standard for infection control? Surprisingly, refrac-tive surgeons often have very different ideas on what is warranted.

9The Origins and Treatment of Childhood Cataract

Treatment timing and an understanding of the genetic under-pinnings are improving the outlook for congenital cataract.

11IOL Calculations: When Millimeters Counts

How to improve the precision of your IOL calculations.13

clinical update

ON THE COVER: Injection of a CTR through a microincision controlled by a Lester hook. I. Howard Fine, MD

17feature

Ectasia After LASIK

Ectasia induced by refractive surgery can be puzzling. A grow-ing consensus on safeguards and a new registry to track itsincidence may solve that.

Richard P. Mills, MD, MPHChief Medical Editor

EyeNet Magazine/EyeNet Selections


As the population ages, anincreasing number of oph-thalmology patients are like-ly to present with the condi-tion known as intraoperative

floppy iris syndrome (IFIS). Resultingfrom treatment with tamsulosin (Flo-max) as well as other systemic alphaantagonists prescribed for benign pro-static hyperplasia, IFIS can result inpoor pupil dilation, iris billowing andfloppiness, iris prolapse to the incisionsand progressive miosis.

There are a number of techniquesthat the cataract surgeon can use to deal with IFIS, including preoperativeatropine drops, intracameral injectionof alpha agonists, the use of Healon 5with low aspiration flow and vacuum,and, finally, mechanical devices thatexpand and maintain the pupil diame-ter during surgery. Such devices includeiris retractors and a variety of differentpupil expansion rings.

New Ring on the BlockThe newest of the expansion rings is the Malyugin ring (MicroSurgicalTechnology, or MST). Developed byBoris Malyugin of Russia, the foldablesquare device is made of polypropyleneand is much thinner than other rings,making it easier and safer to manipu-late inside the eye, according to DavidF. Chang, MD, who, along with John R. Campbell, MD, first reported IFISsyndrome in cataract patients.1 “The

Malyugin ring has the thin profile of anIOL haptic, and so it doesn’t get in theway of our instruments during surgery.It’s easy to avoid corneal contact duringinsertion,” said Dr. Chang, who is clini-cal professor of ophthalmology at theUniversity of California, San Francisco.The loading and injection system, incontrast to those for other pupil expan-sion rings, is also disposable. The flexi-ble device is injected into the anteriorchamber, where its four circular coilsengage the pupil edge to expand it,according to Dr. Chang.

Go easy on the iris. Because of howthe iris drapes over it, the Malyugin ring,in contrast to iris retractors, creates arounded rather than a square pupillaryopening. It expands the pupil withoutoverly stretching or traumatizing it,and is therefore very gentle on the iris,according to Dr. Chang. “The cleverinjector system devised by MST is used

to both insert and remove the ring fromthe anterior chamber,” Dr. Chang noted.“The learning curve is very fast, and itcan be inserted more quickly than irisretractors, making this an ideal tech-nique for resident cases,” he added.

Dr. Chang noted that he has done 30 IFIS and small-pupil cases with theMalyugin ring, and the outcomes havebeen excellent. As with other devicesthat mechanically expand the pupil, theMalyugin ring is particularly useful forsevere IFIS. “Because the ring is so thinand light, it is still mobile enough toallow the iris to occasionally prolapse tothe side port incision,” Dr. Chang added.“However, the pupil obviously cannotconstrict,” he said. “If the ring seems tode-center to one side, one lateral scrollhas probably hooked the edge of thecapsulorhexis, and can simply be disen-gaged with a Lester hook.”

I. Howard Fine, MD, has also used

New Pupil Expansion Ring for Floppy Iris

C A T A R A C T

Clinical Updatetools and t echn iques

by barbara boughton, contributing writer

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(1) After insertion into the anterior chamber with a disposable injector, the leadand lateral scrolls of the Malyugin ring engage the iris margin. (2) A Lesterhook is used to position final scroll. (3) The ring creates 6-mm diameter pupil.

M a l y u g i n R i n g G o e s t o W o r k1 2 3

This article originally appeared in the January

2008 issue of EyeNet Magazine.

6 s u p p l e m e n t

the Malyugin ring and calls it “veryatraumatic. It goes in quite easily, andholds the pupil in an expanded waywith a nice 6-mm pupillary opening.It’s very easy to work with; rather thanbeing a full 1 mm, it’s like a thin paperclip,” said Dr. Fine, clinical professor ofophthalmology at Oregon Health & Science University in Portland.

Older RingsPupil expansion rings that have been inuse for a while now include the Morcher5S Pupil Ring and the Milvella PerfectPupil—both of which are threaded alongthe pupillary margin using a metalinjector. The Eagle Vision Graether ringis a disposable silicone pupil expansionring that uses a plastic injector. How-ever, all of these rings are difficult toposition if the anterior chamber is shal-low or the pupil is less than 4 mm wide.

Graether. The Graether is a soft sili-cone ring grooved to engage the irissphincter and maintain pupil dilation.The pupil expander is preloaded onto adisposable insertion tool that allows thering to be inserted through the primarysurgical incision. An iris-glide retractorfixates the iris sphincter at the incisionprior to insertion, according to John M.Graether, MD, who developed the ringand is in private practice in Marshall-town, Iowa.

Dr. Graether estimates that in hispractice, he sees IFIS in 3 to 4 percent of his patients, and he uses the Graetherring on up to 10 to 15 percent of hispatients because they may have eitherIFIS or another condition in which thepupil does not dilate well. In contrast,he finds iris retractors problematic.“They put pressure and indentations onthe iris,” he said. Dr. Graether estimatesthat his ring can be inserted in about 30seconds.

Milvella. Strategies for dealing withIFIS often depend on the preference ofthe surgeon, according to Robert M.Kershner, MD. He prefers using the Perfect Pupil expansion ring for severecases of IFIS. It was developed in the1990s by John E. Milverton, MD, ofAustralia, and is a sterile, disposable,polyurethane ring with an integratedarm that allows for insertion into the eye

and removal after surgery. It is insertedthrough an unenlarged clear cornealincision, according to Dr. Kershner, whois clinical professor of ophthalmologyat the University of Utah in Salt LakeCity. Capsulorhexis, hydrodissection,phacoemulsification and IOL insertioncan all be safely carried out with thePerfect Pupil expansion ring in place.

“It’s easy to get in and out, and it canexpand the pupil to 7 to 8 mm,” said Dr.Kershner. It also covers the pupillarysphincter on both sides. “This providesadded protection because it’s possibleduring surgery to hit the pupil with the phaco tip.” Dr. Kershner has used itwith a variety of IFIS cases. “Often thechoice a surgeon will make in IFIS casesdepends on their experience as well astheir comfort level with differentdevices,” he said.

Morcher. Dr. Fine has used theMorcher pupil expansion ring as well as the Malyugin ring and notes thatremoval technique is important withthe Morcher ring. When removing theMorcher, he noted, the leading edge ofthe ring should be perpendicular to theincision, and the ring can then be caughtwith the hook of the injection system.“If you use this technique, the ring canbe removed comfortably and safely.”

IFIS UpdateIFIS was first described in 2005 by Drs.Chang and Campbell in a retrospective/prospective study of 1,600 patients. Dr.Chang agreed that while IFIS was firstreported with the use of tamsulosin, itis also seen with other alpha1 blockerssuch as doxazosin (Cardura), terazosin(Hytrin) and alfuzosin (Uroxatral), apossibility that had been suggested earlyon by Dr. Kershner.2 However, the fre-quency and severity of IFIS is apparent-ly more severe with Flomax, perhapsbecause of its greater affinity for thealpha1a receptor subtype, which is pres-ent in both the prostate and the irisdilator muscle, according to Dr. Chang.

Following the 2005 report by Drs.Chang and Campbell, the FDA approveda labeling change for Flomax, notingthat “the patient’s ophthalmologistshould be prepared for possible modifi-cations to their surgical technique.” The

manufacturer of Flomax now includes a warning in its direct-to-consumeradvertisements.

When using iris retractors, Dr. Changrecommends placing them in a diamondconfiguration.3 The subincisional hookretracts the iris downward and out ofthe path of the phaco tip—in contrast toa square iris hook configuration, whichtents the iris up into the path.

In an audience poll on complicatedcases at the 2007 Annual Meeting inNew Orleans, iris retractors were themost popular method for dealing withIFIS during cataract surgery.

Plan ahead. When the surgeon knowsthe patient is taking tamsulosin, avail-able strategies can provide positive outcomes. In a prospective multicenterstudy published in Ophthalmology, Dr.Chang and fellow researchers studied167 consecutive eyes in 135 patientstaking tamsulosin. Phacoemulsificationwas performed with at least one of fourdifferent IFIS strategies, including topical atropine, iris retractors, pupilexpansion rings or Healon 5 withreduced fluidic parameters.4

The results showed that although 73 percent of patients had moderate orsevere IFIS, the rate of posterior capsu-lar rupture and vitreous loss was only0.6 percent. The study revealed that 95percent of the eyes also achieved a best-corrected visual acuity of at least 20/40.

“When experienced surgeons couldanticipate IFIS and employ compen-satory surgical techniques, the compli-cation rate from cataract surgery waslow and the visual outcomes were excel-lent in eyes of patients with a history oftamsulosin use,” Dr. Chang and fellowauthors concluded.

Drs. Chang, Fine and Kershner report no

related financial interests. Dr. Graether has

a patent interest in the Eagle Vision ring.

1 Chang D. F. and J. R. Campbell. J Cataract

Refract Surg 2005;31:664–673.

2 Kershner, R. M. J Cataract Refract Surg

2005;31:2239–2240.

3 Oetting, T. A. and L. C. Omphroy. J

Cataract Refract Surg 2002;28:596–598.

4 Chang, D. F. et al. Ophthalmology 2007;

114(5):957–964.

C a t a r a c t


It is difficult to believe that a tiny,round device no thicker than 0.22mm could cause lively discussionand dissension among cataractsurgeons. But recent innovations

to the capsular tension ring (CTR)—and the fact that the government refusesto reimburse its use—make for a chargedtopic.

The basics of CTRs are straightfor-ward enough, said Samuel Masket, MD,clinical professor of ophthalmology atthe University of California, Los Angeles.Capsular tension rings are designed tostabilize the capsular bag in cases ofzonular dehiscence, he said, allowing an IOL to be implanted in the bag whenit might otherwise have had to be posi-tioned elsewhere. The open-ended ringhas a flexible horseshoe shape and ismade of PMMA filament, with eyeletsat either end.

The ring works by supporting areasof zonular weakness and allow redistri-bution of the existing zonules. Dr. Mas-ket noted that a standard tension ring isused in patients with less than 4 clockhours of zonule loss and both finitezonule loss and diffuse zonular weak-ness. “In some patients, CTRs can beused in anticipation of later problems,”he said.

Originals Followed by InnovationsTwo manufacturers originally introducedrings to the market. Morcher receivedapproval for its models 14, 14A and 14C

in 2003, and Ophtec received approvalfor its Oculaid and Stableyes in 2004.There also have been some modifica-tions since then:● Robert J. Cionni, MD, medical direc-tor at the Cincinnati Eye Institute, intro-duced the modified Morcher ring, whichhas a fixation hook that can be suturedto the scleral wall without piercing thecapsular bag.● Ike K. Ahmed, MD, assistant profes-sor of ophthalmology at the Universityof Toronto, developed the Ahmed Cap-sular Tension Segment, a partial ringwith a fixation hook that can be placedfollowing anterior capsulotomy and fix-ated using an iris retractor. It can alsobe permanently fixated with a suture.

● Bonnie A. Henderson, MD, assistantclinical professor of ophthalmology atHarvard University, modified the origi-nal 14C Morcher CTR. The new ring,aptly named the Henderson CapsuleTension Ring, is an open C-shaped loopmade of PMMA. Its uniqueness comesfrom eight equally spaced indentationsof 0.15 mm, which are intended toimprove the surgeon’s ability to removenuclear and cortical material whilemaintaining equal expansion of thecapsular bag.● Ehud I. Assia, MD, and colleaguesintroduced the Capsular Anchor (Hani-ta Lenses) at the Academy’s 2007 Annu-al Meeting in New Orleans. Dr. Assia ischairman of ophthalmology at Meir

Capsular Tension Rings:Innovation and Debate

C A T A R A C T


by lori baker schena, contributing writer

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Injection of a CTR through a microincision controlled by a Lester hook.

T e n s i o n t o t h e R e s c u e

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Medical Center in Kfar-Saba, Israel, aswell as associate professor at Tel-AvivUniversity. This device for securing thecapsular bag to the scleral wall is a one-plane intraocular implant made ofPMMA. Robert H. Osher, MD, profes-sor of ophthalmology at the Universityof Cincinnati, explained that the Cap-sular Anchor works like a paper clip,with a central rod that is placed in frontof the capsule, and two lateral armsinserted through the capsulorhexis andplaced behind the capsule. A suture canthen be looped through the “paper clip”and anchored to the eye.

“I must say that at the Academymeeting, Bonnie and Ehud’s modifica-tions were among the most interestingdevices presented at the lectures,” Dr.Osher said. Drs. Osher and Cionni werethe first surgeons to use CTRs in theUnited States, in 1993. Differences ofopinion about the optimal use of CTRs,however, were not ironed out at themeeting.

Controversy #1: Who Needs a CTR?Perhaps no one demonstrates moreenthusiasm for the CTR than HowardFine, MD, clinical professor ophthal-mology at the Oregon Health & ScienceUniversity in Portland. He has been usingthem for more than a decade, serving asa medical monitor in the device’s initialstudies. “Capsular tension rings stabi-lize the cataract and make the surgerysafer,” noted Dr. Fine, who inserted 450CTRs during the early clinical studiesalone. “They convert most cases ofcompromised zonular integrity fromcomplex to routine, and give a level ofprotection from decentration.”

Dr. Fine has a long list of indicationsfor CTRs: all cases of trauma, any meta-bolic or endocrine disease, all cataractpatients with previous glaucoma filter-ing surgery, all cases of radial keratotomy(RK) where there are more than eightincisions, and progressive zonular dis-ease. “There may be weakened zonuleseven when they look intact,” Dr. Finesaid. “RK is a good example of how weuse CTR in a preventive capacity. Whenthere are more than eight incisions, thesurgeon was trying to achieve maximaleffect, and the zonules are now weak in

many of those eyes. So we use CTRs inall cases just to be sure. We also useCTRs in all eyes longer than 27 mm,where there is a tendency to weaken the zonules with cataract surgery.”

In contrast, Dr. Osher said, “I do notagree that surgeons should implant aring in every possible case of suspectedzonular weakness, or make a blanketstatement that all patients with pseudo-exfoliation should have a ring. Other-wise we would have implanted thousandsof rings for naught. You shouldn’t haveto be more aggressive than you need tobe.” He added that while the CTR isvery safe, there have been reports ofproblems. He recalled cases where aring was accidentally placed into theanterior chamber, another ring frac-tured, and another went through thecapsular bag. “The ring may also causedamage to the zonules if the bag isdragged during the insertion, which is why we fully inflate the bag withHealon 5,” Dr. Osher said. “Our experi-ence indicates that you should only putin a ring when you need it.”

Dr. Osher did stress that while notevery case of weak zonules requires aCTR, having the CTR available is imper-ative when performing any phaco pro-cedure because one never knows when a zonular problem will be encountered.

Controversy #2:When Should Rings Be Placed?

Dr. Osher recommends that a ring beused “when you need it and not beforeyou have to. Surgeons should alwayshold off until you have to put it in.”

Kenneth J. Rosenthal, MD, in privatepractice in Manhattan and Great Neck,N.Y., is also an advocate of “trying toplace the ring as late as you can and asearly as you need to, preferably aftercortical cleanup.” He explained thatplacing it early is more challenging, witha higher likelihood of entrapment ofthe cortex between the ring and the bag.

However, Dr. Rosenthal has devel-oped a technique that obviates the riskof cortex entrapment. He explained thatafter capsulorhexis, but before nucleardisassembly, the surgeon removes asmuch anterior and equatorial cortex as possible with either the phaco hand

piece or bimanual irrigation/aspiration.A retentive viscoelastic is then placedwithin the capsular bag, which displacesthe nucleus and any leftover corticalfibers posteriorly. “You next slip thecapsular tension ring just under the rimof the anterior capsule,” he added. “Thecortex will not be trapped because thering is placed anterior and the remain-ing lens material is posterior.”

Dr. Fine maintains that a ringshould be placed right away, beforedoing phacoemulsification and as soonas hydrodissection is completed. “In my experience, the ring stabilizes thecataract and makes the surgery safer,”he said. “We sever the cortical connec-tions before inserting the ring, whichwe do with an injector through a 1-mmsideport incision. We use a Lester hookand a second hook 90 degrees away,which allows us to neutralize the forceson the capsule during implantation ofthe ring. We can then inject the ringtoward the zonular weakness.”

Controversy #3:Who Will Pay for These?

While contention swirls around CTRs,all of these surgeons stressed the valueof having this device available in theirpractice. Said Dr. Fine, “We just thinkCTRs provide a great advantage, and weuse them every time there is a questionof zonular weakness.” A major hurdle,however, is that the device is not reim-bursed by the government.

“Medicare has decided not to reim-burse physicians for using CTRs, callingthem an instrument rather than animplant,” noted Dr. Fine, who cited sta-tistics in which 17 percent of patientswith compromised zonular integritywho underwent surgery without a ringrequired reintervention. “The govern-ment is being penny-wise and pound-foolish,” Dr. Fine said. “As a result, thereis a reluctance among surgeons to usethem because of the cost. Yet they are avery valuable tool.”

Dr. Masket reports no related financial

interests. Dr. Fine is a medical monitor for

Morcher. Dr. Osher is a consultant with

Alcon and AMO. Dr. Rosenthal has received

travel assistance from Ophtec and AMO.

C a t a r a c t


Most surgeons agree thatsome level of infectioncontrol should be achievedin refractive procedures,but there is little agree-

ment about what level that should be. Itis an issue unique to refractive surgery.“No authoritative institution has estab-lished any parameters. We have alladapted to what is reasonable under the circumstances by taking bits andpieces of knowledge and putting themtogether in a way that makes sense forthis procedure,” said Mark F. Ozog, MD,in private practice in Great Falls, Mont.

Gloves or No Gloves?As a result of this ambiguity, the selec-tion of protective wear worn by surgeonsand their staff members falls along acontinuum that ranges from full garb—gown, hat, goggles, booties and gloves—to almost none at all. The choice towear or not to wear sterile gloves duringrefractive procedures inspires an espe-cially contentious debate among refrac-tive surgeons.

Did your teacher wear gloves? Dif-ferences in medical training can influ-ence this choice. Some surgeons weretaught the “no-glove” technique, thetraditional method of performing theprocedure. “I trained at a time whengloves were not used with a keratome,and I do not wear gloves unless I havean open wound, hangnail or other con-dition where I should not be allowing

my hands to come into contact withanything in the surgical field,” said Dr.Ozog. “However, the entire surgicalteam wears scrubs, hats and shoes thatare worn only in the LASIK suite.”

Stuart A. Terry, MD, a private practi-tioner in San Antonio, observes a com-parable protocol: “I do not wear gogglesor gloves,” said Dr. Terry, who referredto a survey by the American Society ofCataract and Refractive Surgery, whichindicates that approximately 50 percentof refractive surgeons wear gloves.1

To protect the surgical field, Dr. Terrysaid he “avoids touching any part of aninstrument that will come into contactwith the eye or lids.” In more than12,000 procedures, only two of Dr.Terry’s patients have acquired eye infec-tions, and, he said,“Both healed to 20/20vision with the appropriate treatment.”

Erring on the side of gloves. J. Trevor

Woodhams, MD, an ophthalmologist in private practice in Atlanta, began hiscareer in the traditional fashion butsubsequently started wearing gloves.“In the early days of anterior lamellarkeratoplasty and LASIK, I did not weargloves because I wanted to reproducethe surgery as I saw it performed by theSouth American doctors who originatedit. However, I later switched to gloves.Once learned, gloved surgery did notoffer any significant compromises intouch or feel so I have never had anoccasion to operate gloveless again.”

Daniel J. Ritacca, MD, in privatepractice in Vernon Hills, Ill., has alwaysworn gloves, even when he performedradial keratotomies. “I was trained atthe University of Illinois in a large hos-pital. We did a lot of intensive surgery,and, as a result, I have always been con-cerned about keeping a procedure as

The Value and Vagaries of Sterile Technique

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by leslie burling-phillips, contributing writer

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Dr. O’Day’s practice employs consistent infection controls during refractivesurgery: gloves, sterile instruments and protected surgical field on every patient.

P r e c a u t i o n s : U n i v e r s a l

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1 0 s u p p l e m e n t

clean as possible. Someone on the sur-gical staff may touch the instrumentthat you were previously using in thesame place where you were touching it.If you don’t wear gloves, bacteria canspread everywhere.”

David G. O’Day, MD, agreed. “I’m aglove wearer; I always have been,” Dr.O’Day is in private practice in Charle-ston, S.C. “However, LASIK and thecorneal refractive procedures that weperform are not conducted as ‘true’sterile procedures. I treat them as asep-tically as I can. Even in the operatingroom with sterile gloves on, there is apossibility of contamination, so glovesare just the extra safety margin that weemploy.”

Simply wearing gloves does notensure that a surgeon’s hands willremain sterile. Once an object outsideof the sterile field is handled, such as apatient’s chart or the microscope ocu-lars, the gloves are no longer sterile. “Inthese cases, the sterile gloves are notdoing any good. But it is easy enough to cover the working surfaces that youneed to touch so that you do not have tocontaminate the gloves while you areperforming surgery,” said Dr. O’Day.Some surgeons use sterile plastic bag-

gies to adjust microscope oculars.Dr. O’Day uses sterile powderless

gloves in his LASIK suite, and has notencountered any problem with flapinterface debris from glove use.

Occupational SafetyProtection for the patient’s sake is onlyone side of the equation for infectioncontrol. The physicians and ancillarystaff should also be protected fromblood-borne infections that might beacquired from the patient, such as bac-terial infections, hepatitis B and C, orthe human immunodeficiency virus.

The sterile gold standard. Universalprecautions delineate a set of measuresdesigned to prevent the transmission ofall blood-borne pathogens to health careworkers. Under these parameters, bloodand some body fluids of all patients,regardless of their history, are consid-ered potentially infectious. These pre-cautions do not apply to tears unlessthey contain visible traces of blood.

That relative risk of infection, in fact,often factors into a surgeon’s decision to wear or not wear protective barriers.Ophthalmologists have a very low risk of becoming infected by patients. Morethan a million cases of HIV infection

have been recorded in the United States,for example, and none were in conjunc-tion with an ophthalmic procedure.

Low risk is not no risk. “The chal-lenge becomes determining that there is no chance of exposure. This is animportant issue when you are talkingabout any type of invasive procedure,even if the procedure is generallybloodless and minimally invasive,” saidArjun Srinivasan, MD, who is head ofthe response team in the Division ofHealthcare Quality Promotion at theCDC. “We encourage those who areperforming invasive procedures, evenwhen there is a perception that the riskis very, very low, to practice standardprecautions because it is the prudentthing to do. And these recommendationsare not solely directed at pathogens likeHIV and hepatitis. They are also directedat bacterial infections such as methi-cillin-resistant Staphylococcus aureus[MRSA] or adenovirus.”

Protect both patient and provider.“It is a two-way street,” said AdelisaPanlilio, MD, MPH, a medical epidemi-ologist who also works in the Divisionof Healthcare Quality Promotion at theCDC. “The personal protective equip-ment that a surgeon wears when he orshe performs a surgical procedure is alsoto protect the patient and prevent prob-lems with surgical site infections. Wehave microorganisms living on our skinand hair and do not want to transmitthose to the patient.”

A New World of Bad Bugs“Infection scares everyone, especiallywhen we continue to identify bacteriathat do not respond to antibiotics. Andthat list continues to expand,” warnedDr. Ritacca. “It is not just MRSA anymore. And it is not just in the hospitalsanymore. These problems are migratinginto surgery centers. We used to be safe,but things are changing; caution isessential. If you get a staph infection in a cornea, it could be a disaster.”

1 Helga P., et al. J Cataract Refract Surg 2005;

31(1):221–233.

The physicians interviewed report no relat-

ed financial interests.

R e f r a c t i v e

● Observe universal precautions: Assume that blood and body fluids—of bothpatient and provider—could be infectious.

● Adhere to hand hygiene without exception. This is the best defense againsttransmitting pathogens and should be observed by staff before and after everypatient encounter.

● Use HVAC filters to thoroughly filter all air that enters the surgical environment.

● Do not wear jewelry in surgery; jewelry can harbor microbes.

● Sterilize equipment meticulously and conduct microscopic inspections to ensurethere are no remaining particles.

● Keep nonsterile items out of a sterile field.

● Do not rely on alcohol to sterilize equipment; it is not an approved sterilizingmethod and could compromise a sterile field.

● Use a no-touch technique so that nothing nonsterile touches the eye.

● Never touch the working end of a surgical instrument.

● Use sterilized covers on laser joystick knobs and change them between patients.

● Change the speculum when operating on both eyes of a patient; the chances ofbacterial contamination increase when an instrument is transferred from one eyeto the other.

● Do not reuse any instruments without sterilizing them first.

1 2 T i p s o n I n f e c t i o n C o n t r o l

e y e n e t s e l e c t i o n s 1 1

Although cataract surgery foradults is a routine procedurearound the world, the samecannot be said for pediatriccataract. Surgery in children

can be complex and challenging, notsimply, of course, because cataractsobscure the image received by the retinabut because the retinal deprivationretards the development of the visualpathway, possibly leading to an intrac-table form of amblyopia.

Worldwide, cataracts are one of themost important causes of blindness inchildren and one of the most preventablecauses of lifelong visual impairment.Visual loss from untreated cataract isuncommon in Western countries but isstill problematic in some developingnations.

A Chilean Cohor tOne ophthalmologist on the front linesof research into the cause of congenitalcataracts is J. Bronwyn Bateman, MD,a geneticist and professor of ophthal-mology at the University of Colorado in Denver. Over the past 15 years, Dr.Bateman has studied more than 50 large,multigenerational families in LatinAmerica to isolate the genetic causes ofcataracts and to catalog their character-istics. Through this work she identified a new locus for autosomal dominantcataract on chromosome 19. Mostrecently, she has been interested in theclinical variability of cataracts among

a cohort of Chilean families that mani-fests pediatric cataracts inherited in anautosomal dominant pattern.

Same mutation, various presenta-tions. In a paper soon to be publishedin the American Journal of MedicalGenetics, Dr. Bateman and her col-leagues studied 28 individuals from fourgenerations of a Chilean family with ahigh incidence of congenital cataracts.Thirteen of the family members hadcataracts caused by mutations in theCRYAA crystalline lens gene, but clini-cally the cataracts varied widely andexhibited some novel features.“What wewere seeing was enormous variability in the clinical features of the cataracts,including the age at diagnosis, the nat-ural history of the cataract and how itaffected the development of vision,” Dr.Bateman said. “When you have a largefamily with hereditary cataracts, such asthose we worked with in Chile, you cantrace the polymorphic DNA markersthrough the family and see which mark-ers are inherited with the cataract.”

Treatment TimingSome of the Chilean patients have nothad their cataracts removed, althoughthe surgery is provided free of charge in Chile. “Many of the families are verypoor. Although some are treated withcataract extraction, a lot of them areafraid of the surgery and don’t want toundergo it,” said Fernando Barria, MD.Dr. Barria is an assistant professor ofophthalmology at the Universidad deConcepción and is on the ophthalmologystaff at the Hospital Clinico Regional de

Concepción Guillermo Grant Benavente.“But often, when the family memberssee the results of these surgeries, thosewho had been unwilling before decideto have the surgery,” he said.

When to wait, when to act. Dr. Bate-man noted that resolution of infantilecataracts often depends on individualcharacteristics of the patient. “If thecataract is particularly dense andobstructs vision, then you want to sur-gically remove it early in life,” she said.However, she said that some peoplewith hereditary cataracts can do quitewell without surgery. Some patients shemet in Chile did not have their cataractsremoved until the age of 30.

Underlying systemic disease? Con-genital cataracts can be unilateral orbilateral. “When bilateral, an examina-tion of the parents may help determineif the cataracts are genetic,” said M.

The Origins and Treatment of Childhood Cataract

P E D I A T R I C S


by barbara boughton, contributing writer

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Dense nuclear cataract in a 5-week-old infant at the time of surgery. Anidentical cataract was removed fromthe other eye one week later.

C l o u d e d C h i l d h o o d

This article originally appeared in the May



Edward Wilson Jr., MD, professor andchairman of ophthalmology at the Med-ical University of South Carolina inCharleston. “It’s important to look for acause if the cataracts are bilateral becauseif the cause is metabolic, then other spe-cialists may need to be called in to treatthe underlying disease,” he said.

Dr. Bateman explained that cataractsurgery for children is quite differentfrom that for adults. Although cataractextraction can be done when a child isseveral weeks old, she said, “You have totake into account how the eye and thevision will develop as the child ages indeciding when to do surgery,” she said.

Dr. Wilson agreed. In kids, he said, theeye is still growing. As the eye becomeslonger front to back, the lens changes its shape to adapt. “However, when weremove the lens, that natural progressiondisappears, and we have to decide if wewill make the eye farsighted, so that as it grows the child will have as near-to-normal vision as possible, or instead fixthe eye with the proper lens at a youngage, and anticipate that the child willbecome nearsighted as he or she getsolder—a problem that will need to be

corrected later with lenses,” he said. Putanother way, removing the lens will leavea refractive error and surgically inducedpresbyopia.“So we want to think carefullybefore we create premature presbyopia.Often whether we do cataract surgerywill depend on the amount of visualtrouble the child is having with thecataract. A mild cataract may not beworth sacrificing accommodation.”

How to avoid amblyopia. If thepatient has a cataract in only one eyeand already has severe amblyopia, themost pressing need might be to rehabil-itate the eye right away. In this case, thebest choice, again, might be a lens withthe proper correction, anticipating near-sightedness later on, Dr. Wilson said.“However, if the cataract is in both eyesand there’s no amblyopia, we mightdecide to have the child be somewhatfarsighted. It’s all a question of whetheryou want to have thicker glasses now toavoid thicker glasses later,” he said.

Dr. Wilson noted that some infantilecataracts worsen over time and somedon’t. If the cataract is a dense nuclearopacity present at birth, surgery is bestdone at 4 to 6 weeks of age, he said. “If

you delay longer there may be moreamblyopia, which will become moreand more difficult to reverse over time,”he said. However, lamellar corticalcataracts, which are also often genetic,tend to appear after birth and progressmore slowly, he said.

How to manage the surgery. Thetreatment of cataracts in children ismore serious than in adults becausechildren have to be put under generalanesthesia for cataract surgery. So thetiming for cataract removal in a child isoften an issue that needs to be analyzedand discussed with the parents.

Dr. Wilson said that while adultcataracts are usually hard and brittle,those in children are often soft andgummy. “So they can be removed withaspiration alone,” he said. “Anothermajor difference in children is the waywe handle the posterior capsule. In chil-dren from birth to about 6 years of age,I perform a primary posterior capsulec-tomy and anterior vitrectomy. My pre-ferred method is to first place the IOLin the capsular bag with the posteriorcapsule intact. I then remove the vis-coelastic from the eye. With the irriga-tion cannula remaining in the anteriorchamber, I make a single microvitreo-retinal stab incision through the parsplana and place the vitrectomy handpiece through the incision. I remove thecentral 4.5 mm of posterior capsule withthe vitrector and then perform enoughof a vitrectomy so that cells that growout from the equator of the remaininglens capsule cannot use the childhoodvitreous face as a scaffolding. Thisapproach is needed, at times, even inolder children who have a posteriorcapsular plaque or those who will notcooperate for a YAG laser capsulotomy,or those older children whose YAG cap-sulotomy closes spontaneously after it is successfully opened.”

The cataract of the future. “Under-standing the genes that cause thesecataracts can help reduce blindness inchildren,” Dr. Bateman said. “It mayeven be helpful, one day, in predictingwho will get age-related cataracts.”

None of the physicians interviewed report

financial interests related to this story. J. B

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P e d i a t r i c s

A lthough many had limited eco-nomic resources, Dr. Bateman’spatients in Chile were often will-

ing to travel for several hours to meetwith her. “The patients I’ve worked within Chile are very concerned about thereasons why people have this disease.As well as wanting to help their familymembers, they want to help society byparticipating in this research project.”

Dr. Bateman, who speaks Spanish,got to know some of the Chilean families quite well through her work. “Often theywould have a family reunion while they met with us.”

On one recent trip involving the families’ blood samples, she tangled with theChilean police. Dr. Bateman had arrived at the local airport in Concepción, whereshe was doing her research, to take a flight to Santiago to meet with ophthalmolo-gists there. In her carry-on bag she had the blood specimens of the families shehad been working with in Concepción. When the airport officials heard of blood inher luggage, they told her the specimens would need to travel in the luggage com-partment rather than under her seat. Concerned that the tubes might rupture, Dr.Bateman instead decided to take the local bus to Santiago—a five-hour trip. As shesat holding the blood samples, the man sitting next to her held a chicken. “He wasvery nice,” Dr. Bateman said. “He helped me with my Spanish verb conjugations!”

G r a t e f u l P a t i e n t s a n d P a t i e n t C h i c k e n s

Dr. Bateman examines a young Chilean boy.


As cataract and refractive sur-geons undoubtedly know, arelatively small axial lengthmiscalculation duringintraocular lens calculations

can result in poor vision—and a veryunhappy patient. And in an era whenrefractive considerations have crept intoevery aspect of IOL surgery, even 80-year-old cataract patients expect out-standing outcomes, said Parag A. Maj-mudar, MD, associate professor ofophthalmology at Rush University inChicago and in private practice atChicago Cornea Consultants. “Meetingthese expectations starts with correctlycalculating IOL power. Of course, prop-er surgical technique is always crucial,but even in patients who have never hadprior ocular surgery, the calculationsare a very important part of IOL im-plantation surgery.”

Spot-On Biometr yWilliam B. Trattler, MD, in private prac-tice in Miami, said the most importantstep in calculating IOL power is accu-rate biometry. This can prove difficultin the eyes of patients who have under-gone prior ocular surgery. And it is achallenge that will continue to intensifywith the increasing number of individ-uals needing cataract surgery who haveundergone previous RK, PRK andLASIK procedures.

Measuring axial length. Dr. Trattlernoted that technology to measure axial

length has dramatically improved withthe advent of the IOLMaster (Carl ZeissMeditec), a device that measures theshape and axial length of the eye to helpthe surgeon fine-tune the power. Its lat-est version features new axial lengthalgorithms and an advanced keratome-try mode.

“Only about five years ago, we wereusing A-scan ultrasound biometry,” Dr.Majmudar noted. “This technology wasdependent on the person taking the

measurements, producing variableresults. The newer technology is morestandardized, and more reproducible—leading to better results.”

Assessing corneal shape. While theability to accurately measure axiallength has improved, measuringcorneal topography is more complex.Dr. Majmudar explained that ker-atometers measure the curvature of theanterior surface about 3.2 mm from thecenter of the cornea. “In patients who

IOL Calculations:When Millimeters Count

R E F R A C T I V E


by lori baker schena, contributing writer

One of several algorithms available on the Web for calculating IOL powers, thiswas designed by Drs. Warren Hill, Douglas Koch, Jianzhong Ma and Li Wang.

C a l c u l a t i o n E a s e

This article originally appeared in the June



have not undergone previous surgery,the value at the center of the cornea isroughly the same as the value at 3.2 mil-limeters,” he said. “However, patientswho have undergone LASIK or PRK canhave altered corneas, and the value atthe central cornea, which is the goal ofmeasurement, may be very differentfrom that at 3.2 millimeters. Conse-quently, if you just rely on the topogra-phy, you may be off, and for every 1diopter you are off in measuring thecorneal curvature, a roughly 1 dioptermiscalculation will result for thepatient’s refractive outcome.”

Working with (or without) preoprecords. Steven I. Rosenfeld, MD, asso-ciate clinical professor of ophthalmolo-gy at the Bascom Palmer Eye Instituteand in private practice in Delray Beach,Fla., also pointed to the challenges ofascertaining accurate corneal topogra-phy. “There are ways to get around theselimitations, and the first one is havinghistorical data to help you calculate thelens implant power,” Dr. Rosenfeld said.“If you are lucky enough to have thepatient’s preoperative informationbefore they underwent PRK or LASIK,and you know their postoperativeresults, that can help guide you and giveyou a more accurate reading. You canplug that into your formulas.”

However, obtaining these preopera-tive data may be easier said than done,especially in places such as Boca Raton,which attract retirees who may haveundergone a refractive procedure in onearea of the country and decided to havecataract surgery in their new retirementcity. “Patients rarely carry this informa-tion with them,” Dr. Rosenfeld said.“And many ophthalmologists purgetheir old records after seven years. Con-sequently, if a patient had LASIK 10years ago and now needs cataract sur-gery, there is a good chance that thephysician may not even have these rec-ords. We have experienced many situa-tions in which we send a record releaseto an ophthalmologist up north just tolearn that the records no longer exist.”

Corneal measurement: backup tools.Dr. Rosenfeld said that without previ-ous records, the next alternative is a con-tact lens overrefraction. This involves

inserting a contact lens of known basecurve and power on the eye in question,and doing an overrefraction to predictthe corneal power. It represents an indi-rect way to obtain information aboutthe shape of the cornea, which can thenbe plugged into an IOL calculation for-mula. “Yet even this approach has itsdrawbacks because ophthalmologistshave varying levels of confidence in mak-ing these estimations,” he said. “Recent-ly, several studies have demonstratedthe value of using the central cornealmeasurements from the HumphreyAtlas corneal topographer, the OrbscanII and the Pentacam, to more accuratelycalculate the correct IOL power.”

Both Drs. Trattler and Majmudaralso noted that the Pentacam can imagethe front and rear surfaces of the corneain patients who have previously under-gone RK, PRK or LASIK, and it can pro-vide a keratometry value that may be putinto the IOLMaster. With this equiva-lent K reading, they said, the surgeonmay not need previous LASIK records.

Refractive Rogues Galler yPrevious refractive surgery can compli-cate IOL calculations unexpectedly.

RK weaklings. Patients who had RKcan experience fluctuations in the shapeof the cornea in the course of a singleday, let alone week to week, making itextremely difficult to obtain an accurateIOL calculation. “Some patients had 16

of these RK cuts, which can permanent-ly weaken the cornea,” Dr. Rosenfeldpointed out. “I will be operating on twopatients within the next month whopresented with this challenge. One is agentleman with a four-cut RK, and henow needs cataract surgery, and anoth-er has a 16-cut RK. Both their visionand corneal curvature fluctuate duringthe day, and thus it will be virtuallyimpossible to achieve a perfect IOL cal-culation. Instead, we do the best we cangiven these anatomic limitations.”

PRK suspects. Dr. Rosenfeld notedthat Baby Boomers seeking cataractsurgery who have had LASIK and previ-ous RK are easy to detect on clinicalexamination. However, this is not thecase with PRK. “If the patient doesn’ttell you he or she had previous surgery,the surgeon can easily make a calcula-tion mistake. Obviously, a thoroughhistory is an important component ofaccurate IOL calculations,” he said.

Contact corruption. Even patientswho have worn contact lenses most oftheir lives, especially the hard, gas per-meable or extended-wear lenses, maypresent challenges. “Contact lenses arenot benign,” Dr. Rosenfeld said. “Theycan cause corneal stress, which can bemanifested in many ways. The corneacan become swollen. In addition, con-tact lenses can change the shape of theendothelial cells and alter the normalmosaic pattern, and some individuals

R e f r a c t i v e

Dr. Majmudar knows the challenges of accurate IOL calculations, which iswhy he and colleague Dennis H. Goldsberry, MD, who is in private practicein Richardson, Texas, created a free, online spreadsheet and calculator.

“The advantage of our site is that it is extremely simple to use,” Dr. Majmudarsaid. “There are some sophisticated calculators out there, and ours is modest. Wejust want to make life a little easier for our colleagues, and one advantage of ourcalculator is that specific topography units are not required in order to be able touse it.” This Web site can be found at www.ocularmd.com.

Dr. Rosenfeld also recommended these calculation tools:● Doctor-Hill.com, created by Warren E. Hill, MD, is a Web site for IOL calculations.● DocHolladay.com, created by Jack T. Holladay, MD, contains the InternationalIOL Registry and information about Dr. Holladay’s IOL Consultant Software.● Douglas D. Koch, MD, and Warren E. Hill, MD, working with Li Wang, MD, andJianzhong Ma, MD, developed an IOL calculation tool for patients who have under-gone previous RK, myopic LASIK and hyperopic LASIK. It is available at http://iol.ascrs.org/.

C a l c u l a t e T h i s !


have experienced loss of endothelial cellsafter decades of use.” Corneal warpageis also a real condition in these patients.

Dr. Rosenfeld recommends thatthese patients stay out of contact lensesfor weeks or even months prior tosurgery, so that the ophthalmologist canobtain accurate keratometry. This alsoholds true for patients undergoingrefractive surgery, as the cornea needs toresume its natural shape before a proce-dure can be done accurately. “We don’tproceed with refractive surgery until thepatient has two visits where the cornealtopography is the same,” he said.

Accuracy Is Ever ything Dr. Trattler noted that the introductionof and increasing demand for presbyopiacorrecting IOLs necessitates even moreaccurate biometry, as these implantsneed to be right on target. “If you endup a quarter- or a half-diopter off withthe ReStor or ReZoom multifocal lens-es, patients will be unhappy,” he said.“This also holds true for the Crystalensaccommodative IOL. Presbyopic patientstend to be extremely sensitive to anymiscalculation.”

He said that in his presbyopic popu-lation, he experiences a 10 percent to 12percent enhancement rate. “In thesepatients, it is important that you canoffer solutions such as laser vision cor-rection or limbal relaxation surgery,”Dr. Trattler said. “The more accurateyou can be with your calculations, thelower the enhancement rate.”

Anatomy is money. Dr. Trattlerstressed that the “unhappiness factor”associated with miscalculating IOLstrength results in added costs for thepractice.” He also stressed the impor-tance of informed consent with anycataract or refractive lens exchangepatient. “Managing expectations is ofvital importance when working withincreasingly challenging patient anato-my and lens technology.”

Dr. Majmudar reports interests in Alcon,

Allergan, AMO and Inspire Pharmaceuti-

cals; Dr. Rosenfeld reports interests in

Allergan; Dr. Trattler reports interests in

Allergan, AMO, Bausch & Lomb, Inspire

Pharmaceuticals and Vistakon.

BY MIRIAM KARMEL, CONTRIBUTING WRITER

“WHEN WE STARTED DOING LASIK, WE DIDN’Treally understand that ectasia was a significant issue,”said William B. Trattler, MD. It took awhile, he said,“to better understand who was at risk or to see this wasreally an issue.” Today, nearly 10 years after the firstcase was reported, iatrogenic, post-LASIK ectasia is oneof the most controversial issues in refractive surgery.

The etiology is unknown, and, as Dr. Trattler pointedout,“there are significant differences in opinion” regard-ing the relevance of risk factors. Yet surgeons may avoidthis particularly insidious complication of LASIK byheeding the possible risk factors, which include: highmyopia, patient age, reduced preoperative cornealthickness, reduced residual stromal bed thickness afterlaser ablation and asymmetrical corneal steepening(forme fruste keratoconus, keratoconus or pellucidmarginal degeneration).

Understanding a safe threshold. Still, questionsabound. How thick should the cornea be to maintainstructural integrity? How deep can the surgeon go? Andwhy do some patients with abnormal topographies notdevelop ectasia following LASIK, while some patientswith normal-looking eyes do?

“There’s still an evolution of trying to understandwho is an appropriate patient for LASIK and whoshould not be offered LASIK,” said Dr. Trattler. Untilpost-LASIK ectasia is better understood, there will beunhappy patients. And there will be doctors who arewary of the medicolegal consequences.


This article originally appeared in the January 2008 issue ofEyeNet Magazine.


Consensus and Consequences In an attempt to clarify some of the issues surrounding post-LASIK ectasia, a committee of cornea and refractive surgeonsassembled by the International Society of Refractive Surgery/American Academy of Ophthalmology and the AmericanSociety of Cataract and Refractive Surgery issued a consensusreport in November 2005.1 The group was convened followinga multimillion-dollar legal judgment in favor of a young manwho developed ectasia following LASIK. The consensus groupspelled out the known risk factors for weeding out unsuitablecandidates for LASIK. The group also stated that ectasia is aknown risk of laser vision correction. When complicationsarise,“it does not necessarily mean that the patient was a poorcandidate for surgery, that the surgery was contraindicated orthat there was a violation of the standard of care.”(For an exam-ple of such a complication, see “Iatrogenic Ectasia,” next page.)

The group described a continuum of clinical findings thatranged from the “clearly normal” to the “clearly pathologic”cornea. The difficulty of accurately predicting which patientswill develop this dreaded complication of LASIK lies in theambiguous middle.

So just how common is it? Fortunately, surgically inducedectasia is rare, though the number of cases is not known. “Wedon’t know the answer to what percentage of LASIK patientsdevelops ectasia,” said J. Bradley Randleman, MD, who sus-pects the number is underreported. “We’ve been pretty goodat screening out a lot of cases,” said Yaron S. Rabinowitz, MD,a member of the 2005 consensus committee. “I’m amazedthere aren’t a lot more.”

“We estimated one in 2,500 cases, with older screeningtechnology,” Dr. Randleman said. “I think there’s a goodchance that it should be lower. With appropriate screening itwill be one in 5,000 or less.”

Anticipating the Major Risks Poor preoperative screening was the focus of two multimil-lion-dollar ectasia lawsuits that found in favor of the plain-tiffs. In one, a 32-year-old man claimed his surgery in October2000 never should have been performed because of kerato-conus, which he said was present before the surgery or couldhave been anticipated. In 2005, a jury awarded him $7.25 mil-lion, nearly doubling the previous record.

As the major risk factors for ectasia become clearer, twovital considerations can help guide the refractive surgeonaround those factors:

Topography. “Most people believe the most common riskfactor is abnormal topography,” said Dr. Rabinowitz. “If youlook at the literature and take out all the other risk factors, inthe vast number of cases there was abnormal topography.”Yetclearly, he added, ectasia can occur in the presence of normaltopography.

He added that there are still suspicious topographic pat-terns that aren’t well understood. “Some are high risk andothers not high risk. That still needs to be worked out.” But,said Dr. Rabinowitz, “knowingly performing LASIK on apatient with keratoconus or pellucid marginal degeneration,”would be a deviation from the standard of care.

Dr. Randleman, who has developed a risk assessment tool (see “Ectasia Risk Assessment”) for post-LASIK ectasia,agrees. “Abnormal topography stands alone as somethingthat can exclude people,” he said. “There are some firm pat-terns that we know are abnormal,” he said. “If a patient has a topographic pattern that indicates keratoconus, pellucidmarginal degeneration or forme fruste keratoconus, thenthey should absolutely be excluded from LASIK, even if theremainder of their examination is normal.”

Pachymetry. Another important factor is preservingenough residual stromal bed; the question, though, is howmuch is that? Traditionally the accepted range has been 200to 325 µm, with 250 µm chosen as the arbitrary cutoff. “Butfor each cornea it’s different. Nobody knows what the magicnumber is,” said Dr. Rabinowitz.

To preserve enough residual stromal bed, Dr. Trattleradded,“it’s most important to measure the patient’s flaps atthe time of surgery.”Yet unpublished data from 2005 surveyconducted by Magill Research Center at the Medical Univer-sity of South Carolina found only 34 percent of U.S. refrac-tive surgeons routinely perform intraoperative pachymetry,he said.

Dr. Rabinowitz agreed that pachymetry during surgery isessential because keratomes produce such variation in thethickness of the flap. “You cut the flap and lift it up, then youmeasure it,” he said. If the measurement is too low, abort theprocedure, he said. “If you don’t have enough tissue, a fewmonths later you can do PRK.”

A registry for reporting cases of ectasia after LASIK had itsdebut recently. The purpose of the registry “is to identify riskfactors that are not currently known and to serve as a basisfor clinical trials in the future,” said Dr. Stulting, who isdirecting the project.

There are twoanticipated phases tothe project. The firstphase will establish a database for sub-mission of informa-tion on patients whodeveloped ectasiaafter LASIK. Thesecases will be evaluat-ed against a controlgroup of LASIK patients who did not develop ectasia, in aneffort to validate known risk factors and discover new ones.Phase two will include prospective clinical trials of LASIK in cases involving unproven risk factors.

Ophthalmologists who care for patients with ectasia areencouraged to participate in the online registry by enteringdata on their patients at www.ectasiaregistry.com.

ECTASIA REGISTRY

ONGOING THINNING. Topography taken two years later shows progression of ectasia.

BEFORE REFRACTIVE SURGERY. 27-year-old patient with preoperative corneal thicknesses of 521µm OD and 524µm OS.The posterior floats are normal, and there is no sign of early keratoconus.

TEN MONTHS POSTOP. LASIK ablation depth was 52 µm OD and 62 µm OS, and the refractive correction was –4.75 +0.25 x 140 = 20/20 OD and –6.25 + 0.75 x 070 = 20/20 OS. A confocal microscope exam determined the corneal flapthicknesses were 120 µm OD and 140 µm OS. But 10 months later, post-LASIK ectasia was diagnosed OU. The maplooks like pellucid marginal degeneration.

A young woman in an ectasia support group shared the historyof her ectasia, below, with Dr. Trattler, who noted that hertopography initially made her seem like a very appropriate

candidate for LASIK. Her case is representative of one thatthe consensus report said “does not necessarily mean that thepatient was a poor candidate for surgery, that the surgery wascontraindicated or that there was a violation of the standardof care.”

IATROGENIC ECTASIA



Other Red FlagsAge. Since 2005, doctors have become increasingly aware ofthe role that the patient’s age plays as a predictive factor, saidR. Doyle Stulting, MD, PhD, who was a member of the con-sensus committee. “Early on we focused on parameters thatwe can measure in the clinic, like corneal curvature, cornealthickness, residual stromal bed and the degree of myopia. Thenwe began seeing people who did not have any of these predic-tive factors and they still developed ectasia,” Dr. Stulting said.“It turned out they’re significantly younger than the ones whohave identifiable risk factors. We believe those are people whomay have developed keratoconus or forme fruste keratoconushad they not had LASIK.”

Douglas D. Koch, MD, agrees. “Be especially wary of ques-tionable topography in young patients who need large correc-tions, as this group has been shown to have a higher incidenceof ectasia.”

Asymmetry. Another red flag is asymmetry between theeyes, said Dr. Trattler. He described a patient whose eyesappeared normal, but who had astigmatism at 90 degrees inone eye and at 180 degrees in the other. Asymmetry may be a sign that one eye is progressing toward keratoconus or pel-lucid marginal degeneration, he said.

Enhancements. Dr. Trattler also urged caution before pro-ceeding with LASIK enhancements. Because LASIK patientswho present for an enhancement with myopic astigmatismmay potentially have early ectasia, he advised carefully exam-ining the topography for asymmetry. Also, it is important to confirm that the topography and refraction are relativelystable, which means obtaining old records for LASIK proce-

dures performed elsewhere.In the meantime, patients who are not good candidates for

LASIK need not despair. PRK is becoming a more commonlyaccepted alternative, Dr. Rabinowitz said.

Dr. Koch agreed. “If there is a good likelihood of leavingtoo little tissue, avoid LASIK and switch to PRK. In eyes withquestionable topography, consider PRK or no surgery at all.”

Treating EctasiaTreatments for post-LASIK ectasia are the same as for kerato-conus, said Dr. Randleman. Treating with contact lenses ismost common; penetrating keratoplasty (PK) is the treat-ment of last resort. Even if an eye warrants PK, the prognosisis excellent, according to the 2005 consensus group, whichreported graft survival rates of 97 percent and 92 percent atfive and 10 years, respectively.

But in the vast majority of cases, PK can be avoided. AtEmory University, where Dr. Randleman has treated some 75 ectasia cases, only about 8 percent have required a cornealtransplant.

There are surgical alternatives to conventional penetratingkeratoplasty, including anterior lamellar keratoplasty, whichenables targeted replacement or augmentation of cornealstroma, without replacement of endothelium.2

Additional interventions designed to enhance corneal sta-bility include:● Intacs. Intrasomal corneal ring segments can be insertedinto the thinned cornea of contact lens–intolerant patients toserve as a “crutch.” They flatten the central area of the corneaand correct myopic refractive error. Intacs may halt progres-

Researchers at Emory University have come up with a riskfactor stratification scale intended to help prevent ectasiaafter LASIK.

After conducting a meta-analysis of published results from1998 to 2005 related to post-LASIK ectasia, the researchersfound that, compared with controls, ectasia cases had abnor-mal preoperative topographies (35.7 percent vs. 0 percent);were significantly younger (34.4 years vs. 40); were moremyopic (–8.53 vs. –5.09 D); had thinner corneas before surgery(521.0 vs. 546.5 µm); and had less residual stromal bedthickness (256.3 vs. 317.3µm).1

Point system. After analyzing the data, they assigned numer-ical scores to the various risk factors, which included topogra-phy pattern, residual stromal bed thickness, age, preoperativecorneal thickness and preoperative spherical equivalent mani-fest refraction. In the topography category, for example, theyassigned four points to forme fruste keratoconus; three pointsto inferior steepening/skewed radial axis; one point to asym-metric bowtie. Zero points were assigned to normal/symmetricbowtie. By adding up the points for all the risk categories, asurgeon should have a better sense of whether the patient has

a low, moderate or high risk for ectasia.“Our current paper was written to put some science behind

the anecdotes of what may or may not be risk factors,” saidDr. Randleman, lead author of the study. “We developed theectasia scale using the literature that was available. Then wefollowed that up with another study where we validated therisk factors.”

The scoring system, which identified more than 90 percentof abnormal patients, was replicated using a separate popula-tion. Dr. Randleman noted that there have been numerousproposed contraindications to LASIK, including a residualstromal bed thickness less than 250 µm, a preoperativecorneal thickness less than 500 µm, keratometry greater than47 D and an Orbscan posterior float value greater than 50 µm.On the other hand, he said that “there were actually very few‘absolute’ cut-off values.”

All about thresholds. “However, when there are too manyabnormalities in combination, then the patient should beexcluded from LASIK,” added Dr. Randleman. The scoringsystem shows that “you can’t look at things in isolation.”

1 Randleman, B. J. et al. Ophthalmology 2008;115:37–50. Also

published online July 12, 2007.

ECTASIA RISK ASSESSMENT


sion, make patients more tolerant to contact lenses and,hopefully, obviate the need for a corneal transplant.● Collagen cross-linking. This potential treatment, for whichclinical trials should soon begin, promotes the integration ofthe natural anchors within the cornea. Collagen cross-linkinginhibits the cornea from bulging out and becoming steep andirregular. This treatment avoids ablation or cutting across thevisual axis. Early reports suggest that it may halt the progres-sion of keratoconus and that it also causes keratoconiccorneas to assume a more normal shape, with consequentimprovements in visual acuity.

What’s In Store?Today researchers are looking for the gene or genes responsi-ble for keratoconus, which could lead to the development ofblood tests that would enable surgeons to identify patients atrisk of ectasia before any clinical signs are evident. Dr. Rabi-nowitz’s group at Cedars-Sinai Medical Center is working onone such molecular genetic test.

In the meantime, questions remain. Not known is whethercurrently identified risk factors are sufficient to allow the pre-diction of ectasia, or whether researchers ought to be lookingat other factors, said Dr. Stulting. “We believe that there is aninherent instability in the corneas of people who are going todevelop ectasia,” he said, adding, “We may be directly able tomeasure that instability.”

1 Binder, P. S. et al. J Cataract Refract Surg 2005;31:2035–2038.

2 Curr Opin Ophthalmol 2007;18(4):284–289.

DOUGLAS D. KOCH, MD Professor of ophthal-mology, Baylor College ofMedicine, Houston. Finan-cial disclosure: Consultantwith Alcon and AMO.

YARON S. RABINOWITZ, MDDirector of eye research at

Cedars-Sinai Medical Center, Los Angeles, andclinical professor of ophthalmology, University of California, Los

Angeles. Financial disclosure: Consultant forWavelight and Intralase.

J. BRADLEY RANDLEMAN, MD Assistant profes-sor of ophthalmology, Emory University.Financial disclosure: None.

R. DOYLE STULTING, MD, PHDProfessor of ophthalmology,and director of the corneaservice, Emory University.Financial disclosure: None.

WILLIAM B. TRATTLER, MD Inprivate practice at the Center for Excellencein Eye Care, Miami. Financial disclosure:None.

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