Dermot McGrathin Rome

ADVANCES in phakic IOL materials anddesign concepts together withimprovements in surgical techniques aregiving surgeons renewed confidence in usingphakic IOLs as a treatment option in theirrefractive practices, according to JosephColin MD.

Addressing a special symposium devotedto phakic IOL implantation during the 9thWinter Refractive Surgery meeting of theESCRS, Dr Colin said that phakic lenseshave many advantages to offer the modernrefractive surgeon.

“Phakic IOLs provide very good refractiveand visual results, they can be easilyimplanted in most cases and they cancorrect myopia, hyperopia, astigmatism andmay help patients with presbyopia.They arevery effective, predictable, and stable, theypreserve accommodation and they can beremoved at a later stage if required,” he said.

Dr Colin noted that while phakic IOLshad initially courted controversy, because ofpotential damage to intraocular tissue,advances in design and biocompatiblematerials have helped to address suchconcerns in recent years.

Anatomical or functional complicationswith phakic IOLs can arise due tounintended contact between the implant andthe cornea, the angle or the crystalline lens,noted Dr Colin, citing as an example the

damage caused to the endothelium by thefirst generation of anterior chamber IOLs.

He said that pupil ovalisation was a keyconcern with the second generation ofphakic anterior chamber IOLs, while cataractremains a worry with posterior chamberphakic IOLs. Other potential complicationsinclude issues of correct sizing, centration,endothelium damage, and iris tolerance.Visual symptoms such as haloes, glare ornight vision difficulties may also poseproblems for patients.

“These different side effects are related tofactors such as the centration of the IOL,and size of the pupil, deformation of thepupil, the size of the optic, IOL design or therefractive index of the IOL material – allthese parameters may induce some visualside effects,” he said.

Dr Colin said that new designs, foldablematerials, better knowledge of complicationsand improved technologies such aswavefront sensing would help to overcomesome of the known limitations of currentrefractive IOLs in the future.

However, he stressed that it wasimportant to remember that implantinglenses constituted a fully-fledged intraocularprocedure and should be treated accordingly.

“In most cases, such IOLs must not beimplanted in eyes with an anterior chamberdepth of less than 3.0 mm, we must lookcarefully at the iridocorneal angle, and assessthe status of the crystalline lens. For patientswith low ametropias we must always discussthe risk-benefit ratio and we must always tellthe patients everything that we know aboutthe long-term tolerances of these lenses,” hesaid.

While all the current phakic IOLs providegood results with few serious complications,Dr Colin said that there was still debateabout the best location, lens design andbiomaterial for long-term success withphakic IOLs. He also warned that all phakicIOLs would need to be removed when thebi-phakic eye develops a cataract, usually 10to 15 years earlier than the emmetropic eye.

Although some have speculated phakicIOLs may one day become the treatment ofchoice for all refractive surgery patients, DrColin said that for the foreseeable futurethey will most likely continue to represent aniche market “addressing a low- to midsingle-digit percentage of the visioncorrection population consisting of highmyopes and high hyperopes”.

Phakic IOLs: pearls, pitfalls and prospects discussed in ESCRS symposium

Rome 2005

“Phakic IOLs providevery good refractiveand visual results, theycan be easilyimplanted in mostcases and they cancorrect myopia,hyperopia,astigmatism and mayhelp patients withpresbyopia. Joseph Colin MD

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Making the right choiceThe factors to be weighed in determining aparticular choice of phakic IOL werediscussed by Emanuel Rosen MD, who saidit was important to remember that therewas no “one size fits all” approach to phakicIOLs.

“One phakic implant does not suiteverybody. I believe that if you are a patientand you are going to have a phakic implantyou are better going to a surgeon whodoes many rather than to a surgeon whodoes few.As surgeons we therefore have todecide what is the minimum number ofphakic implants that we should be doing,because expertise comes with experience,”he said.

Dr Rosen said that even before selectingthe IOL type, surgeons should be askingthemselves if this is really the correctrefractive choice. He noted that factorssuch as the age of the patient, the range ofalternative treatments available, and theextent to which the patient is informedabout the various treatment options shouldall be taken into consideration.

Rigorous preoperative assessments arecritical to obtaining consistently goodoutcomes, noted Dr Rosen.

“It is very important for both thesurgeon and the patient to decide what theaim is and whether we are going to indulgein presbyopic treatment.We have to knowall the various aspects of refractive surgeryassessment and I would particularly stressthe importance of pupillometry and theissue of the patient’s adaptation to a newvisual scene,” he said.

Incision size is also important in achievingthe desired visual outcome, he added.

“It is a refractive procedure, so a smallincision without refractive effect is veryappealing with the latest foldable posteriorchamber IOLs. For anterior chamber IOLsand Artisan-type lenses, you need a largeincision unless you are using a lens such asthe foldable Artiflex.The incision will affectthe refractive result because it will influencethe rehabilitation with sutures and refractivechanges in healing. On the other hand, if theeye has a significant astigmatism then you canuse the incision to correct or attempt tocorrect the astigmatism,” he said.

Dr Rosen said that his own preference hasbeen to concentrate mainly on posteriorchamber lenses and, in particular, the ICLphakic IOL (Staar).

“Our expectations with this lens havebeen fulfilled over the past eight years. It hasperformed extremely well; the surgery isstraightforward and it has a small incisionappeal.They are also invisible in the eyewhich is something that patients reallyappreciate,” he said.

Complications vary according to IOLtypeIn trying to differentiate between the phakicIOLs now on the market, surgeons would beadvised to look carefully at the complicationsassociated with each particular lens type,advised Professor Thomas Kohnen MD.

“If you look just at the visual outcomes,efficacy, safety, stability and predictability,nearly all phakic IOLs perform very well – itis the complications arising from their uniquedesign features and their position in the eyethat separate them,” he said.

To avoid problems of induced astigmatism,Dr Kohnen advocates implanting phakic IOLsthat take account of the magnitude of theastigmatism.

“I think low astigmatic patients are idealcandidates for foldable phakic IOLs. Forpatients with medium astigmatism, incisionsshould be performed on the steep meridianand you can select PMMA IOLs and addlimbal relaxing incisions.And for largeastigmatism, toric IOLs are available as apossible solution,” he said.

Endothelial cell count is another criticalfactor in selecting the correct phakic IOL,noted Dr Kohnen. He said that for youngpatients he preferred to have a cell countover 2,500 mm2 to help ensure the long-

term safety of the implant. For cell countsbetween 2,000 mm2 and 2,500 mm2, thestability of the IOL in the eye is particularlyimportant, and those less than 2,000 mm2usually means implanting a posterior

chamber lens or selecting an alternativeprocedure.

In terms of problems such as glare andhaloes: the optic edge is often the culprit forsuch visual symptoms, said Dr Kohnen. Hehighlighted pupil size and centration of theIOL as other limiting factors in this regard.

Noting ongoing problems with IOL sizing,Dr Kohnen said that there was a growingconsensus that white-to-whitemeasurements alone were not sufficient toensure correct sizing. He noted that iris-fixated lenses achieved the best centrationand were often a good choice for patientswith large or eccentric pupils.

On the issue of cataract formation, DrKohnen said that lens design, lens material,surgical trauma and IOL position could allcontribute to such complications. He notedin particular concerns relating to the ICL,citing a study by Birgit Lackner MD in 2004,which found a 14.5% rate for cataractformation after three years follow-up.

Dr Kohnen concluded by stressing theimportance of adhering to IOL safetyprotocols and using good surgical techniquein order to obtain consistently good resultsfrom phakic IOL implantation.

New imagingtechnologies shedlight on anteriorchamberThe role of newimaging technologiesin exploring theanatomicalcomposition of theanterior segment anddetermining correctsafety distances forphakic IOLs wasdiscussed by GeorgesBaikoff MD.

Over the past twoyears, Dr Baikoff hasbeen using aprototype anteriorchamber opticalcoherencetomography device(Visante AC-OCT,Carl Zeiss Meditec)to examine eyesimplanted with angle-supported, iris-fixatedand posteriorchamber phakic IOLs.Based on theinformation obtainedin those evaluations,Dr. Baikoff suggesteda need for reassessingsome existinginclusion/exclusioncriteria.

Emanuel RosenJoseph Colin Georges Baikoff Thomas Kohnen

Joseph Colin MDHôpital Pellegrin-Tripode -

Service d'ophtalmologieBordeaux, France

joseph.colin@chu-bordeaux.fr

Emanuel Rosen MD, FRCS, FRCOphthThe Rosen Eye Clinic,

Manchester, UKerosen5640@aol.com

Georges Baikoff MD Clinique Monticelli Marseilles, France

g.baik.opht@wanadoo.fr

Thomas Kohnen MDJohann Wolfgang Goethe-

University, Frankfurt, Germany

kohnen@em.uni-frankfurt.de

“It is a refractiveprocedure, so a smallincision withoutrefractive effect is veryappealing with thelatest foldableposterior chamberIOLs.” Emanuel Rosen MD

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D“If you look just at the visual outcomes, efficacy,safety, stability and predictability, nearly allphakic IOLs perform very well – it is thecomplications arising from their unique designfeatures and their position in the eye thatseparate them,” Thomas Kohnen MD

Dermot McGrathin Rome

PHAKIC IOLs will command anever-growing share of therefractive surgery market in thefuture, but surgeons must notlose sight of their primaryresponsibility to ensure the safetyand efficacy of these implants inhealthy eyes, according toScipione Rossi MD.

Dr Rossi was speaking during aspecial symposium on phakicIOLs held during the 9th WinterRefractive Surgery Meeting. Hisown presentation was focused ona two-year follow-up of sevendifferent models of phakic IOLthat had been implanted during alive surgery session at the ESCRSmeeting in Rome in 2003.

Dr Rossi noted that the studyhad been designed as much aspossible to ensure a fair andobjective comparison betweenthe postoperative outcomes ofthe different lenses.All IOLs wereimplanted by experiencedsurgeons and patient selectioncriteria were closely matched foreach IOL type.

“This allows us to performsomething close to a ‘pure’evaluation of the actual IOL.We

can examine not only therespective UCVA, BCVA,endothelial cell counts and soforth, but also factors such aslens positioning andcomplications without worryingunduly about the influence of theactual surgery itself,” said DrRossi.

Seven lenses for sevenpatientsIn 2003, five female and two malepatients were implanted with oneof seven different phakic IOLs: ananterior chamber angle-fixed lenssuch as ICARE, GBR/Vivarte orPhakic 6, an anterior chamberiris-fixated lens such asVerisyse/Artisan or Artiflex, or aposterior chamber IOL such asthe ICL or the PRL.

Reviewing the two-year follow-up results of each IOL, Dr Rossicommented that overall theresults had been very good interms of safety, efficacy andstability.

The Artiflex IOL, implanted byCamille Budo MD, recorded thebest refractive outcome of all theIOLs, although the GBR/Vivarte,the PRL, and the Phakic 6 alsoperformed to an extremely highstandard, remarked Dr Rossi.

In terms of complications, DrRossi said that there were twocases of pupil ovalisation inpatients implanted with theVivarte and the Phakic 6 lenses.

“It is interesting to note thatthis problem occurred with twolenses which are angle-fixated, butin these patients the issue is notvery serious because their BCVAand overall refractive outcomeswere very good,” he said.

More seriously, Dr Rossi notedtwo cases of lens opacitiesassociated with the ICL and theICARE implants. He said thatcareful examination of the videoof the surgery involving the ICLimplantation led him to concludethat it was the lens itself and notthe surgery that was responsiblefor the cataract formation. In thecase of the ICARE, however, hesaid that it was possible that thesurgical procedure itself couldhave played a role in theformation of the cataract.

Demand for phakic IOLslikely to growDr Rossi said that phakic IOLswould continue to command anincreasing share of the refractivemarket in the future.

“The anatomy of the eye,corneal thickness, pupil size andso forth, imposes limits on theamounts of refractive correctionthat can be obtained by reshapingthe cornea. For these patients,phakic IOLs are perhaps the onlyalternative.And the populationeligible for these procedures isgrowing as both surgeons andpatients become more aware ofthe benefits offered by suchprocedures.”

Dr Rossi reflected that IOLshave been implanted in Europefor over 15 years now.

“The initial results were notpromising although thankfullyimprovement in surgicaltechniques and devices havereduced complications.We nowhave a lot of studies showing asignificant percentage of patientsachieving uncorrected vision of20/40 or better with phakicIOLs.”

Over the past decade, anestimated 150,000 refractive IOLshave been implanted in Europe,said Dr Rossi, a figure that isprojected to increase significantlyin the near future.

“In 2003 alone, there were anestimated 32,000 phakic IOLsimplanted in Europe and the

projection for 2008 is around100,000 per year,” he said.

Dr Rossi noted that Americansurgeons were watchingdevelopments in Europe veryclosely.

“First of all they are veryinterested in the results we areachieving with phakic IOLs andthey are also keen to pick upsome tricks and tips forimplanting these IOLs themselvesas the refractive market thereexpands beyond laser onlytreatments,” he said.

European surgeons thus have amajor opportunity andresponsibility to develop the fullpotential of the phakic IOLmarket, said Dr Rossi. Bettermaterials allied to better surgerywould help improve results, raisestandards and instill confidence inthe procedure, he suggested.

“We have not yet attained thehighest standards but we’regetting closer. So let’s beconfident in opting for refractiveIOLs when the anatomicalcharacteristics of the eye imposethis procedure,” he said.s.rossi@idi.it

Performance of phakic IOLs reviewedat two-year follow-up

"This AC-OCT device provides a rangeof useful data for the anterior chamberand is relatively straightforward to use,giving surgeons a non-contact means ofviewing high resolution images of theanterior segment. My belief is that in thenear future this equipment will be asnecessary for preoperative assessment ofphakic refractive IOL patients as

topography currentlyis for cornealrefractive surgery,"said Dr Baikoff.

He said that theAC-OCT deviceprovided a wealth ofuseful clinical andphysiologicalinformation aboutthe anterior segment,such as the fact thatthe anterior chamberis not perfectlycircular but is, in fact,oval or elliptical.

“We found a cleardifference betweenthe vertical internaldiameter andhorizontal length in amajority of patients.This has importantclinical implicationsbecause it means thatthe key to avoiding

rotation and pupilstretching with an angle-supported lens isto fit the lens exactly to the larger axis ofthe anterior chamber,” he said.

Based on studies of eyes implanted withangle-supported phakic IOLs, heconcluded that the anterior chamberdepth safety criteria for candidateselection should be modified to be based

on the chamber’sinternal dimension --the distance from theanterior pole of thecrystalline lens to theendothelium --rather than thedistance to thecornea’s anteriorsurface.

He noted that itwas also vital to takeinto account theforward movementof the crystalline lensthat occurs due toage-relatedthickening and withaccommodation.

“We have to remember that theanterior pole of the crystalline lens willmove by about 20 microns per year.This

means that if you introduce a phakic lensin a 20-year-old patient, by the time thatpatient is 60, the crystalline lens anteriorpole will have moved by 1.0 mm.That’sone third of the diameter of the anteriorchamber and underlines why we have towarn patients that the lens won’t be forlife,” he said.

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“We have to rememberthat the anterior poleof the crystalline lenswill move by about 20microns per year.”

Georges Baikoff MD

Anterior chamber of an 80 year-old

Anterior chamber of a 10 year-old

The Visante OCT