Eyeworld

MAR 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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104 104 EW REFRACTIVE March 2012 Enhancement challenges, responses differ by Rich Daly EyeWorld Contributing Editor needing an enhancement of residual refractive error." The importance of touch-up treatments was elevated by research in recent years that identified the particularly acute need for surgeons to meet refractive targets among multifocal lens recipients, said William W. Culbertson, M.D., professor of ophthalmology, and director, Cornea and Refractive Surgery Services, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine. "The effect of even small amounts of astigmatism on multifo- cal IOLs is very important," Dr. Culbertson said. "We used to disre- gard small amounts of astigmatism, which became much less important in monofocal IOLs. But in multifocal IOLs they are very important." Audrey R. Talley-Rostov, M.D., Northwest Eye Surgeons, Seattle, agreed and noted that multifocal lens recipients require full correc- tions, unlike monofocal recipients who sometimes enjoy the modified monovision of one slightly under- corrected eye. A growing retreatment chal- Source: Chris Ryan/OJO Images/Getty Images Surgeons identify their priority retreatment patients and the most effective approaches they have found to achieve target refractive errors A lthough the rates of re- fractive surgery patients requiring enhancements following their initial treatments vary among procedures and surgeons, such fine- tuning efforts are a leading focus of many surgeons. The surgical re- sponse to those deviations from the targeted refraction also differs among clinicians. Louis "Skip" Nichamin, M.D., Brookville, Pa., identified residual refractive error as "the single most significant issue with regard to re- fractive cataract surgery," especially as it affects patient satisfaction fol- lowing premium presbyopia-correct- ing IOL surgery. "In general, we as surgeons do not do nearly enough to bring pa- tients to the desired refractive out- come, and patient acceptance and penetration of premium lenses would be much greater if we did a better job at bringing them to a plano result," Dr. Nichamin said. Dr. Nichamin urged refractive surgeons to aggressively utilize LASIK or photorefractive keratec- tomy (PRK) when needed "to finish the job." Meanwhile, Christopher J. Rapuano, M.D., director, Cornea Service, and co-director, refractive surgery department, Wills Eye Insti- tute, Philadelphia, has found that current laser algorithms have sharply lowered the incidence of sig- nificant under- and overcorrections compared to even 5 years ago. In ad- dition, he has found small refractive errors are often well tolerated, espe- cially if patients are educated pre-op to understand that plano 20/15 un- corrected vision is never guaranteed. "In my experience, the higher the degree of myopia and/or astig- matism that is being treated, the higher the chance of residual refrac- tive error," Dr. Rapuano said. "Hy- peropes also have a higher chance of lenge, identified by William B. Trattler, M.D., cornea specialist, Center for Excellence in Eye Care, Miami, is the large number of pa- tients who have previously under- gone refractive surgery. These patients—such as corneal transplant patients and Intacs (Addition Technology, Des Plaines, Ill.) recipients—present their own clinical challenges. For example, Dr. Talley-Rostov does not implant multifocal IOLs in patients previously treated with radial keratotomy due to the high risk of aberrations. However, if a premium IOL is implanted in such patients and they need an enhance- ment, she recommends a surface ab- lation with mitomycin C (MMC) to prevent scarring. Retreatment preferences Surgeons see different advantages to various retreatment options avail- able to them. Dr. Trattler uses PRK to enhance both PRK and LASIK. Surface abla- tion allows him to avoid moving the flaps of previous LASIK patients, which carries attendant risks for epithelial ingrowth or flap striae. Additionally, some patients with microkeratome-created flaps have microstriae that become visible when the epithelium is removed. In these cases, PRK treats both the residual refractive error and reduces the striae. "The downside is, of course, that PRK takes longer than a flap-lift for visual recovery," Dr. Trattler said. To minimize a potential prob- lem from PRK—the development of haze—Dr. Trattler always uses MMC 0.02% for at least 12 seconds. Similarly, Dr. Nichamin has found PRK both safe and effective in retreating patients post-IOL implan- tation, especially older patients who require smaller retreatments and who have dry eye or other corneal surface complications. Roger F. Steinert, M.D., Gavin Herbert Eye Institute, University of California, Irvine, said that if ade- quate tissue is available, he has found LASIK provides better results for larger corrections, while PRK is effective for small "touch-ups." "I prefer flap-lift if the residual stromal bed is adequate and there is no peripheral epithelial ingrowth that might expand after lifting," Dr. Steinert said. Dr. Talley-Rostov uses both LASIK and PRK in her retreatments. She prefers surface ablation to en- hance premium IOL implantation but will enhance previous LASIK surgery recipients if their flaps were created with older mechanical microkeratomes, even 10 years after the original procedure. "If their flap was created with a femtosecond laser and it's a couple years post-op, as is usually the case, those are much harder to lift," she said. "So then I'll do a surface abla- tion." Another retreatment option used by Dr. Nichamin is refractive lenses. This is an especially effective option for former LASIK patients who have returned for touch-ups following treatment for myopia or hyperopia. "Once they enter presbyopia and come for an enhancement, I consider lens options: We can fine- tune distance enhancement but also perhaps their near vision," he said. "So we educate them about presby- opia-correcting IOLs." Similarly, Dr. Trattler moves be- yond his usual use of PRK and LASIK for retreatments in pseudophakic pa- tients with significant hyperopia. In these retreatment cases he has found a piggyback IOL procedure most ef- fective. continued on page 105

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