JUL 2013

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

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42 February 2011 Cataract challenges July 2013 EW FEATURE Cataract continued from page 41 An eye after previous RK and LASIK surgery Source: Uday Devgan, MD Choosing an IOL formula Dr. Bowers runs "multiple formulas on all cases (SRK-T, Holladay, Holladay 2, Hoffer Q), and with post-refractive patients I will use Aramberri Double-K modification to add or subtract power from the suggested power by these formulas." She also recommends running the same formulas using Holladay 2 with pre-refractive surgery data plugged in. In post-hyperopic refractive patients, she'll use the current refraction because of the regression issue. Lastly, she'll run the Hill/ ASCRS program. "If I had to pick just one formula, I'd probably use the Hill/ ASCRS site," she said. Dr. Schechter uses "straight Ks from the Pentacam" in post-hyperopic LASIK patients, and advises surgeons to check against the original K readings whenever possible. "We use the Masket formula and sometimes the Feiz-Mannis method just to compare," he said. Once the preoperative readings are complete, there's still the issue of choosing a lens, and various formulas have various advantages. "The third generation IOL calculation formulae are remarkably similar other than the way they calculate effective lens position," Dr. Devgan said. "Use of the Aramberri DoubleK method with a formula like the Holladay can increase our accuracy. It does this by using the measured K value for the IOL power calculation but then using a fixed, average value of about 43.5 for the determination of effective lens position. The third generation formulae (Hoffer Q, Holladay 1, SRK/T) all use the input K value to help determine lens position with a flatter K value indicating a likely shallower anterior chamber. This may hold true in virgin eyes, but in eyes where the central cornea has been flattened with LASIK, there is no change in the anterior chamber depth." Dr. Devgan said the newer generation formulae—Haigis-L and Holladay 2—include data such as measured anterior chamber depth and white-to-white, among others, to increase accuracy of the predicted effective lens position after cataract surgery. (Haigis-L is not recommended for prior RK or for hyperopic treatments, however.) "I take a different approach to determine IOL power after myopic LVC," Dr. Masket said. " If he knows what LVC was performed, he uses his own formula (available on the Lenstar). (See sidebar for comparison on various methods.) If he doesn't know, "we rely heavily on the Haigis-L, True Corneal Power from Optovue [Fremont, Calif.], and intraoperative aberrometry ORA [WaveTec Vision, Aliso Viejo, Calif.]. Although we have not adapted the Shammas formula [Haag-Streit], we understand it is also reliable in this situation and we will be adding that to our regimen in the near term,"Dr. Masket said. Premium lenses People who have already undergone refractive surgery have shown their motivation for spectacle-free living, and most are not deterred just because they have a cataract—in fact, some clamor for multifocal IOLs. "Always look for higher order aberrations (HOAs) to see if there's a prolate cornea in these eyes," Dr. Schechter said. "Whenever you're doing multifocal (MF) lenses the expectations are higher, and in post-refractive cases you need to ensure patients understand it's not the same type of procedure as their refractive surgery was. They need to understand they may not be candidates for a multifocal lens. I always give them reduced expectations." Type A personalities are among those he tries to steer away from MF implantation. daily.eyeworld.org now on iPad d.org www.eyeworl official y News • The EyeWorld Dail ASCRS•ASOA April 20, 201 o Show Daily 3 San Francisc ests Honored Gu ASCRS at n welcomed ral Sessio ening Gene Op r of Public Affairs Directo ASCRS•ASOA ophthalprofessor of he was a full of Tokyo. the University MD, and mology at in many ae Ho Kim, are he has served Stein, MD, Since then, Catholic Harold A. roles at the Guests at this ing direcleadership the Honored osium. of Korea, includ Institute, MD University ASCRS Symp rch Jae Ho Kim, yearÕs Sesal Resea ing General tor of the Clinic Department of At todayÕs Open red for their of the of the chairman be hono al Society, the , and dean sion, they will ophthalmology. Ophthalmologic Eye Diseases, and Ophthalmology In 1994, Dr. Kim nal ns to l. alcontributio Society of Exter Association. He has leading ophth Graduate Schoo an Foundation for ty Dr. Kim is a the Cerns , Korea. the Keratoplas 200 acain Seoul founded more than (CFER). mologist based also written degree at ssional Eye Research his medical Dr. Kim has s and 10 profe emeriand He earned demic paper ssor In recent years, Eye rsity of Korea , he is profe of the 21C Catholic Unive of University, books. Today as director served Hospital Catholic lic University asthe Seoul Paik his PhD from tus at the Catho an of CFER. become an Hospital of the Myungwent on to chairm rsity and where he almology. ed Korea and r in of Inje Unive ssor of ophth a distinguish Clinic Cente Dr. Stein is sistant profe d a National has St. MaryÕs Eye ogy at the , he Dong was name ophthalmol g his long career In 1970, he ational professor of Seoul. Durin ons in many of Health Intern Wilmer positi Institutes the held leadership the Korean al Fellow at ins UniPost-Doctor ns, including organizatio at Johns Hopk Eye Institute ore. By 1978, ital, Baltim versity Hosp by Cindy Sebrell J Harold A. Stein, uting Writer s EyeWorld Contrib S are four en A. Obstbaum, nts the Steph elson, MD, prese Thomas W. Samu Garry P. Condon, MD. to Lecture award e drug ustained releas may be s delivery system the future for the wave of ts, alglaucoma patien systems still though such cted away, predi or five years continu and Erin L. Boyle Staff EyeWorld Senior Writer Toronto, Ahmed, MD, Day Iqbal ÒIkeÓ oma ASCRS Glauc at FridayÕs ns. ence morning sessio use and adher Medication ate s why altern are major reason could work ry systems drug delive ts, he said. oma patien well in glauc on page 4 continued MD, Honored iving with the ur practice thr EHR. Visualize yo ophthalmic Editors' note: Dr. Bowers has no financial interests related to this article. Dr. Devgan has financial interests with Aaren Scientific (Ontario, Calif.), Alcon (Fort Worth, Texas), Bausch + Lomb (Rochester, N.Y.), Gerson Lehrman Group (New York), Accutome (Malvern, Pa.), and LensGen (Irvine, Calif.). Dr. Masket has financial interests with Alcon, Bausch + Lomb (Rochester, N.Y.), Haag-Streit, Ocular Therapeutics (Bedford, Mass.), PowerVision (Belmont, Calif.), and Carl Zeiss Meditec (Jena, Germany). Dr. Schechter has financial interests with Bausch + Lomb and Omeros (Seattle). MD his He earned of Toronto. University University e from the medical degre his residency completed of Toronto, Mayo ogy at the and in ophthalmol ster, Minn., Clinic in Roche from the Royal FRCSC a. earned his Surgeons, Ottaw founded College of , Dr. Stein In the 1960s ant Assohalmic Assist ized the first Opht America, organ ciation in North ed on page 3 s focus Day session es, Glaucoma tic , best prac on imaging ations ov pharma inn by Vanessa Cacere Added Dr. Devgan: "If the patient has had a milder degree of prior refractive surgery and the cornea is regular and symmetric without excessive HOAs, then MF IOLs can work just fine." He cites decentered ablations and "a lot" of induced HOAs from a large degree of prior excimer treatment as exclusionary factors. Dr. Bowers has no qualms about using MF lenses in post-refractive patients. "I've always had very good luck and these are some of my happiest patients," she said. "I aim for plano, but try to pick a lens power that will leave them slightly myopic instead of hyperopic. If there is a refractive surprise, laser enhancement is more predictable and stable with residual myopia than hyperopia. I spend a lot of time with preop patient education on the increased chance that they might need an additional procedure to 'tweak' or 'fine tune' their results because of the previous surgery," she said. Dr. Masket isn't as uniform in his decisions, weighing the time since laser vision correction equally with HOAs to make the determination. "If it's very old style laser surgery, which induced much positive spherical aberration, or if the patient has a high amount of HOAs, I avoid MF lenses," Dr. Masket said. "However, these are a very motivated group for spectacle independence, so I take that into account as well." He evaluates the optical zone size and pupil size, noting that MF lenses will only exacerbate existing night vision issues. "We don't want to introduce new sources of aberrations," he said. EW receive a FREE eBook. Contact information Bowers: barbbowersmd@comcast.net Devgan: devgan@gmail.com Masket: sammasket@aol.com Schechter: bdsch77@aol.com

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