EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78721
February 2011 January 2012 EW REFRACTIVE SURGERY 35 The challenge of treating hyperopia by Michelle Dalton EyeWorld Contributing Editor Although options exist, they are not nearly as numerous as treatments for myopia H yperopes present a unique set of challenges for refractive surgeons— most excimer lasers "do a great job with hyperopia with or without astigmatism, as long as you're not steepening the cornea more than about +3.00 diopters, and that last part is a bit laser-specific," said Daniel S. Durrie, M.D., profes- sor of ophthalmology, University of Kansas Medical Center, and presi- dent, Durrie Vision, Overland Park, Kan. The typical hyperope who wants laser vision corrective surgery is "in his early 50s and is presbyopic," said Richard L. Lindstrom, M.D., adjunct professor emeritus, ophthalmology department, University of Minnesota, Minneapo- lis, and founder, Minnesota Eye Consultants, Minneapolis. Com- pared with the typical myope, who is about 35 years old, "the manage- ment of the two are very different," Dr. Lindstrom said. "The hyperopes typically have great vision until their 40s. By the time they've hit their 50s, they have lousy distance, lousy intermediate, and lousy near vision." In Europe, Diego de Ortueta, M.D., senior consultant, Augenzen- trum Recklinghausen, Germany, said the limits for hyperopic laser treat- ment are 6.5 D, but the limit "is also given by the post-operative K read- ing, which will be higher. To avoid inducing aberrations, the post-oper- ative K reading should not be higher than 49 diopters." Treatment options Once patients fall into the +7-10 D range, "it's not a good idea to use a corneal procedure because the corneal optics will not be adequate afterward," Dr. Durrie said. A lens- based procedure in hyperopes does not carry the risk of retinal detach- ment as it would in a high myope and allows surgeons to replace the lens with any corrective power deemed necessary. For patients in their mid-50s, the issues of presby- opia and nuclear sclerosis are also present and lens-based surgery makes sense, he said. Surgeons are not nearly as unanimous when pa- tients are in their mid-40s, however. A +7 D 25-year-old patient? "There's not a lot of surgeons who will replace a lens in that pa- tient scenario," Dr. Durrie said. While not a common procedure, in his practice some higher hyperopic patients in their 20s or 30s are un- dergoing refractive lens exchange "with excellent results." Dr. Lindstrom said one reason he rarely performs surgery on those who are +3 D or higher is that "only 65% get to 20/20. Laser surgery in- duces more higher-order aberra- tions." Laser surgery just "doesn't generate as high quality vision as we'd like in this group of patients." He prefers monovision or lens-based solutions as well, and added in his hands presbyLASIK "has been disap- pointing." "It's a double-edged sword," he said. "These patients don't see well at any distance, so arguably you have more benefit to give them. But it's hard to make them 'perfect.'" Dr. de Ortueta added, "Phakic lenses are usually not indicated for hyperopic correction as the anterior chamber is too small." His hesitancy with lens-based solutions is the loss of accommodation in younger pa- tients. Dr. Durrie said phakic IOLs also increase the incidence of glau- coma and cataract. Dr. Durrie advised against a par- tial laser correction. "It's been tried worldwide—just do a three diopter correction and the +7 D 20-year-olds will be happy be- Is LASIK continued from page 34 ogy enhancement." "Previously I had termed it 'multifocal incisional enhancement,' but the technique works well for advanced technology lenses—for instance, toric IOLs—as well as multifocals," Dr. Sonntag said. To perform this technique, Dr. Sonntag said that most often, only one incision is needed from the 5- to 8-mm optical zones. "If a second incision is needed, it need not be placed 180 degrees opposite the first. In fact it can be placed just a few clock hours from the first incision," Dr. Sonntag said. "In the right hands, for an expe- rienced surgeon, this is a simple and cost-effective technique," said Dr. Probst. This particular approach may not be as well-known as some sur- geons began to use it around the same time the excimer laser was in- troduced; naturally, ophthalmolo- gists paid more attention to the laser, Dr. Probst believes. "With one or two incisions, you can easily correct 1 or 1.5 diopters of myopia," said Dr. Lindstrom. Dr. Lindstrom, who published on the mini-RK approach about 20 years ago and developed nomograms for its use, no longer performs this tech- nique but does not discourage others from doing it. EW Editors' note: Drs. Devgan and Sonntag have no financial interests related to this article. Dr. Lindstrom has financial interests with Abbott Medical Optics (AMO, Santa Ana, Calif.), Alcon (Fort Worth, Texas), Allergan (Irvine, Calif.), Bausch + Lomb (B+L, Rochester, N.Y.), and Merck (Whitehouse Station, N.J.), among other ophthalmic companies. Dr. McDonald has financial interests with Alcon and B+L, among other ophthalmic companies. Dr. Probst has financial interests with AMO. Contact information Devgan: 800-337-1969, devgan@gmail.com Lindstrom: 612-813-3633, rllindstrom@mneye.com McDonald: 479-521-2555, mcdonaldje@mcdonaldeye.com Probst: 708-562-2020, leprobst@gmail.com Sonntag: 208-377-3937, Jsonn12345@aol.com cause they can still accommodate. They're not. And now you've made their cornea significantly steeper. The optics won't be as good for IOL surgery down the road," he said. Because of those earlier disappoint- ments, Dr. Durrie said when he's faced with +7 D 20- (or 30-) year- olds, "I would do everything possi- ble to keep them in contact lenses for now. I think that's better than giving them bad optics and still hav- ing to do IOLs down the road." Par- tial correction "comes back to haunt you later on," because the IOL calcu- lation is so much more difficult, he said. Although Dr. Durrie advises most young hyperopes to wait as long as possible before having sur- gery, he agreed, "The IOLs we have today—the Crystalens (Bausch + Lomb, Rochester, N.Y.), the ReSTOR +3 (Alcon, Fort Worth, Texas)—those lenses are much better than wearing +7 glasses." Outside the U.S., corneal inlays are also a potential treatment. For younger hyperopes in the U.S., how- ever, Dr. Lindstrom counsels them about future presbyopia and will suggest either blended or monovi- sion LASIK. Patient satisfaction Ideally, patients between +2.00 D and +5.00 D "are the best ones to correct," Dr. de Ortueta said. "They'll get the most benefit of being able to see without spectacle use." Without a doubt, "this group of people are some of the happiest pa- tients in our whole practice," Dr. Durrie said. "Hyperopes are very grateful," Dr. de Ortueta said. "But we do need to be careful with their near vision. We are inducing negative spherical aberrations, which can give more depth of focus so the near vision is better, but as the patients age, they will need spectacles for near vision." In a global survey of patient sat- isfaction with LASIK, Dr. Lindstrom noted satisfaction rates for hyper- opes were equivalent to myopes—at about 95%. "Maybe it's because they're a lit- tle older or maybe it's because they have so much more to gain," he said. EW Editors' note: Dr. de Ortueta has financial interests with Schwind eye-tech solutions (Kleinostheim, Germany). Dr. Durrie has financial interests with Alcon and Abbott Medical Optics (Santa Ana, Calif.). Dr. Lindstrom is a consultant to industry. Contact information De Ortueta: 49 2361 3069770, diego.de.ortueta@augenzentrum.org Durrie: 913-491-3330, ddurrie@durrievision.com Lindstrom: 952-888-5800, rllindstrom@mneye.com