Eyeworld

But is it reasonable to correct before a needed correction? W hen it comes to refrac- tive surgery, ophthal- mologists often think about the here and now. It is important to consider giving patients the best near, intermediate, and distance vi- sion. But what if surgeons knew how much vision was going to change over time? Would it be appropriate to build in the appropriate refractive correction for changes they knew would happen 5 years from now? Ophthalmologists recently had the chance to review an interesting study in which patients were found to have a long-term, against-the-rule change in astigmatism after suture- less cataract surgery. "This change is similar to that of [the] normal cornea, suggesting that the against-the-rule change that occurs subsequently should be taken into consideration at the time of cataract surgery," wrote Ken Hayashi, M.D., Hayashi Eye Hospi- tal, Fukuoka, Japan. The study was published in February in the Ameri- can Journal of Ophthalmology. That's an interesting comment, suggesting to some extent that surgeons should correct ahead of the needed correc- tion. Presented with these findings, some surgeons weighed in on whether they would pre-emptively correct. Correcting now for later? Dr. Hayashi and colleagues analyzed eyes that underwent phacoemulsifi- cation more than 11 years ago and eyes that did not undergo surgery. Between baseline and 5 years, and between 5 and 10 years, both groups underwent an against-the-rule change in astigmatism. The 5-year, against-the-rule, astigmatic change was found to be 0.15-0.25 D, using polar value analysis. "Accordingly, at the time of cataract surgery, surgeons should consider the potential for the long- term change," Dr. Hayashi said. "For example, a small amount of with- the-rule astigmatism, specifically in young and middle-aged patients, could be deliberately undercorrected because the against-the-rule astigma- tism increases subsequently." David DeRose, M.D., Lehigh Eye Specialists, Allentown, Pa., finds the study to be very intriguing. "It makes me want to pursue or observe this in my own cases," Dr. DeRose said. Dr. DeRose added that he has not heard of this kind of idea being addressed much, correcting for a needed correction that has been pre- dicted. "Usually, we want that immedi- ate 'wow' effect in post-op cataract patients," Dr. DeRose said. "We only see patients for the immediate post- operative period. We don't usually follow them for the long-term." That said, Dr. DeRose said he treats 40-year-old cataract patients differently than 50-year-old ones, and 50-year-old patients differently from 60-year-old ones. "For a 50- year-old patient, [correcting for pre- dicted astigmatism changes] is something to think about," Dr. DeRose said. Other physicians were opposed to the idea of a pre-emptive correc- tion for astigmatism. "I aim for the lowest amount of residual post-oper- ative astigmatism," said N. Timothy Peters, M.D., medical director, Clear Advantage Vision Correction Center, Portsmouth, N.H. Dr. Peters added that if a pseudophakic patient has a small amount of post-op astigmatism— such as a quarter of a diopter—that is probably visually insignificant. More significant astigmatism can be handled with either a small limbal relaxing incision (LRI) or laser vision correction, both of which are mini- mally intrusive procedures, he said. Dr. Peters likes toric IOLs be- cause of higher predictability, lower residual astigmatism, and a trend to- ward fewer higher-order aberrations than LRIs, based on research he has performed and presented. There are cases in which Dr. Peters said he does perform pre-emp- tive corrections. First, he said, he sometimes opts for refractive lens exchange in patients who are going to develop cataracts soon. Other- wise, he said, good LASIK effects would be short-lived. Second, he said, in cataract patients who are at high risk for retinal detachment, he performs a special procedure. "We will do an argon laser treat- ment out in the areas of lattice to put on spot welding that might re- duce the risk of retinal detachment during the cataract procedure," he said. He referred to such a procedure as a "precaution." Phillip McGeorge, M.D., Perth, Australia, does not favor pre-emptive correction for the possible future in- duction of astigmatism in patients. "The problem with that idea is it is hard to predict the rate of pro- gression [of against-the-rule astigma- tism]," Dr. McGeorge said. "If you are already using a temporal incision that has a small amount of surgically induced astigmatism, then you can leave things to nature rather than trying to guess what might happen in 5, 10, or 20 years. All surgical or refractive procedures have a time limit." Dr. McGeorge thinks that it is important to try to give patients ex- cellent vision that will last as long as possible. "We are trying to give patients the best vision now and into the fu- ture as far as we can predict," Dr. McGeorge said. EW Editors' note: The physicians mentioned have no financial interests related to their comments. Contact information DeRose: 610-820-6320, francesco26@me.com Hayashi: hayashi-ken@hayashi.or.jp McGeorge: +61 8 9388 0569, philm@perthlaservision.com.au Peters: 603-501-5000, peters3@comcast.net EW REFRACTIVE SURGERY February 2011 35 by Matt Young EyeWorld Contributing Editor Pre-emptive correction: Possible for astigmatism The image shows high astigmatism Source: Loretta Szczotka-Flynn, O.D., M.S. June 2011

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