EyeWorld Asia-Pacific September 2011 Issue

24 September 2011 EW REFRACTIVE High astigmatism Source: Loretta Szczotka-Flynn, OD, MS But is it reasonable to correct before a needed correction? W hen it comes to refractive surgery, ophthalmologists often think about the here and now. It is important to consider giving patients the best near, intermediate, and distance vision. 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 sutureless 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, MD, Hayashi Eye Hospital, Fukuoka, Japan. The study was published in February in the American Journal of Ophthalmology. That’s an interesting comment, suggesting to some extent that surgeons should correct ahead of the needed correction. 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 phacoemulsification 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 to 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 astigmatism increases subsequently.” David DeRose, MD, Lehigh Eye Specialists, Allentown, Pa., USA, 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 predicted. “Usually, we want that immediate ‘wow’ effect in post- op cataract patients,” Dr. DeRose said. “We only see patients for the immediate postoperative 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 predicted astigmatism changes] is something to think about,” Dr. DeRose said. Pre-emptive correction: Possible for astigmatism by Matt Young EyeWorld Contributing Editor Other physicians were opposed to the idea of a pre-emptive correction for astigmatism. “I aim for the lowest amount of residual postoperative astigmatism,” said N. Timothy Peters, MD, medical director, Clear Advantage Vision Correction Center, Portsmouth, NH, USA. 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 minimally intrusive procedures, he said. Dr. Peters likes toric IOLs because of higher predictability, lower residual astigmatism, and a trend toward fewer higher-order aberrations than LRIs, based on research he has performed and presented. Author’s response Ken HAYASHI, MD Hayashi Eye Hospital 4-23-35, Hakataekimae, Hakata-ku, Fukuoka City, Japan Tel. no. +81-92-431-4680 Fax no. +81-92-441-5303 hayashi-ken@hayashi.or.jp Based on the results of our study, 1 almost all eyes that had undergone cataract surgery presented the against-the-rule astigmatic change with subsequent aging. Accordingly, we believe that with-the-rule astigmatism should be left to some extent at the time of cataract surgery in middle-aged and relatively young patients. However, the degree of astigmatic change with aging varies considerably from patient to patient, and it is difficult to determine from this study what amount of with-the-rule astigmatism should be left for patients of each decade. We hope to clarify a minimal or average amount of with-the-rule astigmatism that should be left in patients of 40 or 50 years of age in the next study using a different study design. Reference 1. Hayashi K, Hirata A, Manabe S, Hayashi H. Long-term change in corneal astigmatism after sutureless cataract surgery. Am J Ophthalmol. 2011;151(5):858-65. continued on page 33