Eyeworld

EW INTERNATIONAL 64 April 2015 by Matt Young and Gloria D. Gamat EyeWorld Contributing Writers The tHOA increased from a mean 0.209 +/–0.421 µm preopera- tively to 0.249 +/–0.104 µm postop- eratively within a 3 mm aperture. Corneal HOA increased from 0.479 +/–0.079 µm before surgery to 0.523 +/–0.123 µm after surgery within a 3 mm aperture. Changes of other HOAs also were similar to tHOA before and after surgery. "Phacoemulsification cataract surgery does not systematically de- grade the optical quality of the cor- nea," Dr. Szaflik said, adding "there is a need for further investigations to clarify this tendency." On becoming significant Conventional wisdom suggests that corneal incisions in cataract surgery do not have a significant impact on the spherical equivalent of the cornea pre- and post-surgery. Incisions + phaco = insignificant aberrations? In one prospective case series carried out in Poland, Jacek P. Szaflik, MD, PhD, Department of Ophthalmol- ogy, Medical University of Warsaw, and colleagues measured corneal higher-order aberrations before and after phacoemulsification in 36 eyes of 30 patients. "The main goal of this project was to evaluate higher-order aberra- tions of the cornea after phacoemul- sification surgery," Dr. Szaflik said. Monofocal foldable IOLs were inserted using a 2.4 mm incision plus 1.2 mm side-port incision. Total high order aberrations (tHOA) were analyzed including at ocular 4 mm, corneal 4 mm, internal 4 mm, ocular 6 mm, corneal 6 mm, internal 6 mm, spherical aberration (SA), coma, trefoil, 3rd, 4th, 5th, and 6th order aberrations. Analysis was made with an aberrometer and with cornea/anterior segment OCT. The potential visual side effects of corneal incisions during phaco F or years, ophthalmologists have been working on grad- ually reducing cataract sur- gery incision size, often in an effort to reduce induced astigmatism. Now, at least 3 posters at the 2015 European Society of Cataract & Refractive Surgeons (ESCRS) Winter Meeting in Istanbul in February focused on other visual side effects of corneal incisions. Some posters suggest that incisions, along with phacoemulsification, do have an impact on corneal aberrations, although not significantly. Other research suggests that corneal inci- sions—in specific instances—could have much more significant impact than what conventional wisdom might suggest. M inimizing the visual consequenc- es of corneal incisions was the primary driver of the development of small incision techniques. Gone are the bad old days of 6-mm incisions, multiple sutures, and several diopters of induced astigmatism. We can argue where the point of diminishing returns occurs, but conventional wisdom dictates that any corneal incision of 2.8 mm or less is likely to have minimal effect on the outcome. But is this actually the case? An alternate hypothesis is that we may not have been looking carefully enough to appreciate the effect. In this article, EyeWorld highlights 3 studies looking at the visual consequences of modern small corneal incisions on higher order aberrations as well as spherical cal- culations. Is accounting for the visual effect of a small incision clinically relevant? Read on and judge for yourself. John A. Vukich, MD, international editor The visual impact of corneal incisions beyond induced astigmatism International outlook At the ESCRS Winter Meeting in Istanbul, several scientific posters discussed the impact of corneal cataract incisions on vision.

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