Astigmatism after superonasal and superotemporal clear corneal incisions in phacoemulsification

Abstract

Purpose To determine the astigmatism outcomes after cataract surgery performed using superonasal and superotemporal clear corneal incisions. Setting Department of Ophthalmology, Kartal Training and Research Hospital, Istanbul, Turkey. Methods This prospective study includes consecutive 45 eyes of 34 patients having phacoemulsification with implantation of foldable acrylic intraocular lens through a corneal tunnel incision between January and April 2004. The right eye always had a superotemporal incision while the left eye a superonasal incision. Astigmatism was measured by keratometry readings before surgery and 3rd, 15th, and 45th days postoperatively. The surgically induced astigmatism (SIA) was calculated by the vector analysis using the Holladay–Cravy–Koch method at 3rd day, 2nd and 6th weeks postoperatively. Results The mean preoperative astigmatism was 0.74 ± 0.45 diopter (D) in the temporal incision group and 0.69 ± 0.39 D in the nasal incision group. Fifty-eight percent of eyes had against-the-rule (ATR) astigmatism, 26% had with-the-rule (WTR) astigmatism, and 16% were astigmatically neutral. At 6 weeks, 46% of eyes had ATR astigmatism and 35% had WTR astigmatism. The mean total astigmatism was lower in the temporal incision group than in the nasal incision group at all successive examinations postoperatively. Although the total astigmatism decreased at 6 weeks in both groups, temporal incisions yielded less total and surgically induced astigmatism (P < .05). Conclusions Cataract surgery using superotemporal incision induced significantly less SIA in the early postoperative period.