The change of corneal astigmatism after cataract surgery with different locations of clear corneal incision

Abstract

Objective To analyze the corneal astigmatism before cataract surgery and evaluate the astigmatism changes after cataract surgery performed using clear corneal incisions with different locations.Methods: This randomized prospective clinical study comprised 295 eyes of 218 patients having phacoemulsification and implantation of foldable intraocular lens through a corneal tunnel incision. Patients were randomly divided into three groups depending on the different locations of the incision: temporal, superotemporal and superior. Corneal topography was performed preoperatively and 1 week, 1 month, and 3 months postoperatively. Surgically induced changes were calculated by vector analyses using the Holladay-Cravy-Koch method.Results: Preoperatively, in 60.68% of eyes, corneal astigmatism was between 0.5 and 1.5 diopters (D) and in 11.86%, it was 1.5 D or higher. Meanwhile, about 29.49 percent of eyes had with-the-rule (WTR) astigmatism, while 51.19% had against-the-rule (ATR) astigmatism, and the others had oblique astigmatism. At three follow-up visits postoperatively, the mean magnitude of surgically-induced astigmatism (SIA) was lowest in the temporal incision group and highest in the superior incision group. In addition, an ATR shift was found in the superior incision group. Conclusions: Corneal astigmatism less than 1.5 D was present in most cataract surgery candidates. Cataract surgery using temporal clear corneal incision induced significantly less SIA in the early postoperative period. Superior incision may lead to an ATR astigmatism shift. Key words: Intraocular lenses; Color discrimination; Cataract; Photochromic; Blue light-filtering