Asymmetric Corneal Flattening Effect After Small Incision Cataract Surgery

PURPOSE: To determine whether the flattening effect of corneal incisions differs between the right and left eye. METHODS: A retrospective study of preoperative and postoperative corneal astigmatism was performed for patients who had bilateral cataract surgery by a right-handed surgeon. The change in corneal astigmatism was attributed to the 2.2-mm phacoemulsification incision, and the incisional flattening effect was calculated. The incisions were grouped by position on the eye and whether they were performed on the preoperative steep corneal meridian. RESULTS: A total of 1,298 eyes of 649 patients were evaluated. The flattening effect of temporal 2.2-mm incisions performed on the preoperative corneal steep meridian was different for right eyes (0.53 diopters [D]) and left eyes (0.34 D) (P = .017). The flattening effect of superior 2.2-mm incisions performed on the preoperative corneal steep meridian was equivalent in the two eyes. CONCLUSIONS: The flattening effect of a corneal incision may depend on whether it has been performed on the right or the left eye.