Relationship between preoperative axis of astigmatism and postoperative astigmatic change after superior scleral incision phacoemulsification

PURPOSE: To evaluate the effect of the preoperative axis of astigmatism on the outcome of corneal astigmatism after sutured 5.2 to 5.7 mm superior incision phacoemulsification. SETTING: Departments of Opthalmology, Odense and Vejle Hospitals, Denmark. METHODS: Seventy-three consecutive patients with preoperative corneal astigmatism of 2.0 diopters (D) or less, axial length between 20.0 and 25.5 mm, and no eye disease except cataract were grouped according to preoperative with-the-rule (WTR) or against-the-rule (ATR) astigmatism. The keratometric cylinder, induced keratometric cylinder (subtraction), and induced cylinder (Jaffe) were measured and calculated 10 to 12 months postoperatively. RESULTS: The postoperative keratometric cylinder and induced keratometric cylinder were significantly higher in the ATR group (P < .00001; mean difference [95% confidence limits]: 0.76 D [0.54; 0.98] and 0.69 D [0.46; 0.92], respectively). There was no significant difference between groups in induced cylinder (Jaffe). CONCLUSION: The estimated differences were significantly in favor of patients with preoperative WTR astigmatism. The findings support using temporal incision in cases with a preoperative ATR axis of astigmatism.