Surgically induced astigmatism after phacoemulsification in eyes with mild to moderate corneal astigmatism

Abstract

To determine whether there is a difference in surgically induced astigmatism (SIA) and postoperative uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) between 2 types of clear corneal incisions used in phacoemulsification: the temporal and the on-axis (ie, on the steeper corneal meridian) clear corneal incision (CCTI and CCOI, respectively). Moorfields Eye Hospital, London, United Kingdom. In a prospective randomized controlled trial (pilot study), 61 eyes with cataract and mild to moderate corneal astigmatism (t test. The power of the study was calculated. At the first follow-up, the difference in SIA between the 2 incision types was 0.15 D and it was not statistically significant (0.65 D in CCOI; 0.50 D in CCTI). At the second follow-up, the difference was 0.29 D and it was statistically significant (0.63 D in CCOI; 0.34 D in CCTI; P = .0004). There was no statistically significant difference in the final postoperative visual acuity. The power of the pilot study was 72%. Seven weeks after small-incision phacoemulsification, the CCTI induced less SIA than the CCOI; however, there were no significant differences in the final UCVA and BCVA.