ABSTRACT
PURPOSE: To determine if a difference exists in surgically-induced astigmatism (SIA) and the mean change in keratometric astigmatism in patients who underwent microcoaxial cataract surgery (MCCS). METHODS: A prospective study including 193 eyes with astigmatism of greater than 0.5 diopters was performed. The eyes were randomized into two groups: (1) 95 eyes with steep axis incision, and (2) 98 eyes with temporal incision. A 2.2-mm microcoaxial phacoemulsification was performed. The UCVA, BCVA and corneal topography (Orbscan II, Bausch & Lomb) were measured preoperatively and three months postoperatively. Surgically induced astigmatism was calculated via vector analysis, and the mean change in keratometric astigmatism was also calculated. RESULTS: There were no significant differences in UCVA or BCVA between the two groups three months postoperative. The mean SIA was 0.45 +/- 0.27 diopters in the steep axis incision group and 0.30 +/- 0.17 diopters in the temporal incision group. In the steep axis incision group, the mean keratometric astigmatism showed a mean reduction of 0.31 +/- 0.37 diopter (WTR: 0.37 D; oblique: 0.35D; ATR: 0.16 D), while the mean keratometric astigmatism showed a mean increase of 0.06 +/- 0.29 diopters (WTR: 0.15 D increased; oblique: 0.11 D increased; ATR: 0.13 D reduced) in the temporal incision group. There were statistically significant differences in SIA and change in astigmatism between the two groups (p = 0.002, p = 0.000). CONCLUSIONS: In MCCS, steep axis incision achieved superior astigmatism correction in patients having with-the-rule or oblique astigmatism of greater than 0.5 diopters.