AIM: To compare preoperative and postoperative corneal astigmatism using 3.0mm corneal incision guided by corneal topography system in phacoemulsification.

METHODS:Phacoemulsification was performed on 144 cases 156 eyes with 3.0mm corneal clear incision at the steepest corneal meridian. Preoperative corneal astigmatism and the data 3 months postoperatively were observed by the corneal topography system. Statistical analysis included sample Student's t-test, one way ANOVA test, Kruskal-Wallis test and Pearson correlation test.

RESULTS: According to analysis, the postoperative corneal astigmatism correlated negatively with the preoperative corneal astigmatism(r=-0.69, P<0.01). The corneal cylinder changed significantly in each grade after the surgery(P<0.05). When the preoperative corneal cylinder was between 0.12D and 0.25D, the postoperative corneal cylinder was higher than before. Whereas, the postoperative corneal cylinder became lower than before when the preoperative cylinder ranged from 0.37D to 1.0D.

CONCLUSION: The incision located at the steepest corneal meridian under the guidance of corneal topography changes the preoperative astigmatism. For astigmatic correction, 3.0mm on-axis clear corneal incision phacoemusification is recommended with preoperative corneal astigmatism between 0.37 and 1.0D.