Materials and Methods: 49 eyes of 49 patients who had corneal astigmatism over 0.5 diopters (D) were randomly distrubuted into two groups. A superior clear corneal incision was performed in group 1 (25 eyes) and steep axis incision was performed in group 2 (24 eyes). Corneal topography was performed in all cases at preoperative and postoperative first day, second and fourth weeks. Changes in corneal astigmatism were calculated by vector analysis method.

Results: In group 1, mean corneal astigmatism increased from 1.09±0.44 D to 1.40±0.70 D after surgery. In group 2, mean astigmatism decreased from 1.35±0.85 D to 0.95 ±0.78 D 1 month after surgery. The change in mean corneal astigmatism at first month between two groups was statisticially significant (p<0.001). The astigmatism created by corneal incisions were compared between two groups by vector analysis method. Although surgically induced astigmatism was lower in group 2, this difference was not statistically significant.

Conclusion: Clear corneal incision performed on steep axis results in less postoperative astigmatism compare to standard superior incision in phacoemulsification. Keywords : Phacoemulsification, steep axis, incision, topography, astigmatism