The influence of corneal wound size on surgically induced corneal astigmatism after phacoemulsification.

BACKGROUND/PURPOSE: To determine whether there is a difference in surgically induced astigmatism (SIA) after phacoemulsification for unsutured temporal clear corneal incisions of 2.5 mm and 3.5 mm wound sizes.

METHODS

This study comprised 36 eyes of 18 patients who received cataract surgery from a single surgeon. Patients were randomly assigned to receive a one-piece intraocular lens (IOL; Acrysof SA60AT), through a 2.5 mm incision in one eye, and a three-piece IOL (Tecnis Z9000), through a 3.5 mm incision in the contralateral eye. Corneal topography was performed preoperatively and also postoperatively at 3, 6, and 12 weeks. SIA was calculated by means of vector analysis using the Alpins' method.

RESULTS

The mean SIAs of the groups with 2.5 mm and 3.5 mm incisions were 0.57 diopter (D) and 0.86 D respectively (p = 0.04) at 3 weeks postoperatively, 0.60 D and 0.83 D respectively (p > 0.05) at 6 weeks postoperatively, and 0.58 D and 0.58 D respectively (p > 0.05) at 12 weeks postoperatively. At 12 weeks postoperatively, SIAs of <1.0 D were found in all eyes in the 2.5 mm group and 93% of eyes in the 3.5 mm group. Forty-four percent of eyes in both groups demonstrated SIAs > 0.5 D at 12 weeks postoperatively. The largest SIA was 1.36 D in the 3.5 mm group.

CONCLUSION

Mean SIA in the 3.5 mm group was larger than that in the 2.5 mm group in the early postoperative period, but there was no significant difference for the entire observational period.