The clinical analysis of corneal astigmatism changes after cataract surgery with different locations of clear corneal incision

Objective To evaluate the corneal astigmatism changes after phacoemulsification performed using clear corneal incision with different locations.Methods Seventy-two eyes of 72 patients having phacoemulsification and implantation of foldable intraocular lens through a clear corneal incision were chosen.Patients were divided into two groups by table of random digit:group A (incision at 11:00),group B (incision at the steepest corneal meridian).The change of corneal astigmatism was compared between group A and B postoperatively.Surgically-induced astigmatism (SIA) was calculated by vector analyses using the HoHaday-Cravy-Koch method.Results Preoperative corneal astigmatism between group A and group B had no significant difference [(0.96 ± 0.52) D vs.(0.94 ± 0.56) D,P ＞ 0.05].One and three months after operation,the corneal astigmatism in group A were significantly higher than those in group B [(1.15 ± 0.32)D vs.(0.82 ± 0.43) D,(0.85 ± 0.38) D vs.(0.63 ± 0.40) D,P＜ 0.05].The SIA in group A was significantly higher than that in group B 1 month after operation [(0.85 ± 0.37) D vs.(0.75 ± 0.54) D,P ＜ 0.05],there was no significant difference between group A and group B 3 months after operation [(0.60 ±0.35) D vs.(0.58 ±0.30) D,P ＞0.05].Conclusions Corneal astigmatism is prｅsent in most cataract surgery candidates.Cataract surgery using steepest corneal meridian incision induces significantly less SIA,and correct corneal astigmatism already present preoperatively. Key words: Cataract;  Phacoemulsification;  Clear corneal incision;  Corneal astigmatism