Site of incision and corneal astigmatism in conventional SICS versus phacoemulsification

High astigmatism is an important cause of poor uncorrected visual acuity after cataract surgery.

The aim of the study is to compare the astigmatism induced by a superior and temporal incision in manual SICS, and to compare the astigmatism induced by clear corneal incision versus scleral tunnel in phacoemulsification surgery.

A total of 64 eyes of 64 patients (34 male/30 female) with a mean age of 62.10 years (range 45-82 years) were included in the study. The cases were randomly divided into two groups. One group (Group I) had undergone manual SICS and the other group (Group II) had undergone phacoemulsification. The manual SICS group patients were randomly allotted into two subgroups depending on the site of incision. Group Ia received superior incision while group Ib received temporal incision. The Phacoemulsification group (Group II) patients were randomly divided into two groups depending on the location of the incision. Group IIa received clear corneal incision and group IIb received scleral pocket incision. Informed consent was obtained from all the patients undergoing study. Surgically induced astigmatism is calculated by the substraction method.

We found significantly against the rule shift in astigmatism in the phacoemulsification group and the manual SICS superior incision group. The manual SICS group with temporal incision (Ib) had with-the-rule shift in astigmatism.

At 90 days, conventional SICS superior incisions gave 1.92 +/- 0.53 D against the rule and temporal incisions 1.57 +/- 0.24 D with the rule astigmatism. Phacoemulsification clear corneal incisions showed 1.08 +/- 0.36 D and scleral pocket 1.23 +/- 0.71 D astigmatism.