Reduction in preexisting against the rule astigmatism in temporal manual small incision cataract surgery: Can curvilinear incision be a better choice?

Background: To address the issue of ATR astigmatism in patients who undergo temporal manual small incision cataract surgery (MSICS) surgery. Aim: The aim is to find out whether an incision that is made parallel to the limbus (curvilinear) while doing temporal MSICS can reduce the preexisting against-the-rule astigmatism (ATR). Settings and Design: The study was conducted on those patients who came for cataract surgery in a government general hospital. Materials and Methods: One hundred and five patients with cataract and ATR astigmatism of ≥1D were divided into three groups each with 35 patients. Group A patients underwent curvilinear incision temporal MSICS, Group B straight line incision temporal MSICS, and Group C limbal incision temporal phacoemulsification. The amount of change in ATR astigmatism in each group was calculated by comparing preoperative and postoperative keratometry readings. Statistical Analysis: All data were evaluated using SPSS version 19.0. To test the significant difference between pre- and post-operative astigmatism in each group, paired t -test was used. To test the significant difference in astigmatism between the three groups, ANOVA was used. Results: The reduction in the mean astigmatism in Group A was 0.89D, in Group B 0.62D, and in Group C 0.086D. The significant reduction of the ATR astigmatism in Group A and Group B could be due to the flattening of the horizontal curvature which is higher in patients with ATR astigmatism. Among these two groups, the curvilinear incision produced more flattening than the straight line incision. Conclusion: If a curvilinear (limbus parallel) is done while doing temporal MSICS in patients with higher ATR astigmatism, there can a significant reduction of ATR astigmatism giving a better uncorrected visual acuity.