Comparative study of surgically induced astigmatism in superior and temporal scleral incisions in manual small-incision cataract surgery patients

Abstract

Background: The purpose of the study is to evaluate surgically induced corneal astigmatism and visual outcome in patients undergoing small-incision cataract surgery (SICS) by modifying incision site on the basis of type of regular astigmatism. Material and Methods: This is a prospective study including 100 patients, having senile immature cataract, divided in two groups of 50 patients each according to the type of preoperative corneal astigmatism over a period of January 2018 to June 2019. A detailed preoperative evaluation was done including automated refractokeratometry, on the basis of which patients having steeper vertical axis (90° ±30°), i.e., “with the rule” astigmatism placed in Group A and subjected to superior SICS, and those having horizontal steeper axis (150°–180° and 0°–30°), i.e., “against the rule” astigmatism, were placed in Group B and subjected to temporal SICS. All surgeries were performed by a single ophthalmic surgeon with a similar technique of a 6.00 mm superior or temporal scleral straight incision. Surgically induced astigmatism (SIA) was calculated by a computer application SIA calculator version 2.0 on the 45th postoperative day and compared. Results: Present study showed mean SIA was significantly less in the temporal group (1.09 ± 0.42 D) as compared to the superior group (1.38 ± 0.62 D). Conclusion: Modification of incision site in SICS as per preoperative astigmatism produces comparable results to other sophisticated techniques such as phacoemulsification, and hence, it provides an alternative path to attain better visual outcome and reduced SIA with limited resources available in most of the developing countries.