Surgically Induced Astigmatism in Manual Small Incision Cataract Surgery Following Straight, Frown and Chevron Incision

Abstract

 Background: Surgically Induced Astigmatism (SIA) remains a major determinant of uncorrected visual acuity following manual Small-Incision Cataract Surgery (SICS). Incision configuration is a modifiable factor influencing postoperative refractive outcomes. To compare postoperative visual acuity and surgically induced astigmatism among straight, frown and chevron incisions in manual SICS.

Materials and methods: This prospective observational analytical study was conducted at a tertiary care hospital in Bangladesh from February 2022 to January 2023. A total of 110 patients aged  40 years with uncomplicated age-related cataract and with-the-rule astigmatism were enrolled. Patients underwent manual SICS using straight (n=37) frown (n=49) or chevron (n=24) incisions by a  single experienced surgeon. Postoperative uncorrected and  best-corrected visual acuity, keratometric astigmatism, and SIA were evaluated at six weeks. SIA was calculated using SIA Calculator version 2.1. Data were analyzed using SPSS version 25.0.

Results: Baseline demographic and preoperative visual parameters were comparable among groups. At six weeks, best-corrected visual acuity  6/18 was achieved in nearly all patients across all incision types. However, uncorrected visual acuity was significantly better in the frown and chevron groups compared to the straight incision group (p=0.034). Mean SIA was highest in the straight incision group (0.95 D) and significantly lower in the frown (0.58 D) and chevron (0.57 D) groups (p<0.001).

Conclusion: Frown and chevron incisions in manual SICS result in significantly lower surgically induced astigmatism and better early uncorrected visual outcomes compared to straight incisions. These incision techniques may be preferred to optimize refractive outcomes in high-volume, resource-limited settings.

JCMCTA 2026 ; 37 (1) : 138-144