COMPARATIVE ANALYSIS OF INCISION DESIGNS AND THEIR IMPACT ON SURGICALLY INDUCED ASTIGMATISM AND VISUAL OUTCOMES IN MANUAL SMALL INCISION CATARACT SURGERY

Abstract

Background: Surgically induced astigmatism (SIA) is a critical factor influencing visual quality following manual small incision cataract surgery (MSICS). The architecture of the scleral tunnel may significantly influence postoperative refractive stability and visual recovery. Methods: This comparative study included 480 eyes undergoing MSICS, equally assigned to four incision groups: Chevron, Back-cut Straight, Frown, and Straight (n = 120 each). Baseline ocular characteristics were comparable. Uncorrected and best-corrected visual acuity (UDVA, BCVA) and SIA (vector analysis) were assessed at postoperative Day 1, Week 1, Week 4, and Week 6. Results: By the sixth week, the Chevron group achieved the most favorable outcomes, recording a mean UDVA of 0.18 ± 0.13 logMAR and BCVA of 0.08 ± 0.07 logMAR. Back-cut Straight incisions produced intermediate results, followed by Frown, while Straight incisions yielded the least improvement. Mean SIA was lowest in the Chevron group (0.48 ± 0.36 D) and highest in the Straight group (1.12 ± 0.62 D) (p < 0.001). Residual cylinder ≤0.50 D was highest in Chevron (70.0%) and lowest in Straight incision cases (31.7%). Conclusion: Chevron incisions demonstrated the greatest refractive predictability and visual recovery in MSICS. Back cut Straight incisions may serve as a practical alternative for achieving controlled astigmatism while maintaining technical simplicity. Tailoring incision design can enhance visual outcomes without additional instrumentation.