Comparison of surgically induced astigmatism in chevron, straight, and frown incisions in manual small-incision cataract surgery

PURPOSE: The study was conducted to calculate and compare the surgically induced astigmatism (SIA) in chevron, frown, and straight incisions in manual small-incision cataract surgery (MSICS). METHODS: A prospective, hospital-based study was conducted on 90 patients aged 50 years and above with nuclear sclerosis of grade 4 or more. Each group had 30 patients, divided into Group V (chevron incision), Group S (straight incision), and Group F (frown incision). Patients who had with-the-rule (WTR) astigmatism were operated on through a chevron or straight incision superiorly, while patients who had against-the-rule (ATR) astigmatism underwent MSICS through a temporal frown incision. The patients were followed up post-operatively on days 1, 7, 6 weeks, and 12 weeks, and at each visit, the uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and SIA were calculated and compared. RESULTS: The mean age of all the patients was 66.22 ± 8.05 years. BCVA of at least 6/18 or better at 12 weeks post-operatively was achieved in 29 patients (97%) in Group V, 28 patients (93%) in Group F, and 29 patients (97%) in Group S. The mean SIA in Group V was 0.34D ± 0.22D, in Group S was 0.97D ± 0.29D, and in Group F was 0.575D ± 0.25D. CONCLUSION: SIA by chevron incision is the least followed by the frown incision and straight incision. The superiorly placed chevron incision in WTR astigmatism provided optimal results for the best UCVA and minimal SIA. The temporal frown incision in ATR astigmatism also had good results.