Comparison of astigmatism correction following straight and frown incisions in manual small incision cataract surgery

Abstract

The type of incision is the major contributory factor to the postoperative astigmatism. Different incisions may cause different degrees of astigmatism. It becomes imperative to compare the SIA caused by the commonly used incisions like straight and frown incisions. OBJECTIVES Ÿ To evaluate and compare the postoperative astigmatism following straight and frown incision Ÿ To compare the efficacy of straight and frown incision to reduce the postoperative astigmatism. MATERIALS AND METHODS For this prospective study a total of 96 eyes fulfilling the inclusion criteria were selected and allotted into two groups by simple randomization technique. Group1 – 48 patients – underwent MSICS with straight incision. Group2 – 48 patients – underwent MSICS with frown incision. This prospective study was conducted in the department of ophthalmology at R. L. Jalappa Hospital And Research, Kolar attached to Sri Devaraj Urs Medical College, between February 2019 and March 2019. Post-operative visual acuity was assessed with Snellen's chart. Post-operative keratometry was SIA calculator version 2.1 was used to calculate the SIA. RESULTS The mean magnitude of preoperative astigmatism in straight incision was 1.26± 0.92 D and in frown incision was 0.98 ± 0.83 D. The mean magnitude of postoperative astigmatism in straight incision was 1.52±1.17 D and in frown incision was 0.99 ± 0.82D and was found to be statistically significant, p= 0.012. The centroid of SIA for straight incision was 1.4x10 with a coherence of 90% and the centroid of SIA for frown incision was 0.62x20 with a coherence of 70%. CONCLUSION The mean magnitude of postoperative astigmatism in straight incision was 1.52±1.17 D. The mean axis of postoperative astigmatism in straight incision was 96.5 ± 74.9 D. The mean magnitude of postoperative astigmatism in frown incision was 0.99 ± 0.82 D. The mean axis of postoperative astigmatism in frown incision was 74.96 ± 68.78 D. The magnitude of postoperative astigmatism was greater in straight incision when compared to frown incision and the difference was statistically significant. Straight incision should be used for highly significant and significant WTR astigmatism while frown may be used for significant astigmatism and non-significant WTR astigmatism.