A clinical study comparing post-operative astigmatism with straight and frown scleral incision in manual small incision cataract surgery

Abstract

Background: Cataract surgery is considered refractive surgery. Apart from implanting the right dioptric power of Intra ocular lens (IOL), minimizing postoperative astigmatism plays an important role in good visual rehabilitation. Hence, surgical incision is of major importance in minimizing postoperative astigmatism and reducing or abolishing preexisting astigmatism.Objectives: The objective of this study is to compare surgically induced astigmatism (SIA) following straight and frown scleral incisions in manual small-incision cataract surgery (MSICS).Materials and Methods: This is a prospective randomized comparative study conducted among two groups of patients undergoing MSICS, where the straight scleral incision was performed in one group with 29 cases and the frown incision was performed in the other group with 29 cases. Postoperatively, patients were followed up on postoperative day 1, week 1, and week 6. Uncorrected visual acuity, Kv and Kh readings, and SIA were noted at each postoperative visit.Results: SIA on the postoperative day 1 in the straight incision group (SIG) was 1.4914D ± 1.251 and in the frown incision group (FIG) was 0.629D ± 0.288. On the postoperative week 1 in SIG, it was 0.9655D ± 0.699, and in FIG, it was 0.474D ± 0.397. On the postoperative week 6 in SIG, it was 0.8793D ± 0.599, and in FIG, it was 0.414D ± 0.286. SIA was significantly less in FIG compared to SIG (P = 0.011). Postoperative uncorrected visual acuity was better in FIG compared with SIG. More amount the rule astigmatism was noted in FIG on the postoperative 6th-week follow-up, which is favorable to the patient, while SIG witnessed more amount against the rule astigmatism.Conclusion: Frown incision is a better incision than the straight incision in MSICS to create a sclerocorneal tunnel.