A comparative study of sclero-corneal and clear corneal tunnel incision in manual small-incision cataract surgery.

BACKGROUND Cataract surgery techniques have improved a lot over the years from couching to the latest micro-incision cataract surgery. OBJECTIVES To compare the temporal sclero-corneal and clear corneal tunnel incisions in patients undergoing manual small-incision cataract surgery (SICS) with respect to the surgically-induced astigmatism. MATERIALS AND METHODS The present study included 60 patients who underwent manual SICS with posterior chamber intraocular lens implantation. Group A comprised of 30 patients, selected randomly, who underwent sutureless manual SICS through 6 mm curvilinear clear corneal tunnel incision made temporally and Group B comprised of 30 patients, selected randomly, who underwent sutureless manual SICS through 6 mm straight sclero-corneal tunnel made temporally. The patients were assessed at 1 week, 2 weeks, 1 month and 2 months post-operatively and visual acuity and keratometry findings were recorded. The amount of surgically induced astigmatism was calculated using Holladay's formula. STATISTICS Numerical data were compared between the two groups using unpaired Student's t-test. The p value of less than 0.50 was considered significant. RESULTS The mean induced astigmatism in Group A was 2.69 ± 0.84 D at 1 week, 2.31 ± 0.77 D at 2 weeks; 2.03 ± 0.82 D at 4 weeks and 1.98 ± 0.54 D at 8 weeks post-operatively. In group B, it was 1.85 ± 0.62 D, 1.56 ± 0.54 D, 1.35 ± 0.49 D and 1.34 ±0.45 D at 1 week, 2 weeks, 4 weeks and 8 weeks postoperatively. Uncorrected visual acuity (UCVA) of 20/ 20 was seen in 20 % of patients in group A and in 40 % in group B at 8 weeks postoperatively. CONCLUSION Surgically-induced astigmatism is significantly higher in clear corneal manual SICS than in sclero-corneal. Our study confirmed the safety and improvement in visual acuity after small-incision cataract surgery using sclero-corneal tunnel incision.