Quantification of the Corneal Astigmatism Following Extracapsular Cataract Extraction Vs Small Incision Cataract Surgery with Intraocular Lens Implantation” - A Randomised Controlled Trial

Abstract

Background and Objectives: ABSTRACT To quantify and compare the induced corneal astigmatism in extracapsular cataract extraction and small incision cataract surgery. Methods: This was a randomized control study in which 120 patients with senile cataract were divided into 2 groups of 60 each. Patients in group A underwent manual small incision cataract surgery with posterior chamber intraocular lens implantation ( with superior straight 6mm incision) . Patients in group B underwent extracapsular cataract extraction with posterior chamber intraocular lens implantation ( with superior 6mm mid limbal incision and 3 interrupted 10-0 nylon sutures. Keratometric readings were taken preoperatively as well as at 1-2 weeks, 6-8 weeks and 10-12 weeks postoperatively. Surgically induced astigmatism was calculated using the preoperative and postoperative keratometry readings by the vector method. Results: The number of patients with a surgically induced astigmatism of <1.5D was 77% in group A and 70% in group B. The average surgically induced astigmatism at 3 months postoperatively in group A ( SICS ) was -1.13 ± 1.04 D and -1.29 ± 0.95 D in group B ( ECCE ) . This difference was not found to be statistically significant ( unpaired t test= 0.895, DF=118, P=0.372 ) . IX Conclusion: The average SIA in SICS was -1.13 ± 1.04 D and that of ECCE was -1.29 ± 0.95D. Since the difference in the surgically induced astigmatism between the two groups was not statistically significant, this study demonstrated that by using a 6mm mid limbal incision and placing only 3 interrupted 10-0 nylon sutures in extracapsular cataract extraction, the surgically induced astigmatism can be reduced and can be made comparable to that of small incision cataract surgery with a 6mm superior self sealing corneoscleral tunnel incision.