Comparison of surgically induced astigmatism after sutureless temporal clear corneal and scleral frown incisions

Abstract

Purpose: To compare the corneal astigmatic changes induced by clear corneal incisions with those induced by scleral tunnel frown incisions, both from a temporal approach, in sutureless cataract surgery.Setting: Department of Ophthalmology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China.Methods: This prospective study comprised 120 eyes divided into two groups of 60 each based on incision type. All patients had examinations with an autokeratometer preoperatively and 1 week and 1, 3, and 6 months postoperatively.Results: Simple subtraction of the scalar analysis in each group showed minimal astigmatic changes; however, the standard deviation of astigmatic change was greater in the clear corneal incision group. The mean vector analysis of surgically induced astigmatism in the scleral frown incision group was 0.69, 0.75, 0.72, and 0.61 diopter (D) at 1 week and 1, 3, and 6 months, respectively. In the clear corneal incision group, it was 1.55, 1.12, 0.93, and 0.92 D at the same intervals. In the scleral frown incision group, Naeser's polar value also showed minimal changes in polar astigmatism throughout the study; in the clear corneal incision group, it showed a mean with-the-rule (WTR) astigmatic shift of +0.73, +0.22, +0.13, and +0.08 D at 1 week and 1, 3, and 6 months, respectively.Conclusion: Corneal stability was achieved with minimal astigmatic change 1 week after scleral frown incisions, while clear corneal incisions induced greater WTR astigmatism with delayed stabilization 1 to 3 months postoperatively.