Surgically Induced Astigmatism after Superotemporal and Superonasal Clear Corneal Incisions in Phacoemulsification

Abstract

Introduction: Cataract surgery has undergone various advances since it was evolved from ancient couching to the modern phacoemulsification. A clear corneal incision has the benefit of being bloodless and having an easy approach but surgically induced astigmatism (SIA) remains one of the most common complications.

Objective: To determine and compare the SIA in clear corneal phacoemulsification by superotemporal (ST) approach in right eye and by superonasal (SN) approach in left eye.

Methodology: This was a hospital-based, interventional, analytical study conducted in the department of Ophthalmology at Nepal Medical College, from 2024 January to 2025 March after institutional ethical approval. Patients enrolled by consecutive sampling technique were divided into two groups. In Group A, patients with immature cataract in the right eye underwent ST corneal incision. In Group B, patients with immature cataract in the left eye underwent SN clear corneal incision. Group A had 31 eyes and Group B had 34 eyes. Astigmatism was measured by keratometry readings pre and post-operatively at first and sixth week. The SIA was calculated by the vector analysis at first and sixth week post-operatively.

Result: Mean SIA was lower in Group A (0.36 ± 0.32 D at the first week, reducing to 0.31 ± 0.29 D at sixth week) compared to Group B (0.37 ± 0.22 D at the first week and 0.35 ± 0.25 D at sixth week. The SIA of both groups decreased post-operatively at sixth week. No statistically significant difference was found in SIA at both first and sixth post-operative week between two groups (p = 0.83; p = 0.55).

Conclusion: The incisions, either ST or SN in phacoemulsification showed no statistically significant difference in SIA.