Changes of Corneal Topographic Measurements and Refractive Errors after Horizontal Muscle Surgery. A Case Series

Abstract

Abstract Background: Refractive and corneal topographic changes after routine strabismus surgery have been reported and can occur even after a successful surgery. Study aims to evaluate the effect of horizontal muscle surgery on refractive errors and corneal measurements. Patients and methods: This study includes 25 eyes of 22 patients who have manifest strabismus. The patients were divided into two groups. Group A (10 eyes of 7 patients) subjected to unilateral lateral rectus recession. Group B (15 eyes of 15 patients) all of them subjected to lateral rectus recession and medial rectus resection in the same eye. Cycloplegic automated refraction (including spherical equivalent, astigmatic error and astigmatic axis) were recorded preoperatively, one month and 3 months after surgery. Corneal topography including flat K, steep K were recorded preoperatively, one month and 3 months after surgery. Results: A significant change of spherical equivalent towards myopic shift after horizontal rectus muscle recession was observed (P=0.000). A significant change of refractive cylindrical power with rule was found in both groups (P=0.000). Corneal topographic parameter (flat k) showed a significant change in the both groups (P=0.000). . These changes persisted till the last postoperative visit. Conclusion: Horizontal muscle surgery induced a statistically significant change of astigmatism power that persists till the 3rd. postoperative month. A significant change of spherical equivalent was found in the postoperative period after horizontal strabismus surgery only in recession group.