Epithelial uniformity pattern post topo-guided LASIK – Role of cyclosporine versus standard of care

Abstract

PURPOSE: To evaluate epithelial remodeling after topo-guided LASIK using a novel Epithelial Uniformity Index (EUI) and to assess whether topical cyclosporine improves postoperative epithelial uniformity compared to standard care. METHODS: In this retrospective comparative study, we analyzed 122 eyes of 62 patients undergoing topo-guided LASIK, divided into cyclosporine ( n = 60) and non-cyclosporine ( n = 62) groups. Epithelial thickness was measured using spectral-domain optical coherence tomography across four corneal zones (central, inner, middle, outer) preoperatively and at 1, 3, and 6 months. The EUI was calculated as 1 minus standard deviation/mean across 25-point thickness maps; higher EUI indicates greater uniformity. Visual acuity, corneal aberrations, and patient-reported outcomes were assessed. RESULTS: Both groups showed significant epithelial thickening in the central and inner zones, increasing from ~54 μm at baseline to ~59 μm at 6 months ( P < 0.001). The middle zone also thickened by 6 months ( P < 0.05), while the outer zone thinned at 1 month before recovering. No significant intergroup differences were observed ( P > 0.18). EUI declined significantly at 1 month (inner: 0.98 to 0.96; overall: 0.96 to 0.92; P < 0.05) and showed only partial recovery by 6 months, remaining lower than baseline ( P < 0.05), with no significant differences between groups ( P > 0.1). Higher baseline refractive error correlated with greater EUI reduction (r = 0.58, P < 0.001). Lower EUI weakly correlated with worse uncorrected visual acuity and increased coma (both P < 0.05). CONCLUSIONS: Topo-guided LASIK induces central/paracentral epithelial thickening with reduced uniformity. The EUI is a useful tool to quantify remodeling. Cyclosporine did not significantly enhance epithelial uniformity.