Comparative analysis of epithelial remodeling after photorefractive keratectomy and keratorefractive lenticule extraction for myopia

Abstract

PURPOSE: This study aims to characterize and compare the patterns of epithelial remodeling following photorefractive keratectomy (PRK) and femtosecond small incision lenticule extraction (Femto-SMILE) using high-resolution anterior segment optical coherence tomography (OCT) imaging. METHODS: In this prospective comparative study, 48 eyes of 24 myopic patients underwent PRK (Group A) or Femto-SMILE (Group B). Preoperative assessments included a full ophthalmologic examination, corneal topography, and epithelial mapping using the MS-39 anterior segment OCT. Postoperative evaluations were conducted at 1 week, 1 month, and 6 months, with epithelial thickness changes analyzed and compared. RESULTS: The mean preoperative minimum epithelial thickness was 42.33 µm in Group A and 44.25 µm in Group B, while the mean maximum epithelial thickness was 54.46 µm and 54.25 µm, respectively. At 6 months, the thinnest epithelial point increased in all patients. There were no statistically significant differences in epithelial thickness in the paracentral quadrants between the two groups. However, the central 3-mm zone exhibited early postoperative epithelial thickening after PRK, which later normalized over time. CONCLUSIONS: PRK and Femto-SMILE exhibited different patterns of epithelial remodeling, with more pronounced early changes observed after PRK. By 6 months, both procedures showed stable epithelial profiles. These findings highlight the value of epithelial mapping in postoperative evaluation and suggest the need for further studies to validate these trends.