Corneal Epithelial Remodeling in a 6-Month Follow-up Period in Myopic Corneal Refractive Surgeries

Abstract

Purpose:To investigate corneal epithelial thickness changes during a 6-month follow-up period after transepithelial photorefractive keratectomy (tPRK), femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE).Methods:This prospective study included 76 eyes of 76 participants who underwent myopic refractive surgery (23 FS-LASIK, 22 SMILE, and 31 tPRK). Epithelial thickness and anterior curvature were averaged over 4 regions (subdivided into 25 areas) and measured by spectral-domain optical coherence tomography and Scheimpflug tomography before the operation (pre) and at 1 or 3 days (pos1-3d), 1 week (pos1w), and 1 month (pos1m), 3 months (pos3m), and 6 months (pos6m) postoperatively.Results:The epithelial thickness of the three groups was similar in both the pre and pos6m (allP> .05), but the tPRK group fluctuated the most during the follow-up period. The largest increase was in the inferior-temporal paracentral area (7.25 ± 2.58 μm for FS-LASIK; 5.79 ± 2.41 μm for SMILE; 4.88 ± 5.84 μm for tPRK; allP< .001). Only the epithelial thickness of tPRK increased from pos3m to pos6m (P< .05), whereas all changes for FS-LASIK and SMILE were not significant (P> .05). A positive correlation of thickness changes with curvature gradient in the paracentral region of tPRK was found (r= 0.549,P= .018), but not in other regions in all groups.Conclusions:Epithelial remodeling followed different trends after different surgeries from the early postoperative stage onward, but exhibited similar values at pos6m. Although remodeling after FS-LASIK and SMILE stabilized by pos3m, it remained unstable at pos6m after tPRK. These changes may affect corneal profile and lead to deviation from the intended surgical outcome.[J Refract Surg. 2023;39(3):187–196.]