Purpose: To evaluate the longitudinal changes in corneal epithelial thickness following femtosecond laser-assisted in situ keratomileusis (FS-LASIK), keratorefractive lenticule extraction (KLEx), and transepithelial photorefractive keratectomy (tPRK). Setting: Multicenter, international. Design: Systematic review and meta-analysis Methods: This study is registered with INPLASY (INPLASY202510085). A systematic search of electronic databases was conducted through January 2025 in accordance with PRISMA guidelines. Studies reporting both baseline and postoperative corneal epithelial thickness in myopic eyes treated with FS-LASIK, KLEx, or tPRK were included. Data from 33 studies (n=2,579 eyes) were extracted, with 23 studies incorporated into the meta-analysis. Meta-regressions were performed to identify predictors of epithelial thickness changes. Results: FS-LASIK-treated eyes exhibited a central epithelial thickness increase of 3.31±0.75 µm at 1 month, further increasing to 4.58±0.72 µm at 6 months. KLEx resulted in central thickening of 2.51±0.28 µm at 1 month and 3.82±0.35 µm at 6 months. In contrast, tPRK eyes initially demonstrated epithelial thinning, followed by central thickening reaching 3.89±0.38 µm at 6 months. Meta-regression analyses indicated that each additional diopter of myopic correction was associated with 1.05 µm greater central thickening in FS-LASIK and 1.04 µm in KLEx at 3 months postoperatively. Additionally, an increase in the programmed OZ corresponded to a reduction in postoperative epithelial thickness. Conclusion: Distinct epithelial remodeling patterns were observed: rapid, early thickening and stabilization with FS-LASIK and KLEx versus delayed regeneration with tPRK. Baseline SE and programmed OZ are predictors of corneal epithelial thickness changes, suggesting procedure-specific remodeling profiles that may support future refinement of refractive planning.
Tsai et al. (Wed,) studied this question.