Corneal Epithelial Mapping as a Biomarker After Accelerated Corneal Cross-Linking for Keratoconus

purpose: To evaluate regional corneal epithelial remodeling following accelerated corneal cross-linking (CXL) in progressive keratoconus using anterior segment optical coherence tomography (AS-OCT), and to correlate these changes with anterior curvature and spherical equivalent. Design: prospective case series Methods: Ninety eyes of 75 patients with progressive keratoconus were enrolled. Epithelial thickness profiles were assessed using AS-OCT preoperatively and at 1 and 3 months post-CXL. Changes were analyzed in relation to keratometry and spherical equivalent. Results: Baseline central epithelial thickness was 59.7 ± 5.8 µm. It decreased by 0.6 ± 2.0 µm at 1 month and increased by 3.2 ± 1.8 µm at 3 months (P < 0.001). Significant thinning (1.0–3.6 µm; P < 0.005) was observed in the nasal and inferior regions. The standard deviation increased slightly (6.0 to 6.3 µm; P = 0.24). The minimum–maximum epithelial thickness range within the central 5 mm zone decreased by 1.5 ± 4.9 µm (P = 0.16). Minimum thickness increased by 1.0 µm (P = 0.19), while maximum thickness showed a non-significant decrease decreased (P = 0.83). The thinnest point shifted from inferotemporal to inferonasal. K-max remained stable (P = 0.051) ,and epithelial changes did not significantly correlate with keratometry. Spherical equivalent remained unchanged (P = 0.19). Conclusion: Early epithelial remodeling is characterized by central thickening and nasal/inferonasal thinning, with a shift in the thinnest point. These changes may reflect initial healing preceding stromal stabilization. Epithelial mapping may offer a valuable, independent marker for monitoring keratoconus progression and treatment response.