Corneal epithelial mapping after accelerated corneal cross-linking: early remodeling patterns.

PURPOSE: To evaluate early regional corneal epithelial thickness changes following accelerated epithelium-off corneal cross-linking (CXL) in progressive keratoconus using anterior segment optical coherence tomography (AS-OCT), and to explore their relationship with anterior corneal curvature and spherical equivalent.

DESIGN

Prospective case series.

METHODS

Ninety eyes of 75 patients with progressive keratoconus underwent accelerated epithelium-off CXL (9 mW/cm2 for 10 min). Epithelial thickness profiles were assessed using spectral-domain AS-OCT preoperatively and at 1 and 3 months postoperatively. Changes in central and sectoral epithelial thickness were analyzed using repeated-measures ANOVA with post hoc adjustment. Correlations between epithelial parameters, spherical equivalent, and maximum keratometry (Kmax) were evaluated.

RESULTS

Baseline central epithelial thickness was 59.7 ± 5.8 µm. At 1 month, central thickness showed minimal change, while at 3 months it increased to 62.9 ± 4.0 µm (P < 0.001). Sectoral analysis demonstrated relative thinning in nasal and inferonasal outer regions (1-3 µm; P < 0.05) and thickening in selected temporal sectors. The thinnest epithelial point shifted from the inferotemporal to the inferonasal regions. Kmax demonstrated a borderline postoperative change (P = 0.051), and no statistically significant correlations were observed between epithelial thickness changes and Kmax at any time point. Spherical equivalent remained unchanged (P = 0.19).

CONCLUSIONS

Accelerated epithelium-off CXL was associated with early, region-specific changes in epithelial thickness within three months after surgery. Variability in measurements due to the tear film and the short follow-up period likely influences these results, reflecting early surface remodeling rather than permanent stromal stabilization. Epithelial mapping may provide additional structural information during early postoperative monitoring; however, its ability to predict long-term treatment outcomes requires further research.