Corneal Epithelium Remodeling After Corneal Cross-Linking Analyzed By Optical Coherence Tomography

This is a prospective, cohort study that included sixty-three eyes of patients diagnosed with progressive keratoconus between January 2021 and January 2023. All patients underwent accelerated epi-off corneal collagen CXL (10 minutes irradiation, nine mW/cm²) using the Avedro System (Massachusetts, USA). Pre and postoperative follow-up at 8 months were evaluated by anterior segment optical coherence tomography (AS-OCT) using the MS-39 (CSO, Scandicci, FI, Italy) to assess epithelium thickness (ET) changes at 12 points and across the central 6-mm of the corneal apex. Data from visual acuity, keratometry, pachymetric, stromal thickness, and higher order aberrations (HOAs) were also analyzed. Statistical analysis was performed using Program R. 

Significant changes in epithelial thickness were observed in the entire cohort.  Minimum ET increasing from 41.90 ± 3.72 μm at baseline to 43.78 ± 5.24 μm (p < 0.001), maximum ET increasing from 60.40 ± 4.99 μm at baseline to 64.97 ± 7.77 μm (p < 0.001). Mean minimum-maximum difference in ET from 10.97 ± 5.97 μm to 12.80 ± 6.84 μm (p < 0.001). Epithelial HOAs increased 0.13 ± 0.45 (p < 0.001). Changes on keratometry were not significant (p= 0.78). Changes on stromal thickness were not significant (p=0.089).