Objectives: To examine the effect of accelerated epi-off crosslinking (A-CXL) on visual acuity and quality in adolescent patients with progressive keratoconus. Materials and Methods: The study included 109 eyes of 109 patients (mean age 16.24±2.55 years). MS-39 anterior segment optical coherence tomography images from before A-CXL and 1 month, 6 months, and 12 months after A-CXL were analyzed. Corneal tomographic parameters, total corneal aberrations, corneal epithelial aberrations, and optical quality indicators such as modulation transfer function (MTF) and Strehl ratio of the point spread function (PSF) were recorded. Results: A significant improvement in corrected distance visual acuity was observed at 6 and 12 months after A-CXL (0.23±0.10 and 0.22±0.10 logarithm of the minimum angle of resolution logMAR) compared to the pre-A-CXL value (0.30±0.12 logMAR) (p<0.001 for both). MTF-5 and MTF-15 values were significantly higher at 12 months after A-CXL compared to before A-CXL (p<0.001). However, almost all MTF and PSF values were significantly lower at 1 month after A-CXL than at the other visits (p<0.05). Significant improvements were seen in root mean square higher-order aberrations (RMS-HOAs), vertical coma, and vertical trefoil values at 12 months after A-CXL compared to before A-CXL. A significant improvement was also detected in corneal epithelial aberrations, specifically in the vertical coma value. The change in corrected distance visual acuity at 12 months after A-CXL was significantly correlated with changes in keratometry values, with total corneal RMS-HOAs, vertical coma, and vertical trefoil, and with corneal epithelial RMS-HOAs (all p<0.05). Conclusion: Besides total corneal aberrations, corneal epithelial aberrations may also influence the improvement of visual acuity and quality after A-CXL.
Erdal et al. (Mon,) studied this question.