Morphological modification of the cornea after standard and transepithelial corneal cross-linking as imaged by anterior segment optical coherence tomography and laser scanning in vivo confocal microscopy

PURPOSE: In vivo analysis of corneal modifications after traditional and transepithelial corneal cross-linking (CXL). METHODS: Forty eyes of 35 patients underwent traditional or transepithelial CXL; there was randomization of 20 eyes to each group. By means of in vivo confocal microscopy and anterior segment ocular coherence tomography, we evaluated corneal alterations at 1 week, 1 month, and 3, 6, and 12 months after the treatment. RESULTS: During follow-up, in vivo confocal microscopy showed a significant decrease in anterior keratocyte density (P = 0.001) and more evident stromal edema and keratocyte activation (P = 0.001) in the traditional group, whereas in the transepithelial group, no significant changes were observed (P > 0.05). Anterior segment ocular coherence tomography indicated the presence of hyperreflective stromal line significantly deeper and more persistent in the traditional group (P < 0.001). CONCLUSIONS: The preliminary results suggest that traditional CXL induced marked corneal modifications, which were poorly evident in the transepithelial group.