Clinical research on corneal collagen cross-linking for the treatment of keratoconus

Objective To evaluate the efficacy of standard (epithelium-off) corneal collagen cross-linking and transepithelial corneal collagen cross-linking with the induction of riboflavin for keratoconus. Methods The data of 46 eyes of 38 cases with keratoconus and corneal thickness>400 μm were retrospectively analyzed. The patients were divided randomly into two groups: group A, 26 eyes, underwent epithelium-off corneal collagen cross-linking surgery and group B, 20 eyes, underwent transepithelial corneal collagen cross-linking surgery. The visual acuity, corneal thickness, the changes of maximum k-reading(Kmax) and posterior corneal surface height at 1, 3 and 6 months postoperatively between the two groups were compared. Results The difference of visual acuity at different times postoperatively was not significant between the two groups (P>0.05). The thinnest corneal thickness in group A postoperatively decreased with the time increasing. The difference was significant between before and after surgery(P 0.05). Conclusion The efficacy of epithelial-off corneal collagen cross-linking is significantly better than that of transepithelial collagen cross-linking for keratoconus. Key words: Keratoconus; Cross-linking, collagen, cornea; Epithelium, corneal; Photochemotherapy