Evaluation of corneal changes after conventional versus accelerated corneal cross-linking: a randomized controlled trial.

To evaluate the outcome of accelerated and conventional corneal cross-linking (CXL) procedures regarding their effect on morphological and optical properties of the cornea. One hundred fifty-three eyes of 153 patients were evaluated before and during a 15-month follow-up period after CXL (76 eyes in the conventional group and 77 eyes in the accelerated group). Measured variables include corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), refraction, maximum keratometry, endothelial cell density, anterior and posterior stromal keratocyte density, and subbasal nerve density. All variables were compared between the two study groups. Cylindrical and spherical components of refraction improved significantly during 15 months of follow-up. No difference was observed between the two study groups. UDVA and CDVA improved in the same manner, with no intergroup differences. Endothelial cell density did not change significantly during the follow-up period in either group. K-max increased slightly in the first month of the follow-up, but started to decrease at postoperative visits without any significant difference in the two groups. Anterior stromal keratocyte density and subbasal nerve density decreased significantly in both groups 1 month postoperatively. Both variables had a more significant decrease in the conventional group at all visits before the 1-year visit. At the final 15-month visit, there were no significant differences in any value between the two groups. Accelerated and conventional CXL seem to have a comparable and acceptable effect on keratoconus in the short-term follow-up period.