Transepithelial corneal collagen crosslinking for keratoconus: six-month results.

PURPOSE To evaluate the safety and efficacy of corneal collagen crosslinking (CXL) using a transepithelial technique to treat keratoconus. SETTING Cornea and refractive surgery subspecialty practice. DESIGN Prospective clinical trial. METHODS Transepithelial CXL was performed in eyes with keratoconus using proparacaine with benzalkonium chloride (BAK) 0.01% to facilitate riboflavin absorption and riboflavin 0.10% without dextran. Eyes were randomized to receive ultraviolet-A treatment (365 nm, 3 mW/cm(2)) with concurrent administration of riboflavin randomized to every 1 minute or every 2 minutes for 30 minutes. The principal outcomes included uncorrected (UDVA) and corrected (CDVA) distance visual acuities and topography-derived maximum keratometry (K) values. Patients were followed for 6 months. RESULTS Thirty eyes of 25 patients were treated. The mean maximum K value flattened by 0.9 diopter (D) (baseline 58.7 D; 6 months 57.8 D) (P=.01). The maximum K worsened by 2.0 D or more in 1 patient. The mean CDVA improved by 0.83 Snellen lines (P=.03). One patient lost 2 lines of CDVA. There were no differences in the UDVA, CDVA, or keratometry outcomes between the 1-minute instillation subgroup and the 2-minute instillation subgroup. CONCLUSIONS Transepithelial CXL resulted in a statistically significant improvement in maximum K values and CDVA at the 6-month follow-up. Further follow-up is necessary to ascertain the ability of transepithelial CXL to achieve long-term stabilization of the cornea in eyes with keratoconus.