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.