Oxygen-supplemented transepithelial-accelerated corneal crosslinking with pulsed irradiation for progressive keratoconus: 1 year outcomes

Purpose: To investigate the effects of combining oxygen supplementation with enhanced UV-A light and increased riboflavin permeability in improving the efficacy of epithelium-on crosslinking (epi-on CXL). Setting: Private eye clinic in Brisbane, Queensland, Australia. Design: Retrospective single-center nonrandomized uncontrolled longitudinal cohort case series. Methods: Transepithelial CXL was performed on keratoconic eyes. Applications of an oxygen goggle and pulsed UV-A irradiation (1 second on, 1 second off) were used to enhance oxygen kinetics during epi-on CXL. Additional procedural modifications included the use of benzalkoniumchloride and high UV-A irradiance level (30 mW/cm(2)) to improve the stromal bioavailability of riboflavin and UV-A. The main efficacy outcomes were the changes in mean corrected distance visual acuity (CDVA) and safety over 12 months. Additional refractive and keratometry (K) outcomes were also observed. Results: 53 eyes (38 patients) were included in this study. 12 months postoperatively, mean CDVA improved from a mean of 0.18 +/- 0.2 at baseline to 0.07 +/- 0.1 logMAR (P < .0001). No statistically significant change was observed in maximum K (Kmax) andmean K, which were respectively 51.7 +/- 5.8 diopters (D) and 46.4 +/- 3.85 D at baseline and 51.2 +/- 5.7 D (P = .152) and 46.0 +/- 3.84 D (P = .06) 12 months postoperatively. Only 3 eyes experienced an increase of more than 2 D in Kmax; however, none of these eyes experienced a CDVA loss. There were no reported infections, corneal scarring, or other severe adverse effects. Conclusions: Performing supplemental oxygen epi-on CXL with accelerated, pulsed UV-A irradiation in conjunction with riboflavin permeability enhancers resulted in improved CDVA (P < .0001) and stable keratometry up to 12 months postoperatively with a good safety profile. Copyright (c) 2022 Published by Wolters Kluwer on behalf of ASCRS and ESCRS