Oxygen-supplemented and topography-guided epithelium-on corneal crosslinking with pulsed irradiation for progressive keratoconus.

ABSTRACT

PURPOSE: To investigate the effects of customized topography-guided epithelium-on crosslinking (epi-on CXL) with oxygen supplementation on procedural efficacy and corrected distance visual acuity (CDVA) in patients with progressive keratoconus (KC) at 1 year. SETTING: Private eye clinic, Brisbane, Australia. DESIGN: Retrospective, single-center, nonrandomized case series. METHODS: Topography-guided epi-on CXL using the Mosaic system was performed on patients with progressive KC. Oxygen goggles; transepithelial riboflavin; and pulsed, high UV-A irradiance (1 second on, 1 second off; 30 mW/cm2) were applied to enhance oxygen kinetics and bioavailabilities of riboflavin and UV-A. Guided by baseline topography, a higher UV-A dose (15 J/cm2) was applied to the area of steepest anterior curvature with decreasing fluence (as low as 7.2 J/cm2) toward the outer 9 mm. Postoperative CDVA and maximum keratometry (Kmax) were evaluated. RESULTS: 102 eyes (80 patients) were followed for 11.5 ± 4.8 months. At the latest follow-up, mean CDVA (logMAR), mean K, and Kmax (diopters [D]) improved from 0.18 ± 0.28, 46.2 ± 3.8, and 53.0 ± 5.67 at baseline to 0.07 ± 0.18, 45.8 ± 3.7, and 51.9 ± 5.56, respectively (P < .001). 3 eyes (3%) lost more than 1 CDVA line, and another 3 eyes (3%) had increased Kmax greater than 2 D. 43 eyes were followed for at least 12 months (n = 43) mean CDVA, mean K, and Kmax improved from 0.19 ± 0.33 logMAR, 46.5 ± 3.5 D, and 53.6 ± 5.67 D to 0.07 ± 0.17 logMAR, 46.0 ± 3.5 D, and 52.33 ± 5.49 D, respectively (P ≤ .002). No complications were observed. CONCLUSIONS: Tailoring oxygen-supplemented epi-on CXL with differential UV-A energy distributions, guided by baseline topography, in patients with KC seems to be safe and effective. At 1 year, study reports sustained improved CDVA and corneal stabilization.