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

Abstract

Purpose: To investigate effects of customized topography-guided epithelium-on crosslinking (epi-on CXL) with oxygen supplementation on procedural efficacy and best corrected visual acuity (CDVA) in progressive keratoconus (KCN) patients at 1 year. Setting: Private eye clinic (Brisbane, Australia). Design: Retrospective single-center non-randomized case series Methods: Topography-guided epi-on CXL via the Mosaic system (Glaukos) was performed on progressive KCN patients. Oxygen goggles, transepithelial riboflavin and pulsed, high UVA irradiance (1 sec on, 1 sec off; 30mW/cm2) were applied to enhance oxygen kinetics and bioavailabilities of riboflavin and UVA. Guided by baseline topography, a higher UVA dose (15 J/cm2) was applied to the area of steepest anterior curvature with decreasing fluence (as low as 7.2 J/cm2) towards the outer 9mm. Postoperative CDVA and maximum keratometry (Kmax) were evaluated. Results: 102 eyes (80 patients) were followed for 11.5±4.8 months. At latest follow-up, mean CDVA (logMAR), average K and Kmax (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<0.001). Three eyes (3%) lost more than one CDVA line and another 3 eyes (3%) had increased Kmax greater than 2D. Forty-three eyes were followed for at least 12 months (n=43): mean CDVA, average K and Kmax improved from 0.19±0.33 logMAR, 46.5±3.5D and 53.6±5.67D to 0.07±0.17 logMAR, 46.0±3.5D, and 52.33±5.49D (p≤0.002). No complications were observed. Conclusion: Tailoring oxygen supplemented epi-on CXL with differential UVA energy distributions, guided by baseline topography, in keratoconus patients appears to be safe and effective. At 1 year, study reports sustained improved CDVA and corneal stabilization.