Oxygen-Supplemented And Topography-Guided Epi-On Corneal Crosslinking With Pulsed Irradiation For Progressive Keratoconus

To investigate the effects of customized topography-guided epithelium-on crosslinking (epi-on CXL) with oxygen supplementation on procedural efficacy and best corrected visual acuity in progressive keratoconus (KCN) patients at 1 year.

A retrospective study included progressive KCN patients who underwent topography-guided epi-on CXL via the Mosaic system (Glaukos, Burlington MA).

Oxygen goggles, transepithelial riboflavin, and pulsed, high UVA irradiance (1 sec on, 1 sec off; 30mW/cm²) were applied to enhance the oxygen kinetics and bioavailabilities of riboflavin and UVA during a novel epi-on CXL procedure. Guided by baseline topography, a higher UVA dose of 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 treatment zone. Post-operative best spectacle corrected visual acuity (CDVA) and maximum keratometry (Kmax) were evaluated.

The study included 102 eyes (80 patients) who were followed for 11.5±4.8 months (min 4.1; max 26.9; median 11.1). At the latest post-operative follow-up (mean 11.5±4.8 months), mean CDVA improved from 0.18±0.28 at baseline to 0.07±0.18 logMAR (p<0.001). Mean Kmax improved from 53.0±5.67 at baseline to 51.9±5.56 D (p<0.001). Only 3 eyes (3%) lost more than one line of their CDVA and 3 eyes (3%) had an increased Kmax more than 2D. Forty-three eyes were followed up for at least 12 months (n=43): mean CDVA improved from 0.19±0.33 at baseline to 0.07±0.17 logMAR (p<0.001) and mean Kmax improved from 53.60±5.67 at baseline to 52.33±5.49 D (p<0.001). No complications were observed.

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, this study reports improved post-operative best corrected distance visual acuity, while also achieving corneal stabilization in this progressive keratoconus cohort.