Clinical Outcomes Of Topography-Guided Oxygen-Supplemented Transepithelial-Accelerated Corneal Crosslinking For Progressive Keratoconus

To evaluate the one-year clinical outcomes of topo-guided oxygen-supplemented transepithelial accelerated corneal crosslinking (TG O₂ epi-on CXL) in patients with progressive keratoconus (KCN).

Single-center eye clinic in Australia

Epithelium-on CXL was performed using the Mosaic system and Paracel ophthalmic riboflavin (Glaukos, Burlington, USA). Oxygen goggles and pulsed high-intensity UV-A irradiation (1 second on, 1 second off; 30 mW/cm²) were utilized to enhance oxygen kinetics and UV-A bioavailability. Based on corneal topography, a targeted UV-A dose was applied, with the highest fluence (15 J/cm²) centering on the steepest posterior curvature, tapering to 7.2 J/cm² peripherally. Visual acuity, higher-order aberrations (HOAs), keratometry (K), and corneal biomechanics via CBI (Corvis, Oculus, Wetzlar, Germany) were assessed.

102 KCN eyes underwent TG O2 epi-on CXL (November 2019 – August 2022). At one year (mean follow-up: 352 days), Kmax significantly decreased (53.02±5.67 D to 51.92±5.56 D, p <0.001), along with reductions in K1, K2, and mean K (all p<0.001). HOAs (4 mm) significantly improved from 0.89±0.49 to 0.74±0.47 (p<0.001), and primary spherical aberration (SA Z40 at 6 mm) improved from -0.23±0.61 to -0.07±0.49 (p<0.001). Coma at 90° decreased significantly (-1.79±1 to -1.45±1.15, p<0.001), while coma at 0° showed a slight reduction (p=0.063). Visual acuity (LogMAR) improved, with BCVA (0.16±0.21 to 0.08±0.1811, p<0.001) and UCVA (0.48±0.32 to 0.41±0.38, p=0.002) showing significant gains. However, CBI remained unchanged (p>0.05).

Topo-guided oxygen-supplemented epi-on CXL demonstrated significant improvements in corneal shape, HOAs, and visual acuity, suggesting enhanced efficacy in stabilizing and regularizing keratoconus corneas while maintaining epithelial integrity. However, biomechanical changes in CBI were minimal, warranting further explorations on other corneal biomechanical metrics to ascertain long-term structural effects.