Accelerated Pulsed High-Fluence Corneal Cross-Linking for Progressive Keratoconus

Abstract

Purpose: To report on 2-year results of accelerated corneal collagen cross-linking (CXL) in progressive ectasia using the Avedro KXL system.

Design: Prospective interventional case series.

Methods: A total of 870 patients (1,192 eyes) attending Moorfields Eye Hospital after CXL were included. All patients undergoing CXL had progressive keratoconus. Corneas with a minimum stromal thickness <375 μm were excluded. Riboflavin 0.1% soak duration was 10 minutes. High-fluence pulsed UVA was delivered at 30 mW/cm² for 4 minutes, with a 1.5-second on/off cycle (total energy 7.2 J/cm²). Subjective refractive, corneal tomography, and specular microscopy were performed at baseline, 6, 12, and 24 months postoperatively. The primary outcome measure was a change in maximum keratometry (Kmax) at 24 months.

Results: Twelve- and 24-month follow-up data were available on 543 and 213 patients, respectively (mean age 25.4 ± 6.6 years). In mild cones (Kmax < 55 diopter [D]), mean keratometry remained unchanged at 24 months. In more advanced disease, we observed modest corneal flattening compared to baseline (Kmax 63.2 ± 6.5 D vs 61.9 ± 8.1 D, P = .02), but no significant changes in central keratometry (K1 or K2). Keratometric stabilization was confirmed in 98.3% of eyes. Mean CDVA, manifest refraction and endothelial cell density did not change. Overall, 2.7% of eyes lost more than 2 lines of CDVA.

Conclusion: Accelerated pulsed CXL is a safe, effective, and refractively neutral intervention (at 2 years) to halt disease progression in keratoconus.