Abstract
Purpose :
Long term-effectiveness of standard (UVA intensity: 3mW/cm2, duration: 30 minutes) vs accelerated (UVA intensity: 9mW/cm2, duration: 10 minutes) corneal crosslinking (CXL) for stabilizing progressive keratoconus is unknown. This study aimed to compare the long-term (5 years) efficacy and safety of these protocols in keratoconus using the real-world data from the Save Sight Keratoconus Registry (SSKR).
Methods :
Data from the routine clinical practice (15 sites across Australia, New Zealand and Italy) were captured through a web-based registry system for this observational study. A total of 100 eyes (75 patients) who had standard CXL and 76 eyes (66 patients) who had accelerated CXL, with a follow-up visit at five-year post-CXL were included. The mean age of the participants was 24.2±7.7 (standard 24.3 ± 7.3 vs accelerated 23.7±7.7) years, and 35.0% were female (standard 33.3% vs accelerated 34.8%). The outcome measures included changes in visual acuity, keratometry (maximum keratometry, Kmax; and central steepest keratometry, K2), minimum corneal thickness (MCT), and frequency of adverse events. The outcomes were compared using mixed-effects regression models adjusted for age, sex, visual acuity, keratometry, pachymetry, doctor, practice, and eye laterality.
Results :
Both CXL protocols were effective and safe in stabilizing keratoconus and improving outcomes (Fig 1). The adjusted mean changes (95% CI) in outcomes were better in standard than in accelerated CXL [habitual visual acuity gain, 10.2 (7.9 to 12.5) vs 4.9 (1.6 to 8.2) logMAR letters; pinhole visual acuity gain, 5.7 (3.5 to 7.8) vs 0.2 (-2.2 to 2.5) logMAR letters; Kmax, -1.8 (-4.3 to 0.6) vs 1.2 (-1.5 to 3.9)D; K2, -0.9 (-2.2 to 0.3) vs 0.1 (-1.3 to 1.6)D; MCT, -3.0 (-13.7 to 7.7) vs -11.8 (-23.9 to 0.4) µm (p values for visual acuity, pinhole visual acuity, Kmax: <0.05; for K2 and MCT: >0.05)]. The frequency of adverse events at the 5-year follow-up visit was low in both groups [standard, 5 (5%; haze 3; scarring 1, epithelial defect 1) and accelerated 3 (3.9%; haze 2, scarring 1)].
Conclusions :
This real-world observational study found that both standard and accelerated CXL were safe and effective procedures for stabilising keratoconus in the long term. The standard CXL resulted in greater improvements in visual acuity and keratometry.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.