Prospective two-year study of clinical outcomes following epithelium-off pulsed versus continuous accelerated corneal crosslinking for keratoconus

Abstract

Importance: Keratoconus is a debilitating condition with a disproportionately high impact on health resources and vision-specific quality of life. Background: This study aimed to compare 2-year outcomes of epithelium-off pulsed (p-ACXL) and epithelium-off continuous (c-ACXL) accelerated corneal crosslinking in progressive keratoconus. Design: Prospective, interventional case series. Participants: Eighty eyes of 80 patients were included. Methods: The visual, refractive and tomographic results of the two crosslinking protocols were compared. Main Outcome Measures: Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE) and maximum keratometry (KMAX) on corneal tomography assessment. Results: The mean patient age was 22.51 ± 6.12 years (SD) and 22.08 ± 5.72 years in the p-ACXL and c-ACXL groups, respectively. The mean CDVA significantly improved from 0.30 ± 0.16 logMAR at baseline to 0.23 ± 0.17 logMAR at 24 months (P =.04) in the p-ACXL group and from 0.36 ± 0.22 logMAR to 0.26 ± 0.27 logMAR (P =.02) in the c-ACXL group. The mean induced change in MRSE (+1.79 ± 2.30 D vs +0.27 ± 3.19 D, P =.04) and KMAX (−1.75 ± 1.80 D vs −0.39 ± 1.95 D, P =.04) were superior in the c-ACXL group compared to the p-ACXL group at 24 months. No complications were encountered. Conclusions and Relevance: In this prospective study, both p-ACXL and c-ACXL treatments were safe methods to halt the progression of keratoconus within a follow-up period of 24 months. c-ACXL appeared to offer superior refractive and tomographic outcomes when compared to p-ACXL but this did not translate into better visual outcomes.