Skip to main content
  • Cornea/External Disease, Refractive Mgmt/Intervention

    Review of: Safety and efficacy of repeated corneal collagen crosslinking in progressive keratoconus

    Berar O, Rotenberg M, Yoav B, et al. Cornea, April 2023

    In a small retrospective study of patients who experienced keratoconus progression after initial epithelium-off crosslinking, repeating the crosslinking procedure via an accelerated protocol appears to be effective and well tolerated.

    Study design

    This single-center, retrospective study included 10 eyes of 9 patients who demonstrated progression of keratoconus after initial epithelium-off crosslinking and, therefore, underwent repeated crosslinking. Progression was defined as a >1 D increase in Kmax and a decrease in minimal pachymetry of >10 microns within 1 year. Accelerated epithelium-off crosslinking was performed using UV-A irradiation at 9 mW/cm2 for 10 minutes.


    The mean age at initial crosslinking was 22.5 years, the mean time between initial crosslinking and demonstrated progression was 3.1 years, and the mean length of follow-up after repeat crosslinking was 2.1 years. Mean best corrected distance visual acuity remained stable over the course of the study. Before initial crosslinking, the mean Kmax was 60.4 D; mean Kmax increased to 62.2 D before repeat crosslinking, and then decreased to 60.3 D at last follow-up. Mean minimal pachymetry decreased from 464 microns before initial crosslinking to 428 microns before repeat crosslinking and was 415 microns at last follow-up. Four eyes experienced corneal haze after initial crosslinking; these eyes remained stable after repeat crosslinking, and no eyes developed new haze or any other postoperative complications.


    Limitations of this study include the small sample size and retrospective nature. Another limitation is the relatively short length of follow-up, since progression of keratoconus can occur many years after crosslinking is performed.

    Clinical significance

    In patients who demonstrate continued progression of keratoconus after crosslinking, repeat crosslinking with an epithelium-off accelerated protocol appears to be a safe and effective option. A prospective randomized controlled trial comparing repeat crosslinking using the traditional Dresden protocol versus accelerated protocols with extended follow-up would be useful to evaluate the best way to treat these patients.

    Financial Disclosures: Dr. Kristin Hirabayashi discloses no financial relationships.