Safety and Efficacy of Repeated Corneal Collagen Crosslinking in Progressive Keratoconus

Purpose:Keratoconus is a progressive visually impairing disorder. Despite the beneficial effects of epithelial off-crosslinking (CXL) on the stabilization of keratoconus, progression may still occur. We report the efficacy and safety of a repeated CXL for significant progression of keratoconus after a single CXL procedure.Methods:This retrospective study includes patients diagnosed with progressive keratoconus who were previously treated with CXL and underwent repeated CXL. Demographic, clinical, and surgical data were retrieved and analyzed.Results:Ten consecutive eyes of nine patients who developed progressive keratoconus after CXL were identified. The mean age at diagnosis of keratoconus was 20.2 ± 6.0 years. The post-repeated CXL follow-up period was 2.1 ± 1.3 years. The mean best corrected visual acuity (BCVA) remained stable throughout the follow-up period. The mean Kmax at baseline was 60.4 ± 3.6 D. Before the repeated CXL, Kmax progressed significantly (P = 0.018) and was 62.2 ± 6.3 D, and at the last follow-up, the value decreased significantly (P = 0.037) and was 60.3 ± 6.4 D. The mean minimal pachymetry was 464.0 ± 27.0 µ at base line. Before the repeated CXL, minimal pachymetry was significantly lower (P = 0.018), and after the repeated CXL, the minimal pachymetry was stable (P = 0.2). No intra- or postoperative complications were noted.Conclusions:Repeated CXL is a safe and effective treatment option when failure of the initial CXL is diagnosed, even in young patients. This procedure may prevent visual deterioration and a potential need for keratoplasty.