Randomized controlled trial of corneal collagen cross-linking in progressive keratoconus: Preliminary results

PURPOSE: This prospective, randomized, controlled trial aims to provide evidence in relation to the efficacy and safety of corneal collagen cross-linking (CXL) in the management of progressive keratoconus. METHODS: Eligible eyes were separately randomized into either treatment or control groups. Collagen cross-linking was performed using 0.1% riboflavin (in 20% dextran T500) and ultraviolet A (UVA) irradiation (370 nm, 3 mW/cm(2), 30 min) in accordance with a previously published protocol. At each review, a full clinical ophthalmic examination was performed including endothelial cell count and confocal microscopy. RESULTS: To date, 66 eyes of 49 patients with documented progression of keratoconus have been enrolled and randomized. Interim analysis of treated eyes showed a flattening of the steepest simulated keratometry value (K-max) by an average of 0.74 diopters (D) (P=.004) at 3 months, 0.92 D (P=.002) at 6 months, and 1.45 D (P=.002) at 12 months. A trend toward improvement in best spectacle-corrected visual acuity was also observed. In the control eyes, mean K-max steepened by 0.60 D (P=.041) after 3 months by 0 60 D (P=.013) after 6 months, and by 1.28 D (P <=.0001) after 12 months. Best spectacle-corrected visual acuity decreased by log-MAR 0.003 (P=.883) over 3 months, 0.056 (P=.092) over 6 months, and 0.12 (P=.036) over 12 months. No statistically significant changes were found for spherical equivalent or endothelial cell density. CONCLUSIONS: Preliminary results of this randomized controlled trial suggest a temporary stabilization of all treated eyes after CXL.