A 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 crosslinking was performed using 0.1% riboflavin (in 20% dextran T500) and ultraviolet A (UVA) irradiation (370 nm, 3 mW/cm2, 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 < or = .0001) after 12 months. Best spectacle-corrected visual acuity decreased by logMAR 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.