Collagen cross-linking provided good long-term visual, refractive and topographic outcomes in eyes treated for progressive keratoconus, a study found. The prospective case series included 42 eyes of 32 patients with progressive keratoconus and a mean age of 22.4 years. Bilateral surgery was performed on 11 patients. The mean interval between diagnosis and treatment was 2.2 years. Uncorrected and corrected distance visual acuity, refraction, topography and corneal aberrations were evaluated at baseline and 6, 12 and 24 months after surgery.