Corneal collagen cross-linking using riboflavin and ultraviolet A for the treatment of mild to moderate keratoconus: 2-year follow-up.

Objective: To evaluate the safety and efficacy of corneal ultraviolet A/riboflavin collagen cross-linking (CXL) in patients with mild-to-moderate keratoconus.

Design: Retrospective cohort study.

Participants: Thirty-nine eyes from 30 patients who underwent CXL for progressive mild and moderate keratoconus were included.

Methods: Clinical charts for keratoconus patients who had undergone CXL alone from November 2008 to February 2011 were reviewed for preoperative and postoperative uncorrected and best corrected distance visual acuity (UDVA and BDVA, respectively), manifest refraction, topographical and Scheimpflug imaging, as well as ultrasound pachymetry and haze. Mean and steepest keratometry, central corneal thickness, and root mean-square from corneal aberrations were extracted from the topography. Central and thinnest corneal thicknesses were extracted from the Scheimpflug imaging

Results: A significant improvement in UDVA was seen at 3, 6 and 24 months with an average change in logMAR of 0.39 (p = 0.003) at 24 months compared with baseline. Change in BDVA failed to reach significance, but subgroup analysis showed that a baseline BDVA worse than 0.1 logMAR was associated with better improvement. Stability of refraction, keratometry, and aberrations was demonstrated. Presence of haze was statistically significant up to 12 months (p≤0.001), being maximal at 3 months, then insignificant by 24 months. No complications were observed during the follow-up period.

Conclusions: CXL is a safe and effective stabilizing strategy for progressive mild-to-moderate keratoconus with significant improvement of the UDVA. There was a trend toward improvement of BDVA in patients with lower preoperative BDVA value.