Contralateral eye study of corneal collagen cross-linking with riboflavin and UVA irradiation in patients with keratoconus.

PURPOSE To assess the progression of keratoconus in patients treated with collagen cross-linking with riboflavin and ultraviolet A (UVA) irradiation. METHODS Thirty-eight eyes of 19 patients with progressive keratoconus were enrolled in a prospective comparative study. Average follow-up was 9 +/- 2 months (range: 5 to 12 months). The worse eye was treated with collagen cross-linking, and the fellow eye served as the control. Corneal epithelium was mechanically removed. Riboflavin 0.1% solution in dextran T-500 20% solution was applied every 2 to 3 minutes for 30 minutes throughout the irradiation. Ultraviolet A irradiation (370 nm) was performed using a commercially available UVA lamp for 30 minutes. RESULTS The group treated with collagen crosslinking demonstrated a mean decrease (less myopic) in spherical equivalent refraction and cylinder of 1.03 +/- 2.22 diopters (D) (range: -5.25 to +3.75 D) and 1.04 +/- 1.44 D (range: -2.00 to +4.00 D), respectively (P < .01), and an increase in uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) of 0.06 +/- 0.05 (range: 0.00 to 0.20) and 0.10 +/- 0.14 (range: -0.10 to 0.34), respectively (P < .01). The maximal curvature decreased by 1.57 +/- 1.14 D (range: 0.00 to 3.90 D), and intraocular pressure increased by 2 +/- 2 mmHg (range: -1 to 6 mmHg), which was statistically significant. No statistical difference was noted regarding central corneal thickness (P = .06) and endothelial cell count (P = .07). The untreated group showed no statistical difference for any of the clinical parameters, apart from UCVA and BSCVA, which decreased by 0.08 +/- 0.12 (range: -0.40 to 0.10) and 0.06 +/- 0.09 (range: -0.20 to 0.10), respectively (P < .01). CONCLUSIONS Riboflavin/UVA collagen cross-linking appears to be efficacious in inhibiting the progression of keratoconus by reducing the corneal curvature, spherical equivalent refraction, and refractive cylinder in eyes with progressive keratoconus at average 9-month follow-up.