Corneal collagen crosslinking for keratoconus and corneal ectasia: One-year results

PURPOSE: To evaluate 1-year outcomes of corneal collagen crosslinking (CXL) for treatment of keratoconus and corneal ectasia. SETTING: Cornea and refractive surgery subspecialty practice. DESIGN: Prospective randomized controlled clinical trial. METHODS: Collagen crosslinking was performed in eyes with keratoconus or ectasia. The treatment group received standard CXL and the sham control group received riboflavin alone. Principal outcomes included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, astigmatism, and topography-derived outcomes of maximum and average keratometry (K) value. RESULTS: The UDVA improved significantly from 0.84 logMAR +/- 0.34 (SD) (20/137) to 0.77 +/- 0.37 logMAR (20/117) (P = .04) and the CDVA, from 0.35 +/- 0.24 logMAR (20/45) to 0.23 +/- 0.21 logMAR (20/34) (P<.001). Fifteen patients (21.1%) gained and 1 patient lost (1.4%) 2 or more Snellen lines of CDVA. The maximum K value decreased from baseline by 1.7 +/- 3.9 diopters (D) (P<.001), 2.0 +/- 4.4 D (P = .002), and 1.0 +/- 2.5 D (P = .08) in the entire cohort, keratoconus subgroup, and ectasia subgroup, respectively. The maximum K value decreased by 2.0 D or more in 22 patients (31.0%) and increased by 2.0 D or more in 3 patients (4.2%). CONCLUSIONS: Collagen crosslinking was effective in improving UDVA, CDVA, the maximum K value, and the average K value. Keratoconus patients had more improvement in topographic measurements than patients with ectasia. Both CDVA and maximum K value worsened between baseline and 1 month, followed by improvement between 1, 3, and 6 months and stabilization thereafter.