Corneal collagen cross-linking with riboflavin and ultraviolet a irradiation for keratoconus: long-term results.

Objective: To evaluate the long-term results of corneal collagen cross-linking (CXL) in patients with progressive keratoconus. Methods: Prospective case series. Methods: This study was conducted on 40 eyes of 32 patients with progressive keratoconus between 2006 and 2012. Methods: Patients underwent CXL no later than 1 month after baseline examinations. For CXL, ultraviolet irradiation was applied for 30 minutes, during which riboflavin instillation was repeated every 3 minutes. Methods: Patients were tested for best-corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), manifest refraction spherical equivalent (MRSE), and Scheimpflug imaging from which we extracted maximum keratometry reading (max-K), average of minimum and maximum keratometry readings (mean-K), central corneal thickness (CCT), and anterior and posterior elevation at the apex at baseline, at 1, 3, 6 months after CXL, and 1, 2, 4, and 5 years later. We studied results at 5 years after CXL as well as the trend of changes over the 5-year period. Results: Mean UCVA was 0.67 ± 0.52 logarithm of the minimum angle of resolution (logMAR) at baseline and 0.65 ± 0.51 logMAR at 5 years after the procedure. For mean BCVA, these values were 0.31 ± 0.28 and 0.19 ± 0.20 logMAR, respectively (P = 0.016). The mean MRSE changed from -3.18±2.23 diopters (D) to -2.77 ± 2.18 D, and mean refractive cylinder error changed from -3.14 ± 2.22 to -2.49 ± 1.71 D (P = 0.089). Mean max-K and mean-K decreased by 0.16 ± 2.20 and 0.10 ± 1.69 D, respectively. The CCT increased from 483.87 ± 29.07 to 485.95 ± 28.43 μm. Mean anterior elevation at the apex changed from 13.9 2 ± 8.28 to 11.45 ± 8.18 μm (P = 0.030) and posterior elevation at this point changed from 29.54 ± 18.39 to 26.34 ± 19.59 μm. The mean-K, max-K, UCVA, and astigmatism showed no change over time during these 5 years. After the first year, BCVA, MRSE, and CCT showed no change and stabilized, whereas elevation readings continued to decrease up to 5 years after CXL. Conclusions: Based on our 5-year results, treatment of progressive keratoconus with CXL can stop disease progression, without raising any concern for safety, and can eliminate the need for keratoplasty.

Background: The authors have no proprietary or commercial interest in any of the materials discussed in this article.