Epithelium-off corneal cross-linking in progressive keratoconus: 6- year outcomes.

Objective: To evaluate the long-term results of corneal collagen cross-linking (CXL) with epithelium removal in patients with progressive keratoconus.

Methods: This retrospective study included 27 eyes of 18 patients who underwent CXL surgery for progressive keratoconus between April 2009 and March 2012. Best-corrected visual acuity (BCVA), manifest refraction spherical equivalent (SE), maximum keratometry reading (K max), mean of the minimum and maximum keratometry readings (mean-K), central corneal thickness (CCT), and anterior and posterior elevation at the apex preoperatively and year 1, 3 and 6 were evaluated and compared. P values<0.05 were considered to be statistically significant.

Results: Mean BCVA was 0.35±0.28 logMAR preoperatively and 0.23±0.20 logMAR 6 years after the procedure (P=0.01). Mean SE decreased from -4.3±2.45 diopters (D) to -3.91±2.12 D (P=0.03). Mean K max decreased from 49.6±3.2 D to 48.6±2.8 D (P=0.04), and mean-K decreased from 47.6±2.5D to 46.9±2.6 D (P=0.04). CCT decreased insignificantly from 466.5±32.1μm to 465.4±26.6μm (P=0.65). Mean anterior elevation at the apex decreased from 12.8±7.9 to 12±8.3μm (P=0.04), and posterior elevation decreased from 27.1±17.4μm to 26.8±18.5μm (P=0.27). Mean-K, max-K, BCVA and CCT showed no change over the last 5 years. After the first year, no significant change was observed in BCVA, SE, max-K, mean-K and CCT, which were therefore considered stable. On the other hand, anterior and posterior elevation readings continued to decrease up to 6 years after CXL.

Conclusions: Based on our 6-year results, CXL can halt progression of keratoconus and reduce the need for keratoplasty.