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

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

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.

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.

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