Effectiveness and safety of accelerated (9 mW/cm) corneal collagen cross-linking for progressive keratoconus: a 24-month follow-up.

OBJECTIVES

To examine the effectiveness and safety of accelerated corneal collagen cross-linking (CXL) for keratoconus over a 24-month period and to explore potential prognostic factors for post-treatment visual outcome and progression.

METHODS

A retrospective, non-comparative, interventional case series. All patients who underwent accelerated epithelium-off CXL, using 9 mW/cm ultraviolet-A irradiation for 10 min, for progressive keratoconus in Sunderland Eye Infirmary, UK, between May 2014 and July 2016 were included. All patients completed 24 months' post-CXL follow-up. Significant post-CXL progression of keratoconus was defined as >1 D increase in Kmax from preoperative to 24-month visit.

RESULTS

Fifty-two eyes of 48 patients were included. At 24-month post-CXL, there was a significant improvement in corrected-distance visual acuity (CDVA; -0.05 LogMAR; p = 0.026), Kmax (-1.68 D; p < 0.001), K1 (-0.64 D; p = 0.002) and Kmean (-0.50 D; p = 0.009). The proportion of eyes with CDVA ≥ 0.3 LogMAR significantly improved from 43 (82.7%) eyes preoperatively to 50 (96.2%) eyes at 24 months (p = 0.026). Corneal haze (12, 23.1%) was the only postoperative complication and no adverse event was noted. Final CDVA was associated with lower CDVA (p = 0.002) and greater Kmax (p = 0.018) at baseline. Post-CXL progression of keratoconus was associated with greater preoperative Kmax (p = 0.12) and Kmean (p = 0.11), though statistical significances were not achieved.

CONCLUSIONS

Accelerated CXL (9 mW/cm) serves as an effective and safe treatment for halting the progression of keratoconus and stabilising the vision over a 24-month period. Our observation suggests that accelerated CXL might be more effective in stabilising keratoconus of milder severity; however further larger studies are required to elucidate this finding.