Long-term results of corneal collagen crosslinking for progressive keratoconus

Purpose: To evaluate long-term keratoconus stability after corneal crosslinking (CXL) with riboflavin. Methods: In this prospective study, 57 eyes of 55 patients with progressive keratoconus, consecutively treated with ultraviolet A (UVA) – riboflavin CXL, were examined with the corneal topographer Pentacam, the biometer IOLMaster and the analyzer of corneal biomechanics Ocular Response Analyzer before and during a 24 months follow-up after CXL. Results: Twenty-four months after CXL, there was a significant improvement in best corrected visual acuity (BCVA) (P < 0.01), a significant decrease in corneal thinnest point (CTP), keratometry readings at the keratoconus apex (K max), and corneal volume (CV) (P < 0.01), and a significant increase in axial eye length (AL) (P = 0.01). No significant changes in anterior chamber volume (ACV) and depth (ACD), (P = 0.8), corneal hysteresis (CH) (P = 0.16) and corneal resistance factor (CRF) (P = 0.06) were found. However, in the subgroup of patients with decreased K max readings 24 months after treatment, both CH and CRF showed a significant reduction (P < 0.01). Conclusion: In the first month after the procedure, CXL induces a reduction in corneal volume. During the 24 months follow-up the cornea tends to recover its original volume with a persistence of the CXL efficacy