Accelerated Versus Conventional Corneal Collagen Cross-Linking in the Treatment of Keratoconus: A Meta-analysis and Review of the Literature

Aim Our aim was to examine existing literature, and determine if there are outcome differences between accelerated corneal collagen cross-linking (A-CXL) and conventional corneal collagen cross-linking (C-CXL). Methods A systematic review of the literature was conducted examining studies which compared A-CXL to C-CXL. Available studies were combined and the weighted mean difference (WMD) was calculated for range of outcome measures including maximal keratometry ( K max ), mean keratometry ( K mean ) and minimum keratometry ( K min ), spherical equivalent, best corrected visual acuity (BCVA), and central corneal thickness (CCT). Results Seven eligible studies were included in our meta-analysis, with 283 eyes (135 in A-CXLand 148 in C-CXL). In the combined analysis, there was no statistically significant difference observed in K min or K max between A-CXL and C-CXL for at least 6 months after the procedure. K mean was statistically higher in the C-CXL group in comparison with the A-CXL group for at least 6 months after the procedure (WMD − 3.15, 95% CI − 4.34 to − 1.97, p < 0.01).No statistically significant difference observed in spherical equivalent or central corneal thickness between the A-CXL group and C-CXL group for at least 6 months after the operation. The BCVA was statistically higher in the A-CXL group in comparison with the C-CXL group for at least 6 months after the procedure (WMD − 0.05, 95% CI 0.00–0.10, p < 0.05). No surgery complication was recorded in the researches. Conclusion Our study demonstrated greater reductions of K mean in the A-CXL group in comparison with the C-CXL group. Overall A-CXL is comparable to C-CXL from outcome basis.