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

AimOur 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).MethodsA 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).ResultsSeven 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 6months after the procedure. K-mean was statistically higher in the C-CXL group in comparison with the A-CXL group for at least 6months 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 6months after the operation. The BCVA was statistically higher in the A-CXL group in comparison with the C-CXL group for at least 6months after the procedure (WMD-0.05, 95% CI 0.00-0.10, p<0.05). No surgery complication was recorded in the researches.ConclusionOur 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.