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Figure 2: The measurements of keratometry before and after epion CXL and epioff CXL. (a) The mean keratometry. *Wilcoxon signedrank test, the reduction of K_{mean}in epioff CXL: P = 0.005 at 12 months and P = 0.005 at 18 months' followup, and in epion CXL: P = 0.06 at 12 months and P = 0.06 at 18 months' followup. †Mann–Whitney Utest, the comparison of epion and epioff CXL in terms of reduction of K_{mean}at 18 months' followup, P = 0.011. (b) The maximum keratometry. *Wilcoxon signedrank test, the reduction of K_{max}in epioff CXL: P = 0.005 at 12 months and P = 0.005 at 18 months' followup and in epion CXL: P = 0.05 at 12 months and P = 0.05 at 18 months' followup. †Mann–Whitney Utest, the comparison of epion and epioff CXL in terms of reduction of K_{max}at 18 months, P = 0.04. CXL=Corneal collagen crosslinking 
