Comparison of Central Corneal Thickness Measurements by Visante-OCT,Sirius and A-scan

Objective To evaluate the differences and agreement in central corneal thickness(CCT)measurements by Visante-OCT,Sirius and A-scan.Methods The CCTs of 43 healthy eyes were measured by Visante-OCT,Sirius and A-scan.The differences,correlations and agreements among three measurements were evaluated with one way analysis of variance(ANOVA),Pearson correlation coefficients and Bland-Altman plots respectively.Results The measured CCTs were(522.88±33.53)μm,(538.35±35.05)μm and(532.23±34.16)μm respectively by Visante-OCT,Sirius and Ascan.There existed high pairwise correlations.The difference between A-scan and Visante-OCT was(9.35±7.39)μm which was not significant(P=0.208),and the 95% limit of agreement was(-3.4-22.1)μm.The difference between A-scan and Sirius was(-6.12±7.39)μm which was not significant(P=0.409),and the 95% limit of agreement was(-18.9-6.7)μm.The difference between Visante-OCT and Sirius measurements was(-15.47±7.39)μm which was significant(P=0.038),and the 95% limit of agreement was(-30.2--0.7)μm.Conclusion Visante-OCT and Sirius have good coincidence with A-scan in measuring CCT and can replace A-scan in clinic,but cautious selection is needed.Visante-OCT and Siriu measurements have difference and can't replace each other.