AIM:To compare the difference, correlation and consistency of the thinnest corneal thickness(TCT)in myopic patients among Sirius, Oculyzer, anterior segment optical coherence tomography(AS-OCT)and A-mode ultrasound pachymetry, in order to provide a reference for clinical applications.

METHODS: TCT was measured in 81 patients(162 eyes)treated between March and April, 2016 using Sirius, Oculyzer, AS-OCT and A-mode ultrasound pachymetry before femtosecond LASIK, and then the values were statistically analyzed.

RESULTS: TCT measured by A-mode ultrasound pachymetry, Sirius, Oculyzerand AS-OCT were respectively(537.91±24.12)μm,(538.12±22.64)μm,(538.20±23.74)μm,(527.04±23.11)μm(P<0.01). There was a significant difference in TCT measurements among the four measurements. The results of AS-OCT were significantly smaller than those of the other three methods. There was no statistical difference among A-mode ultrasound pachymetry, Sirius and Oculyzer.Pearson correlation coefficient of measured value by the four measurements were more than 0.9(r=0.920, 0.914, 0.951, 0.908, 0.929, 0.919, P<0.001), which means there were highly correlation between each other. The 95% CI of the consistency interval of A-mode ultrasound pachymetry and Sirius, A-mode ultrasound pachymetry and Oculyzer, A-mode ultrasound pachymetry and AS-OCT were(-18.77-18.33)μm,(-19.79-19.19)μm,(-3.79-25.53)μm, respectively. The Bland-Altman Plots demonstrates relatively good consistency between A-mode ultrasound pachymetry and the other three methods.

CONCLUSION:The TCT measured by AS-OCT were thinner than that measured by A-mode ultrasound pachymetry. There were a high correlation and consistency of the thinnest corneal thickness in myopic patients among Sirius, Oculyzer, AS-OCT and A-mode ultrasound pachymetry. The TCT measured by the four measurements can be referenced but not replaced since the 95% of the consistency intervals were wide.