Comparison of central corneal thickness measurements with different non-contact devices in healthy children

Purpose: To investigate the agreement of the Combined Scheimpflug-Placido Disk System (Sirius), specular microscopy (Tomey EM-4000), non-contact tonopachymetry (Canon TX-20P), and optical low-coherence reflectometry (Lenstar LS 900) devices in the measurement of central corneal thickness (CCT) in healthy children. Method: Eighty-three eyes from 83 healthy children were included in the study. The mean age of the children was 11.1 +/- 2.8 (range, 7-17) years. CCT was measured using the Sirius topography, Tomey specular microscopy, Canon TX-20P, and Lenstar LS 900 devices. To examine the agreement among these devices, 95% limits of agreement (LoA) and intraclass correlation coefficients (ICC) were determined. Results: The mean CCT values obtained using the Sirius topography, Tomey SM, Canon TX-20 P, and Lenstar 900 devices were 555.9 +/- 37 mu m, 553.5 +/- 39 mu m, 569.3 +/- 33 mu m, and 559.7 +/- 38 mu m, respectively. With the ICC method, the agreement rates were determined as 0.875 between Canon TX-20P and Sirius topography, 0.903 between Canon TX-20P and Lenstar LS 900, 0.842 between Canon TX-20P and Tomey EM-4000, 0.979 between Sirius Topography and Lenstar LS 900, 0.978 between Sirius topography and Tomey EM-4000, and 0.969 be-tween Lenstar LS 900 and Tomey EM-4000. Conclusion: The devices with the closest results to each other were the Sirius and Tomey EM-4000 devices, with a statistically strong agreement. There was also a strong agreement between Sirius and Lenstar LS 900, although there was a 3.7-unit difference between them. Nevertheless, despite the strong agreements among these devices, because their CCT values varied statistically significantly, these devices should not be used interchangeably in clinical practice.