Comparison of central cornea thickness data measured by ultrasonic pacimetry, specular microscopy and optic coherance tomography

PURPOSE: To evaluate the reproducibility and comparability of central corneal thickness data obtained from Ultrasonic pachymetry (Pacscan 300P, Sonomed, New York, ABD), CSO specular microscopy (SP-01, CSO, Florence, Italy) and Cirrus optical coherence tomography (Model 4000, Carl Zeiss, Meditec, Dublin, CA, ABD). MATERİALS AND METHODS: The central corneal thickness of 96 eyes of 48 healthy volunteers aged 20 to 53 years was measured three times with each device. The reproducibility of the 3 measurements obtained from each device was evaluated by the coefficient of variation (%) and the intraclass correlation coefficient. Wilcoxon analysis was used to compare the central corneal thickness difference between the devices. RESULTS: The coefficients of variation for ultrasound pachymetry, CSO optical pachymetry, and Cirrus optical coherence tomography were 6.5, 7.3, and 6.2, respectively, while the intraclass correlation coefficients were 0.993, 0.968, and 0.998, respectively. The mean corneal thickness was 561.5, 555.7 and 553.0 microns, respectively. Central corneal thickness obtained from CSO optical pachymetry and Cirrus optical coherence tomography was significantly lower than the data obtained from ultrasonic pachymetry (p <0.001, p <0.001, respectively). CONCLUSIONS: Optical pachymetry devices measure the thickness of the central cornea thinner than standard ultrasonic pachymetry. The reproducibility of the corneal thickness measurements obtained from the CSO optical pachymeter is lower than other devices. Key Words: Central Korneal Thickness, Ultrasonic Pachymetry, CSO Specular Mikroscopy, Optical Koherens Tomography, repeatability