Comparison of central corneal thickness measured with anterior segment optical coherence tomography versus ultrasonic pachymetry.

PURPOSE To compare central corneal thickness measured with anterior segment optical coherence tomography (AS-OCT) and ultrasonic pachymetry (UP). METHOD A prospective, observational and cross-sectional study was performed. The central corneal thickness was measured in 112 eyes of 112 consecutive patients with AS-OCT and UP. All examinations were performed by the same examiner. The measurements obtained between the 2 instruments were compared to assess the level of agreement. RESULTS The average corneal thickness value obtained by AS-OCT was 531.47 ± 26.23 μm, while that measured by UP was 532.51 ± 26.04 μm. The intraclass correlation coefficient was 0.957 (P <.001). The Student's t-test did not show a statistically significant difference (1.04 ± 7.70 μm, P =.158). Finally, the Bland-Altman analysis showed a high level of agreement between 2 methods of measurement. CONCLUSIONS In the context of normal corneas, there was good agreement between the measurement of central corneal thickness with AS-OCT and UP, although there was a slight overestimation of the measurement using UP (1.04 μm).