Anterior Segment Biometry Using Spectral-Domain Optical Coherence Tomography

PURPOSE: To compare the anterior chamber and anterior chamber angle measurements obtained with spectral-domain anterior segment optical coherence tomography (AS-OCT) and time-domain AS-OCT. METHODS: The anterior chamber of healthy participants was imaged with spectral-domain AS-OCT (Casia SS-1000; Tomey, Nagoya, Japan) and time-domain AS-OCT (Visante; Carl Zeiss Meditec, Dublin, CA). Central corneal thickness (CCT), anterior chamber depth (ACD), angle opening distance at 500 and 750 mu m (AOD 500 and AOD 750), trabecular iris space area at 500 and 750 mu m (TISA 500 and TISA 750), and scleral spur angle were measured. The intraclass correlation coefficients (ICCs) were calculated. The Pearson correlation test was used to evaluate the correlation between the measurements and Bland-Altman plots to evaluate the agreement. RESULTS: One hundred one eyes of 101 healthy participants were analyzed. Excellent repeatability was found with both devices for CCT, AOD 500, AOD 750, TISA 750, and scleral spur angle (ICC = 0.90 to 0.98 and 0.89 to 0.97, respectively) and excellent to moderate repeatability was found for TISA 500 (ICC = 0.68 to 0.97 and 0.70 to 0.93, respectively). For all parameters, Casia and Visante measurements were significantly correlated (r = 0.76 to 0.98; P <.02). ACD measured with the Casia was significantly larger (mean difference = 0.12 +/- 0.08 mm; P <.0001), and the scleral spur angle measured with the Casia was significantly lower (mean difference = 4.85 degrees +/- 5.30 degrees; P < .01). There were nonsignificant differences between the devices for the other parameters (P >.06). CONCLUSIONS: Both Casia and Visante AS-OCT demonstrate high repeatability. Except for the ACD and scleral spur angles, the two devices show good agreement.