We compared the measurements of anterior chamber depth (ACD) and anterior chamber angle (ACA) using ultrasound biomicroscopy (UBM) in the sitting position compared with IOL Master®, Pentacam®, and Spectralis optical coherence tomography (OCT) to evaluate the clinical usefulness of UBM in the sitting position.

We evaluated 92 eyes in 47 healthy adults. ACD was measured by IOL Master®, Pentacam®, and UBM. ACA was measured using Pentacam®, UBM, and Spectralis OCT. UBM was performed in the sitting position using bag/balloon technology. Measured values were compared statistically.

ACD measured by IOL Master®, Pentacam®, and UBM was 3.57 ± 0.32 µm, 3.64 ± 0.33 µm and 3.51 ± 0.32 µm, respectively. UBM measurements of ACD were significantly shallower than with the other methods ( p < 0.001). The results among the 3 methods were strongly correlated ( r > 0.8, p < 0.05 in all groups). Mean ACA of 4 directions was not significantly different among the 3 methods ( p > 0.05). There was strong correlation between UBM and Spectralis OCT ( r = 0.957) but moderate correlation between Pentacam® and UBM and Pentacam® and Spectralis OCT ( r = 0.557, 0.571, respectively, p < 0.05). Specifically, ACA of the superior quadrant showed a low correlation between Pentacam® and UBM and Pentacam® and Spectralis OCT ( r = 0.257, 0.295, respectively).

ACD measured by UBM in the sitting position was shallower compared to the other methods; however, ACD measured by IOL Master®, Pentacam®, and UBM showed significant correlations among the methods. The mean ACA measured by Pentacam®, UBM, and Spectralis OCT showed no significant differences. Due to the high correlation of ACA measurements between UBM and Spectralis OCT in the present study, UBM is expected to be a good tool for measuring anterior segment parameters.