Li F, et al. - Researchers evaluated volumetric parameters for their ability to distinguish narrow angle from open angle and discover different configurations of narrow angle. They subclassified angle configurations into type 1 (pupillary block) and type 2 (non-pupillary block and multiple mechanisms) based on ultrasound biomicroscopy (UBM) images. Outcomes revealed faster and more easy detection of patients with narrow angle from open angle with anterior chamber volume than angle open distance (AOD) and anterior chamber depth. Furthermore, compared with UBM, the combination of iris volume, iris thickness and AOD750 measured by swept-source optical coherence tomography could further classify configurations of angle closure in patients with narrow angle.