Role of ultrasound biomicroscopy in the differentiation of block glaucomas.

Ultrasound biomicroscopy has allowed us to elucidate the anatomic variations and underlying mechanisms in angle-closure glaucoma. Four levels of anatomic block can be distinguished, and a specific approach to treatment exists for each level to correct the abnormal forces leading to closure of the angle. As more quantitative approaches are developed, our understanding of these disorders will become increasingly sophisticated.