Fig. 1

Schematic diagram of the ultrasound biomicroscopy parameters. A circle with a radius of 500 μm centered on the sclera spur (SS) is drawn. Angle-opening distance at 500 μm (AOD500) is the distance from corneal endothelium to the anterior iris perpendicular to a line drawn along the trabecular meshwork 500 μm from the SS. Iris thickness at 500 μm (IT500) is iris thickness at 500 μm from the SS (point b). Trabecular-ciliary process distance (TCPD) is a line extending from the corneal endothelium 500 μm anterior to the sclera spur (point a) toward the ciliary process (point d). Iris-ciliary process distance (ICPD) is the posterior surface of the iris 500 μm anterior to the sclera spur (point c) toward the ciliary process (point d). Maximum ciliary body thickness (CBTmax) is the distance from the most inner point of the ciliary body to the inner wall of sclera or its extended line. Iris curvature (IC) is the perpendicular distance from a line between the most central to the most peripheral points of the iris pigment epithelium to the posterior iris surface at the point of greatest convexity