Fig. 1

Determination of the following anterior segment parameters by ultrasound biomicroscopy. (1) central anterior chamber depth (ACD), the distance between central inner corneal surface and anterior surface of the lens or artificial lens; (2) lens vault (LV), the perpendicular distance between the anterior crystalline lens or intraocular lens (IOL) pole and the horizontal line of scleral spurs (SS, green dot line); (3) anterior vault distance (AVD), the perpendicular distance between the anterior lens pole and the horizontal line of ciliary sulcus (red dot line); (4) maximum ciliary body thickness (CBTmax), the distance from the most inner point of the ciliary body to the inner border of the sclera or its extended line; (5) ciliary body thickness at the point of the scleral spur (CBT0) and at a distance of 1000 mm (CBT1000) from the scleral spur; (6) anterior placement of the ciliary body (APCB), the maximal distance from the anterior margin of the ciliary body to the vertical line extended from the scleral spur; and (7) trabecular-ciliary angle (TCA), the angle between the posterior surface of the cornea and the anterior surface of the ciliary body