Iridocorneal angle (ICA) in dogs: images from ICA sections versus ultrasound biomicroscopy.

<p>(a-b) Normal histological sections of the ICA (stained with hematoxilin/eosin) are shown on the left, with the corresponding UBM images on the right. ICA structures in (a) are compared with those obtained by UBM (b). The pectinate ligament corresponds to the anterior delineation of the ciliary cleft. The trabecular meshwork, which fills the ciliary cleft (CC), is clearly visible. (c-d) The width of the entrance of the ciliary cleft (CCW) was measured by determining the distance between the corneoscleral limbus and the iris root as follows. A line outlining the pectinate ligament was traced. Another line, outlining the inner wall of the sclera in the anterior portion of the CC, was then traced. The CCW corresponds to a line perpendicular to the inner wall of the sclera and crossing the pectinate ligament halfway along its length. (e-f) The length of the CC (CCL) was determined as the distance from the pectinate ligament (or the most anterior visible portion of the uveal trabecular meshwork) to the anterior portion of the ciliary body as follows. A line was traced outlining the pectinate ligament. The CCL corresponds to a line parallel to the long axis of the CC, crossing the pectinate ligament halfway along its length at the anterior and reaching the ciliary muscle at the posterior. (g-h) Determination of the distance between Schwalbe's line (the peripheral termination of Descemet's membrane, i.e. the borderline between the cornea and sclera) and the anterior capsule of the lens (DSAC). The scale bar corresponds to 1 mm for all images. The ICA sections were obtained from the same dog as the UBM images.