physiology
Last reviewed 06/2022
The intra-ocular pressure is maintained by the aqueous within the anterior and posterior chambers of the eye. These two anatomical areas are separated by the iris and communicate via the pupil. The cornea marks the anterior border of these regions; the anterior lens surface, the posterior border. The anterior chamber is largest.
Aqueous is produced in the ciliary body region, adjacent to the posterior chamber. It enters this area by ultrafiltration and active secretion by the epithelium on the surface of the ciliary body. It then passes into the anterior chamber and leaves by one of two routes. The major flow - 75% - is via the trabecular meshwork in the angle formed by the iris and cornea. The remainder leaves through the uveoscleral route close to the trabecular region.
Intra-ocular pressure depends upon the balance between production and drainage of aqueous.