Fig. 1. Cross section through the anterior segment of the eye illustrating the chamber angle. Aqueous humor is formed by active secretion from the ciliary processes (A). Drainage occurs via the outflow pathways, principally the trabecular meshwork (B) and Schlemm's canal (C) into the aqueous veins (D). A smaller proportion of the aqueous humor makes its way directly into the ciliary body (uveoscleral pathway) and is drained by way of the ciliary muscle, the suprachoroidal space, and the sclera (E). (From Karnezis TA, Murphy MB: Dopamine receptors and intraocular pressure. Trends Pharmacol Sci 9:389–390, 1988, with permission.)