What are the outflow dynamics of aqueous humor?

What are the outflow dynamics of aqueous humor?

• A. Aqueous humor drains exclusively via the canal of Schlemm
• B. Trabecular meshwork = conventional (MAJOR drain); uveoscleral = non-conventional (limited in most but over 50% in horses)
• C. Aqueous humor drains into the vitreous body
• D. There is no outflow; aqueous accumulates

Answer: (B)

Outflow of aqueous humor occurs through two main pathways. The conventional (major) drainage goes from the anterior chamber through the trabecular meshwork into Schlemm’s canal, then into the venous system. The non-conventional route, called uveoscleral outflow, goes through the interstitial spaces of the ciliary body and iris into the suprachoroidal space and sclera, also reaching the venous circulation. In humans, the conventional pathway is the primary route, while the uveoscleral pathway contributes a smaller portion. In horses, the uveoscleral route can be quite substantial, sometimes exceeding half of total outflow. This dual-pathway description best matches how aqueous humor dynamics actually work. The other statements are incorrect because aqueous humor does not drain exclusively via Schlemm’s canal, it does not drain into the vitreous body, and there is indeed outflow rather than none.

Outflow of aqueous humor occurs through two main pathways. The conventional (major) drainage goes from the anterior chamber through the trabecular meshwork into Schlemm’s canal, then into the venous system. The non-conventional route, called uveoscleral outflow, goes through the interstitial spaces of the ciliary body and iris into the suprachoroidal space and sclera, also reaching the venous circulation. In humans, the conventional pathway is the primary route, while the uveoscleral pathway contributes a smaller portion. In horses, the uveoscleral route can be quite substantial, sometimes exceeding half of total outflow. This dual-pathway description best matches how aqueous humor dynamics actually work. The other statements are incorrect because aqueous humor does not drain exclusively via Schlemm’s canal, it does not drain into the vitreous body, and there is indeed outflow rather than none.