Which sequence describes the flow of aqueous humor?

• A. Produced by choroid; flows behind the iris; drains into the vitreous
• B. Generated by the iris; flows to the posterior chamber; drains via optic nerve
• C. Produced by ciliary body; flows through the pupil to the anterior chamber; exits via the canal of Schlemm
• D. Produced in the cornea; flows into the lens; absorbed by conjunctiva

Answer: (C)

Aqueous humor is produced by the ciliary body, specifically the ciliary processes, and is secreted into the posterior chamber. From there it flows through the pupil into the anterior chamber, where it drains mainly via the trabecular meshwork into Schlemm’s canal (the conventional outflow pathway) and then into the scleral venous sinus. This flow maintains intraocular pressure.

The other options don’t fit because production sites and drainage routes are incorrect: the choroid and vitreous are separate compartments, not the source or primary route for aqueous humor; the iris doesn’t produce aqueous humor and drainage via the optic nerve isn’t how the eye disposes of it; and the cornea doesn’t produce aqueous humor and the described flow into the lens with conjunctival absorption isn’t accurate.