Which compartment contains aqueous humor and is behind the iris to the sides of the lens?

• A. Posterior chamber
• B. Anterior chamber
• C. Vitreous body
• D. Iris

Answer: (A)

The space behind the iris that contains aqueous humor is the posterior chamber. This narrow compartment lies between the iris anteriorly and the lens (with the ciliary body) posteriorly, sitting to the sides of the lens. Aqueous humor is produced by the ciliary processes in this chamber and then flows through the pupil into the anterior chamber, where it is drained. The anterior chamber is in front of the iris, between the cornea and iris, not behind it. The vitreous body fills the large posterior segment behind the lens, not the aqueous compartment. The iris is a structure, not a fluid-filled chamber. So the described location corresponds to the posterior chamber.