Which structure primarily produces aqueous humor in the eye?

Which structure primarily produces aqueous humor in the eye?

• A. Retina
• B. Lens
• C. Iris
• D. Ciliary processes of the ciliary body

Answer: (D)

Aqueous humor is produced by the ciliary processes of the ciliary body. These processes, located behind the iris, contain nonpigmented ciliary epithelium that actively secretes fluid into the posterior chamber. From there, the fluid flows through the pupil into the anterior chamber, providing nutrients to avascular structures like the cornea and lens. The retina, lens, and iris each have their own primary roles—receiving light, focusing it, and regulating pupil size, respectively—but none are responsible for making the aqueous humor. Understanding that production occurs at the ciliary processes helps explain how intraocular pressure is maintained and how medications that inhibit secretion (such as carbonic anhydrase inhibitors) can reduce aqueous humor production.

Aqueous humor is produced by the ciliary processes of the ciliary body. These processes, located behind the iris, contain nonpigmented ciliary epithelium that actively secretes fluid into the posterior chamber. From there, the fluid flows through the pupil into the anterior chamber, providing nutrients to avascular structures like the cornea and lens. The retina, lens, and iris each have their own primary roles—receiving light, focusing it, and regulating pupil size, respectively—but none are responsible for making the aqueous humor. Understanding that production occurs at the ciliary processes helps explain how intraocular pressure is maintained and how medications that inhibit secretion (such as carbonic anhydrase inhibitors) can reduce aqueous humor production.