What process accounts for the majority of aqueous production?

The majority of aqueous humor production occurs through active secretion by the ciliary processes in the eye. This process involves the movement of ions, primarily sodium and bicarbonate, across the cell membranes of the ciliary epithelial cells. The active transport of these ions into the posterior chamber creates an osmotic gradient that draws water into the aqueous humor, resulting in its formation.

This process is crucial because it ensures that the eye maintains a proper intraocular pressure and provides nutrients to the avascular structures, such as the lens and cornea, while simultaneously facilitating waste removal. Active secretion differs from passive processes like diffusion and ultrafiltration, which do not involve the energy-dependent transport of solutes and instead rely on concentration gradients or hydrostatic pressure differences. Additionally, while filtration may play a minor role under certain conditions, it is not the primary mechanism for aqueous production. This understanding of active secretion highlights its importance in ocular physiology and the maintenance of eye health.