Which of the following is a function of the retina?

The retina plays a crucial role in vision by detecting light through specialized cells known as photoreceptors. These cells, which include rods and cones, convert light into electrical signals that are then transmitted to the brain via the optic nerve. Rods are primarily responsible for vision in low light conditions, while cones are responsible for color vision and detail in brighter light.

The other functions listed in the options do not pertain to the retina. For instance, the secretion of aqueous humor is a function of the ciliary body, not the retina. The processing of auditory signals is managed by the auditory system, specifically structures in the ear and associated brain regions. Eye movement is controlled by extraocular muscles and the cranial nerves that innervate them, rather than by the retina itself. Therefore, the correct option accurately identifies the primary function of the retina in the visual system.