What area of the retina is supplied by the retinal pigment epithelium?

The retinal pigment epithelium (RPE) plays a crucial role in the health and functionality of photoreceptor cells, particularly the cones and rods, which are located in the outer portion of the retina. The RPE lies directly beneath the photoreceptor layer of the retina and is pivotal for processes such as the absorption of excess light, the recycling of visual pigment, and the maintenance of the blood-retinal barrier.

The outer one-third of the retinal structure primarily consists of the photoreceptor cells—cones and rods. Cones are the photoreceptors responsible for color vision and function best in bright light conditions, while rods are more sensitive to low light conditions. The RPE's relationship with this outer layer is essential for phototransduction, where light is converted into electrical signals that the brain can interpret.

By supplying nutrients, transporting waste products, and facilitating the regeneration of visual pigments from phototransduction, the retinal pigment epithelium supports the functionality and health of these photoreceptor cells. Hence, the correct association with the area of the retina supplied by the retinal pigment epithelium is indeed the outer one-third where the cones and rods exist.