What is the function of the Retinal Pigment Epithelium (RPE)?

• A. Nourishes the retinal visual cells and is essential for their health
• B. Produces aqueous humor
• C. Detects light and color changes
• D. Forms part of the sclera

Answer: (A)

The main idea is that the retinal pigment epithelium primarily nourishes the retinal visual cells and keeps them healthy. This single layer sits between the photoreceptors and the choroid and provides essential support: it transports nutrients from the blood supply to the retina, clears metabolic waste, and phagocytoses shed photoreceptor outer segments to renew them. It also participates in the visual cycle by helping regenerate the light-sensitive molecules, absorbs stray light to improve visual contrast, and helps maintain the blood-retina barrier. Because of these nourishing and maintenance roles, its function is best described as supporting the health of retinal visual cells. The other options describe activities not performed by the RPE: aqueous humor production by the ciliary body, light detection by photoreceptors, and structural formation of the sclera.