What is the function of the pigmented epithelium in the retina?

• A. Reflect light back into retina
• B. Absorb stray light and prevent internal scatter beneath the retina
• C. Generate action potentials
• D. Form the optic nerve

Answer: (B)

The retinal pigment epithelium absorbs stray light and prevents internal scatter beneath the retina. This layer, rich in melanin, lies between the photoreceptors and the choroid and acts like a light-absorbing shield. By soaking up excess photons that pass through the photoreceptors, it reduces reflections and backscatter that would otherwise blur vision and lower contrast, helping the image stay sharp.

In addition to this light-absorbing role, the RPE supports photoreceptors by phagocytosing shed outer segments, recycling visual pigment, and transporting nutrients and ions to maintain the photoreceptor environment. It also forms part of the outer blood-retina barrier. It does not generate action potentials, and it does not form the optic nerve. The idea of reflecting light back into the retina is more characteristic of a tapetum in some animals, not humans.