Retinal pigment epithelium

Micrograph of the retinal pigment epithelium cells

The Retinal Pigment Epithelium (RPE) is a layer of cells that lies between the retina and the choroid in the eye. It plays a crucial role in visual function.

Structure

The RPE is a single layer of pigmented cells that is hexagonal in shape. The pigmentation helps to absorb light and prevent its reflection within the eye. The RPE is closely associated with the photoreceptor cells in the retina, and it provides nutrients to these cells and removes their waste products.

Function

The RPE has several important functions:

• Light Absorption: The pigmentation of the RPE helps to absorb light and prevent its reflection within the eye, which could cause a decrease in visual acuity.

• Epithelial Transport: The RPE transports nutrients from the choroid to the photoreceptor cells in the retina, and it removes waste products from these cells.

• Phagocytosis: The RPE phagocytizes the tips of the photoreceptor outer segments that are shed daily.

• Visual Cycle: The RPE is involved in the visual cycle, which is the process by which light is converted into electrical signals in the retina.

Clinical Significance

Dysfunction or damage to the RPE can lead to a number of eye diseases, including age-related macular degeneration (AMD), retinitis pigmentosa, and Stargardt disease. In AMD, the RPE cells die, leading to loss of vision. In retinitis pigmentosa and Stargardt disease, mutations in genes that are expressed in the RPE lead to degeneration of the RPE and the photoreceptors.

See Also

• Retina
• Choroid
• Photoreceptor cells
• Age-related macular degeneration
• Retinitis pigmentosa
• Stargardt disease