Retina

Thin layer of light-detecting cells at the back of the eye, similar to the film or digital sensor found in a camera.

The retina contains the light-detecting cells in the back of the eye. If the eye is a camera, consider the retina to be like the film or digital sensor. The retina contains several nerve cell types that are considered to be an extension of the brain, and thus part of the central nervous system. The cell types and structures that are considered to be part of the retina include: photoreceptor nerve cells (rods and cones); other types of nerve cells that relay the signal to the optic nerve "cable" (horizontal, bipolar, amacrine, ganglion, Müller cells); retinal vessels; RPE cells; and, Bruch's membrane. The photoreceptor cells of the retina absorb light and convert this light into electrical signals (see Phototransduction). The electrical signals are transferred from the photoreceptors to other, secondary nerve cells (listed above) which then send the electrical signals through the optic nerve to the visual cortex region of the brain for interpretation.