The retina is a thin nerve membrane that detects light entering the eye. Nerve cells in the retina send signals of what the eye sees along the optic nerve to the brain.

The retina lines the back two-thirds of the eye and is made up of two layers: the sensory retina and the retinal pigment epithelium (RPE).

The macula, near the centre of the retina at the back of the eyeball, provides the sharp, detailed, central vision a person uses for focusing on what is directly in the line of sight. The rest of the retina provides side (peripheral) vision, which lets a person see shapes but not fine details.