The retina is a thin layer of tissue that lines the back of the eye on the inside. It is located near the optic nerve. The purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition. The retina is made up of 200 million neurons. The retina contains photoreceptors that absorb light and then transmits those signals through the optic nerve to the brain 1 The photoreceptors in the retina are called rods and cones.