It is the retina that allows one to see. The retina lines the back of the eye and consists of extremely thin layers of light-sensitive cells called photoreceptors, nerve cells, and support cells responsible for nourishing the photoreceptors. Together, the cells of the retina translate light, shadow, movement, and contrast into recognizable images. The photoreceptors of the retina, known as rods and cones, capture light, which is instantly changed to electrical impulses. These signals then travel from nerve cell to nerve cell, along the optic nerve, and ultimately to the brain, which converts them to understandable forms.
Different concentrations of rods and cones are found throughout the retina. The macula is a small but very important area of the retina located directly in line with the pupil. Because of its location and its high concentration of cones, it is responsible for the detail and sharpness of central vision.
The retina has a pivotal role in vision. When the functions of retinal cells are compromised, vision may be impaired in any of a number of ways.