the innermost coat lining the interior of the eyeball, containing various layers of photoreceptive cells that are directly connected to the brain by means of the optic nerve
See retina in American Heritage Dictionary 4
(rĕtˈn-ə)
nounpl.ret·i·nas or ret·i·nae(rĕtˈn-ēˌ)
A delicate, multilayered, light-sensitive membrane lining the inner eyeball and connected by the optic nerve to the brain.