Real Dictionary

retina in American English
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
noun: the innermost coat of the posterior part of the eyeball that receives the image produced by the lens, is continuous with the optic nerve, and consists of several layers, one of which contains the rods and cones that are sensitive to light

retina in British English
noun: the light-sensitive membrane forming the inner lining of the posterior wall of the eyeball, composed largely of a specialized terminal expansion of the optic nerve. Images focused here by the lens of the eye are transmitted to the brain as nerve impulses