Anatomically essential to seeing, this is a delicate, multilayered, light-sensitive membrane lining the inner eyeball, opposite the eye's lens. It is a sheet of photoreceptors (light receptors), millions of specialized brain cells (neurons) which are excited by light. These light receptors are differentiated into neurons called rods and cones, which are connected by the optic nerve to the brain.The retina is much like a sheet of film inside an analog camera, but it has a hole in it known as a blind spot. At this location, neurons pass as a bundle through the photoreceptor sheet to form the optic nerve, which carries information from the eye to the rest of the brain. Here there are no photoreceptors, and hence the brain gets no information from the eye about this particular part of the picture of the world.(pr. RE-tə-nu)Related resources: A diagram of the human eye.Also see afterimage, binocular vision, colorblind, gestalt, night blindness or nyctalopia, Op Art, ophthalmology, optical, optical mixing, perception, peripheral vision, photography, pupil, refraction, retinal art, stereoscopic vision, and vitreous humor.