Eye

The organ of sight. Thef unction of each eye, taken singly, is to formupon the retina, or nervous membrane which lines the inside and back part of the organ, a sharply defined inverted image of any objectlooked at. The eye resembles a photographer's camera inasmuch as the image produced uponthe retina is precisely the same as that produced on the ground glass of a camera. Bymeans of the optic nerve the image that is re- ceived on the retina is conveyed to the brain,which recognizes the visual appearances andcompletes the act of seeing.

Source: Ophthalmic Dictionary including pronunciation, derivation and definition of the words used in Optometry and Ophthalmology by James J. Lewis, Oph. D. Professor of Optometry in the Northern Illinois College of Ophthalmology and Otology, Chicago.