Image from The Sourcebook of Medical Illustration, P. Cull, ed., The Parthenon Publishing Group, 1989 and are copyright-free as long as they are used for educational purposes (Source: http://www.msjensen.gen.umn.edu/webanatomy/Images/default.html).

The eye: this incredible dynamically adjustable lens/aperature and photovoltaic sensory apparatus is quite simply only the beginning of the visual perception system which is corporeally (bodily) linked with all of the other senses through the central processor - the brain.