http://science.howstuffworks.com
The human eye is made up of the
parts shown above. When you see light, the light first travels through
the cornea, aqueous humor, then the lens and the vitreous humor. Finally,
the light reaches the retina where it is sensed with rods and cones. When
they are detected, it creates electrical impulses in the optic nerve, and
is sent to your brain.