How The Eye Works
When you look at an object, light enters your eye though the cornea. The cornea is a very important part of the eye, but you can hardly see it because it's made of clear tissue.
After light enters the pupil, it hits the lens. The lens sits behind the iris and is clear and colorless. The lens' job is to focus light rays on the back of the eyeball - a part called the retina.
The retina is the innermost coat of the back of the eye, formed of light-sensitive nerve endings that carry the visual impulse to the optic nerve.
The optic nerve is a bundle of nerve fibers that carries visual information from the eye to the brain.