Facts About Eyes

Optic Nerve 

Intricate cord of nerve fibers between the eye and the brain. The visual "signal" runs from the retina to the brain through the optic nerve. Vision occurs in the brain.

Sclera 

The tough, white covering over most of the eye. Sclera protects the inside of the eye from harmful things like germs.

Pupil 

The black area in the middle of the iris. Light passes through the pupil to the retina. The pupil appears black because the back of the eye is dark and filled with fluid.

Cornea

The clear, window-like covering over the iris. The cornea allows light to pass through to the retina. For good vision, it is very important the cornea remains clear and healthy.

Iris 

The colored part of the eye. Similar to a camera's shutter, the iris controls the amount of light that enters the eye. 

Retina 

Thin tissue covering the back of the eye with the specialized nerve cells that see color, light, and dark. Light is focused upon the retina much like the image of a photograph is focused upon the film in the back of a camera.

Lens 

The clear, round object behind the iris. The lens helps to focus the things we look at by bending the light that passes from the front of the eye (cornea) to the back of the eye (retina). As we get older, certain types of light rays may cause the clear lens to become cloudy or yellow. When this happens, it is called a cataract.