Do you mean:
* The eyelid? This protects the eye from foreign objects and helps keep it moist.
* The eyelashes? These help to filter out dust and debris.
* The pupil? This is the black hole in the center of the eye that controls how much light enters.
* The iris? This is the colored part of the eye that surrounds the pupil and helps to regulate the amount of light that enters.
* The sclera? This is the white part of the eye that provides structure and support.
* The cornea? This is the clear outer layer of the eye that helps to focus light.
* The lens? This is a clear, flexible structure that helps to focus light onto the retina.
* The retina? This is the light-sensitive layer at the back of the eye that converts light into electrical signals that are sent to the brain.
Once you tell me which part of the eye you're interested in, I can give you a more specific answer!