Slide show: A look inside your eyes
Illustration of the eyelid
Previous Next 1 of 7 Eyelids

Your eyes are your windows to the world — but they need to be shielded from the elements to keep you seeing clearly.

Upper and lower eyelids protect the front of your eyeballs by blocking foreign objects and bright light. Your eyelids also involuntarily open and close (blink) every few seconds when you're awake.

See more Multimedia March 17, 2017