Eyelids

Upper and lower eyelids protect the front of your eyeball (orbit) by blocking foreign objects and bright light that can damage your eye. Your eyelids involuntarily open and close (blink) every few seconds to help protect your eyeball. You can, of course, blink intentionally as well.

With each blink, tear fluid (fluid arising from tear glands around the eye) passes over the cornea and lubricates the surface of the eye. This helps wash away germs, dust, eyelashes or other foreign objects and helps keep your eyes from drying.