What Are the Eyes and What Do They Do?
Only part of the eye is visible in a person’s face. The whole eye – the eyeball – is about the size and shape of a ping-pong ball. The eye – both the parts that are visible and those that aren’t – is extremely delicate. The body has several ways of protecting this vulnerable organ. The eyeball sits in the eye socket (also called the orbit) in a person’s skull, where it is surrounded by bone. The visible part of the eye is protected by the eyelids and the eyelashes, which keep dirt, dust, and even harmful bright light out of the eye. Our eyes are also protected by our tears, which moisten the eyes and clean out dirt, dust, and other irritants that get past the defenses of our eyelashes and eyelids. Tears also help protect the eyes against infection. Every time we blink, our eyelids spread a layer of mucus, oil, and tears over the cornea(pronounced: kor-nee-uh), which covers the eye. The lacrimal (pronounced: lah-kruh-mul) glands in the upper outer corner of each eye socket produce tears
