What a Blink Does

Your eyelids move many times each minute without you deciding to move them. This quick movement is called a blink. Why does it matter? The front of your eye needs moisture. Use the headings below to find out how blinking helps.

A Moving Cover

An eyelid is a fold of skin that can cover the front of an eye. During a blink, the upper eyelid moves down and back up. The movement takes less than a second. Most blinks happen automatically, without a person thinking about them.

A Fresh Tear Layer

Tear glands above the eyes make the watery part of tears. Tears are not just for crying! Each blink spreads a thin layer of tears, called a tear film, across the eye's front surface. Without enough moisture, this surface can feel dry. The film keeps it moist and smooth. Blinking also helps move tiny bits of dust toward the inner corner of the eye.

Where Tears Go

Old tears drain through tiny openings near the inner corners of the eyelids. Small tubes carry them into the nose. Meanwhile, fresh tears keep arriving. This steady supply helps the tear film cover the eye between blinks.

Sidebar: Blink or Wink? A sidebar is a short note beside the main text. This one compares two movements. A usual blink closes both eyes briefly. A wink closes one eye, often on purpose to send someone a playful signal.

Picture caption: A blink spreads tears over the eye. The drawing shows the tear film in blue so readers can see it. Real tears are clear. A caption explains what a picture shows.

To learn more online, type the key words blinking tear film into a search box. These words focus your search on how blinking spreads tears. On this page, the hyperlink labeled tear glands leads to another page about where tears are made. A hyperlink is text you can select to open another page.