The Scientist: Michelle Yagoda, M.D., a New York-based doctor trained in both facial plastic surgery and otolaryngology (ear, nose and throat).

The Answer: It’s happened to most people at least once: that annoying sensation that your eyelid is twitching and you can’t make it stop.What’s happening is that the circular muscle that surrounds your eye is getting stimulation from the nerve that connects it to your brain. But instead of the normal firing that leads to a blink, it’s firing so rapidly that the lid (upper or lower) doesn’t have time to close all the way.

Doctors don’t know what causes the spasms exactly, but there are some known triggers. Stress and exhaustion are commonly associated with those tiny twitches. (If you’re wondering: They’re so small that they’re practically imperceptible to anyone else.) Anything that strains your eyes can be a culprit, which can include vision problems (i.e. you’ve got poor eyesight and have yet to correct it, or your glasses/contacts are no longer the right prescription) or squinting at the computer all day. Dry eyes—which can be due to aging or allergies—can also prompt a twitch, as your eyelids go a little crazy in an attempt to moisturize your eyeball.

To get rid of an eye twitch, treat the root cause. If you’re tired, catch up on sleep. If you’ve got dry eyes, squeeze out some moisturizing eye drops, drink lots of water and stay away from dehydrating agents such as caffeine and alcohol. And while you’re at it, make sure the prescription on your contacts or glasses is up to date.

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