Have you ever had a staring contest? It deserve to be daunting to store your eyes open for lengthy periods the time since of the natural instinct come blink. Yet why do we have to blink?

There room two main reasons, claimed Dr. Brenda Pagan-Duran, a clinical spokesperson for the American Academy the Ophthalmology and also an ophthalmologist in new Jersey. First, blinking removes away corpuscle from the eyes. "If there"s a international body, the helps get rid of it," she said Live Science. "It can be under the eyelid or something that blew in."

Second, blinking lubricates the eyeballs. The eyes require a smooth surface ar for irradiate to properly emphasis on, therefore vision doesn"t end up being blurry. Blinking publication a tear movie — i beg your pardon mostly is composed of water, oil and also mucus — to save the surface ar of the eyeball smooth. It also prevents the eye from drying out, which deserve to be uncomfortable. "When you have a huge area the dryness, it practically feels like a scrape on her cornea," which is the eye"s outer protective layer, Pagan-Duran said. This deserve to be really painful, because there are plenty of nerve end in the cornea.

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The tear film also supplies oxygen come the eye. Blood vessels don"t with the cornea, however the tear film straight transfers oxygen to it. The film likewise contains enzymes the fight bacteria and help prevent the eye from ending up being infected.

Blinking helps throughout emotional times, too. Once you cry, friend blink more often come clear away the tears, Pagan-Duran said. This prevents them from building up a lake ~ above the eye, which could blur vision.

Blinking is a reflex. It happens involuntarily, yet you can additionally make you yourself blink. It takes the average human being 400 milliseconds to blink, Pagan-Duran said. Most people blink somewhere between 10 and also 20 times per minute, usually about 15 or 16 times, she added. However, there space some scenarios that make people blink much more or less often.

For example, you might blink much more frequently if there"s something in her eye. Particular conditions, such as an structure eyelash, can make that feel like there"s something in your eye, which provides you blink more. Allergies, pink eye and also other varieties of inflammation can additionally trigger the reflex. Some people have tics, or habitual involuntary movements, that lead them to blink frequently, and stress and anxiety deserve to make friend blink an ext too, follow to Pagan-Duran. If you have uncorrected vision problems, you may blink more often due to the fact that your eye are naturally trying to correct the blurry vision.

If there is damage to the face nerve, which is responsible because that closing the eyelid, a person may blink more slowly or much less often, Pagan-Duran said. Fatigue and also some medications can cause a similar effect. When you"re focusing on something like watching a movie, you may blink much less to strengthen your focus. Because that example, as soon as reading, world tend to blink at the end of a sentence rather than in the middle, she said.

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—Why perform my eye close as soon as I sneeze?

People blink much more often 보다 is required to lubricate the eye, which might be to give the mind a quick rest, according to a 2013 study published in the journal Proceedings of the nationwide Academy the Sciences. "It"s not purely the technical part of protecting the eyeball and also lubricating and clearing particles," Pagan-Duran said. "It"s more of an concern of when, exactly, to give that little mental break to the brain."

Originally released on Live Science.

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Tara Santora is a contributing editor at Fatherly and a freelance science journalist who covers everything related come science, health and the environment, particularly in relationship to marginalized communities. They have written for popular Science, clinical American, company Insider and more. Born and also raised in the Philadelphia suburbs, Tara graduated from Oberlin College through a bachelor"s level in biology and new York University with a master"s in science journalism.