“If you don’t close you’re eyes when you sneeze, you’ll pop out an eyeball!” It’s what the kids on the playground always said, right?
And like much of the information crowdsourced from your friends when you were 7, it’s not exactly true.
Closing your eyes when you sneeze is a reflex — a rapid and involuntary response to a stimulus, the stimulus in this case being signals from the brain to the nose saying, “SNEEZE!!” But like yawning, we don’t know for sure what it’s for.
The one thing it’s not for is keeping your eyes in your head while sneezing. For starters, your eyes are anchored to your skull by the six extraocular muscles, the ones that let you move your eyes around.
And it’s not like your eyelids are adding much structural support when you sneeze. The muscles that move your eyelids have one job — to move your eyelids. They wouldn’t have the strength to keep your peepers in place should the extraoculars tear and enough pressure were to build up in your eye sockets to make things go pop.
Which it wouldn’t in the first place, because your orbits are separated from your nasal passage, which is where sneezes start,by bone and membranes. Pressure building up in your nose doesn’t transfer into your eye sockets.
So why is it then that when the sneeze is coming that your eyes snap shut like a crocodile nabbing a snack? I hate to say it, but it’s that we don’t really know.
Is it to keep stuff from flying into your eyes when you sneeze? Well, when you sneeze, you’re expelling air, mucus, and other stuff from your face at about 100 miles per hour (though in a study published this year in the journal PLoS One, the fastest sneeze by a group of volunteers clocked in at a measly 10 mph).
According a 2004 article on Boston.com:
”It is unclear, but scientists theorize that we close our eyes to protect them. We may be protecting our eyes from microorganisms and particles from our sneezes,” said Dr. Bonnie Henderson, director of comprehensive ophthalmology at the Massachusetts Eye and Ear Infirmary.
But it may also be as simple as a wiring mixup. You don’t just sneeze with your head…you sneeze with your whole body. There are lots of nerve signals and muscle contractions going on all over the place when you sneeze, and your eyelids may just be getting caught up in the act.
Regardless of the reason — or lack thereof — it’s a tough reflex to counteract, as Mythbusters’ Adam Savage discovered when he tried:
So sneeze on, and remember, we may not know why you close your eyes, but they’re not going anywhere. Just please cover your mouth and nose, ok?