Has anybody ever told you that you shouldn't sneeze（打喷嚏）with your eyes open and your eyeballs will pop out？This might sound reasonable，because our eyelids（眼皮）always close when we sneeze. But is that true？

Actually，this is highly likely. Although a sneeze can burst from your nose in a speed of 320 kilometers per hour，it can't transfer（转移）that pressure to your eyes. Plus，there's no muscle directly behind the eye what could push the eyeballs outward. Thus，your eyelids don't have much muscle power，so even if they are responsible for keeping your eyeballs in place，they would fail.

But then why do we always close our eyes when we sneeze？It's simple a reflex（反射）of the body，just like how our legs kick when our knees tapped. The nose and eyes are linked by nerves. so the stimulation（刺激）from the sneeze travel up one nerve to the brain then down another nerve to the eyelids，cause a blink（眨服）for most people. It's just an involuntary reaction with no real purpose.