What causes a sneeze?
Sneezing can be an early symptom of a cold or allergy and is the result of the inflammation of the trigeminal nerve in the nose. This nerve is linked to the “sneeze centre” of the brainstem and send signals that prompt a person to sneeze. On the one hand, this reflex may help the body expel viruses before they infect the tissues of the respiratory tract. On the other hand, sneezing spreads disease by creating aerosol droplets containing the viruses that caused the infection, which may then be inhaled by healthy individuals. A single sneeze can produce up to 40,000 droplets.
What happens if you sneeze with your eyes open?
There are many superstitions related to sneezing. One common belief is that if you sneeze with your eyes open, your eyeballs will come out of your head. But this simply isn’t true. Most people naturally close their eyes when they sneeze as a reflex. The brain sends signals to your eyes telling them to close but, like any reflex, this urge can be suppressed. If you keep your eyes open, your eyeballs will stay firmly planted in your head. Your eyes have muscles holding them in place (in other words, they’re not kept in your head by your eyelids). Though the blood pressure behind your eyes does slightly increase when you sneeze, it’s not enough to dislodge your eyeballs from your head. So while you should always cover your nose and mouth when sneezing to keep others from getting sick, you don’t need to worry about keeping your eyes shut.