My cat closes her eyes when she sneezes. My dog too. My infant daughter too. I've seen horses sneeze, their eyes closed tight. I've even seen an elephant sneeze. It's eyes closed. Next time you sneeze, try to pay attention to the rest of your body. It'll be a challenge as the tickle in your nose will be quite distracting. When I sneeze doors slam, ceiling tiles come loose, ears pop and I get phone calls from people upstairs saying, "Bless you!" I've noticed that a lot of muscles in my body tense up. There are three muscle types in the body. Skeletal, smooth and myocardial. Some muscles response exclusively to the involuntary nervous system. Others respond to both the involuntary and the voluntary. Like the diaphragm and the eyelid muscles. I breathe and blink without thinking, but I can control these things whenever I want. Perhaps when the need to sneeze comes along, our brains send out a general signal to the involuntary nervous system. This signal has to be strong enough to overcome our voluntary controls. After all, we don't usually expell air (and snot) through our nostrils at 60 mph in the course of everyday breathing. Perhaps this signal, being as strong as it is, causes more than just our diaphragms and eyelids to flex suddenly. Just a thought. I'm gonna Google it now.