As a chef I always find myself slicing, dicing, chopping onions more than I would care to. It's not that I hate doing it or that I'm lazy. I just get very teary eyed, just like the millions of other people who get onion emo!
Again I found myself slicing and crying last week, and as always I was joking around with my other chef, Koko-san, saying something along the lines of, "Damn, this onion is so beautiful I can't hold it back," as tears ran down my cheek. Koko then said, "Hey, next time light a candle on each side of the cutting board and the heat and flame will pull the vapors away!"
Who would have known? It kinda worked! At least enough so that I could finish a batch without walking away and wiping my tears back.
I notice that when I don't wear my contact lenses, my eyes water like crazy. But with contacts, I've never been bothered by onions, spicy peppers, etc.
Obviously more suited for the home cook, but if I'm choppin' up a large volume of onions, I've been known to put a small fan anywhere near me to push the vapors away from my face. Works wonderfully.