Onion tears are caused by 2 different chemicals held apart by the onion's cellular structure. Every time you cut an onion, the cells rupture and mix, aerosolization and making you cry when the acid gets into your eyes. A sharp knife (as mentioning in another comment) would help minimize the amount of cellular damage and therefor the gas produced. You can also wear goggles.
Everything else is bunk. From-A former professional chef and person particularly sensitive to onions. (I just learned to cut onions with my eyes closed)
Don’t know why everything else would automatically be bunk.
If you refrigerate your onions, you might be fine for some amount of time and you'll be lessening damage and it's going to help but not solve it at volume (cut one onion, you're fine. Cut 100, not so much).
Or even just contact lenses. At least for me it eliminates onion tears completely. I had been using them for at least a decade before I started to cook my own proper food, I'll never forget that one time I tried cutting up onions wearing my glasses instead...
I've known people who just have seemingly no reaction to onions whatsoever, and others who break into tears the second the first cut happens.
Going fast works.
If you're not a professional, using an onion comb (which costs less than $2 and lasts a lifetime) will change your onion-cutting experience. It lets you go way faster and therefore reduce the time you're exposed to tear-inducing chemicals (assuming you're cutting 1-2 onions and not cooking for a whole army).
It's likely that at least half of the effect of a sharp knife is due to time improvements too.
https://www.amazon.com/Sharper-Your-Knife-Less-You/dp/014311...
They must have a better way. And their way will work for 1 onion or 50!