A friend told me years ago to wear safety goggles - pulled tight - when chopping onions.
It works!!!!
The only problem I have been faced with the last few years is that I end up with terrible hayfever like symptoms so take antihistamines before I start. Unfortunately this year even that has not helped, so this morning I nipped to the local shop and a packet dust masks. (our local shop is an Aladdins cave and has almost everything)
Note of caution if anyone decides to try this at home. . . . don't answer the door till you have
completely finished the task in hand. Ask me how I know