So, as I understand it there are three main spots on the body where COVID infection typically takes place -- the nose, the mouth, and the eyes. It is relatively easy to obtain a very protective mask for the nose and mouth (n95/p100), but a large majority of people seem to be using masks that do not provide eye protection. How much extra protection can be gained by protecting your eyes?
(Obviously, the degree of protection one might use can vary -- on the low end we might have "wear glasses", while then we might progress further with things like "disposable face shield over mask", "wear a full face respirator rather than nose/mouth only", and then even "full head positive pressure hood" on the very high end.)
This could be an interesting thing to study. Anecdotally, I think I've seen more people give 'fogged glasses' as a reason/excuse not to wear a mask, or to pull it right down, than as a reason to fit the mask properly. For some people and some mask types, there seems to be an assumption that air escaping out the top is inevitable.