Like many people who wear glasses, one of the biggest problems I run into is having them fog up when I wear a mask.
And now that it's mandatory we wear them, I can't really escape it...so how do we fix it?
The easiest way is to put a tissue folded inside your mask at the top to catch the moisture before it reaches your lenses.
Another thing is to pick a mask that fits more snuggly to your nose and cheeks...a tip that is also beneficial as anything sealing away your nose and mouth is a plus.
Also, cleaning your glasses with soapy water and letting them air dry is supposed to do wonders for keeping them fog free.