I have to wear a mask at work and my glasses fog up all the time. On the first day of class, I gave my class a 15 minute break (it's a three hour class). I left the room, my glasses fogged up, I walked into a door and got a bloody nose. I was worried that I wouldn't be able to stop the bleeding, but I got it cleaned up and went to my car to get another mask. Additionally, I give a lab at the end of class where I walk around and help students with an assignment. It's a big lecture hall with stairs all over the place, so I have to be careful! I also hate lecturing with a mask because it muffles my voice and the voices of students asking questions.