I use a face mask. There's one they sell that's supposedly anti-fog, saw it in midwestern turkey supply catelog. There are also anti-fog wipes that work too. I used this stuff from prestone that's supposed to keep your windshield from fogging up, it works on glasses too. I quit wearing my glasses while hunting though because I HATE wearing glasses when using binos. Luckily, my vision isnt that bad so I can see well enough to not to have to wear them.