Naphtali, I switched from glasses to contacts solely for the purpose of hunting. I was tired of them fogging up and slipping down my nose in hot weather.
I use a primos face mask that is tight against my face like the spandoflauge ones are. In some places that I hunt, I am hiding from other hunters as much as hiding from the deer. That means gloves and face covering. Have you ever watched another hunter across a field? You can see movement from a mile away, but it seems like you can see movement of uncovered hands and face about 10 times that far.