My glasses fog when I stop. My rule is nothing over my eyes in the winter. Sometimes my eyelashes get icy, that can be annoying. Salt in the eye hurts also.

Of course, the nothing over the face rule falls apart when it is super-cold.

This is literally what I do when the temps are below zero (like they are today!) - I start the commute with goggles and have my glasses in an accessible case. I ride like this until the goggles fog up. Usually 15 or twenty minutes. During this time my entire face is covered. When that falls apart I pull the googles up on my helmet and ride with glasses. After about 30 minutes I find myself looking over the top of my glasses, which are fogged up. I do this for about 15 minutes and by that time I am at work!