I correct it by not wearing glasses in a pancake.
In certain conditions the lens will still fog even without glasses. No way I can wear glasses in a pancake. Some guys do but won't work for me. Fogged in the winter, and sweat in the summer. I can get away with it under ideal conditions, but of course conditions are seldom ideal ; )
Sorry I can't be of any help but that's the way it is for a lot of guys I know..
JTMcC.
1Mancrew,
If it is necessary for you to wear glasses because of a vision issue, then you could look into "cheater lenses" or switch to a regular hood. If vision is not the issue and you are just worried about safety, with a well adjusted pancake hood, it is not required or IMHO necessary to wear safety glasses under a pancake hood. HOWEVER, when you pop that hood up and your helper starts doing his thing, you need to put on the safety glasses. :-)
Keep your hood at as nuetral of a temp. as possible, don't leave it in the tool box in extreme conditions and don't set it on the dash to heat up on the way to work.
jrw159