Everytime I do a long distance ride, it seems I end up in epic torrential down pours somewhere long the route. I've bought just about every pair of glasses known to mankind, and came up with the same conclusion as MR, the better the seal, the worse they fog. And worse, the better they seal, the harder they are to clear. Nothing worse than watching a big drop of water slowly collecting on the inside of the lens which eventually lets go right into your eye.
Seeing I normally end up hitting a helmet required state along the trek anyway, I've just have gotten into the habit of just wearing my HD Stealth flip up modular helmet on all long rides. While the front shield doesn't seal 100%, in the heaviest downpours, I usually only get a drip once in a while that runs across the inside, but never hits my eyes or face and is totally comfortable. The nice thing about the helmet is, behind my batwing at least, I can flip up the entire face of the helmet in sunny conditions and it feels like a 1/2 helmet. Then when I get to my destination, if it's not a helmet state, I'll just ace leave the helmet in the hotel room until the return ride.