Eh, uh, VM, about that fog. I have a solution.
Step one, put a dab of toothpaste on your finger and rub it all over the lenses. Rub it in really well. This has two purposes, it scours the lens clean due to the particulates in the toothpaste and it removes any oils that may have been used to ship the glasses (water wouldn't remove the oil, and oil would interfere with step two). You should only have to do this once, and of course you'll want to rinse the toothpaste off very thoroughly (perhaps get a narrow head toothbrush), but some dried toothpaste may still remain in the cracks between frame and lens no matter what you do, so you may want to do this to a separate pair of glasses.
Step two, before each battle spit on the inside of each lens and smear it all over the surface, then lightly rinse it off with water. This serves the purpose of putting concentrations of moisture on your glasses. This will prevent your glasses from fogging up, though you may find it necessary to repeat every few hours.
Lets look at the "science" behind this. Condensation is caused when hot air comes in contact with a cold surface. Warm air can carry much more moisture than cold air, so when the air cools from the contact it deposits the water on the surface; look at a glass of cold water on a warm day; the outside is covered in condensation. Your glasses are in contact with the cooler exterior air and the warm, moist air from your breath and near your skin. The glasses are cooler, and so water condenses on the inside of the lens.
The action I described does not interrupt this process. However, lets look at what the problem really is. The infinitesimal droplets form in a layer over your glasses, which appears as fog. Their mass is too light in relation to the attraction to the glass, a hydrophilic material, and so they stay in place. Water is extremely hydrophilic, and so is strongly attracted to other water molecules (this is related to the molecular shape; I can explain later if you would like). I'm not sure exactly why, but spitting on your glasses leaves a film that facilitates the movement of water molecules. The water that would have formed dew migrates down this film and towards larger concentrations of water, forming drops large enough to fall off. This film is totally transparent; the opacity of the fogging is from the refraction caused by light passing through the hemispherical fog-droplets. The film is flat, and so light passes through with uniform refraction, and is not noticed.
This is actually a SCUBA diving trick. SCUBA masks are shipped with a layer of oil, hence the toothpaste. SCUBA divers always spit in their masks before each dive. Rinsing it out is the normal practice, but I have found that I fog up anyway, and so leave the spit on the lens, rubbed in thoroughly. The ocean is cold and there is a pocket of moist air trapped by the masks, so they tend to fog rather aggressively, but when I do not rinse it out I never suffer a fogging problem, and can still see very clearly.
They do sell defogging liquid, which does the same thing as spit, and you can buy it for ski goggles as well, but to be honest, nothing works nearly was well as the method I described. (
this stuff actually works quite well, though; I use it for my ski goggles. I've never tested it with scuba gear, but I had the toothpaste and spit route.)
Don't trust me?