Couldn't tell exactly what sort of goggles you're using there, but I'll throw my two cents in. Double-lensed goggles (they sometimes call them thermal) would probably be the best investment you could make. They've got a gap between the two lenses, and it works absolute wonders in preventing the inner lens from fogging. If you don't have thermal lenses for your goggle, that should be your number-one investment. Something that ventilates well, but also has that double-lens so that the lens isn't the coldest part of the air pocket. There's also anti-fog fluids... I've worked with these before and they're not nearly as effective as a good thermal lens - and though they're a much cheaper initial investment, they'll rack up their cost over time as you have to use them kind of excessively. It's annoying, and it doesn't work that well. If the thermal isn't quite cutting it, tacking on anti-fog fluid might help - but I'd get a thermal-lensed goggle first.