I had been riding without goggles until about 3 weeks ago, when my 7 mile ride to work here in Minneapolis was performed at -10. By the time I got to work my eyelashes had literally frozen to each other, hindering opening of my eyes. It was at this time I decided I needed some goggles. I bought a pair from my local bicycle co-op and they worked great, only fogging up when stopped. This was until 2 weeks ago when the temp dropped to negative 23 (before windchill) at which time I developed a layer of ice on the inside lens of the goggles. It was so bad that 1/2 way through my ride, I saw a bus going near where I was, and caught it just to get away from the cold.
Winter sucks here, although we got up to 43 today, the first time over freezing in about 45 days.