The helmet certainly fits over smaller framed glasses, but with medium to large frames, you're either going to encounter some difficulty getting into the thing or you'll have to pull out the muzzle as far as it can go. IMO, the helmet looks better with the muzzle back.
My glasses were ok inside, but they pressed against the visor and were not extremely comfortable. I now wear contact lenses, which is great - but if you're only going to wear glasses, I'd suggest you find somewhere to try the helmet on first. It would be pretty unpleasant to splash out on a piece of kit that is uncomfortab