I've just bought these rather nice sports glasses from Shoptic:
They are varifocal, anti-glare coated and photochromic. The vision is really superb and you'll notice that the designer has cleverly combined a curved frame with a flatter lens by using "sub frames" for the lenses, which gives the optician a much bigger choice of lens blanks and keeps the price down as well as giving less optical distortion. I don't think they would darken enough to be used as ski glasses but on the bike they're superb. A standard non-prescription lens also fits into the area occupied by the sub frame, if you want them for eye protection only.
These cost about £220, which i don't begrudge at all. For anybody in the NW they came from the very excellent Ideal Eye Care just outside Blackburn.
Edit: They are not Shoptic but I can't remember the brand!