Photo Chromatic Lenses

[andrew_s]

How did they fare in the snow? I have a pair of Oakleys with photocromatic lenses and had a terribe time when caught in a bit of a whiteout in Chamonix. I couldn't read the gradient of the slopes which is pretty dangerous on the moguls and have sinced ditched the specs in favour of prescription Polarised lenses.

Glasses of any kind won't help in a proper whiteout, although they may help if it's not a full-on whiteout.
There's light coming from every direction, so there are no shadows of any kind and all snow is an identical shade of white with no texture. I've known people walk straight off a 15 foot vertical drop because they couldn't see it was there.
If there's something dark nearby, that can make a difference and allow you to see some texture. "Something dark" could even be your legs, allowing you to see the shape of the ground within 3 or 4 feet of your feet, and something bigger will provide contrast over a bigger area.
You can even get whiteout in 20 mile visibility if there's full coverage of snow on the ground and complete snow cover.