In reply to buzby:
I've had varifocals for a number of years, always with reactolite lenses and they were fine for peaks such as Toubkal. They have always been fitted to what I would call 'conventional' frames, in my case thin metal so the arms don't interfere with peripheral vision. After a couple of day's cross-country skiing in the French Jura 5 years ago, travelling with the sun mostly coming from one side, I got snow-blindness in one eye. So, my optician got me a pair of wrap-round Tagheur frames and I had those fitted with my varifocal prescription. Expensive, yes, but you only get one set of eyes. My prescription has changed since then but not enough that I can still use them to read with and use a map. They get used for sea kayaking as well. Ironically the frames were made about 10 km down the valley from where I got the snowblindness.