Ryan Spaulding wrote a review of Smith Parallel D-Max Sunglasses on November 23, 2011
My go-to sunglasses for all my trail running ventures. The Parallel D Max is insanely light and very low-key, but still provides great coverage. I have a small face size and these fit me very well. I did not purchase extra lenses, so I am unable to comment on how simple it is to swap them out.
I find that these guys will fog up- generally when I come to a stop or walk during or after a run- but I can't say that I've ever worn a pair of shades that did not fog up during moderate to strenuous activity.