given that you are from ****tsford, sunglasses aren't going to help you.
I've been riding on the North Shore for 20+ years, mostly without glasses.
Most of the riding we do is technical, and slower speed, so not much thrown back in your face.
I assume your riding is similar.
However, I do have a pair of Smiths with the interchangable lenses. Dark sun lens, orange, and yellow.

Sunglasses in the forest of the Pacific NOrthwest ?..... you can't see anything even on a bright sunny day.
On a dark rainy day, the yellow lens is awesome.... its like someone actually turned on a light in the dark forest, and keeps stuff out of your eyes for the decents where you do get speed.
The orange lenses are good for the days when its not so dark in the woods.