I completely, 100% recommend going to Brett Hunter at Sports Optical:
http://www.sportsoptical.com/
My Zeal Maestro sunglasses are easily the best RX sunglasses I have ever owned, and I am pretty nearsighted (-3.25 in right eye, -2.75 in left). Brett Hunter pioneered the technique of RX'ing wrapped sunglasses and is also a former competitive cyclist.