I use a pair of Liquid sunglasses with a prescription insert. ANSI Z87.1 rated. They also come with a foam liner to be completely sealed off for biking, parachuting, or in my case airsofting. I think it was around $130 for the glasses and $170 for the prescription lenses, but again insurance covered some. And Liquid is a local company too!
Not trying to sell for them, I'm just a satisfied customer!
http://www.liquidpolarized.com/Edit: They also offer lens replacement for $20 bucks, which is nice if they get real scuffed up.