I had prescription inserts made for Bolle cycling glasses about 5 years ago, but was never satisfied with the vision. Even after taking them back for adjustment (heating and bending of the insert), the vision just wasn't great. Believe this was due to the bend in the inserts, necessary for them to fit into the wrap-around glasses. I have astigmatism, which makes the exact alignment of lenses critical.
Anyway, the solution for me is to use my old trusty Ray-Ban aviator wire frames with new polarized plastic tinted lenses. They seem to offer plenty of wind/bug protection as well as much better vision than I get looking through two lenses with the Bolles.