You definitely need to look into cycling-specific glasses. The ones I have are from Rudy Project and have prescription inserts. Cycling glasses have much better eye coverage, arms that grip the sides of your head without the need to wrap around your ears, and lenses that are designed to filter UV rays. They're not cheap, but, your vision, safety, and comfort are worth it.I agree that it is worth spending on some cycling specific glasses. That said, I found that for me inserts were not as nice as just having the lenses be prescription. The inserts made for extra surfaces to fog up or get dirty. I used glasses with inserts on the Trans America and they were OK, but I like my new cycling glasses much better.
I got really good service from Sportrx online. The guy who helped me (Rob) was an avid cyclist and an optician and seemed to really know his stuff. The price wasn't that bad either.