Do yourself a favor: skip glasses and go directly to contact lenses. I wore glasses for years because contacts would start to bug me after 4-5 hours. Still, when bicycling or motorcycling I always wore contact lenses (along with regular Smith sunglasses that had interchangeable lenses). I finally found contact lenses I could wear all day (Accuvue One-Day Moist, in my case) and I've given up on glasses entirely. Contact lenses provide much better vision, and especially much better peripheral vision. Now that I have contact lenses I can tolerate, I'll never go back to wearing glasses...