I wear a pair of sunglasses that fit over your prescription pair, they're called "Panorama" and made by 'Solar Shield', they have and excellent wide angle view with complete peripheral coverage, not bulky, comfortable enough that I'm not even aware of them. They keep the bugs out and still have enough ventilation to keep from fogging up. Got them at my drug store, here's a link to their site:
Solar Shield | Fit Over Sunglasses