Here’s a hint for you. I wear very expensive frameless glasses that I didn’t want to risk at the track. Just get your prescription and go to one of the online eyeglasses sites and buy some simple and sturdy glasses for wearing in a helmet. I used 39dollarglasses.com but there are several sites around. Since I was only going to use these for karting I dropped the progressive part and had them tinted yellow for better daytime vision. I received them in a couple of weeks and I think I paid about $60 total. I wear them in a Bell Sport with no issues.