Actually, there are many place that you can bought prescription sports eyeglasses. You can have a look at walmart or eyeglasses shop around your eyes. In common, they provide prescription sports glasses. If you can't find sports glasses you want from them, you can search them online. And there are many eyeglasses shop provide prescription eyeglasses such as firmoo.com, sports-eyewear.com etc. Just search them in Google.
Regarding to your question, actually, you can buy prescription sports glasses from online optical eyeglasses or you can buy glasses from your local eyeglasses stores. A lot of eyeglasses store or online eyeglasses store sell prescription sports glasses. what you need to do is to choose your style and find out a pair which fits you well.
Sales of glasses online are growing steadÂiÂly. So you can search prescription sports eyeglasses at online shops such as firmoo.com. To get lenses online, ask your doctor for a copy of your eyeglass prescription, plus your pupillary distance number (the distance, measured in millimeters, between the centers of the pupils in each eye).