Yeah, I know because I have seen many famous players wearing glasses without lenses. I think there are two reasons why they do so. On one hand, they wear the glasses without lenses for style, and you know LeBron James who often wears only wear the frame. Frankly, they really look fashion with the glasses (maybe just called the glasses frame). On the other hand, there are other reasons why they are do like that. As we all know, our eyes can help us collect the light from the items appearing in our eyes. If something blocks the light, then our eyes can not get it. So according to my understanding, the glasses (frame) can help us collect the light we need so that they can figure out the right place of the ball. Hope my idea help you.
You mean they wear`em on the court, or off the court? Anyway, as a matter of fact, they are always trying to be cool , to be a little of low-profile. Sunglasses will not only make them look more mysterious,but also more difficult to be identified by the general public, especially their fans. Because famous people, celebrities, including NBA stars, are pursuing privacy. They don't wanna be harassed by paparazzi and anyone else. Thus, sunglasses became their best pals to stay away from those annoying things. And they look really cool with sunglasses!
We often see many stars tend to wear the eyeglasses without the lenses. First of all, they are not short sighted. Thus, there is no need for them to wear the prescription lenses. Secondly, such making up will let them look cool and fashionable. The eyeglasses are just the accessory.