I'm assuming you mean glasses prescribed by the examiner correct? I have terrible vision. When I played ball for my freshman basketball team, I only used contacts as my glasses would keep falling off, especially whenever I drove, etc. When I get hit hard, my glasses would always fall off. It would be good though, because half the time I would get 'fouled.'
The only problem is if you tend to sweat a lot, it does fog it up. I recommend if you get prescription glasses, make SURE to try it, AND MAKE SURE. I MEAN MAKE sure to see if it feels comfortable after ten minutes. I mean it. If you have to wait there for 3-4 hours trying different glasses, then do it!
The reasoning behind it is that occasionally in some glasses, the area where the frame is placed to fit snugly on your nose doesn't feel comfortable, and if its too high up, or the elevation is too low the lenses may fog up especially if you work or sweat a lot. This was extremely uncomfortable, and eventually I had to buy new ones or get my other ones replaced. Also whenever I would serve, and I would go back and forth sweating the area around my lenses kept fogging and it was so irritating.
I don't recommend playing with prescription glasses. Either get contacts, Lasik, or find another sport that doesn't require physical activity. If you look at my glasses that I used to have, its so dirty, but it really isn't. All the thin scratches are due to charges, and other fouls I've taken in my freshman year.
By the way my vision is -8. If its past -10, you are technically legally blind.