If you can still point out the position of balls without glasses, you'd better take off your glasses while playing squash. As the balls can rebound, it is possible for you to get injured when play it. That's why many players need to wear goggles to protect their eyes.Many athletes do not wear glasses when they play squash. So in order to protect your eyes better, you'd better not wear glasses when playing squash. On the other hand, if you cannot watch things a little bit clear without glasses, I advise you to wear glasses. Anyway, if you cannot see the ball clear, how can you play it? Only keep your safety in mind. By the way, do not wear contact lenses when you are doing sports because of convenience. The reason is simple, you will sweat. And it will affect your eyes, which will lead to inflammation and contact lenses may hurt your cornea when you do sports.