No. The laws of rugby prohibit wearing glasses or goggles because it would be dangerous to yourself and to other players. So you are not allowed to wear sports glasses when playing rugby. But you are allowed to wear contacts when playing rugby if you don't have good vision.
No. There are rules that you mustn't wear glasses or sports glasses in the rugby field. If you are nearsighted, you can wear contact lenses when playing rugby. If you are slightly nearsighted, there is no problem to play rugby without glasses or contacts.
You can't wear sports glasses when playing rugby unless you want shatters of glass in ur eyes. It is so dangerous. I have a team mate in high school who was bloody near blind, but never played with glasses or contacts.