It is obvious that contact lenses are much better than glasses when you play rugby or other sports. Optometrists recommend the use of soft lenses rather than hard lenses. When you are playing a contact sport, you should aviod wearing something that can cut your eyes or face. It is best to use soft, disposable contact lenses. Warm tip: do not touch your eyes with your hands while you are playing rugby because there are many sweat and germs on them. They will casue eye infection.
You'd better not wear the contact lenses when you play rugby because the sweat coming into your eyes may get the eye infection. And the eyes will be knocked by the rugby. If you want to wear the contact lenses for the right vision, you could wear the helmet and wear the contact lenses. Thus it will be safe.
As a matter of fact, there will simply be no negative impacts on your eyes or something by wearing contact lenses while playing sports games. However, you gotta be very careful not to get your eyes crashed. In fact, there are some contact lenses especially designed for sports use. You may have a look at them over the Internet. Of course, they will cost you more.