If the scratches are not deep, you can use the toothpaste and the clean soft cloth to repair it. However, if not, only by removing the thin film on the lenses of the oakley sunglasses which is mainly for the protection from the uv and other strong lights. Then you will have to buy new one and stick on it. It is a little complicated thing. You'd better protect the oakley sunglasses.
Well, as you have got some scratches on the surface of your glass lenses. And typically speaking, you cannot remove them with simple things as water. So, you can only go to some professional glasses stores to ask help from their clerks. Because they have got some special equipment and solutions which is able to eliminate those scratches. But usually it will cost you some money. I suggest that you take good care of your glasses from this moment, for sometimes they are really fragile.