Those are the athena sunglasses by Oliver Peoples. I have them in white Love them! Hers are a pretty color Hilary Duff had a pair of green ones that are nice, too.
Eeek, that's not the best model for those sunglasses. I promise, they look much better than that in person! I think it's because the model has her hair tied back. These glasses look better if your hair is down and loose, in my opinion