I don't want to start some crazy rumors, but I think Britney Spears might be experimenting with tinted contacts.  Which is surprising, because she normally lives her life with such a quiet dignity, this kind of showy attention grabber is unlike her.  She might as well have gotten red cats eyes or contacts that look like an 8 ball.  You could put fake contacts on a dog and it would look more natural than this.  The good news, by the end of the week, we'll probably get to see her wearing a big handlebar mustache or maybe dressed like Lincoln.