Identical Twins

Well, one of my twin grandsons has had to wear glasses all of the time for about 3 years now. So when you looked at them from any distance you could always tell one from the other. They are actually mirror image twins. Meaning one is right handed and one is left handed. So it is like they are looking in the mirror at each other. So, now the other twin just had to get glasses that he will need to wear all of the time too. Now, what will we do to tell one from the other. My daughter has already called one of them by the other twins name. I tell you the truth I am too old for challenges like this.