Anisometropia okay, which is an uneven prescription. So one eye might see perfectly and the other eye might see not so good but the eyes work together in the way that they see things. So if one eye is in focus and the other eye is not in focus it creates a discrepancy in the brain and either the brain tells the eye that is not seeing to shut down and ignore it, which then will become amblyopic or you get a really big headache and we see a lot of strenuous headaches and people that have anisometropia. You can help people with glasses with an uneven prescription the problem that we have with glasses is the further away you put your refractive surface from the eye it changes the image that is seen and what I mean by that is if you think about Sherlock Holmes and his magnifying glass is that he uses his magnifying glass to to find clues or to magnify things. Well if one eye has a magnifying glass on it which is your prescription and the other eye does not have a magnifying glass then one eye sees things that are really big and the other eye sees things that are normal size. And when you have that size discrepancy you can get a really bad headache. Contact lenses can sit right on top of the eye now when you deal with magnification because the contact lense sits right up against the eye the refractive surface is up against the eye and whether the prescriptions a -10 or a plus 20 because it sits on the eye and the distance that the light has to travel to hit the eye is 0 because it's sitting on the eye. Thus the magnification or minification is 0 so you have zero size discrimination when you wear contact lenses in a case of a patient that has anisometropia.