Archives: Confirming what I was taught by a great “old school” neuroophthalmologist, Dr. Barest, there is no need to do MRI’s on typical, isolated cranial nerve palsies (3rd, 4th and 6th). MRI’s were negative for 93 consecutive patients except one, and even in that one case there was nothing treatable. If doctors adhered to this principle in general, a lot of money can be saved. It just means doctors have to use their wits a little more.