@kjoed53 Yes PMR is not confirmable with any test, it is a default Dx. Thus, everything else that it could be needs to be eliminated first. A tentative Dx of PMR is what everyone has initially - nothing new.
A new ophthalmologist is just as concerned as your previous ophthalmologist was with the possibility of you going blind. Please give them a call and let them make the decision. You may feel fine right now but this is a real threat and best to get it behind you than in front. Simply tell them you are being treated for PMR and are now getting severe headaches. That is the truth, let a trained professional make the call.