I would also suggest the arterial biopsy at the temple to rule out a cousin of PMR, Giant Cell Arteritis. Both can cause sudden blindness if the inflammation threatens the optic nerve. Steroids are a part of the ongoing treatment for both diseases. If you are near a teaching hospital or have an ophthalmologist you trust, go with your wife and let her give her history to them as soon as possible.
Although it is rare, I have a friend with PMR, and two with GCA. All of them have doctors monitoring them closely. One lost the sight in one eye in the early stages of being diagnosed with GCA. Good luck to you both, and I am glad for your tenacity in getting help.