I gained whatever info I have on the affected muscle (inferior rectus) from the neuro-opthalmologist, who had a CAT-scan done in July 1995. There are five muscles that control the movements of the eye and that is the muscle that was attacked by the thyroid eye disease, in my right eye. The first occurrence of it was about 7 months AFTER the onset of thyroid storm and RAI treatment, at which point I was hypo-thyroid. I was driving at night (Jan.1995) and the highway signs were moving everywhere and nothing I did could make a difference. For a few weeks it would come and go, until March when it was constant and I had it checked out. The first prisms were press on but I only used them for driving long distance. I was told NOT to use them unless I needed them, so I would cock my head to the right and most things would merge together. Since the surgery, I no longer have primary gaze, but downward gaze ddvv, like you have. So I am really interested in knowing that your prisms are helping. Thats encouraging! If you knew the muscle affected,I’d like to know. I hope the doctors at Duke U. are able to help. I see them Thursday!