The ER checked my thyroid yesterday and it was okay. The double vision is only in my left eye, it goes away when I cover it and look out my right eye.
They likely only checked your thyroid hormone levels (or maybe just the TSH). The thyroid receptor antibody test would take a few days to come back and I doubt they checked that. You CAN have thyroid eye disease with normal thyroid hormone levels.
Still - if you only have double vision in the left eye (meaning if you close the right eye and JUST look out the left, the double vision is still there) then the problem is likely IN the eye. I'm assuming they checked your eye pressures and there is no glaucoma?
