Thyroid Eye Disease (TED) is an auto immune diease caused by the activation of orbital fibroblasts by autoantibodies directed against thyroid receptors. It is an eye disorder that causes inflammation and damage to the tissue around the eye. In some individuals, the inflammation may involve the eye muscles, causing the eyes to become out of line, leading to double vision. In rare cases, TED can cause blindness from pressure on the nerve in the back of the eye or ulcers that form on the front of the eye (cornea). TED is primarily associated with an over-active thyroid gland due to Graves’ disease, although it can rarely occur in patients with an under-active or normally functioning thyroid gland. About a quarter of patients with Graves’ disease develop TED before, during or after the diagnosis of a thyroid disorder.