The purpose of this study is to determine whether radioactive iodine, as compared to anti-thyroid medications, is a risk factor for the development or progression of thyroid-associated ophthalmopathy in patients with hyperthyroidism due to Graves' disease. The other aim of this study is to determine the incidence of the various ophthalmopathy subtypes and the utility of orbital antibodies in the diagnosis, classification and monitoring of patients with thyroid-associated ophthalmopathy.