IGF1 and Graves ophthalmopathy: Graves’ ophthalmopathy (GO) is a complication of Graves’ disease (GD), in which orbital connective tissues become inflamed and increase in volume and orbital fibroblasts within the orbital fat and extraocular muscles differentiate into adipocytes in vitro when stimulated by hormones, several cytokines, and growth factors including TSH, IGF-1, IL-1, interferon γ, and platelet-derived growth factor.