Clinical Manifestations of Thyroid-Associated Orbitopathy

Thyroid-associated orbitopathy (TAO), otherwise known as Graves ophthalmopathy (GO) or thyroid eye disease (TED) is an autoimmune mediated disease. It typically affects middle-aged females. It has been described as having a biphasic curve characterized by inflammation, stabilization, and regression. Clinical features include signs of inflammation, lid retraction, lid lag, proptosis and extraocular motility problems. TAO is typically seen in the context of Graves’ hyperthyroidism but may also occur in euthyroid and hypothyroid patients as well. Diagnosis is clinically based but may also be aided by laboratory studies and imaging of the orbit. Imaging may show two broad groups; one in which muscle enlargement predominates and a second group with marked orbital fat enlargement. Disease activity refers to the presence of inflammatory features more prominent in the early stages of the condition whilst severity describes the disease burden on the patient. It is essential to control disease activity to avoid long-term sequelae such as strabismus. Different evaluation protocols have been described to guide when intervention is indicated such as the clinical activity scale. Disease severity ranges from mild, which is amenable to conservative measures whilst severe disease needs prompt medical and or surgical intervention. Severe sequelae include severe exposure keratopathy and dysthyroid optic neuropathy which manifests with visual disturbance and a range of clinical signs.