الفهرس 
Anatomy of the OrbitOnly 14 pages are availabe for public view
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Abstract
Thyroid eye disease (TED) is the most common cause of unilateral and bilateral proptosis in adults, accounting for 85% of patients with bilateral proptosis and for 10% to 30% of patients evaluated by an ophthalmologist for unilateral proptosis. TED is the most frequent cause of acquired diplopia unrelated to extraocular muscle palsy in adults. While the majority of patients with TED first present with systemic hyperthyroidism, 5% to 25% of patients present to an ophthalmologist before the diagnosis of systemic disease.1 Patients with Graves’ disease usually develop eye symptoms before or simultaneous with ocular signs of the disease, and clinical studies have reported that 10% to 70% of Graves’ disease patients manifest eye findings at the time of systemic diagnosis.2 Thyroid-associated orbitopathy (TAO) is an autoimmune condition of the orbit which is closely associated with Graves’ hyperthyroidism, although either condition may exist without the other. It may antedate, coincide with or follow hyperthyroidism. Assessment of the frequency of the association depends on the method used for detecting TAO; with sensitive methods subclinical TAO can be demonstrated in 70% of patients with hyperthyroidism. The clinical features of the disorder vary from a mild grittiness of the eyes to severe diplopia, loss of vision and disfiguring proptosis.3 The most obvious pathological change within the orbit is the enlargement of extraocular muscles. Dysthyroid optic neuropathy (DON) is impairment of optic nerve function due to TAO. This potentially blinding complication occurs in up to 25% of patients with TAO. While often obvious at presentation, the diagnosis may be missed in patients without obvious proptosis.