Abstract
A very large number of disorders affect the orbit, and many of these occur in the setting of systemic disease. This lecture covers selected aspects of orbital diseases with systemic associations in which the author has a particular clinical or research interest. Spontaneous orbital haemorrhage often occurs in the presence of bleeding diatheses. Thrombosis of orbital veins and ischaemic necrosis of orbital and ocular adnexal tissues occur with thrombophilic disorders, vasculitis, and certain bacterial and fungal infections. Non-infectious orbital inflammation commonly occurs with specific inflammatory diseases, including Graves' disease, IgG4-related disease, sarcoidosis, Sjögren's syndrome and granulomatosis with polyangiitis, all of which have systemic manifestations. IgG4-related ophthalmic disease is commoner than all these except Graves' orbitopathy. Some of these orbital inflammatory diseases are associated with an increased risk of B-cell lymphoma, usually marginal zone lymphoma of MALT type. Ocular adnexal lymphoma also has an association with infectious agents including Helicobacter pylori and Chlamydia psittaci. Orbital metastasis may be the first presentation of systemic malignancy. A number of orbital neoplasms occur in the setting of familial cancer syndromes, including Neurofibromatosis types 1 and 2. Study of the genetics and molecular biology of orbital diseases such as Graves' orbitopathy and idiopathic orbital inflammatory disease will yield useful information on their diagnosis and management.