Orbital Myositis

Orbital myositis (OM) is a rare syndrome, but it represents the second cause of extraocular muscle compromise, after thyroid orbitopathy. It is usually idiopathic and a diagnosis of exclusion, but it can also be associated with autoimmune or infectious diseases, paraneoplastic phenomena, or medications. Clinically, it is characterized by the triad of unilateral eye pain exacerbated by movement, diplopia, and conjunctival hyperemia. Imaging, with CT-scan or magnetic resonance, is useful for the diagnosis. An early diagnosis allows a good response to corticosteroids that represent the treatment of choice.