Orbital myositis secondary to statin therapy

A 45-year-old man presented with a 3-month history of diplopia and pain on left downgaze, increasing left upper lid oedema, and erythema. Eye movements were full and visual acuity and intraocular pressure normal. His regular medications, both commenced 4 months before presentation, were simvastatin (20 mg/day) and aspirin (100 mg/day). A complete blood count, thyroid function and auto-antibodies, inflammatory markers and creatine kinase were all unremarkable, as was an autoimmune screen. Orbital computed tomography showed left medial rectus and superior oblique enlargement.