Idiopathic inferior rectus myositis: A rare cause of diplopia and a therapeutic success

Orbital myositis is a rare inflammatory condition of a single or multiple extraocular muscles. It usually presents with unilateral or sequential bilateral sub-acute eye swelling, orbital pain, restricted eye movement, and redness of the eyelid. The swelling of extraocular muscles may lead to limited range of motion that produces blurred vision or diplopia. In this article, we report a male patient with idiopathic inferior rectus myositis presenting with diplopia who was managed successfully by medical and surgical intervention. Acute onset of diplopia with eye pain or limited extraocular movement is an ophthalmic emergency requiring urgent assessment and diagnostic imaging studies such as CT or MRI. The present case shows the crucial role of surgery as an adjunctive modality to achieve an improved clinical picture in patients not responding to immunosuppressive therapy. The secret to the success of management includes regular follow-up with frequent examination and comprehensive radiological and tissue investigations.