Orbital Myositis Mimicking Wall-Eyed Bilateral Internuclear Ophthalmoplegia

A 56-year-old woman reported a 2-week history of diplopia associated with mild pain and periorbital edema. On examination, the patient had a large exotropia (A). While vertical eye movements were intact, there was limited adduction of each eye on right (B) and left (C) gaze. These findings were consistent with wall-eyed bilateral internuclear ophthalmoplegia. Postcontrast axial T1 fat-suppressed magnetic resonance imaging (D) revealed bilateral enlargement and enhancement of the medial rectus muscles indicative of orbital myositis. The patient showed prompt improvement with institution of systemic corticosteroids (Magnified version of Figure A-D is available online at www.aaojournal.org).