Heavy duty.

A 54-year-old woman with myopia, hypothyroidism, and asthma presented with intermittent double vision. Serum was positive for anti-low density lipoprotein receptor-related protein 4 (LRP4) antibodies suggesting the diagnosis of myasthenia gravis. There was no improvement with pyridostigmine, prednisone, or azathioprine. Over time her double vision became constant, and she was noted to have mild limitation of abduction in both eyes with an esotropia, left hypotropia, and excyclotorsion. Magnetic resonance imaging showed nasal displacement of the superior rectus and inferior rectus muscles, inferior displacement of the lateral rectus muscles and superotemporal globe prolapse consistent with heavy eye syndrome (HES). The differential diagnosis, clinical and radiological manifestations of HES are discussed.