A 62-year-old male with history of hypertension presented to our emergency department with new onset diplopia. He denied recent trauma. The patient had binocular double vision with abducens nerve palsy. There were no other complaints. We review the  relevant anatomy, multiple etiologies, necessary diagnostic  testing, and treatment of diplopia. Careful physical examination and detail to the patient’s past history is essential for making an accurate diagnosis. Since sudden onset of this entity may represent a serious condition requiring urgent attention, emergency physicians should be familiar with this dysfunction. Most importantly, visual disturbances may be the initial manifestation
of occult disease - tumors, multiple sclerosis, vascular disease, myasthenia gravis, or Miller-Fisher syndrome.