Diplopia, binocular: Double vision (diplopia) that is only evident when looking through both eyes and disappears if one eye is closed or covered. The condition is caused by misalignment of the eyes by the extraocular muscles (the muscles around the eyeball that control gaze). This may be due to strabismus (misalignment of the eyes from birth), neurologic damage to the extraocular muscles (as from a brain abscess, stroke, head trauma or brain tumor), diabetes, myasthenia gravis, Graves disease, or trauma to the eye muscles, as from a fracture of the orbit.