A 54-year-old man developed constant binocular diagonal diplopia. He was initially diagnosed with a fourth nerve palsy.
The evening before symptom onset, he had gone out with friends for dinner and drinks. When he awoke briefly in the middle of the night, he noted blurred vision but returned to sleep. Upon awakening the next morning, he noted new diplopia with obliquely oriented images and presented to an outside hospital for evaluation. His initial ophthalmology exam was notable for a slight abduction deficit in both eyes as well as a right hypertropia and esotropia worse in left gaze but