A 17-year-old man was evaluated in the emergency department with a 1-day history of binocular oblique diplopia present only at distance. He denied head trauma, as well as blurry vision, ocular pain, numbness, weakness, paresthesias, dysphagia, or difficulty breathing. He had no recent illness, denied drug, or alcohol use and had no history of strabismus. He did report right-sided ptosis, presumably due to traumatic levator dehiscence from participating in multiple contact sports. The ptosis developed 18 months previously and was surgically repaired 6 months before the onset of diplopia. His medical history included inflammatory acne for which he was taking benzaclin 5% gel daily, minocycline 100 mg twice daily, sulfacetamide sodium-sulfur 1...