A 37-year-old man with no history of vision problems presented with subacute loss of vision in his right eye for 1 week. The patient described a paracentral scotoma that progressed to involve central fixation over the course of 3 days. Two weeks earlier, the patient and his children had developed malaise, low-grade fever, and a rash. He worked in the armed services and denied foreign travel, tick bites, or recent immunization. The patient had been evaluated by his primary care clinician and was referred to an ophthalmologist for further evaluation.