A 58-year-old man with a history of hypertensive retinopathy presented with acute-onset, painless vision loss in his right eye accompanied by tinnitus and severe intermittent headaches. His extraocular movements were full, and he had no other neurologic deficits. His visual acuity was 20/400 OD and 20/30 OS, respectively, and his fundi were notable for bilateral optic nerve edema. Results of recent computed tomography and angiography of the head and neck and magnetic resonance imaging of the brain and orbits were reportedly normal, and lumbar puncture revealed an opening pressure of 26 cm H2O (normal range, 6 to 25 cm H2O) with elevated protein. The patient was given acetazolamide and referred to neuro-ophthalmology.