Review Question - QID 212619

A 58-year-old woman is brought to the emergency room by her husband complaining, “I can’t see out of my right eye.” She was watching television last night when she covered her left eye due to an itch and discovered that she could not see. The patient denies any precipitating event, pain, swelling, flashes, floaters, or headaches. Her past medical history is significant for uncontrolled hypertension and angina. Her medications include hydrochlorothiazide, lisinopril, atorvastatin, and nitroglycerin as needed. Her physical examination is unremarkable. Fundus examination demonstrates generalized pallor and slight disc edema with no hemorrhages. What is the most likely explanation for this patient’s symptoms?