A 39-year-old Haitian woman at 26 weeks’ gestation with a medical history of pregestational diabetes, obesity and preeclampsia presented to the emergency department because of sudden vision loss in the left eye.She reported approximately 6 months of nearly daily predominantly left-sided throbbing headaches that began during pregnancy and were atypical for her baseline headaches, which typically improved with acetaminophen. In the 5 days preceding presentation, she also noted intermittent blurry vision in the left eye, often occurring concurrently with the headaches. On the day of