Terson Syndrome

A 54-year-old woman with untreated hypertension presents with the worst headache of her life, followed by loss of consciousness and neck stiffness. Non-contrast CT head shows diffuse subarachnoid hemorrhage in the basal cisterns. Two days after endovascular coil embolization of a 7 mm anterior communicating artery aneurysm, she develops bilateral blurred vision with floaters. Dilated funduscopy of the right eye reveals the structure marked **A** in the diagram—a large boat-shaped preretinal hemorrhage covering the posterior pole with overlying vitreous hemorrhage partially obscuring the optic disc. The left eye shows a smaller intraretinal hemorrhage. What is the most likely diagnosis, and what is the underlying pathophysiological mechanism responsible for the hemorrhage marked **A**?