You are correct. Branch retinal artery occlusion presents as painless vision loss w/ retinal pallor along the distribution of the affected artery. Cause is usually embolic. Medical investigation in this pt included an echocardiogram, which revealed a patent foramen ovale. PFO is a recognized cause of a right-to-left shunt, which is a risk factor for an ischemic event secondary to a paradoxical embolus.