A 77 year old female patient was admitted to our hospital because of a rapid onset left-sided visual loss. Occlusion of the left central retinal artery was confirmed by the consultant ophthalmologist. The patient was further evaluated to exclude a thromboembolic event. Chest x-ray was consistent with pulmonary hypertension. Doppler echocardiography revealed a secundum atrial septal defect with a bi-directional shunt. In this 77 year old patient, arterio-arterial embolism from atherosclerotic plaques is the most probable cause of her central retinal artery occlusion. Yet, paradoxical embolism might be another reason for acute visual loss in this setting, which, however, is difficult to confirm definitively.