Recently my brother had an incident of chest pain and breathlessness. His blood pressure was extremely high. A very large black spot, somewhat opaque around the edges against a bright light, blocked most of his field of vision in both eyes. He has a history of heart attack and mild subarachnoid hemorrhage. Since the incident, he's had a battery of cardio tests done and nothing has changed in that area. Is this possibly a symptom of a neurological problem? And if so, what?