Optical Coherence Tomography Angiography in Neurological Disease

Inclusion Criteria: * Age 18 years or older * Patient admitted to the neuroscience intensive care unit with a diagnosis of: subarachnoid hemorrhage, intracerebral hemorrhage, intracranial aneurysm (ruptured or unruptured), intracranial vascular malformation, ischemic stroke, seizure disorder, intracranial infection, intracranial tumor(s), inflammatory demyelinating disease, traumatic brain injury and/or neuromuscular respiratory failure OR subjects from the community without major neurologic, cardiovascular, pulmonary or metabolic disease Exclusion Criteria: * Pregnancy * Non-English speaking * GCS motor score less than 6 (i.e. must be able to follow commands) * Temporary or permanent physical limitation that renders the patient unable to sit up and look inside OCTA device