Insights From the Retina on Cerebral Microvascular Dysfunction in Haemorrhagic Stroke

Inclusion Criteria: * All groups * Primary ICH or aSAH with symptoms onset \< 3 days * 18 to unlimited years of age * Signed informed consent obtained from legal representative or patient ICH group * Primary ICH localized either in basal ganglia, thalamus, pons or cerebellum aSAH group * Ruptured aneurysm visualized in contrast-enhanced computed tomography (angio-CT), MRI or cerebral angiography Control group * Stroke due to perimesencepahlic subarachnoid hemorrhage, arteriovenous malformation or isolated traumatic brain injury Exclusion Criteria: * All groups * Cerebral amyloid angiopathy or other neurodegenerative disease * History of migraine with aura or ischemic stroke * Contraindication for pupil dilation (intracranial hypertension, allergy against mydriatics, angle closure glaucoma) * Any pre-existing or manifest ocular condition affecting either the integrity of retinal vessels, transparency of optical media or the risk of acute angle closure glaucoma * Concomitant instable critical illness (e.g. sepsis, multi-organ failure) * Intracranial pressure \> 20mmHg and refractory to cerebrospinal fluid drainage * Pregnancy