Retinal Neuro-vascular Coupling in Patients With Multiple Sclerosis

Inclusion criteria for healthy subjects: * Men and women aged over 18 years * Non-smokers * Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant * Normal ophthalmic findings, ametropy \< 6 Dpt. Inclusion criteria for patients with MS: * Men and women aged over 18 years * Diagnosis of relapsing-remitting multiple sclerosis (RRMS) according to clinical evaluation and McDonald criteria (revision 2010) * History of AON in one eye at least one year ago * Non-smokers * Normal ophthalmic findings, ametropy \< 6 Dpt. * Adequate visual acuity to allow participation in the ocular blood flow measurements * A potential participant has to be on stable doses of all medications he/she is taking because of consisting illnesses according to medical history (except MS therapy itself which will be recorded separately) for at least 30 days prior inclusion, if considered relevant by the investigator. Any of the following will exclude a healthy subject from the study: * Diagnosis of "possible MS" according to the McDonald criteria (revision 2010) * Presence or history of a severe medical condition as judged by the clinical investigator * Untreated Arterial hypertension * History or family history of epilepsy * Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator * Family history of MS, optic neuritis, neuromyelitis optica (NMO, Devic disease) or NMO spectrum disorders * History of inflammatory or infectious disease of central nervous system * Best corrected visual acuity \< 0.5 Snellen * Ametropy ≥ 6Dpt * Pregnancy or planned pregnancy * Alcoholism or substance abuse Any of the following will exclude a patient from the study: * Presence or history of a severe medical condition other than MS as judged by the clinical investigator * History of neuromyelitis optica (NMO, Devic disease) or NMO spectrum disorders * History of inflammatory or infectious disease of central nervous system other than MS * Untreated Arterial hypertension * History or family history of epilepsy * Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator * Best corrected visual acuity \< 0.5 Snellen * Ametropy ≥ 6 Dpt * Pregnancy, planned pregnancy * Significant neurological disease other than MS, if considered relevant by the investigator * Alcoholism or substance abuse