Eye camera spots hidden inflammation in MS patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Group 1: * Age between 18 and 60 years old. * Relapsing remitting MS (criteria of McDonald 2017) * Less than 10 years of disease duration * Subject who has never presented a clinical episode of optic neuritis * Affiliation to a social security scheme or beneficiary of such a scheme Group 2: * Age between 18 and 60 years old * Relapsing remitting MS (criteria of McDonald 2017) * Less than 10 years of disease duration * Subject presenting an acute episode of retrobulbar optic neuritis within 3 months from onset * After optimal treatment for the retrobulbar optic neuritis * Affiliation to a social security scheme or beneficiary of such a scheme Group 3: * Age between 18 and 60 years old * Primary or Secondary progressive multiple sclerosis within 10 years of progressive phase; * Affiliation to a social security scheme or beneficiary of such a scheme Group 4 (Healthy Subjects): * Age between 18 and 60 years old * Affiliation to a social security scheme or beneficiary of such a scheme Exclusion Criteria: For all patients (Group 1; 2; 3): * Corticosteroid treatment within one month from inclusion * Other neurological, ophthalmologic or systemic disease; * Severe symptoms of uncontrolled chronic disease (renal, hepatic, hematologic, gastro-intestinal, pulmonary or cardiac or any intercurrent uncontrolled disease at inclusion) * Severe renal dysfunction (glomerular filtration rate \< 30mL/min). This non-inclusion criteria will be verified by serum creatinine test within six months from inclusion; * Contraindication for MRI; * Pregnancy or breast-feeding; * Unwillingness to be informed in case of abnormal MRI (with a significant medical anomaly) * Incapacity to understand or sign the consent form; * Adults legally protected (under judicial protection, guardianship, or supervision), persons deprived of their liberty. For healthy subjects (Group 4): * Neurological, ophthalmologic or systemic disease; * Severe symptoms of uncontrolled chronic disease (renal, hepatic, hematologic, gastro-intestinal, pulmonary or cardiac or any intercurrent uncontrolled disease at inclusion); * Contraindication for MRI; * Pregnancy or breast-feeding; * Unwillingness to be informed in case of abnormal MRI (with a significant medical anomaly) * Incapacity to understand or sign the consent form; * Adults legally protected (under judicial protection, guardianship, or supervision), persons deprived of their liberty.