Isoelectric Focusing of Tears in Children With Radiologically Isolated or Clinically Isolated Syndrome

Inclusion Criteria: * age \< 18 years old * informed consent from the child and the parents (at least one of the two legal guardians) * child covered by social security For the RIS population: * asymptomatic child * fortuitous discovery of lesions strongly suggesting sclerosis multiple on a Magnetic resonance imaging (MRI) scan For the CIS population: \- child presenting a CIS in the past three months Exclusion Criteria: * patient with remitting MS * patient with progressive MS * patient with eye infection * patient under immunosuppressive therapy on the day of inclusion due to the treatment of another disease than MS