MS vision loss mystery: is it scarring or cell death?

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

Inclusion Criteria: * Inclusion criteria for patients * All patients may have a clinically definite, laboratory-supported diagnosis of multiple sclerosis according to the Mac Donald criteria (2010). * All patients may present a chronic visual complaint. * All patients may present mild to moderate chronic optic neuropathy (cf infra) * All patients may not have recent acute optic neuritis (\<2 years) * All patients will be informed about the design and purpose of the study, and all will give their informed, written consent to the protocol, which may have been approved by the local ethics committee. * Age: \> 18 * Able to understand the instructions * Having a health coverage * Able to sit down for 1 hour Diagnosis of mild to moderate chronic optic neuropathy For the diagnosis of optic neuropathy, patients will have to meet 3 of the 6 next criteria: 1. Far Visual Acuity (ETDRS charts, 100% contrast) \< 85 letters 2. Far Visual Acuity (ETDRS charts, 2.5% contrast) \< 60 letters 3. Mean visual field defect on static perimetry\> 2dB 4. Mean pRNFL in OCT \< 80 µ. 5. Color vision score \> 35 6. Disc pallor Diagnosis of mild to moderate optic neuropathy * Far Visual Acuity (ETDRS charts, 100% contrast) \>70 letters Diagnosis of chronic optic neuropathy * Stable or worsening of visual acuity, visual field and/or RNFL in OCT, at 6 month of interval \- Inclusion criteria for controls * Age \> 18 years * Visual acuity score (ETDRS) \> 85 * Able to understand the instructions * Having a health coverage * Informed and consenting to give his written consent Exclusion Criteria: * Non inclusion criteria for patients. * Ophthalmological * Other ophthalmological disorder that could impair corrected visual acuity (Maculopathy, Retinopathy…) * Ocular instability in primary position of gaze * Neurological * Ongoing seizure * Severe handicap that does not allow sitting down position for 1 hour * General * Unstable medical state * Severe renal insufficiency * Allergy to gadolinium * Claustrophobia * Implanted electrical stimulator (pace maker) * Metallic prosthesis or orthesis, cochlear implants * Intraocular foreign material * Pregnancy (on questioning) * Tutelage or any legal protection measure * Non inclusion criteria for controls * Any ophthalmological disorder that could impair corrected visual acuity * Any neurological disorder * MRI contraindication * Allergy to gadolinium * Severe renal insufficiency * Claustrophobia * Implanted electrical stimulator (pace maker) * Metallic prosthesis or orthesis, cochlear implants * Intraocular foreign material * Pregnancy (on questioning) * Tutelage or any legal protection measure