Optic neuritis (ON) can remain isolated or reveal a widespread and chronic disease of the central nervous system (CNS), a multiple sclerosis (MS) or, more rarely, a Devic's neuromyelitis optica (NMO) or a systemic disease.

The optical coherence tomography (OCT) is a retinal imaging technique to measure the thickness of the retina and its different layers with an accuracy of 4-6 µM.

Costello et al have shown that approximately 75% of 54 MS patients have developed within 3 to 6 months after a ON a loss of 10 to 40 µM in the thickness of the peripapillary retinal nerve fiber layer (RNFL).

The etiologic diagnosis of ON has been transformed in recent years. MS can now be diagnosed by McDonald's MRI criteria and NMO by the AQP4 antibodies (anti-aquaporin- 4) antibodies and the anti-MOG (myelin-oligodendrocyte glycoprotein) antibodies.

The diagnosis and prognosis value of the OCT in patients with ON is not well known

Inclusion Criteria:

• first onset of an optical neuritis lasting for less than 3 months

Exclusion Criteria:

• Contra-indication to MRI
• Patient opposed to participation in the study
• Pregnant or lactating woman
• Patient under a measure of legal protection
• Absence of affiliation to social security or universal health coverage (CMU)

Patients seen at the Adolphe de Rothschild ophthalmological foundation for the first onset of an optical neuritis