Patient A.R. was born in 1984 referred to the clinic with complaints about a sharp decrease vision of right eye. From history: noticed a sharp deterioration of vision in right eye, pain when moving eyeballs, complaints of headaches, general weakness. The patient was hospitalized with the diagnosis of «OD-optic neuritis». The patient had - ophthalmic, laboratory, instrumental and special methods of investigation.Visual acuity OD-0.03, IOP-18 mm Hg, perimetry - concentric narrowing, decreased color vision. Ophthalmoscopy: OD - the optic disc pale colors, borders indistinct, veins of normal caliber, macular reflex smoothed. OCT - in the macular area the retinal thickness decreased (thinning), relief fovea saved. Marked thinning of the ONH and RNFL peripapillary zone in all segments.VEP latency - 146 ms (n = 102 ms), the amplitude - 4.26 mcV (n =8.4 mcV). Magnetic resonance tractography: thinning of the fibers in the projection of the occipital forceps connection with the visual radiance. Magnetic resonance imaging of the brain and cervical spine revealed white demyelinating foci. Blood was tested for antibodies to Aquaporin-4. The result was positive. After treatment an increase of visual functions in the right eye: OD-0.08, perimetry - concentric narrowing, ophthalmoscopy: OD - the optic disc pale, indistinct borders, macular reflex is absent.But after 3 months, the patient developed optical neuritis in the left eye. Acute myelitis also developed. Thus, Devik's neuromyelitis is a rapidly progressing disease with damage to the optic nerve and spinal cord, and with an unfavorable outcome of the disease.