devic s disease , also known as neuromyelinitis optica ( nmo ) , is a severe , rare demyelinating disorder , previously considered to be a form of multiple sclerosis ( ms ) . the aim of this study was to present the case report of 21-year - old woman with a very early diagnosis of devic s disease , established following electrophysiological testing . a 21-year - old woman was referred to warsaw medical university , department of ophthalmology , with subjective visual impairment . the patient underwent a full clinical examination , colour vision and goldmann visual field testing , fluorescein angiography , oct , multifocal erg , and visual evoked potentials ( veps ) . visual evoked potentials are a very useful diagnostic tool in optic nerve neuropathies . in our patient , the electrophysiological testing allowed us to establish a proper diagnosis very early , before typical clinical signs of devic s disease . devic s disease , or neuromyelitis optica ( nmo ) , is an uncommon demyelinating syndrome of the central nervous system , characterized by bilateral optic neuritis and transverse acute myelitis , with no other neurological involvement . the first description of the disease was provided by eugene devic at the end of the 19 century in lyon , france . nmo was previously considered to be a subtype of multiple sclerosis . most nmo patients produce auto - antibodies against aquaporin-4 ( aqp-4 ) , also known as nmo - igg . aqp-4 is a water channel expressed on astrocytes and in brain blood vessels [ 46 ] . in 2006 , wingerchuk proposed revised diagnostic criteria for nmo : 2 major criteria optic neuritis and transverse myelitis , and at least 2 of 3 supportive criteria  mri lesions extending over 3 vertebral segments , onset brain mri not meeting diagnostic criteria for multiple sclerosis , and nmo - igg seropositive status . devic s disease most frequently affects non - caucasian women who are older than those with multiple sclerosis . in comparison to ms , devic s disease also leads to more severe neurological impairment [ 1,810 ] . a 21-year - old woman presented with non - specific ocular phenomena , referred as a subjective visual impairment and  blurry  vision for 3 weeks . no other complaints were reported , and the family history concerning general and ocular diseases was negative . the patient had previously been examined in 2 other ophthalmic departments and no abnormalities were found , so the patient was classified as having psychosomatic disturbances and a psychological consultation was recommended . the patient s best corrected visual acuity was 6/6 in both eyes on snellen charts . examinations of pupillary reflexes , anterior segment , the eye fundus and the visual field ( full field 120 , humphrey ) were normal . a fluorescein angiography and macular oct ( cirrus , zeiss ) these symptoms were still unclear , so the patient underwent electrophysiological testing by using the retiscan retiport system ( roland consult ) . pattern visual evoked responses ( pver ) were performed according to iscev standards and compared with normal values . the latencies of p100 wave was 132 ms and 127 ms in right and left eye , respectively , so they were prolonged over 20% in both eyes in comparison to normal values . the brain mri with contrast revealed 3 lesions not meeting diagnostic criteria for multiple sclerosis . the patient was referred to the neurology ward and a suspicion of devic s disease was established . within 6 weeks after first symptoms ( three weeks after ophthalmic examination ) the patient presented a weakening of the lower limbs and developed clinical transverse myelitis . the diagnosis of devic s syndrome was established , which was later confirmed by nmo - igg seropositive status . in 4 years observation , the visual function remains quite good ( 6/9 in both eyes ) , but urinary incontinence and walking disorders significantly worsen the 25-year - old patient s quality of life . it was reported that 55.8% of nmo patients need support to walk within 5 years from diagnosis , mortality rate ranges from 2.9% to 25% , and about 50% of patients have severe visual deficits within 5 years from diagnosis [ 1,811 ] . although it is very rare disease , its early diagnosis may allow administering proper treatment ( iv steroids , plasmapheresis , imuran , rituximab ) , thus preventing mortality . our paper presents a case report of very early nmo diagnosis . in our patient , non - specific ocular phenomena preceded the neurological manifestations . although the ophthalmologic examination and tests were normal , visual evoked potentials pointed to a demyelinating process . further diagnostic procedures ( brain and spinal cord mri , neurological consultation ) allowed establishing a proper diagnosis . we would like to emphasize that non - specific ocular symptoms or subjective visual impairment in young patients in their 20s or 30s , with full visual acuity , normal ophthalmic and accessory investigation results , should be examined by visual evoked potentials testing to exclude demyelination . in these cases , it is essential to exclude a neuromyelitis optica , a disease with a worse prognosis than multiple sclerosis .
summarybackgrounddevic s disease , also known as neuromyelinitis optica ( nmo ) , is a severe , rare demyelinating disorder , previously considered to be a form of multiple sclerosis ( ms ) . 
 the aim of this study was to present the case report of 21-year - old woman with a very early diagnosis of devic s disease , established following electrophysiological testing.case reporta 21-year - old woman was referred to warsaw medical university , department of ophthalmology , with subjective visual impairment . 
 the patient underwent a full clinical examination , colour vision and goldmann visual field testing , fluorescein angiography , oct , multifocal erg , and visual evoked potentials ( veps).conclusionsvisual evoked potentials are a very useful diagnostic tool in optic nerve neuropathies . in our patient , 
 the electrophysiological testing allowed us to establish a proper diagnosis very early , before typical clinical signs of devic s disease .