title: Clinical value of electrophysiology in determining the diagnosis of visual dysfunction in neuro-ophthalmology patients.
abstract: OBJECTIVE
  To assess clinical value of visual electrophysiology in identifying causes of visual dysfunction in patients referred from neuro-ophthalmology clinics.
  
  
  METHODS
  A review of 410 subjects (aged 0.3-88 years) referred for visual electrophysiology from neuro-ophthalmologists between 2009 and 2013 was performed. Subjects were divided into those with unexplained poor vision, visual field defects, visual symptoms or other reasons (e.g. monitoring for drug toxicity or known conditions). Subjects underwent pattern, full-field and multifocal electroretinography (ERG) and pattern visual evoked potential (VEP) tests. Flash and multifocal VEP were included where indicated.
  
  
  RESULTS
  Most subjects referred for poor vision (n = 158) had electrophysiology findings suggestive of retinopathy (37 %) or post-retinal pathology (34 %). Those with poorer vision (worse than 6/24) were more likely to have abnormal recordings (86 vs. 62 %, p = 0.002). Among subjects with unexplained visual field defects (n = 102), findings of retinopathy, post-retinal pathology and normal recordings were noted in 31, 24 and 28 %, respectively. Most subjects with other visual symptoms (n = 97) had normal findings (69 %). The multifocal ERG was most sensitive for detecting retinopathy (96 %) and maculopathy (95 %), while pattern VEP was most sensitive for post-retinal pathology (94 %). An indeterminate result was noted in 9 %.
  
  
  CONCLUSIONS
  Electrophysiology was effective in differentiating between retinopathy, post-retinal pathology and normality in 91 % of subjects. Pre-testing provisional diagnoses of retinopathy and post-retinal pathology were revised in 30 and 42 %, respectively, after electrophysiology. Appreciation of characteristics of each test, correlation with the clinical picture and interpretation of results in totality are required to localize the site of pathology.
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore.|Singapore General Hospital, Singapore, Singapore.
authors.forename: G H
authors.initials: GH
authors.lastname: Yap
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore.
authors.forename: L Y
authors.initials: LY
authors.lastname: Chen
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore.
authors.forename: R
authors.initials: R
authors.lastname: Png
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore.
authors.forename: J L
authors.initials: JL
authors.lastname: Loo
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Tow
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore.
authors.forename: R
authors.initials: R
authors.lastname: Mathur
authors.affiliation: Singapore National Eye Centre, 11 Third Hospital Road, Singapore, 168751, Singapore. wla_chia@yahoo.com.|KK Women's and Children's Hospital, Singapore, Singapore. wla_chia@yahoo.com.
authors.forename: A
authors.initials: A
authors.lastname: Chia
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004594:Electrophysiology; D004596:Electroretinography / Q000379:methods*; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012164:Retinal Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012165:Retinal Ganglion Cells / Q000502:physiology; D012189:Retrospective Studies; D014786:Vision Disorders / Q000175:diagnosis* / Q000503:physiopathology; D014794:Visual Fields / Q000502:physiology
keywords: Diagnostic value; Electroretinography; Neuro-ophthalmology; Neuropathy; Retinopathy; Visual evoked potential