title: Pattern visual evoked potentials in the early diagnosis of optic neuropathy in the course of Graves' ophthalmopathy.
abstract: OBJECTIVE
  To investigate by means of pattern visual evoked potentials (PVEPs) early neuropathic changes in Graves' ophthalmopathy (GO) patients without any clinical symptoms of optic neuropathy in order to evaluate the prevalence of subclinical optic neuropathy in GO patients and to elucidate whether there is a relationship between PVEP (P100 and N75 latency), intraocular pressure (IOP) and exophthalmometry.
  
  
  METHODS
  Two groups of patients were examined: 15 patients with GO without clinical signs of dysthyroid optic neuropathy (DON) and 12 healthy controls. The correlations between the N75 and P100 latencies, IOP and Hertel exophthalmometry were investigated.
  
  
  RESULTS
  The mean PVEP N75 and P100 latencies were significantly delayed in the GO uncomplicated with DON in comparison with controls (LP100- 106.2 +/- 4.4 ms vs. 102.4 +/- 2.7 ms, p < 0.01 and LN75- 79.0 +/- 3.7 ms vs. 73.9 +/- 2.8 ms, p < 0.001). In GO patients we documented a positive correlation between the LN75 latency and exophthalmometric readings (R = 0.51; p < 0.01). The value of LP100 and LN75 was above the normal limit in 5/30 eyes (17%) and in 3/30 eyes (10%) respectively.
  
  
  CONCLUSIONS
  The assessment of PVEPs (especially the P100 latency) in GO patients without clinical signs of DON is a useful tool for the early diagnosis of optic nerve involvement.
authors.affiliation: Department of Paediatric Ophthalmology, Medical University of Białystok.
authors.forename: Przemysław
authors.initials: P
authors.lastname: Pawłowski
authors.forename: Janusz
authors.initials: J
authors.lastname: Myśliwiec
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Mrugacz
authors.forename: Alina
authors.initials: A
authors.lastname: Bakunowicz-Łazarczyk
authors.forename: Maria
authors.initials: M
authors.lastname: Górska
mesh_terms: D000328:Adult; D042241:Early Diagnosis; D005074:Evoked Potentials, Visual; D005260:Female; D049970:Graves Ophthalmopathy / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000209:etiology; D014786:Vision Disorders / Q000175:diagnosis / Q000209:etiology; D058609:Visual Field Tests / Q000379:methods; D014794:Visual Fields