title: Pattern electroretinography and visual evoked potentials in optic nerve diseases.
abstract: BACKGROUND
  To evaluate transient pattern electroretinography (PERG) and pattern visual evoked potential (VEP) for the diagnosis, differential diagnosis and follow-up of optic nerve diseases.
  
  
  METHODS
  Twenty-nine consecutive patients (14 female, 15 male) with the diagnosis of ischaemic optic neuropathy (n=14) and optic neuritis (n=15) were included in this study. Mean age of the patients with ischaemic optic neuropathy was 63.3+/-3.3 (60-78) years and the mean age of the patients with optic neuritis was 28.3+/-8.4 (19-43) years. In each patient ophthalmological examination and systemic evaluation were done and VEP and PERG were recorded. As a control group, VEP recordings of 35 healthy subjects were included.
  
  
  RESULTS
  In the ischaemic optic neuropathy group (group 1), mean VEP amplitude (+/-SD) (1.96+/-0.95 microV) was found to be decreased significantly in the affected eyes in comparison to the control group and the unaffected eyes. The delay in latency (116.3+/-20.14 msec in the affected eyes compared with 101.31+/-6.19 msec in unaffected eyes) was statistically significant when compared with the healthy subjects. In the optic neuritis group (group 2), VEP amplitude was decreased (4.13+/-4.04 microV vs 6.97+/-3.35 microV and 6.97+/-4.43 microV) and latency was increased (122.59+/-20.09 msec vs 101.31+/-6.19 msec and 108.76+/-13.57 msec) in affected eyes significantly in comparison to the unaffected eyes and control group, respectively. Even though there were no significant differences for P50 latency and N95/P50 ratios between affected and unaffected eyes in both groups, N95 amplitude decreased significantly in the affected eyes of the ischaemic optic neuropathy patients and N95 latency was found to be decreased in optic neuritis patients. There was no correlation between VEP and PERG findings in both groups.
  
  
  CONCLUSIONS
  VEP amplitude decreased significantly in ischaemic optic neuropathies while latency delay was more significant in patients with optic neuritis. PERG findings showed decreased N95 amplitude in ischemic optic neuropathy without associated latency changes.
authors.affiliation: Department of Ophthalmology, School of Medicine, Ankara University, Ankara, Turkey. huban@babaylon.com
authors.forename: Huban
authors.initials: H
authors.lastname: Atilla
authors.forename: Oya
authors.initials: O
authors.lastname: Tekeli
authors.forename: Kemal
authors.initials: K
authors.lastname: Ornek
authors.forename: Figen
authors.initials: F
authors.lastname: Batioglu
authors.forename: Atilla Halil
authors.initials: AH
authors.lastname: Elhan
authors.forename: Teksin
authors.initials: T
authors.lastname: Eryilmaz
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D004596:Electroretinography / Q000379:methods*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009901:Optic Nerve Diseases / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology