title: Early detection of P-VEP and PERG changes in ophthalmic Graves' disease.
abstract: BACKGROUND
  In Graves' disease the optic neuropathy (ON) is due to direct compression of the nerve and/or of its blood supply. The aim of the present study was to detect early changes in the visual functions of patients affected by ophthalmic Graves' disease (OGD) by using electrophysiological tests (P-VEP and PERG).
  
  
  METHODS
  We studied 50 OGD patients who were in a range between class 2 and class 5 according to the Donaldson-American Thyroid Association classification, i.e. had no evident ON and normal visual acuity. We recorded transient reversal PERG and P-VEP in response to the stimulation of one eye at three spatial frequencies (2.2, 1.1 and 0.5 c/d).
  
  
  RESULTS
  Our results showed a statistically significant reduction in PERG amplitude in class 5, while the P-VEP amplitude was already reduced in class 2.
  
  
  CONCLUSIONS
  The electrofunctional tests were useful to detect small changes in the visual function of patients affected by initial stages of OGD. Therefore, P-VEP and PERG recordings appear to be a useful tool for early diagnosis of the optic nerve involvement in Graves' disease.
authors.affiliation: University of L'Aquila, Department of Ophthalmology, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Spadea
authors.forename: G
authors.initials: G
authors.lastname: Bianco
authors.forename: T
authors.initials: T
authors.lastname: Dragani
authors.forename: E
authors.initials: E
authors.lastname: Balestrazzi
mesh_terms: D000328:Adult; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006111:Graves Disease / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology; D010364:Pattern Recognition, Visual; D012189:Retrospective Studies; D014792:Visual Acuity