Unexplained Visual Acuity Loss

Occasionally a patient will present whose only symptom is decreased visual acuity. To determine whether the retina or optic nerve is the source of the problem, the multi-focal ERG and pattern VEP can be used for differential diagnosis. Abnormal multi-focal ERG amplitude indicates that the acuity loss is probably at the level of the retina.

Related Tests

  • ERG
  • Multi-Focal
  • VEP
  • Pattern VEP

Related Products

  • RETeval® Visual Electrodiagnostic Device
  • UTAS Visual Diagnostic System

Malingering

Because the VEP is an objective test of the visual system, it can be used to test patients who claim they cannot see but have no obvious pathology. A normal VEP, especially at small check sizes, is an indication that the optic pathways are functioning normally, at least to the level of the primary visual cortex. You should watch suspected malingerers carefully to make sure that they do not close their eyes or avert their gaze from the test pattern during the recording process.

Related Tests

  • VEP

Related Products

  • RETeval Visual Electrodiagnostic Device
  • UTAS Visual Diagnostic System