The effects of retinal abnormalities on the multifocal visual evoked potential.
OBJECTIVE
To examine the effects on the amplitude and latency of the multifocal visual evoked potential (mfVEP) in retinal diseases associated with depressed multifocal electroretinograms (mfERG).


METHODS
Static automated perimetry (SAP), mfERGs, and mfVEPs were obtained from 15 individuals seen by neuro-ophthalmologists and diagnosed with retinal disease based on funduscopic examination, visual field, and mfERG. Optic neuropathy was ruled out in all cases. Diagnoses included autoimmune retinopathy (n = 3), branch retinal arterial occlusion (n = 3), branch retinal vein occlusion (n = 1), vitamin A deficiency (n = 1), digoxin/age-related macular degeneration (n = 1), multiple evanescent white dot syndrome (n = 1), and nonspecific retinal disease (n = 5). Patients were selected from a larger group based on abnormal mfERG amplitudes covering a diameter of 20 degrees or greater.


RESULTS
Fourteen (93%) of 15 patients showed significant mfVEP delays, as determined by either mean latency or the probability of a cluster of delayed local responses. Thirteen of 15 patients had normal mfVEP amplitudes in regions corresponding to markedly reduced or nonrecordable mfERG responses. These findings can be mimicked in normal individuals by viewing the display through a neutral-density filter.


CONCLUSIONS
Retinal diseases can result in mfVEPs of relatively normal amplitudes, often with delays, in regions showing decreased mfERG responses and visual field sensitivity loss. Consequently, a retinal problem can be missed, or dismissed as functional, if a diagnosis is based on an mfVEP of normal or near-normal amplitude. Further, in patients with marked mfVEP delays, a retinal problem could be confused with optic neuritis, especially in a patient with a normal appearing fundus.
Chen
John Y
JY
Department of Psychology, Columbia University, New York, New York 10027, USA.
Hood
Donald C
DC
Odel
Jeffrey G
JG
Behrens
Myles M
MM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time; D012160:Retina / Q000503:physiopathology*; D012164:Retinal Diseases / Q000503:physiopathology*; D058609:Visual Field Tests; D014794:Visual Fields