Differential effects of optic media opacities on mfERGs and mfVEPs.
OBJECTIVE
To assess different effects of image degradation that could result from optic media opacities on multifocal retinal (mfERG) and cortical responses (mfVEP).


METHODS
Monocular flash-mfERGs and pattern-reversal mfVEPs were recorded. MfERG-P1 amplitudes and implicit times and mfVEP root-mean-square values (RMS) and delays were compared for different filter conditions (none, 8% luminance, 50% luminance, 50% luminance plus blur) in a total of ten participants with normal vision.


RESULTS
Reducing stimulus luminance down to 50% and 8% reduced mfERG amplitudes to 86% and 42%, respectively, with no significant effect on mfVEP amplitude. Implicit times were increased for mfERGs by 0.9 ms and 6.0 ms, respectively, and for mfVEPs by 1.0 ms and 6.3 ms, respectively. For '50% luminance plus blur' mfERG amplitudes were significantly reduced centrally and enhanced peripherally and delayed by 1.3 ms. MfVEPs were reduced close to noise level independent of eccentricity.


CONCLUSIONS
Degradation of the retinal image is a potential source of discrepancies between mfERGs and mfVEPs. Image blur suppresses the mfVEP at all locations and changes mfERG topography, resulting in a selective loss of central responses.


CONCLUSIONS
Considering optic media opacities is of importance for the correct interpretation of mfERG and mfVEP recordings, particularly in elderly patients.
Visual Processing Laboratory, Ophthalmology, Otto-von-Guericke-University, Magdeburg, Germany.
A
A
Herbik
G C
GC
Hölzl
J
J
Reupsch
M B
MB
Hoffmann
D000328:Adult; D000704:Analysis of Variance; D004568:Electrodiagnosis; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods; D004596:Electroretinography / Q000295:instrumentation / Q000379:methods*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D014795:Visual Pathways / Q000502:physiology; D055815:Young Adult