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Simultaneous recording of visual evoked potentials and electroretinograms in patients with unilateral opaque media
Y Mashima1, M Matsuhashi, Y Oguchi
1Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan.
Abstract:
We studied the correlation between preoperative visual evoked potentials (VEPs) and postoperative visual acuities in patients with unilateral opaque media. The fellow eye was used as the control. The filtering effect due to opaque media could be assessed on the basis of the difference of the electroretinogram (ERG) threshold in the two eyes. 'Modified VEPs' were then calculated by eliminating the assessed filtering effects, which improved our ability to detect the potential for visual recovery. In the normal eye, the stimulus threshold for VEP is lower than that for ERG by 2 or 3 log units. Therefore should a higher stimulus threshold be found for VEP than ERG, severe optic nerve damage is highly probable in eyes with media opacties.