Normalization Of Sweep VEP For A Range Of Acuity Levels.

The visual evoked potential (VEP) is an electrophysiological technique that measures some portion of the electrical activity produced by the visual cortex in response to the visual information it has received from the eye. As the eye is presented with a stimulus consisting of a succession of increasing spatial frequencies, the amplitude of the VEP is seen to decrease. It is assumed that so long as the brain is producing a measurable VEP,
the visual pathway is still resolving the stimulus. The point at which the amplitude of the VEP reaches zero would be the level of cortical acuity, as measured by the VEP. It is assumed that the VEP decreases linearly as the spatial frequency linearly increases near the limit of acuity. This was shown by Weiner et al. (1985) An estimate of the cortical acuity level can then be extrapolated by a linear regression from experimental data. Our objective was to evaluate the relationship between the VEP's measure of cortical acuity and traditional
visual acuity as measured by the Tumbling E.