Objective measurement of human visual acuity by visual evoked potentials.

Electrophysiological studies were performed to measure the threshold (upper end of range) spatial frequency using visual evoked potentials and comparison with visual acuity neuron 26 healthy subjects. The aim of the present work was to create a method for objective measurement of visual acuity. This was addressed by initial measurements using a universally accepted method of visual stimulation and processing of electroencephalograms, which allows errors due to individual differences in visual system function to be minimized. These experiments yielded a strong correlation between the threshold spatial frequency of the test grid yielding an evoked potential on presentation and visual acuity, in degrees, expressed as the resolving ability of the visual system for this optotype. A logarithmic relationship was found between these values and an equation allowing automated calculation of visual acuity (resolving ability) from electrophysiological data was derived. The results were independent of the subject's responses and therefore provides a maximally objective assessment of visual acuity.