Accession Number : ADD009701

Title :   Method and Apparatus for Objective Determination of Visual Contrast Sensitivity Function.

Descriptive Note : Patent Application,


Personal Author(s) : Cannon,Mark W , Jr

Report Date : 30 Jun 1982

Pagination or Media Count : 26

Abstract : A method and apparatus for objectively determining the visual contrast sensitivity function of a human subject involves subjecting the vision of the human subject to a plurality of sine wave gratings differing in spatial frequency and contrast levels. As the subject views the grating patterns on a video monitor, the brain wave activity of the subject is detected and steady state Fourier spectra of the activity are recorded. In each spectrum corresponding to a grating pattern of a particular spatial frequency, a visual evoked potential component may be distinguished from noise by adjusting the contrast level of the grating pattern. A contrast threshold used in deriving the visual contrast sensitivity function is identified for each grating pattern of a particular spatial frequency by pinpointing the contrast level at which the visual evoked potential component becomes indistinguishable from noise in the spectrum. (Author)

Descriptors :   *Patent applications, *Vision, *Test equipment, Contrast, Sensitivity, Measurement, Threshold effects, Monitoring, Spectra, Fourier analysis, Gratings(Spectra), Patterns, Sine waves, Test methods

Subject Categories : Psychology

Distribution Statement : APPROVED FOR PUBLIC RELEASE