Patent US 5,500,699

A method and apparatus for measuring and quantifying generalized visual sensitivity in terms of contrast sensitivity, spatial frequency response and eye brain recognition of image alignments or shapes is disclosed. A multiplicity of distinctly different information areas are provided, each of these information areas being generally delineated by indicia so as to eliminate patient or system search for an image and to generally designate the proximity of the information area for visual interrogation. The information areas may contain a grating having successive parallel aligned light and dark areas, which parallel aligned light and dark areas have a substantially linear character with the contrast levels and/or spatial frequency or size of occurrence differing for different information areas. Each successive information area has a background with mean luminance being the average of that mean luminance found within the information area. Further, all information areas are provided with a taper at their edges, preferably a Gaussian taper, which taper imparts to the edges boundaries that blend into the mean luminance background. There results for images on the threshold of visual acuity information areas which only with careful examination can be discriminated from their backgrounds.