The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eyedisease.
Contrast sensitivity function webvision.med.utah.edu
Contrast sensitivity function www.cns.nyu.edu
Contrast sensitivity en.wikipedia.org
Poor contrast sensitivity is www.biopticdrivingusa.com