title: Setting the absolute threshold of vision.
abstract: The performance of sensory systems in many cases is limited by the physical nature of the stimulus. For vision, the quantal nature of light limits detection by dark-adapted observers; only now are we beginning to be aware of the subtleties in the biophysical mechanisms underlying this exquisite sensitivity.
authors.forename: Alapakkam P
authors.initials: AP
authors.lastname: Sampath
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Fain