Exponent of the Broca-Sulzer flash duration as a function of retinal eccentricity.
The flash duration producing maximum brightness-enhancement changes as a power function of luminance, that is, the time locus of the Broca-Sulzer flash duration TB, decreases as luminance L increases: TB = k x L beta , where beta is the duration exponent. The exponent of TB was estimated for 1-deg white flash fovea, 10-, 20-, 30-, 40-, 50-, and 60-deg temporal eccentricities of the dark-adapted human right eye. The following method of brightness maximization was used: the observer adjusted the duration of constant luminance flashes to produce a maximally bright flash. Duration was adjusted by rotating a microprocessor-based potentiometer. The results showed that the duration of the brightest flash TB decreased as L increased with the negative power exponent. Furthermore, the size of the negative exponent decreased as a function of increasing retinal eccentricity. Time-dependent brightness processing in the fovea and periphery is discussed in terms of the psychophysical brightness power function.
D003623:Dark Adaptation; D005584:Fovea Centralis / Q000502:physiology*; D006801:Humans; D008266:Macula Lutea / Q000502:physiology*; D008838:Microcomputers; D010775:Photic Stimulation / Q000295:instrumentation / Q000379:methods*; D055585:Physical Phenomena; D010825:Physics; D012160:Retina / Q000502:physiology*