Critical flicker frequency as a function of stimulus area and luminance at various eccentricities in human cone vision: a revision of Granit-Harper and Ferry-Porter laws.

When the photopic luminous flux collected by ganglion cells was kept constant at all retinal locations by reducing average stimulus luminance in inverse proportion to photopic Ricco's area (F-scaling), critical flicker frequency to stimuli of 1.2-88 deg2 in area, presented at various eccentricities along the temporal meridian of the visual field, increased as a single logarithmic function of the number of retinal ganglion cells stimulated. Their number was calculated by multiplying stimulus area by the ganglion cell receptive field density of the human retina. When the number of ganglion cells stimulated was kept constant by enlarging the stimulus area in inverse proportion to the ganglion cell density (M-scaling), the logarithm of CFF to green, yellow, orange and red cone-targets increased as parallel linear functions of logarithmic flux, calculated by multiplying retinal illuminance by photopic Ricco's area.