Critical flicker-fusion of solid and annular stimuli.
Critical flicker-fusion thresholds were measured with both solid disks and annular stimuli. The former subtended 1, 4, and 8 degrees of visual angle, and the latter subtended 4 and 8 degrees. The illuminated region of the 4-degree annulus provided the same area of stimulation as that of the 1-degree disk. The illuminated region of the 8-degree annulus provided the same area of stimulation as the 4-degree disk. Annular stimuli significantly reduced critical flicker-fusion thresholds relative to those obtained with disk stimuli of the same area. The effects are not explicable in terms of heterogeneous retinal sensitivity. Laws relating critical flicker-fusion to area seem to be valid only under the restricted condition of homogeneous stimulation.
D005425:Flicker Fusion; D006801:Humans; D008029:Lighting; D010786:Photoreceptor Cells / Q000502:physiology*