Measurements of the contrast threshold for peripheral vision for size d of the circular test spot between 4' and 420' and for flash time t between 0.02 and 1 sec are presented. Wave lengths for adapting field 21 and test stimulus 22 6500 and 5250 A so that four 21 - 22 combinations were explored. The merits of theoretical speculations on the perception of contrast considering the statistical fluctuations in the number of incident quanta and nerve impulses are discussed. It proved that the perception of red light is dominant over the stimulation of the rod system by the background and that the state of adaptation of the one eye and the perception of light via this eye is not affected or influenced by the actual stimulation or state of adaptation of the opposite eye when influences due to variations in pupil size are eliminated. Exceptions must be made for very high brightness of a green background.
Samenvatting