Change of wavelength difference limit for binocular color fusion with wavelength and brightness of stimuli

In this study, we measured the wavelength difference limit for binocular color vision, using a three-dimensional display to present dichoptic stimuli to the left and right eye, respectively. The size of stimulus was 2° arc of visual angle, the wavelength range of the stimuli was selected from 450 nm to 650 nm, and the brightness of the experimental stimuli was set four levels, as 3 cd/m², 7.5 cd/m², 15 cd/m², and 30 cd/m². The following results were obtained: (a) the binocular color fusion ceases when the color difference introduced between the left and right eyes exceeds a certain threshold value. The range of binocular color fusion limit is less than 10-80 nm. (b) The limit of binocular color fusion becomes smaller with the increase of the brightness of the stimulus.