Effects of luminance and size of stimuli upon binocular color fusion limit

We aimed to examine the effects of luminance and size of stimuli upon the binocular fusion limit. A three-dimensional display was used to present dichoptic stimuli to the left and right eye, respectively. The range of dominant wavelength was from 450 to 650 nm. We measured the binocular color fusion limits Δλ _d for each dominant wavelength λ _d quantitatively with different luminance. The results show that the binocular color fusion ceases when the color difference introduced between the left and right eyes exceeds a certain threshold value, and the color fusion limit becomes smaller with the increase of the luminance of stimuli. In experiment 2, we adjusted the visual size of stimuli from 2 to 10° and found that color fusion is more difficult to achieve at 10° than at 2°.