yellow-blue dichromacy

a form of dichromacy characterized by lowered sensitivity to yellow light; so rare that its existence has been questioned

rare form of dichromacy characterized by a lowered sensitivity to blue light resulting in an inability to distinguish blue and yellow

a deficiency of color vision in which the person can match any given hue by mixing only two other wavelengths of light (as opposed to the three wavelengths needed by people with normal color vision)