Which color vision defect is best described as a blue-yellow weakness?

Which color vision defect is best described as a blue-yellow weakness?

• A. Tritanomalous
• B. Protanomalous
• C. Deutanomalous
• D. Achromatopsia

Answer: (A)

Blue-yellow discrimination depends on the function of the short-wavelength (S) cones. When those cones are partly defective, the result is tritanomaly, a blue-yellow weakness. This is distinct from red-green color defects, which come from abnormalities in the long- and medium-wavelength cones (protanomalous and deutanomalous). Achromatopsia is a severe condition involving little or no color vision at all due to broader cone dysfunction. So a blue-yellow weakness best fits tritanomaly, reflecting a partial S-cone anomaly that specifically disrupts blue-yellow color processing.

Blue-yellow discrimination depends on the function of the short-wavelength (S) cones. When those cones are partly defective, the result is tritanomaly, a blue-yellow weakness. This is distinct from red-green color defects, which come from abnormalities in the long- and medium-wavelength cones (protanomalous and deutanomalous). Achromatopsia is a severe condition involving little or no color vision at all due to broader cone dysfunction. So a blue-yellow weakness best fits tritanomaly, reflecting a partial S-cone anomaly that specifically disrupts blue-yellow color processing.