Red weakness is Protanomalous.

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

Answer: (A)

Red weakness points to an issue with the long-wavelength (L-cone) system, which is protanomaly. In protanomaly, the L-cone pigment is abnormal, shifting its sensitivity so red signals aren’t processed as strongly. This makes red colors appear duller and can blur red-green distinctions, since reds start to look more like greens. It’s a form of anomalous trichromacy, meaning color vision is altered but not completely lost.

This differs from green weakness (deuteranomaly), blue-yellow issues (tritanomaly), or complete color blindness (achromatopsia). Deuteranomaly involves the M-cones, Tritanomaly involves the S-cones, and achromatopsia is total color insensitivity with poor visual acuity.