What colors do the color blind confuse?
Anomalous trichromats are such a diverse group that they are difficult to characterize. Dichromatic confusions, on the other hand are more homogeneous and predictable. A technical answer requires looking at cone activity. Recall that color is initially determined by the relative activity of the three cone classes. Protanopes, who are missing “red” cones, cannot distinguish lights which produce equal ratios of activity in the “green” and “blue” cones. Similarly, a deuteranope, who is missing “green” cones, cannot distinguish lights that produce identical activity ratio between the “red” and “blue” cones. Experts often plot these as “confusion lines” on a CIE diagram. For a more qualitative understanding, look at the location of the protanoptic and deuteranopic neutral points located in at the edge of the green range. It should be clear that protanopes and deuteranopes will confuse reds-yellows-greens on the one hand and blues on the other. They have little ability to distinguish saturat