Green Blind

A misleading name for Deuteranopia.

The name derives probably from the red-green opponent channel, which is – by definition – skewed permanently to the far red side in Deuteranopes, typically because they are missing the M-Cones that balance the channel.

“Green blind” infers that the individual sees any shade of green as white, black, gray, or transparent. While Deuteranopes typically see all greens as darker, because the S- and L-Opsin Absorbance Spectrum overlap, there is no “Green” Wavelength (or in the entire Visible Range) that a Deuteranope will see consistently as black. They also still perceive greens as a color, even if that color is a confusion pair with Orange / Yellow / Red / Brown. In fact, Deuteranopes are more likely to see Cyan as White/Gray than Green.

See Green Weak.