Which type of color deficiency has poor color discrimination at wavelengths greater than 540 nm?

The type of color deficiency characterized by poor color discrimination at wavelengths greater than 540 nm is Tritanopia. Tritanopes have difficulties specifically in distinguishing colors in the blue-yellow spectrum due to a defect in the blue-sensitive cone photoreceptors. At longer wavelengths, particularly those beyond 540 nm, their ability to differentiate colors diminishes.

While protanopia and deuteranopia also involve color discrimination issues, they primarily affect the red-green spectrum. Protanopes, who lack the red-sensitive photopigment, have reduced sensitivity to longer wavelengths, but their difficulties are more pronounced below 540 nm. Deuteranopes, lacking the green-sensitive photopigment, experience similar red-green color discrimination problems.

Therefore, the statement that all types have poor color discrimination at wavelengths greater than 540 nm is misleading, as only Tritanopes specifically present this challenge in that spectral region.