Color vision and X-inactivation.

[Lionel Mandrake]

8. Types of colorblindness

Last edited Sat Aug 1, 2015, 08:59 PM - Edit history (1)

Anyone who tries to read the scientific literature on colorblindness will encounter a bizarre terminology for different types of colorblindness. Most of the bizarre terms fit into a neat pattern, as shown in the following table:

...................................................................................Anomalous
Cone ........................ Generic ........... Dichromacy ........ Trichromacy
Type ......................... Terms ....................................... (Anomalous
....................................................... (Dichromat) ..........Trichromat
....................................................................................or Anomal)


Red .............................. ? ................. Protanopia ......... Protanomaly
(L)
............................... Protan ............. (Protanope) ......... Protanomal


Green ........................... ? .............. Deuteranopia ......... Deuteranomaly
(M)
............................... Deutan ........... (Deuteranope) ....... Deuteranomal



Blue ............................ ? .................. Tritanopia .......... Tritanomaly
(S)
................................ Tritan .............. (Tritanope) ......... Tritanomal


The table requires some explanation.

The three types of cones are sometimes called red, green, and blue, but more often they are called L, M, and S, which stand for long, medium, and short (wavelength), respectively.

The table shows words for various types of deficiency (e.g., tritanopia) and words for people who have deficiencies (e.g., tritanope). A question mark indicates that I am not aware of any word that fits in a particular spot in the table. For example, AFAIK there is no word for the deficiency that a protan has.

The generic terms include dichromats and anomalous trichromats. Thus a protan has either protanopia or protanomaly, a deutan has either deuiteranopia or deuiteranomaly, and a tritan has either tritanopia or tritanomaly.

The words protanomal, deuteranomal, tritanomal, and anomal, which I added to this table on the first edit, are exceedingly rare.