protanopia

   Also known as protan colour deficiency and protan colour blindness. The term protanopia comes from the Greek words protos (first), an (not), and opsis (seeing). It translates roughly as 'not being able to see the first of the primary colours (i.e. red)'. It is used to denote a type of * colour vision deficiency characterized by a loss of red sensitivity. Due to this loss of red sensitivity, there is no perceptible difference between the colours red, orange, yellow, green, and brown, and between various shades of purple. In addition, the brightness of these colours is reduced in comparison to the brightness experienced by individuals with normal trichromasy. The term protanopia was coined in or shortly before 1837 by German physicist August L.F.W. Seebeck (1805-1849) to denote a type of colour vision deficiency in which the colour system is reduced to blue and yellow, with a shortening of the spectrum length at the red end. When the long-wavelength cones (L-cones) are missing, the term red-dichromacy protanopia is used. When these cones are present, but functioning defectively, the term *protanomaly applies. Protanopia is inherited as a sex-linked Mendelian recessive characteristic. The term is used in opposition to the terms *deuteranopia and * tritanopia.

   References

   McIntyre, D. (2002). Colour blindness. Causes and effects. Chester: Dalton Publishing.

   Seebeck, A. (1837). Ueber den bei manchen Personen vorkommenden Mangel an Farbensinn. Annalen der Physik und Chemie, 42, 177-233.