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New observations concerning red–green color defects
Author(s) -
Pokorny Joel,
Smith Vivianne C.
Publication year - 1982
Publication title -
color research and application
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.393
H-Index - 62
eISSN - 1520-6378
pISSN - 0361-2317
DOI - 10.1002/col.5080070222
Subject(s) - photopigment , trichromacy , photopic vision , color vision , chromatic scale , biology , locus (genetics) , optics , evolutionary biology , genetics , retina , physics , gene
Abstract The majority of research on X‐chromosomal defects has been with a 2° field of view. The studies concur in a view of dichromacy as a loss or reduction system, and anomalous trichromacy as an alteration system. According to this view, protanopes have no functional LWS (long‐wave‐length‐sensitive) photopigment; deuteranopes have no functional MWS (middle‐wavelength‐sensitive) photopigment. With larger fields of view, dichromats show trichromacy which is mediated by rods at low photopic luminances, and by anomalous cones for retinal illuminances above 1000 trolands. These studies suggest that the same (or similar) anomalous (L'WS) photopigment is formed at the protan locus and the same (or similar) anomalous (M'WS) photopigment is formed at the deutan locus for both the anomalous trichromatic and dichromatic forms of the defects. Family studies reveal that intrafamilial variability in chromatic discrimination is less than interfamilial variation. A possible interpretation of such studies is that multiple, rather than three or four, alleles may be involved in X ‐chromosomal color‐vision defects, with the alleles determining the proportion of functional anomalous cones.