July 16, 2012 Disorders of color vision can be roughly divided into congenital and acquired. Congenital defects are almost always in the red-green area (they are found in 8% of men and 0.5% of women and are inherited mostly X-recessive), and acquired are mostly in the blue-yellow field and affect both sexes equally.
Furthermore, congenital disorders were equal in both eyes and do not progress during life, whereas acquired are usually stronger in one than the other eye and are getting worse over time.
Anomalous threechromates form the largest group of disorders with color distinction. They are not blind to a particular primary color (red, green or blue), but tend to vary its tone more difficulty than other people. So to the protanomal requires greater amounts of red in a red-green mixture to equal it with yellow – anomaloscopic test.
Classification of disorders of color vision:
Threechromates = normal
1. ANOMALOUS THREECHROMATES – do not differ shades of one of the three primary colors (red, green, blue)
Protanomals – do not differ shades of red
Deuteranomals – do not differ shades of green
Tritanomals – do not differ shades of blue
2. DICHROMATES – do not recognize one of the three primary colors
Protanopes – do not recognize the color red
Deuteranopes – do not recognize the color green
Tritanopes – do not recognize the color blue
Dichromates, in contrast to anomalous threechromates, do not recognize one of the primary colors. Their cones have just two of the three pigments needed for color recognition, while anomalous threechromates have all three pigments, one of which is little changed.
There are two forms of achromatopsia or monochromasia, and in both the patient does not recognize it. Monochromators with chopsticks do not have functionally capable cones in the retina, and because of that – except the lack of possibility to distinct between colors – have a low visual acuity, nystagmus, photophobia and abnormal electroretinogram.
Monochromators with cones also cannot differ colors, but don’t have any other disturbances and their electroretinogram is normal.
Monochromators with chopsticks see everything in shades of one primary color. If you look through colored glass, the whole world seems to be yellow, red, etc, depending on the color filter. Monochromators with chopsticks see the world as such, but have no previous experience of the normal colors to be able to tell in which color they see.
Monochromators with cones do not vary even shades, but see all “black-white”.
Color vision is very important in the professional orientation – the law does not permit carrying out of many jobs for people with deficient color vision (e.g., professional participants in the land, sea and air transport).