There are many false colorblinds.
It is imperative to correct the patient: small test.
In this case it is very difficult to read otherwise than well corrected, we are not all so color-blind. It will be necessary in a case like this one to increase the contrast with glasses of low vision.
- There are 4 main shades corresponding to the 4 cases of pathology.
We test these colors for the circumstances corresponding to the patient.
We then graduate in intensity to try to lose as little detail as possible on the other colors.
- ColorX # 1.3
- ColorX # 2.3
- ColorX # 3.3
- ColorX # 4.3
Or in darker intensity for outdoor, or in more severe cases.
- ColorX # * .1 Very clear
- ColorX # * .2 Clear
- ColorX # * .3 Base
* being the main color determined beforehand.
A little theory
- ColorX # * .3 Base
- ColorX # * .4 Very dark
Types of dyschromatopsia (wikipedia)
- The human eye is able to identify about 200 shades by color ...
The old publications speak of 15000 different colors.
The most recent ones speak of 300 000 different colors or even 2 * 21 is 2097152 shades of different colors.
- The distribution of 6 to 7 million color photoreceptors:
- Green cones 58%.
- L Located mainly in the center of the fovea, there are some on the outskirts.
- Sensitive to green.
- Blue cones 3%.
- Located at the periphery of the fovea at 1 ° regular, they are few but big.
- Sensitive to violet blue.
- Red cones 38%.
- Distributed on the fovea and periphery.
- Sensitive to yellow.
- Sensitive to monochromatic turquoise blue.
- The color vision is analyzed in 3 ways.
- Light or Dark.
- Yellow Blue Axis: is this more yellow or is this more blue.
- Red Green Axis: is it redder or greener.
- For color blindness:
We are all trichromates, with 3 functional cones and even if some deficiencies, there are no particular genes.
There are perception problems on some shades of red or blue green colors, but all colors are well perceived.
It is more disabling, the absence of sensitivity blue cone or green cone or red cone, only two types of cones are functional.
It is the most disabling.
- It is the absence of green and red cone sensitivity.
- More rarely, it is the absence of blue cones.
- Achromatopsia: complete absence of color vision, associated in its congenital form with strong photophobia, reduced visual acuity.
- Deutéranopia :absence in the retina of green reception cones; people who are affected are unable to differentiate red from green. This is the form of John Dalton (the diagnosis of deuteranopia in him was confirmed in 1995, more than 150 years after his death, by DNA analysis taken from one of his eyeballs preserved up to us ). The other forms of color deficiency are color blindness only through abuse of language.
- Deutéranomaly : presence of a pigment mutation in the perception of green; the sensitivity to this color is diminished. Consists of the majority (about half) of congenital anomalies of color vision.
- Protanopia :absence of red retinal receptors; this color is undetectable by the subject.
- Protanomaly : presence of a mutation of the pigment of the vision of red; the sensitivity to this color is diminished.
- Tritanopia : absence of retinal receptors in blue; this color is undetectable by the subject.
- Tritanomaly : presence of a mutation of the pigment of the blue vision; the sensitivity to this color is diminished.