Color Blindness by Inheritance
Red Green Color Blindness
Red Green Color blindness is predominantly found only in men. The gene that leads to red green color blindness is found in the X Chromosome. Males only have one X chromosome whereas females have 2; typically in females the stronger chromosome takes precedence so they retain correct vision. The son of a woman carrying a faulty gene has a 50% chance of inheriting the faulty X chromosome and as a result – suffering from color blindness. The daughter of the same woman is unlikely to be color blind unless her father is color blind; however she retains a 50% chance of being a carrier for the defective gene.
Blue Color Blindness
Blue color blindness (often referred to as blue yellow color blindness) is extremely rare, so rare that only 5% of color blind people suffer from it. Unlike red green color blindness, the chance of having blue color blindness is equal in both men and women as the gene is found on a different chromosome ( chromosome 7). This gene is shared equally by men and women and blue color blindness comes from a mutation of this gene.
Color Blindness By Nationality
One might expect the percentage of affected people to be relatively constant in all countries however this is far from the truth. In most Caucasian societies up to 1 in 10 men suffer, however only 1 in 100 Eskimos are color blind. There is no solid proof as to the cause of this however it is logical to assume that less of the ‘original Eskimos’ carried the defective gene, so the likelihood of it infecting the gene pool was quite a lot lower.
Developed Color Blindness
Whilst almost all color blindness is inherited, infrequently a change in the chromosome during early development can cause color blindness. Various injuries involving trauma to the eye, and even some diseases can also cause color blindness to develop in a person of any age.
As mentioned elsewhere on this website, cataracts are not a form of color blindness, so you won’t see them in the table below. Cataracts are a clouding that develops in the crystalline lens of the eye, and have the effect to dull colors, and blur vision. It is not common to mistake someone with cataracts as someone who is color blind, as color blindness normally becomes apparent early in life, whereas cataracts don’t usually form until ones senior years. However if you are unsure, you can take the free online tests available on this website in the menu on the left to find out now.
The Below table displays the percentage of men and women suffering the different forms of color blindness, you can click on each defect to learn more about it.
|Red-green (Overall)||7 to 10%||—|
(disfunctional, abnormally shaped or no cones)
|Protanopia (L-cone absent)||1% to 1.3%||0.02%|
|Deuteranopia (M-cone absent)||1% to 1.2%||0.01%|
|Tritanopia (S-cone absent)||0.001%||0.03%|
|Protanomaly (L-cone defect)||1.3%||0.02%|
|Deuteranomaly (M-cone defect)||5.0%||0.35%|
|Tritanomaly (S-cone defect)||0.01%||0.01%|