It is quite astounding the amount of males that are colorblind. Overall, about 8% of the male population is colorblind. Only about 0.5% of the female population is affected by this genetic disorder.
Before we break down the colorblind population by type, let's talk about rods and cones for a moment.
The retina is made up of rods and cones. Cones are good in daytime conditions, but rods are good in night conditions. Cones are the only one that can perceive color. If a person's cone wavelength (which is usually 400 to 700 nm) is wrong because of genetics, then tne person will be sensitive to different wavelengths which makes them colorblind. The three types of cones are L, M, and S-- Long, Medium, and Short, respectively.
A breakdown of the type of colorblindness is as follows:
Monochromacy - These are the truly color blind. They only see differences in lightness and can't distinguish any color hue at all. To have this type of colorblindness, you must inherit a gene for the disorder from both parents. This is very rare and is estimated to be about 3 in a million.
Protanomaly - (about 1% of males) These are people who are red weak due to a weakness in the long wavelength (L) cones. Red, orange, yellow and yellow-green appear paler and more green. Violet and lavender are also a problem and may appear blue.
Protanopia - (about 1% of males) Similar to above but these people have a lack of reciptors in the long wavelength (L) cones. This means brightness is affected as well.
Deuteranomaly - (about 5% of males) These people are green weak. This is similar to protanomaly. People with this are poor at discriminating small differences between hues in red, orange, yellow and green region of the spectrum. The weakness in the cones for this type of colorblindness is in the medium (M) wavelength cones.
Deuteranopia -(about 1% of males) Same as protanopia but without brightness being affected. This is due to a lack of receptors in the medium (M) wavelength cones.
Tritanopia - (not common) Under this category, blues and greens can be confused, and yellows are sometimes seen as lighter shades of red. This is due to a lack of receptors to short (S) wavelength cones.
Sources per www.colorvisiontesting.com
www.tedmontgomery.com/the_eye/macula.html
http://webaim.org/articles/visual/colorblind
You havn't yet said what type you have? Both the Protanomalous L cones and the Deuteranomous M cones are actually more sensitve to yellow than normal. Thus Deuteranomaly and Protanomaly are acutally not blindness to any colour but weakness. Tritanomaly, while rare does exist.
ReplyDeleteIf you think about what causes these anomalies, one might wonder if they have enhanced perception of other colours, and this has been shown to be the case with Deuteranomaly.