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Sunday 8 June 2014

Color Blindness

Facebook founder Mark Zuckerburg is red-green color blind. The Facebook logo is blue because that is the color that he can see best.

Color Blind people can see the differences in texture and brightness more intensely than normal people and were even used in World War II to spot camouflage.

Ernest "Boots" Thomas, one of the U.S. Marines who raised the flag on Iwo Jima, was able to enlist in spite of being color blind by memorizing the results of another man's test.

Because color blind people may not see the difference between colors such as red and green, some countries, such as Romania have refused to give them driving licenses.

In the United Kingdom, electricity wires in houses used to be red, black and green. They were changed to brown, blue and green/yellow to help color blind people see the difference between the "live" and "earth" wires.

Colors of traffic lights are confusing to some dichromats, as there is insufficient apparent difference between the red/amber traffic lights. In the Eastern provinces of Canada horizontally mounted traffic lights are generally differentiated by shape to facilitate identification for those with color blindness.

Horizontal traffic light in Halifax, Nova Scotia, Canada. By Sprocket at the English language Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16067961

It is mostly men who inherit color blindness, affecting about 1 in 20 men for every 1 in 200 women.

About 7% of American men have red-green colorblindness.

A significant proportion of the population (about 10%) of the small Pacific Island of Pingelap are completely colorblind due to total absence of working cones in their eye retinas. The condition limits vision in full sunlight, but may lead to sharper vision at night, like for night fishing. on the atoll of Pinglelap, This is due to a population bottleneck caused by a typhoon in 1775 that left 20 survivors on the atoll. One carried the colorblindness gene.

Former snooker world champion Peter Ebdon is color blind - not ideal given his profession. He has wrongly potted the brown on several occasions thinking it was red.

Emerson Moser retired after making 1.4 billion crayons for Crayola for 37 years, and then announced he was colorblind.

In all animals, including humans, the perception of color is determined by the presence of cells in the eye called cone photoreceptors. 


The only animal that has been confirmed to see only in black and white is a fish called a Skate. This is because it has no cones in its eyes. 

Contrary to popular belief, dogs aren't color blind; they can see shades of blue, yellow, green and gray. The color red registers on a gray scale in a dog's vision.

Owls are the only birds that can see blue.


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