Color Blindness

Side-by-side comparison of two images of apple...

Side-by-side comparison of two images of apples as seen by a trichromatic observer and the same apples as seen by a deuteranope (color blind individual). Simulation performed using the vischeck website ( with an algorithm originally developed by Brettel et al, 1994. Original images of apples are taken from the Wikipedia commons: and Author: Alex Wade (Photo credit: Wikipedia)

I have a friend whose brother is color blind. She told me that it took some years for her family to figure out that he didn’t see the colors like everybody else. When her brother was little, he would use weird colors to make drawings. Once he drew a green dog. When people asked him if he had ever seen a dog that color, he said that yes, many dogs look like that. For him, that shade of green was the same as brown. Another situation she told me was when they went to a beach house that they hadn’t been for a while. Her brother got the family curious by saying that the tap water in the washroom was coming out green.When they went to check it out, the water was actualy brownish, because of the rust inside the water pipes.

This conversation with my friend made me curious, so I’ve checked some information about color blindness online. There are different types of this color vision deficiency. My friend’s brother has difficulties in distinguishing some shades of green, red and brown. He has the red-green color blindness type. But there are rare cases in which the person only sees shades of grey. There are some tests to find out if a person is colorblind or not. Check the picture below. If you can’t see the number 74, you may have the red-green color blindness.

Color blindness is more common in men, as it is caused by damaged recessive genes that are carried by the X chromossome. In my friend’s case, her grandfather was color blind. Her mother then carried the defective genes, but didn’t have the deficiency. When her brother started to mix colors up, her mother soon suspected he could be color blind. So for a woman to be color blind, both of her X chromossomes have to carry the defective genes.

Depending on the type of the color blindness, it may affect the lives of people who have the deficiency. In some countries, they may not be able to get a driver’s license, for example. My friend’s brother has not had any problems so far.


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