ColorBlindness FAQ

"NORMAL" COLORVISION

What is Colorblindness?

In the vast majority of cases, “colorblindness” is not the inability to see colors, but rather color confusion.  

With the most common kind—Red/Green color blindness—a person finds it difficult or impossible to differentiate red, green, or yellow, or any colors that contain red, green, or yellow;  cyan (blue + green) or purple (red + blue) which may look gray.

A much rarer type of colorblindness is Blue/Green colorblindness, where a person has difficulty in differentiating blue and green.  

How Common is Color Blindness?

Approximately one in every twelve men (8%), and approximately 1% of women are is Red/Green colorblind.  

Approximately one in every 500 men and women is Blue/Green colorblind.

Other types—including the inability to see any colors—are much more rare.

Is Colorblindness Catching?

No.  You become colorblind because of the genes you get from your parents.

How Do You Get Colorblind?

Red/Green Colorblind

If you are male, you get Red/Green colorblindness by inheriting a gene for colorblindness from your mother.  That’s because the genes for the red and green color receptors in your eye are carried on the X chromosome, and you get only one X chromosome, from your mother.   If on that X chromosome, a male gets a gene for what is called an anomalous (non-standard) red or green receptor, then he is Red/Green colorblind.  Approximately 8% of men are Red/Green colorblind.

Why are more men than women colorblind?

A woman gets two X chromosomes: one from her mother and one from her father.  If she gets two anomalous genes, then she is Red/Green colorblind, so that happens less often than a man getting one gene.

Green/Blue Colorblind

Men and women have equal chance of being Green/Blue colorblind because the gene for this kind of colorblindness is not carried on the X or Y chromosomes.  You have approximately 1 in 500 chance inheriting two of these anomalous genes (one from your mother and one from your father) and of thus being Green/Blue colorblind.

How do These Non-Standard Genes Cause Red/Green Colorblindness?

With the most common kind, the sensitivity range of your red and green receptors are less different than they are in someone with normal color vision.  This means your brain does not get as clear a color signal from your eyes and therefore has difficulty in telling greens and reds apart.  

Is There a Cure for ColorBlindness?

There is no known cure for Red/Green colorblindness.  In rare cases, Green/Blue colorblindness can can be caused by injury or other medical conditions, so in those rare instances a cure may be possible

What about Special Filters?

Filters cannot reverse Red/Green colorblindness.  A specific filter may help you better differentiate some specific shades of reds, greens, or yellows, but it will then make other colors that you could successfully differentiate before more difficult to tell apart with the filter.  

What is Daltonism?

Daltonism is what the British call color blindness.   It is named after John Dalton, who, in 1798, was the first scientist to describe and explain colorblindness.  interestingly, both he and his bother were colorblind.   Colorblindness is known as “daltonisme” in French, and daltonismo  in Spanish, Portuguese and Italian.