Colour Blindness -- Colour Deficiencies

"Color Vision Deficiency" is the more accurate term for the condition that people many people call Color Blindness.

4The term Color Blindness is often misunderstood as only meaning the inability to see or discriminate any colors at all.

The World as a "Colourblind" person sees it...

As you see it As a red/green colour deficit person sees it As a blue/yellow colour deficit person sees it
earth from space image earth, deuteranope earth, tritanope

 

This is an Ishihara plate commonly used to check for red/green color blindness This is what a red/green color-blind person might see. Note that the digit (3) is practically invisible
original image as seen by a deuteranope


4Having defective color vision does not mean that one sees everything in black, white, and gray. It is only in extremely rare cases that no colors can be discriminated. This condition is called achromatopsia or monochromatism.

4In most cases, a color deficient person is able to see certain colors normally and unable to distinguish certain other colors and shades normally.

4Approximately 8.0% of men and 0.5% of women in North America and Europe have a color vision deficiency. This accounts for more than 15 million people in North America with defective color vision.

Color vision deficiencies are traditionally categorized into three categories.

Deuteranamolous - Red and Green color confusion 
Protanamolous - Red and Bluish-Green color confusion
Tritanamolous - Blue and Yellow color confusion

Deuteranopia is the most common type of color vision deficiency and Tritanopia is the most rare type of color vision deficiency.

4The severity of color vision deficiency varies from person to person.

4Although the majority of people with defective color vision have inherited it, people can also acquire defective color vision over the course his life.
 

COLOUR DEFICIENT POPULATION
 

Area Males Females
North America 8.00% 0.50%
Europe 8.76% 0.50%
Eastern Europe 9.31% 0.50%
Asia 6.00% 0.50%
Africa 4.00% 0.50%

 

Caucasian Population Males Females
Normal Trichomats 91.9% 99.6%
Anomalous Trichromats 5.5% 0.4%
Dichromats 2.6% 0.05%
Monochromats 0.0015% 0.015%

Note:
There are more than 15 million Inherited Color Deficient people in North America alone. There are more than 250 million Color Deficient people world-wide. Acquired Deficient people are excluded from the above figures.

Take a Quick Colorblindness Test