What Is Color Blindness?

The Howard Hughes Medical Institute explains that color blindness is more prevalent in men than women. In fact, color blindness affects approximately 10 million men in the United States. It has been established that color blindness is an inherited trait that is carried in the X chromosome. Women have two sets of X chromosomes and men have just one. The extra set of X chromosomes in women can make up for the color blindness deficit that may be present in the first set of X chromosomes; unfortunately, because men lack the second set of X chromosomes, there is no opportunity for compensation.

Misconceptions

• Contrary to popular belief, those who are color blind do not see strictly in grayscale. In fact, completely lacking the ability to see color is a very rare genetic occurrence referred to as achromatopsia. The Achromatopsia Network reveals that there are approximately 100 million rod-shaped photoreceptors in the human eye and 6 million cone photoreceptors. Someone who has inherited achromatopsia has non-functioning cones; therefore, he must completely rely on rod vision for sight. Rods do not illuminate color, so for someone with achromatopsia, the world can only be seen through varied shades of gray.

Red and Green

• The inability to distinguish between the colors red (protanopia) and green (deuteranopia) is the most common form of color blindness, and a challenge that approximately 6 percent of the male population, and 4 percent of the female population, must face. A person affected by the red and green color deficit often sees the two individual colors differently than someone without the deficit, but in some cases there may be a complete absence of these two colors together. According to All About Vision, the inability to detect these two colors can be attributed to a malfunction of photoreceptors within the eye that register the colors red and green.

Blue and Yellow

• The inability to see the color blue is a color-blind deficit referred to as tritanopia. But, a person with tritanopia may also have a difficult time identifying the color yellow as well. The University of Illinois at Chicago Department of Ophthalmology and Visual Sciences explains that tritanopia is sometimes referred to as "blue-blindness" and occurs equally among males and females.

Evaluation

• According to The Eye Care Source, the most common test used to evaluate color blindness consists of Ishihara plates. Circular plates contain smaller circles that are strategically colored to determine if there is a deficiency present. Some of the plates have numbers in the center that are of a contrasting color to help evaluate the extent of the color loss and which category the deficiency falls into.

Treatment

• There is no cure for color blindness, but treatments such as the use of special lenses may help to enhance colors, making them more recognizable. If color blindness is recognized in the early stages of a child's life, specialized learning materials can be used in school that will help make colors more discernable. Unfortunately, the inability to view colors normally can interfere with earning a living throughout adulthood. For safety reasons, those who are color blind are unable to secure jobs as aircraft pilots or police officers.