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The Challenges of Being Color Blind

By Leslie Keith

 

Everyday as the world is waking up and people are beginning to get motivated, most will look around and experience life in full color. They will see the blue sky, the green grass, the diverse colors of the buildings around them, which range anywhere from plain white to a vibrant blue, and many more sights. However, there are some who start their day with little to no color experience at all. These people are color blind.

Those who are color blind are not actually sight blind. Being color blind simply means that a person has trouble telling the difference between colors or identifying the different colors around them. There isn’t just one type of color blindness either. There are three major types: red-green color blindness, blue-yellow color blindness, and complete color blindness.

Red-Green color blindness is the most common type of a color vision deficiency. It is due to the loss or limited function of red cone, also known as protan, and green cone, also known as deutran, photopigments. There are four different categories in which this vision deficiency is ranged which include: Protanomaly, Protanopia, Deuteranomaly, and Deuteranopia.

Protanomaly is where the red cone photopigment is abnormal. Red, orange, and yellow appear to be a shade of green and colors are not very bright. This is typically a mild condition and doesn’t have much impact on daily living. It is an X-linked disorder and is estimated to only affect one percent of males.

Protanopia is where there are no working red cone cells. The color red will appear as black and certain shades of orange, yellow, and green will appear as yellow. This is also an X-linked disorder and is estimated to only affect one percent of males.

Deuteranomaly occurs when the green cone photopigment is discovered to be abnormal. Yellow and green will appear to be a shade of red while it is difficult to tell the difference between violet and blue. This condition will not have a major change in daily living for those who have it. It is an X-linked disorder and is estimated to have an affect on five percent of the male population.

Deuteranopia is when there are no working green cone cells. People with this condition will see red as a brownish-yellow and green as a beige. It is an X-linked disorder and only affects one percent of males.

Now that the different types of red-green color blindness is known, information about blue-yellow color blindness can be shared. Blue-Yellow color blindness is rarer than red-green color blindness. Blue cone, also known as tritan, photopigments are either missing or have a limited function. There are two types of blue-yellow color blindness which are: Tritanomaly and Tritanopia. People with Tritanomaly have functionally limited blue cone cells. Blue appears greener and it is difficult to tell red and yellow from pink. It is extremely rare and is an autosomal disorder and affects males and females equally. People with Tritanopia lack blue cone cells. Blue appears green and yellow appears violet or a light grey. Tritanopia is a rare autosomal recessive disorder and affects males and females equally.

The last type of color blindness, complete color blindness or monochromacy, is where people don’t experience color at all and the clearness of their vision may also be affected. Just like blue-yellow color blindness, monochromacy only has two types which include: Cone Monochromacy and Rod Monochromacy or Achromatopsia.

Cone Monochromacy is a rare form of color blindness that results from a failure of two of the three cell photopigments to work. There is a red cone monochromacy, green cone monochromacy, and blue cone monochromacy. People with cone monochromacy have trouble distinguishing color because the brain needs to compare the signals from different types of cones in order to see color. When only one type of cone works, the brain can not make this comparison. People with blue cone monochromacy may also have reduced visual acuity, near-sightedness, and uncontrollable eye movements, a condition known as nystagmus. Cone Monochromacy is an autosomal recessive disorder.

Rod Monochromacy, or Achromatopsia, is also rare and is the most severe form of color blindness. It is present at birth. None of the cone cells have functional photopigments. People with Rod Monochromacy see the world in white, gray, and black. Since rods respond to dim light, people with Rod Monochromacy tend to be photophobic – very uncomfortable in bright environments. They also experience nystagmus. This is also an autosomal recessive disorder.

Now that the different forms of color blindness is known the question is: How is color blindness diagnosed? Eye care specialist use a variety of tests to diagnose color blindness that quickly shows the certain type of color blindness.

The most common test for red-green color blindness is the Ishihara Color Test. The test consists of a series of colored circles, known as Ishihara plates, that have a collection of dots in different colors and sizes. Within the circle are dots that form a shape which is clearly visible to those with normal color vision, but invisible or difficult to see for those with red-green color blindness.

Another test is the Farnsworth-Munsell 100 Hue Test. It uses a set of blocks or pegs that are roughly the same color but in different shades. The goal is to arrange them in a line in order of the shades. This test measure the ability to discriminate subtle color changes and is used by industries who depend on the accurate color perception of its employees, such as graphic design, photography, and food quality inspection.

Once someone is tested and diagnosed, there is no cure for color blindness. However, people with red-green color blindness may be able to use a special set of lenses to help them perceive colors more accurately. These lenses can only be used outdoors under bright lighting conditions. Visual aids have also been developed to help people cope with color blindness. There are iPhone and iPad apps, for example, that help people with color blindness discriminate among colors. Some of these apps allow users to snap a photo and tap it anywhere on the image to see the color of that area. More sophisticated apps allow users to find out both color and shades of color. Research is still being done to try and find a cure for the disorder, but no cure has been discovered.

The Factual Information Above was Provided By:

https://nei.nih.gov/health/color_blindness/facts_about

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