Shades of Gray? The Facts of Color-blindness
En Español (Spanish Version)


Color-blindness is a common condition that is mainly found in men. It is also somewhat of a misnomer. Color-blindness usually doesn't make someone blind to all colors. It is more of a color vision defiency. The reason is because people with the deficiency see colors, but less of them than everyone else.

In most cases, color-blindness is an inherited disorder that is passed from mother to son. Others acquire color-blindness from a health condition or medications that cause damage to the retina of the eye. The retina is the back part of the eye where there are two types of cells that are light sensitive. The light sensitive cells are called rods and cones. The cone cells are able to detect three colors: red, green, and blue. The type of color-blindness you have depends on how the many of and how well the three cone cells work.

Types of Color-blindness

There are several types of color blindness. In each type, the cones work a little differently. Here is an overview of each type.

Trichromacy
People with normal color vision use all three types of cone cells which help differentiate colors and shades of colors. This is called trichromacy. There are variations of trichromacy, which affect color vision.

With anamalous trichromacy, all three cone cells work, but one is slightly off creating a wide range of color perception depending on which cone is faulty:

  • Protanomaly—reduced ability to see red
  • Deuteranomaly—the most common type, with reduced ability to see green
  • Tritanomaly—extremely rare, with reduced ability to see blue
People who have reduced ability to see reds and greens are known as red-green color-blind. They have trouble seeing differences with reds, greens, browns, oranges, yellows, and grays. They also have a tendency to confuse blues and purples.

Dichromacy
Dichromats have two types of cones that see color and one that doesn't. Dichromacy includes:

  • Protanopia—inability to see red, with confusion among dark shades, such as dark red and black
  • Deuteranopia—inability to see green, with confusion among medium shades of red that have similar tones to greens or oranges
  • Tritanopia—inability to see blue
People who are color-blind to reds or greens see most colors as muddy green, blue, or yellow.

Monochromacy
Monochromacy is very rare. People with monochromacy only see shades of gray with no color at all, much like an old black and white movie.

Living with Color-blindess
Color-blindness is not routinely tested for. A child may be tested if they are having trouble telling shades of color apart, or is doing poorly in school. For those that have inherited forms, there currently are no effective treatments. Some people use tinted glasses, but others find them more difficult to use. Acquired color-blindness sometimes can be treated with a change in medications, stopping medications, or treating the condition causing the deficiency.

For now, the best that somone with color-blindness can do is manage to live with it. It is true to a certain extent that someone who can't see color doesn't know what they miss, but in a world of color, not seeing it makes navigating life difficult. Take a minute to look around you and imagine what it would be like to see shades of the same color or no color at all.

It affects many aspects of daily life. It may keep someone from a job they want, like a chef, pilot, graphics designer, or doctor. With those that have jobs, it can create problems in the workplace. For example, color documents with graphs may create confusion or misunderstanding. New employees may struggle to hide their deficiency until they feel comfortable enough to fit in for fear of being fired. Others may have trouble with traffic lights with its reds and greens, while others may struggle differentiating signal lights on cars.

Everyday diversions, like art or gardening, may hold no interest to someone who can't detect color differences. And then there is the daily task of getting dressed or putting on make-up.

For now, more research is needed to determine if treatments need to be developed or if living with color-blindness is the only option.




RESOURCES:
Nemour's Kids Health

The American Academy of Ophthalmology

CANADIAN RESOURCES:

Canadian Family Physician

References:
Colour blindness. Colour Blindness Awareness website. Available at: http://www.colourblindawareness.org/colour-blindness. Accessed October 4, 2013.

Types of colour blindness. Colour Blindness Awareness website. Available at: http://www.colourblindawareness.org/colour-blindness/types-of-colour-blindness. Accessed October 4, 2013.

What is color blindness? The American Academy of Ophthalmology website. Available at: http://www.geteyesmart.org/eyesmart/diseases/color-blindness.cfm. Accessed October 4, 2013.

Last Reviewed October 2013



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