What are the causes of Color Blindness and how does it present?

What is Color Blindness?

The first report on color blindness was written by the British chemist John Dalton who was himself afflicted with it. Your ability to see colors across the spectrum begins with your eyes ability to accurately distinguish the 3 primary colors; red, blue and green. Light enters the eye through the lens and passes through the transparent main body of the eye called the vitreous body. It then hits color sensitive cells called cones in the retina at the back of the eye. Chemicals in these cones distinguish among colors and send information through the optic nerve to the brain. If your cones lack one or more light sensitive chemicals you may see only two colors for example; either red and green or blue and yellow.

Symptoms:

The most common color deficiency is an inability to see red and green. Instead of a normal spectrum, a person with red-green color deficiency will have one or two neutral or grey areas where these colors normally appear. Most people with red-green deficiency are not aware of their problem. For them leaves are green and roses are red but they may not see the same colors as people with normal vision. Their green may be what normal sighted people see as yellow. Because they know leaves are green, they interpret what they see as green. n most cases, the genetic information that results in color deficiency is passed from mother to son. About one in twelve boys is born with some degree of color deficiency. An eye doctor can quickly and easily test to see if you have a color deficiency. The test uses a book containing several multi-colored, dot-patterned test to provide a simple and accurate assessment of color vision deficiency is inherited at birth. If you do not have a color vision deficiency, you will be able to pick out numbers and shapes from within the dot patterns. However, if you have a color deficiency, you will either find it difficult to see anything among the dots or you will not see anything at all. There is no cure or prevention for color vision deficiencies.

Find out more about Color blindness by visiting the National Medical Library's MedlinePlus Encyclopedia

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