Color BlindnessColor blindness or color deficiency is caused by an absence of certain color-sensitive cells in the retina a special light sensitive nerve layer at the back of the eye.
The normal eye has three types of light sensitive cone cells, which located in the retina. Each type is sensitive to either blue, green, or red light. You see colors when these cells detect different amounts of these three primary colors. When one or more of these types of cone cells is absent or reduced in number, you may not see one of these three colors or you may see a different color. The term "color vision deficiency " is often used instead of color blindness because almost always people with “color blindness” can see some color. Very few people with the condition see no color at all. Most color vision problems are inherited (genetic) and are present at birth. Other color vision problems are caused by aging, disease, injury to the eye or as a side effect of certain medications. Inherited color vision problems are much more common than acquired color deficincies and are more common in males. The symptoms of color vision problems vary.Some people having minor problems and others finding great difficulty distinguishing even just a few different shades. The most common test to determine a deficiency in color vision is the Ishihara pseudoisochromatic plate test. In this test, you look at an arrangement of colored dots and identify a pattern, such as a letter or number. The type of color vision problem you have can then be determined by which patterns you can and can't see in the various plates used for the test.
Inherited color vision problems can be treated with the use of a special contact lens. Some acquired color vision problems can be treated,eg:those caused through cataracts can be cured by removal of the cataract, or if it arises as a side effect of medication, often the medication type or dosage can be altered.
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