Poor color vision is an inability to distinguish between certain shades of color. Although most people call it colorblindness, true colorblindness describes a lack of color vision. The ability to see only shades of gray is rare.

Most people with poor color vision can't distinguish between certain shades of red and green in dim light. Some people can't distinguish between red and green shades even in bright light. Less commonly, people can't distinguish between shades of blue and yellow.

Poor color vision is an inherited condition in most cases. However, eye diseases and the effects of some medications also can cause color deficiency. About 8 percent of men and 1 percent of women have a deficiency of color vision.

Screening and diagnosis

If you have trouble seeing certain colors, your eye doctor can quickly and easily test to see if you have a color deficiency. Many ophthalmologists use a book containing several multicolored dot-pattern tests to provide a simple and accurate assessment of color vision deficiencies inherited at birth. If you don't have a color vision deficiency, you'll be able to pick out numbers and shapes from within the dot patterns. However, if you do have a color vision deficiency, you'll either find it difficult to see anything among the dots, or you won't see anything at all. 

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Treatments