What Is Color Blindness?

Color blindness, also called color vision deficiency, is usually an inherited condition that can range from a slight difficulty in telling the shades of a color apart to the rare condition of not being able to identify any color.

The most common type of color blindness is one in which the person can't distinguish between red and green. The second most common type is the inability to distinguish between blue and yellow.

Causes

The dazzling visual experience of color begins when light strikes nerve cells in the retina at the back of the eye. These cells are called rods and cones. Rods help us distinguish light and dark; cones contain components that identify color and send the message to the brain that enables us to see color. People who are color blind are lacking in one or more of the components contained in the cone.

Color blindness affects millions of Americans. The most common type, red-green color blindness, is much more common in boys than in girls, affecting 8 percent of males and 0.5 percent of females, according to the US National Library of Medicine. White children are affected more than children in other ethnic and racial groups.

Types

Color blindness can range from mild to severe. In the milder forms, a person will not see colors with the same intensity that people with normal color vision see them. In the more severe forms, a person will have difficulty distinguishing among colors.

The most severe form of color blindness, achromatopsia, is the inability to see any color. It is rare.

If you suspect someone has a problem with colors, suggest that he or she see a doctor for testing. The test usually involves trying to identify a shape in a multicolored dot-pattern book. The shape or a number in the middle of the dot pattern can be identified by people with normal color vision.

Helping a child cope

If your child has inherited color blindness, you can work with your child's teachers to help your child learn effective ways to cope with it. If there is another cause for color blindness, then treatment of that cause may help. Here are suggestions:

• Learn all you can about color blindness.

• Be sensitive to your child's condition. Provide visual cues other than color, such as textures and patterns.

• Make sure teachers know your child is color blind.

• Buy scented crayons.

• Let your child pick certain articles of clothing. Then choose other articles that match those choices.