What is color blindness?

Color blindness

Color blindness results from an absence of color-sensitive pigment in the cone cells of the retina, the nerve layer at the back of the eye that converts light into nerve signals that are sent to the brain. A person with color blindness has trouble seeing red, green, blue, or mixtures of these colors.

Most color vision problems are inherited and are present at birth. Other color vision problems, called acquired colored vision problems, are caused by aging, disease, injury to the eye, optic nerve problems, or a side effect of medicines. Inherited color blindness is more common than acquired color blindness and affects males far more often than females.

Inherited color vision problems cannot be treated or corrected. Some acquired color vision problems can be treated, depending on the cause.

What happens when you have color blindness?

Color blindness affects people in different ways. You may be able to see some colors or a few shades of color but not others. Or you may see enough colors that you may not know that you are color blind until you have a routine eye exam. In rare cases, some people see only black, white, and gray.

For some people it may be hard to tell if a piece of red meat is rare or well done. It can make food look like it's not good to eat. It can also be a challenge to see traffic lights or use technology with red and green LED lights.

What are the symptoms of color blindness?

The symptoms of color vision problems vary.

  • You may be able to see some colors but not others. For instance, you may not be able to tell the difference between some reds and greens but can see blue and yellow easily.
  • You may see many colors, so you may not know that you see color differently from others.
  • You may only be able to see a few shades of color, while most people can see thousands of colors.
  • In rare cases, some people see only black, white, and gray.

How is color blindness treated?

Inherited color vision problems cannot be treated or corrected.

For the most common type of color blindness—red-green color deficiency—no treatment is needed, because you function normally. You may not be aware that you do not see colors the way they are seen by others.

Some acquired color vision problems can be treated, depending on the cause. For example, if a cataract is causing a problem with color vision, surgery to remove the cataract may restore normal color vision.

You can find ways to help make up for a color vision problem, such as:

  • Wearing colored contact lenses. These may help you see differences between colors. But these lenses don't provide normal color vision and can distort objects.
  • Wearing glasses that block glare. People with severe color vision problems can see differences between colors better when there is less glare and brightness.
  • Learning to look for cues like brightness or location, rather than colors. For example, you can learn the order of the three colored lights on a traffic signal.

How is color blindness diagnosed?

Tests can measure how well you recognize different colors.

  • In one type of test, you look at sets of colored dots and try to find a pattern in them, such as a letter or number. The patterns you see help your doctor know which colors you have trouble with.
  • In another type of test, you arrange colored chips in order according to how similar the colors are. People with color vision problems cannot arrange the colored chips correctly.

Because a color vision problem can have a big impact on a person's life, it is important to detect the problem as early as possible. In children, color vision problems can affect learning abilities and reading development. And color vision problems may limit career choices that require you to tell colors apart. Most experts recommend eye exams for children between ages 3 and 5. Vision screening is recommended for all children at least once before entering school, preferably between the ages of 3 and 4.

How can you adapt to color blindness?

There are ways to adapt to the challenge of being color blind. Here are some things you can try.

  • Learn to look for cues like brightness or location, rather than colors. For example, you can learn the order of the three colored lights on a traffic signal.
  • Wear colored contact lenses. These may help you see differences between colors. But these lenses don't provide normal color vision. Be aware that they can distort objects.
  • Wear glasses that block glare. You may be able to see differences between colors better when there is less glare and brightness.

What causes color blindness?

Most color vision problems are inherited (genetic) and are present at birth.

People usually have three types of cone cells in the eye. Each type senses either red, green, or blue light. You see color when your cone cells sense different amounts of these three basic colors. The highest concentration of cone cells are found in the macula, which is the central part of the retina.

Inherited color blindness happens when you don't have one of these types of cone cells or they don't work right. You may not see one of these three basic colors, or you may see a different shade of that color or a different color. This type of color vision problem doesn't change over time.

A color vision problem isn't always inherited. In some cases, a person can have an acquired color vision problem. This can be caused by:

  • Aging.
  • Eye problems, such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy.
  • Injury to the eye.
  • Side effects of some medicines.

What is color blindness?

Color blindness is a vision problem that means you have trouble seeing shades of red, green, or blue or a mix of these colors. It happens when there's a problem with some of the cells found in the layer of nerves (retina) at the back of the eye.

Almost always, the problem runs in families and is something you are born with. It's found more often in males than in females. Color blindness that you are born with can't be treated or corrected. But you can learn ways to adapt to being color blind.

How can you help a child who has color blindness?

Color vision problems may make it harder for children to learn and read, which can lead to poor schoolwork and low self-esteem.

You can help your child these ways.

  • Make sure your child is tested for color vision problems during routine eye tests.
  • Tell your child's teachers and other school staff about the problem. This may be helpful. Suggest seating your child where there is no glare and using a color of chalk that your child can see.

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The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.