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Color Blindness

What is color blindness?

Color blindness is when you are unable to see colors in a normal way. It does not mean you can’t see color. It means you perceive color in a different way.

The retina is the light-sensitive part of your eye that sends visual information to your brain. Your retina has three types of cone cells (green, red, and blue). These are special cells that detect color. If you have a problem with any of these types of cone cells, you may have problems distinguishing colors. In most cases, the condition will not affect your overall visual sharpness.

If you have the most common kind of color blindness, you have trouble distinguishing red from green. The colors appear the same. This form of color blindness is quite common. It is much more common in men than in women. You may have trouble distinguishing blue from yellow, which is less common. Even more rarely, some people with color blindness can only perceive shades of gray.

In most cases, color blindness is present at birth. But there are types of acquired color blindness. These may be more common in older adults.

What causes color blindness?

Most of the time, color blindness is present from birth. It results from problems with the cones normally found in your retina. This happens because of abnormalities in the genetic information passed from parents to their children. An abnormal gene can cause a certain type of cones to form improperly, or not to form at all. Problems with the red or the green cones are more common than problems with the blue cones.

In rare cases, color blindness can be caused by a medical condition such as:

  • Optic neuritis
  • Macular degeneration
  • Diabetic retinopathy
  • Other diseases affecting the optic nerve or retina
  • Diseases affecting the lens
  • Toxic effects from drugs
  • Stroke (especially involving the occipital lobe)

Who is at risk of getting color blindness?

Having other family members with color blindness may increase a person’s risk for the problem. Even if you don’t have the condition, you may be at risk of passing it to your children. If the problem runs in your family, ask your health care provider about the risks for you and your children.

The most common kind of color blindness is due to a gene. The gene is found on the X chromosome. For a man to get this kind of color blindness, he needs only to inherit the gene from his mother. For a woman to get color blindness, she must inherit the gene from both her mother and her father. This is why color blindness is much more common in men.

What are the symptoms of color blindness?

The most common kind of color blindness is trouble distinguishing reds from greens. Some people may be able to distinguish between these colors, but only with great difficulty. Others might not be able to tell the difference at all. Depending on the type of problems you have with your cones, your color blindness might be very slight. You may not even know you have it for many years. Other people have red/green color blindness that is more severe. Less commonly, color blindness causes a problem seeing the difference between blue and yellow.

Most kinds of color blindness do not affect the sharpness of your vision. Usually, the only problem present is trouble distinguishing colors. If you have a rare and severe form of color blindness (called achromatopsia), you only see shades of gray. You may have other symptoms. These include poor sharpness of vision and involuntary eye movements.

These kinds of color blindness are present from birth. They always affect both eyes. If you have acquired color blindness due to a health condition, your symptoms may get worse slowly over time. They may also affect one eye but not the other. You may find it especially hard to pick out dark colors, especially blues.

How is color blindness diagnosed?

An eye doctor can diagnose color blindness with a special eye exam. The exam may use special pictures to see if you can tell the difference between colors. If your eye care doctor finds a problem, you might need even more detailed color vision tests. These are to find out how severe the problem is.

A color blindness test may be given as part of a standard eye exam. Other times, a parent or teacher might ask for an exam if a child appears to have trouble seeing colors. People with mild color blindness might not find out until they take a screening test for a job that requires seeing colors accurately. Anyone who has a family history of color blindness needs screening.

How is color blindness treated?

Currently, there is no treatment for color blindness that is present from birth. If you have this condition, you may benefit from special color glasses or contact lenses. These aids may help you distinguish between certain shades, but they do not restore normal color vision.

If you have acquired color blindness, your health care provider will try to address your underlying problem. This can help cause the color blindness to become less severe. Or, it may cause it to go away. In other cases, treatment may help stop the symptoms from getting worse.

Can color blindness be prevented?

There no way to prevent color blindness that is present at birth. You may be able to reduce your chance of having color blindness later in life. Get regular eye exams, see your health care provider regularly, and have a healthy lifestyle. These may help reduce your risk of getting color blindness later in life.

Coping with color blindness

If you are color blind, you may have problems with certain everyday tasks such as:

  • Distinguishing ripe and unripe fruit
  • Finding matching items of clothing
  • Distinguishing undercooked meat
  • Telling sporting jerseys apart in a sporting event
  • Distinguishing information presented on graphs

Organizing and labeling objects may help you with some types of tasks. People with color blindness can also learn to focus more on spatial arrangement. (For example, the red light is always at the top in a traffic light.) It may be helpful for your friends and work colleagues to know that you have color blindness.

Certain careers may not be an option for people with color blindness. If you are considering a career, make sure your color blindness will not be a major barrier.

Key points

Color blindness happens when you are unable to distinguish certain colors in a normal way. This happens because of problems with special cells, called cones, found in the eye.

  • Color blindness is usually present from birth. Less commonly, it comes on later in life, because of another medical condition.
  • If you have the most common form of color blindness, you may have trouble distinguishing reds and greens.
  • Some forms of color blindness are more severe than others. Some people might not know they have color blindness for many years.
  • Currently, there is no treatment for color blindness present from birth. Special glasses, contextual clues, and organizational strategies may help you cope with color vision deficiency.
  • You may need testing for color blindness if you have a family member with the condition.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Haupert, Christopher L, MD
Online Medical Reviewer: Ziegler, Olivia, MS, PA
Last Review Date: 10/1/2016
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