What is color blindness?

Color blindness is when you don’t see colors in a normal way. It’s also known as color vision deficiency or dyschromatopsia.                                        

The retina is the light-sensitive part of your eye that sends visual information to your brain. Your retina has special cells that detect color. These are called cone cells. A normal retina has 3 types of cone cells: green, red, and blue. If you have a problem with any of these types of cone cells, you may have problems seeing colors. But in most cases, the condition will not affect your overall vision sharpness.

The types of color blindness include:

  • Trouble seeing the difference between red and green. The two colors look the same. This form of color blindness is common. It occurs much more often in men than in women.
  • Trouble seeing the difference between blue and yellow. This is less common.
  • Seeing only shades of gray. This type is rare.

What causes color blindness?

In most cases, a person is born with color blindness. But there are types of acquired color blindness. These can be more common in older adults.

Color blindness that’s present from birth results from problems with the cones in the retina. This happens because of problems in the genetic information passed from parents to their child. An abnormal gene can cause certain type of cones to form incorrectly, or to not form at all. Problems with the red or the green cones are more common than problems with the blue cones.

The most common kind of color blindness is because of a gene problem. 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.

In rare cases, color blindness can be caused by a health condition. These include:

  • Optic neuritis
  • Macular degeneration
  • Glaucoma
  • Diabetic retinopathy
  • Multiple sclerosis
  • Parkinson disease
  • Alzheimer disease
  • Other diseases that affect the optic nerve or retina
  • Diseases that affect the eye lens
  • Toxic effects from medicines
  • Stroke, especially in the occipital lobe

Who is at risk of getting color blindness?

Having other family members with color blindness may increase ypur 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 healthcare provider about the risks for your children.

What are the symptoms of color blindness?

The most common kind of color blindness is trouble seeing the difference between reds and greens. They may both look gray. 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. These may look gray.

Most kinds of color blindness don’t affect the sharpness of your vision. Usually, the only problem is trouble distinguishing colors.

If you have a rare and severe form of color blindness, you only see shades of black, white, and gray. This is called achromatopsia. You may also 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 because of 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. These typically look like circles containing hundreds of dots of different sizes. Some of the dots have a different color than the others and are arranged to create a number or figure. If your color vision is normal, you will be able to identify the number or figure. If your color vision is impaired, you won't be able to. Your eye healthcare provider may also ask you to use a special device that needs you to try to match two colored lights on a screen.

If your eye care doctor finds a problem, you might need 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. 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 cure for color blindness that is present from birth. If you have this condition, you may benefit from special color glasses or tinted 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 healthcare 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. But you may be able to reduce your chance of having color blindness later in life. Get regular eye exams, see your healthcare provider regularly, and follow a healthy lifestyle. These may help reduce your risk for acquired color blindness.

Coping with color blindness

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

  • Seeing the difference between ripe and unripe fruit
  • Finding matching items of clothing
  • Seeing if meat is undercooked
  • Telling sporting jerseys apart in a sporting event
  • Seeing information shown in color on graphs or charts

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 problem.

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.
  • 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.

Next steps

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

  • Know the reason for your visit and what you want to happen.
  • 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 name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • 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.