Color Blindness

(Color Vision Problem; Color Vision Deficiency)


Color blindness usually affects a person’s ability to tell the difference between shades of red and green or shades of blue and yellow. Complete color blindness, which is rare, causes a person to see most objects in shades of gray.

Causes    TOP

Color blindness occurs when light-sensing receptors in the eye do not work properly. In most people, color blindness is inherited. Acquired color blindness is caused by a disease that affects the retina or optic nerve. It can also be caused by certain medications.

Anatomy of the Eye

Normal Anatomy of the Eye
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Risk Factors    TOP

Genetics is the main risk factor for color blindness. If your mother, father, or grandparents were color blind, you may have the gene(s) that cause color blindness. The condition is also more common in men.

The following risk factors increase your chance of developing acquired color blindness:

  • Having certain diseases, such as glaucoma and macular degeneration
  • Taking certain medications that can damage the retina and optic nerve, such as hydroxychloroquine

Symptoms    TOP

People with color blindness cannot distinguish between some colors, especially red and green or blue and yellow.

Most people with inherited color blindness do not have symptoms. However, they may not see colors the same way as others without color blindness.

Diagnosis    TOP

You will be asked about your symptoms and medical history. An eye exam and vision test will be done. Or, you will be referred to an ophthalmologist (eye specialist) for testing. You may want to consider going to an eye specialist first. The eye specialist may be better able to make a diagnosis.

Your vision will be tested. This can be done with:

  • Ishihara plates test
  • An arrangement test

Treatment    TOP

There is no cure for inherited color blindness. Most people with color blindness learn methods to tell the difference between colors.

Talk with your doctor about coping skills. Depending on the level of color blindness, some doctors recommend using color-corrective glasses or contact lenses. Some mobile devices have apps that can help someone determine the differences between colors and some shades of color.

In some cases of acquired color blindness or deficiency, treatment of the medical problem or changing medications may correct the color blindness.

Prevention    TOP

To help reduce your chances of getting acquired color blindness, discuss your use of prescribed medications with your doctor.


American Academy of Ophthalmology
Howard Hughes Medical Institute


Canadian Association of Optometrists
Canadian Ophthalmological Society


Colour blindness. Colour Blind Awareness website. Available at:
...(Click grey area to select URL)
Accessed June 1, 2016.
Facts about color blindness. National Eye Institute (NEI) website. Available at: Updated February 2015. Accessed June 1, 2016.
What is color blindness? American Academy of Ophthalmology website. Available at:
...(Click grey area to select URL)
Accessed June 1, 2016.
Last reviewed June 2016 by Michael Woods, MD
Last Updated: 6/1/2016

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