Definition

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.

Color blindness is when light-sensing receptors in the eye do not work properly.

Causes

Most color blindness is inherited. Less frequently, color blindness is caused by a disease that affects the optic nerve or retina. This is referred to as acquired color blindness.

Risk Factors

Heredity 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

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

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

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.

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

Prevention

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

Howard Hughes Medical Institute http://www.hhmi.org

Canadian Ophthalmological Society http://www.eyesite.ca

Harrar, Sari N. Blue clue. Prevention. 2004; 56(11): 38.

More on color blindness. Child Health Alert. 2005; 25: 4-5.

Tsuda H, Ishikawa H, et al. A neuro-ophthalmological analysis in 80 cases of multiple sclerosis. Rinshō shinkeigaku (Clinical neurology). 2004; 44:513-521.

What is color blindness? EyeSmart website. Available at:
http://www.geteyesmart.org/eyesmart/diseases/color-blindness.cfm
Accessed May 26, 2015.