Color Blindness

What is color blindness?

Color blindness occurs when you are unable to see colors in a normal way. Most commonly, color blindness (also known as color deficiency) happens when someone cannot distinguish between certain colors, usually between greens and reds, and occasionally blues.

Color blindness can occur when one or more of the color cells of the eye’s retina are absent, nonfunctioning, or detect a different color than normal.

There are different degrees of color blindness. Some people with mild color deficiencies can see colors normally in good light but have difficulty in dim light. Others cannot distinguish certain colors in any light. The most severe form of color blindness, in which everything is seen in shades of gray, is uncommon.

Color blindness is usually something that the patient has from birth; when parents may notice a problem with their child when he is learning his colors. However, it can be acquired later in life. Change in color vision can signify a more serious condition. Anyone who experiences a significant change in color perception should see an eye doctor.

Color blindness since birth usually affects both eyes equally and remains stable throughout life. Whereasacquired color blindness often affects both eyes differently, and usually gets worse over time.

Except in the most severe form, color blindness does not affect the sharpness of vision. The inability to see any color at all and to see everything only in shades of gray is often associated with poor vision, nystagmus (involuntary, rapid eye movement), and light sensitivity.

Who is at risk for color blindness?• Men are at much higher risk for being born with color blindness than women, who seldom have the problem. An estimated one in ten males has some form of color deficiency.• Having certain conditions, including glaucoma, macular degeneration, Alzheimer’s disease, Parkinson’s disease, chronic alcoholism, leukemia and sickle cell anemia, may increase your risk for acquired color deficiency.• Certain medicines may also increase your risk for acquiring color blindness. The medicinehydroxychloroquine (Plaquenil) can cause color blindness. It is used to treat rheumatoid arthritis, among other conditions.• Eye or head trauma.• Some vascular diseases.


Your eye doctor will be able to conduct a simple test to determine if you have color blindness.

The test consists of showing you a pattern made up of multi-colored dots. If you do not have a color deficiency, you will be able to see numbers and shapes among the dots. If you are color blind, you will have a hard time finding the number or shape in the pattern or you may not see anything in the pattern at all.

A person with color deficiency may not be able to see the number 5

among the dots in this picture

How can color blindness be treated?

There is no treatment for color blindness developed since birth. It usually does not cause any significant disability. However, there are special contact lenses and glasses that may help people with color blindness tell the difference between similar colors.

Acquired forms of color blindness may be treated by addressing the underlying condition or medicine that caused the problem.