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Color Blindness: Types, Causes, Test and Treatment

All about Color Vision Deficiency (Color Blindness): Introduction, Types, Symptoms, Risk Factors, Causes, Test (Diagnosis), and treatment.

Do you think your eyes don’t see all colors? Do you have any confusion in distinguishing red or green color while looking at a combination of colors? If yes, then you may have color vision deficiency (or color blindness). 

While color blindness means the inability to distinguish any of the colors, color vision deficiency is a difficulty in distinguishing specific colors like red or green.

As most of the books and journals use the term “color blindness” to describe any type of color vision deficiency, we are using the term “color blindness” throughout the article. 

Surprisingly, men are more affected by this problem than women. In this article, you will learn a lot about the color vision problem. 

One in every ten men has color blindness. Till now, there is no exact cure for this problem, but there are special glasses and contact lenses that help color blind people see the color to some extent.


The person is said to have color vision deficiency if he/she sees colors differently than most people. Most of the time, they have a lot of difficulty in distinguishing the color, but we can’t call it a severe illness.

Colorblind people do not have difficulty in their daily lifestyle as they can adjust colors and combinations in their specific way, based on the hue and contrast of the objects. 

People who have color vision deficiency are usually not able to differentiate between red and green colors, but some people are unable to differentiate between red, green as well as blue colors.

Such people have a big problem while driving on the road because they can’t differentiate between red and green traffic lights.

Color deficiency runs in families due to abnormality in the gene in males. One in every ten men has color blindness. Till now, there is no exact cure for this problem, but there are special glasses and contact lenses that help color blind people see the color to some extent.

The retina inside the eyes is responsible for the inability to distinguish colors. There are primarily two types of cells in the retina, rod cells which are active mostly in dim light and dark, and cone cells activate in bright light and are responsible for identifying color and contrast.

Again, there are three types of cone cells namely, red, green, and blue, responsible for thousands of color combinations. That is why red, green, and blue are called primary colors. 

In the case of color blindness, one or more types of cone cells are not present in the retina or do not work effectively. Likewise, all types of cone cells are absent in some cases which are called total color blindness. 

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Types of Color Vision Deficiency

Red and green color vision deficiency is the most common type of color blindness which makes it persons hard to distinguish between red and green colors. 

Another type of color vision deficiency makes it hard to tell the distinction between blue and yellow color. 

People with a rare type of color vision defect called total color blindness don’t see color at all.

The three types of inherited or congenital color vision deficiencies are (Source: Wikipedia): 

Monochromacy: total color blindness

–Rod monochromacy (achromatopsia): it is the inability to distinguish any colors due to absence or nonfunctioning of retinal cone cells

–Cone monochromacy: damage or lack of more than one cone in the retina


–Protanopia: the complete absence of red cone cells in the retina

–Deuteranopia: it is the complete absence of green cone cells in the retina

–Tritanopia: the complete absence of blue photoreceptors in the retina

Anomalous trichromacy

–Protanomaly: it is caused by the altered spectral sensitivity of red retinal receptors (closer to green receptor response) results in poor red-green hue discrimination

-Deuteranomaly: it is caused by the altered spectral sensitivity of green retinal receptors (closer to red receptor response) results in poor red-green hue discrimination

-Tritanomaly: it is a hereditary color vision deficiency affecting blue-green and yellow-red/pink hue discrimination due to malfunctioning S-cone (cone responsible for blue color)

Symptoms of Color Vision Deficiency

It is known from the name that a color-blind person has a problem differentiating red, green, or blue color. They may have trouble seeing:

  • how bright colors are
  • the difference between colors
  • different shades of colors

The symptoms are often so mild that you may not notice them quickly. And once you become adept at seeing colors in your own way, then you do not even know that you have color blindness.

People with the severe color problem may also have other symptoms, such as nystagmus (quick jerk or pendular side-to-side eye movements) or extreme sensitivity to light (photophobia)

Color Blindness Risk Factors

Generally, men are at a much higher risk of having color vision deficiency than women. Red-green (R-G) color vision deficiency is the most common form and it is followed by blue-yellow color vision deficiency and total color blindness.

In Northern European descent, R-G color blindness is found up to 8 percent in males and 0.5 percent in females. The persons with the following systemic and ocular diseases are at higher risk of developing color blindness:

  • Diabetes
  • Glaucoma
  • Macular degeneration
  • Parkinson’s disease
  • Chronic alcoholism
  • Leukemia
  • Sickle cell anemia


Generally, the most important cause of color blindness is genetic (or inherited), which means they have been received from your family. If the cause of color vision deficiency is genetic, your color vision will neither improve nor deteriorate over time. 

Some inherited diseases that cause color blindness are:

  • Cone-rod dystrophy
  • Cone-dystrophy
  • Achromatopsia
  • Blue-cone monochromatism
  • Leber’s congenital amaurosis
  • Retinitis pigmentosa (RP)

In addition to genetic factors, you can also have color blindness if you have any disease or injury that can affect your eyes, visual pathway, or brain. 

Some of the systemic and ocular conditions responsible for acquired color vision deficiency are sickle cell anemia, diabetes, macular degeneration, Alzheimer’s disease, multiple sclerosis, optic nerve atrophy, Parkinson’s disease, chronic alcoholism, leukemia, and medicines used for the treatment of tuberculosis, arthritis, neurological disorders, autoimmune diseases, heart diseases, erectile dysfunction. 

In acquired color blindness, one eye may be more affected than the other, and if the underlying disease is treated, it may improve color loss. In hereditary or genetic color blindness, however, both eyes are equally affected. 

Your ability to see color gradually deteriorates according to your age due to the change in color of the natural crystalline lens of the eyes (lens becomes yellowish with age). 

Diagnosis: Color Blind Test

If you have trouble seeing certain colors or differentiating certain colors from the mixture of colors, your eye doctors (optometrist or ophthalmologist) will do a color blind test to see if you have color blindness.

During this time your eyes will be thoroughly tested and you will be shown plates of different designs made of colored dots (Ishihara color blind test), in which the numbers or shapes are hidden in a different color, which you have to identify and tell.

If you have color blindness then you will have trouble seeing the dots and your doctor will advise you for the treatment of color blindness. 

For online color blind test visit ENCHROMA COLOR BLIND TEST

Treatment of Color Blindness

Most people with color vision deficiency don’t require treatment. If the cause of color deficiency is acquired due to disease, injury, or medicines, it can be treated. 

With the treatment and gradual improvement of underlying disease or injury, your color vision will return to normal.

In some cases, you are prescribed to wear a colored filter (red-tint) over glasses or colored contact lenses, which will enhance the perception of color. But it is not the treatment option for all types of color vision deficiency. 

Home remedies can help to reduce the effect of color blindness in our daily life. 

-learn to remember colored objects in order, traffic lights can also be remembered in order (may vary in different countries).

-regularly label colored items that you want to match with other colored items

-take the help of a person with normal color vision to choose your clothes and help label them. Place your clothes in your wardrobe or drawer in an orderly manner so that the colors worn together are close to each other. 

-there are apps (color detectors) for phones and PCs that can help you identify colors.


  • Learn about Color blindness https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/color-blindness
  • Bang W (2011), Points of view: Color blindness https://www.nature.com/articles/nmeth.1618
  • Ishihara http://www.eyemagazine.com/feature/article/ishihara

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