The types of color blindness depend on the causes, but you should know how to distinguish them in order to learn how to treat them right.

Color blindness is a deficiency, almost always inherited, that affects men more than women. In its most serious form, patients can only see in black and white.

Color blindness is a vision defect that makes it difficult or impossible to distinguish colors. The degree of involvement is highly variable. Sometimes it is only difficult to differentiate some shades of red, green, yellow or blue; in the most severe cases, the patient distinguishes no color.

This condition has to do with an abnormality in photoreceptor cells in the eye called rods and cones. These work in combination and connect with the brain centers through the optic nerve. When cells are defective they fail to produce the image of pigments and color blindness arises.

What are the causes of color blindness?

The perception of color occurs in the retina, since that is where the rods and cones are. The seconds detect white, black and the entire range of gray. The cones are sensitive to blue, red and green. Their combined work makes a person can perceive the different colors and their tones correctly.

Color blindness occurs when the rods, cones, or both are abnormal or absent. The reasons for this to occur are hereditary, due to the action of medications or the effect of a disease. Let’s see.


Most cases of color blindness have a hereditary cause. The most common is that it is the mother transmits it to the child and that it does not generate any other type of visual defect. Although women are the carriers of the defective chromosome that causes the disease, men are more likely to inherit it.


There are several medications that can cause distortion in color vision. Some antipsychotics, such as chlorpromazine and thioridazine, cause color blindness in certain cases.

Likewise, the antibiotic ethambutol, which is used to treat tuberculosis, can alter the visual perception of colors. These adverse effects should be considered by the physician whenever the drugs in question are prescribed.


There are several eye diseases that can lead to color blindness. Glaucoma, for example, sometimes damages the optic nerve and may decrease the ability to distinguish colors or shades. On the other hand, macular degeneration and diabetic retinopathy destroy the retina and cause the same effect.

In cataracts, the perception of color is not lost, but it can be significantly attenuated. Other diseases such as diabetes, multiple sclerosis, Alzheimer’s disease, or Parkinson’s disease can also cause color blindness.

Other factors

It has been established that aging could cause a deficiency in the perception of color in some people. Likewise, exposure to toxic chemicals such as styrene, which is in some plastics, is associated with the loss of the ability to differentiate colors.

Types of color blindness

A first classification of the types of color blindness is considering the cause that produces them. From that point of view there are two categories: inherited or acquired. The first is the one that parents transmit to children and the second is the effect of some other factor.

Color blindness can also be classified according to the type of color perception dysfunction. This gives rise to four modalities: anomalous trichromy, achromatic, monochrome, and dichromacy. Let’s see each of them.

Anomalous trichromy

The affected person has cones on the retina, but these are defective and cause color confusion. It is the most common form of color blindness and can occur in three forms:

  • Protanomaly: difficulty perceiving red light.
  • Deuteranomaly: errors when perceiving the green light.
  • Tritanomaly: difficulty perceiving blue light.


These are the cases in which the person can only see in black and white with a range of grays included. It occurs because the affected person does not have cones in the retina or has some neurological damage. It is a very rare condition in which there is only 1 case per 100,000 inhabitants.


Monochrome is also the total color blindness or extreme color blindness. Vision is in black and white with a gray range. There are cones in the retina, but two of the three pigments that must be present in these cells are missing. It affects a very small number of people.


It is a form of color blindness that is severe moderate and in which there is no perception of one of the three types of light. As in the case of anomalous trichromy, there are three modalities.


There is a total absence of retinal red photoreceptors. This causes poor color perception at very long wavelengths. Those affected see these tones as if they were cream or gray. It is the most common form of dichromancy.


In this case there is a total absence of the retinal photoreceptors of the green color. It is difficult to perceive colors with medium wavelengths. It is a less severe form of deuteranomaly.


This is the rarest form of color blindness and in it there is a total absence of the photoreceptors of the retina for the color blue. It is difficult to perceive colors with short wavelengths. Likewise, the patient perceives yellow as pink.

Read more: What Is Miosis and Why Does the Contraction of the Pupils Occur?

Treatments and options to improve the quality of life of the colorblind

There is currently no treatment available for hereditary color blindness. If the disease is due to medications, other pathologies or exposure to toxins, it is appropriate to suppress the factor that causes the condition.

Color filters over glasses or a special contact lens can help to better differentiate colors, but they do not eliminate the deficiency. It is possible in the future to have gene replacement techniques that could completely solve this problem.

There are some techniques and measures that colorblind people can take to overcome the limitations that the disease causes them. For example, they can memorize the order of the colors in a traffic light, so that they can interpret the signal to stop or continue.

Objects of a certain color can also be marked, so that this sign makes the tone recognizable in order to combine them with others. Today there are computer applications that help differentiate colors.

Don’t forget to SHARE the types of color blindness with your friends and family on your social networks!

Share this post: