El colorblindness, also known as discromatopsia, is a visual condition that affects the way a person perceives colors. Most of the time, this condition causes the patient to be unable to correctly distinguish the ranges of red and green, but it can also cause an inability to see blue. 

The degree of involvement can be highly variable and depends, to a large extent, on the types of color blindness that the patient presents. Dyschromatopsia is a hereditary and genetic condition that, unfortunately, has no definitive cure. 

En Área Oftalmológica Avanzada We explain what the types of color blindness are and their causes.  

types of color blindness

What is color blindness and how is it produced?

To understand what color blindness is, you need understand how the visual system. Light from outside that enters the eye passes through the cornea and is projected on the retina

The retina is a photosensitive tissue that contains photoreceptor cells called rods and cones. Cones are sensitive to red, green, and blue colors, while rods are sensitive to white, black, and gray. 

The light that is projected on the retina is transformed into a nerve signal. The optic nerve takes that signal and transports it to the brain. This receives the information, interprets it and transforms it into an image. 

Any problem that may occur in the functioning of the cones of the retina generates a dyschromatopsia. There are different types of color blindness according to cone cells that they are damaged or absent and the degree of their affectation. 

Most common types of color blindness

There are different types of color blindness and degrees of color blindness, which are classified according to the cells and, consequently, the color blind affected. Most are characterized by inability of the patient to differentiate colors


Dyschromatopsia is a moderately serious condition in which the patient has inability to identify one of the three basic colors. This condition is hereditary, of genetic origin and can occur in three different ways, let's see: 


It occurs when there is an absence of photoreceptor cells sensitive to green


It happens when there are no sensitive cells color azul. This dyschromatopsia is the least frequent. 


La protanopia color blindness that occurs when there are no photoreceptor cells sensitive to red


This type of color blindness is characterized by the absence of cone cells in the retina, but it can also occur due to neurological problems. Patients with achromatopsia they can only see in black and white.


This color blindness occurs when there are only cone cells sensitive to a single pigment in the retina. Therefore, the vision of light and color is reduced to a single dimension

Anomalous trichomatic

Cone cells have functional defects that cause the patient to mistake colors for each other. This is the most common color blindness, patients can perceive all three base colors, but their tones are perceived in an altered way


Causes of color blindness

Color blindness occurs when there is absence or malfunction of some type of cone cell of the retina. This can occur because cells do not respond to wave variations in light, which are what allow the visual system to identify color ranges.

In the retina there are normally almost 7 million color-sensitive cone cells. A lower concentration of these photoreceptors or their malfunction can trigger one of several types of color blindness

Color blindness is a hereditary condition and genetics, which is also related to the following conditions: 

  • Parkinson. The neurological damage caused by this disease can affect the function of color-sensitive cells.
  • Glaucoma.
  • Alzheimer.
  • Cataract. The opacification of crystalline it can prevent the correct vision of colors.
  • The medicine Tiagabine, used to treat epilepsy, can affect color vision. 
  • La hydroxychloroquine, widely used in the treatment of rheumatoid arthritis, can also cause color blindness. 

Diagnosis for types of color blindness

Many people with color blindness have this condition from birth. Therefore, they are unaware that they have a alteration in color vision. Other patients, on the other hand, suffer from color blindness as a consequence of other conditions. 

To detect color blindness, it is necessary to perform the patient Ishihara test. This test consists of the patient observing 38 cards one by one and identifying the image he sees in them. 

Ishihara cards are cards in which points of different ranges of colors are observed that together form a number. The numbers that a person with normal vision identifies are different from the numbers that a person with color blindness perceives. 

Is there a treatment for color blindness?

Nowadays there is no definitive treatment or cure for color blindness. Patients with this condition use special glasses for color blind people that help the patient to identify a difference between shades of the same color. Also exist contact lenses for color blind people for the same purpose.  

However, most people with color blindness adapt without too much trouble to the functioning of your retina. However, it is important to note that they present some difficulty when exercising certain professions, such as pilot, police, air traffic controller, electrician or designer, among others. 

En Área Oftalmológica Avanzada we are experts in the diagnosis and monitoring of color blindness. Contact us if you have a color perception problem, we are happy to assist you! 

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Discover all the types of color blindness that exist
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Discover all the types of color blindness that exist
Color blindness, also known as dyschromatopsia, is a visual condition that affects the way a person perceives colors.
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Área Oftalmológica Avanzada
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