How colorblind people see


Surely, more than once, you have heard of the curious sight condition called color blindness. And, if you have ever passed a medical examination in your company, you will remember that one of the tests that you usually do is to identify numbers in an image made up of green and red dots.

How colorblind people see

Color blindness is a vision condition that causes an incorrect perception of colors. The lack of information or the incorrect use of it often causes us to have a wrong image in our minds of what it means to be colorblind. There are several types of color blindness , as well as different levels, so not all color blind people see the same colors.

What is color blindness and types

Color blindness is usually inherited and is a disorder characterized by impaired or limited color perception . This is due to the malfunction, or the total absence, of the cones or cells of the retina responsible for capturing color and all its ranges.

The cones (our eyes have millions of them) are divided into three categories: those that are used to perceive red, those that are sensitive to blue and those that perceive green. If one of these is absent, the eye is unable to see the color that those cones should perceive.

In most cases, any colorblind person is able to see colors. However, they see them differently and inaccurately from how the majority of the population sees them. This type of condition usually remains stable and lasts throughout the life of the human being.

The most common types of color blindness are:

  • Dichromatism : this occurs when the person is not able to distinguish between two colors due to the lack of one of the three cones that perceive color.
  • Anomalous trichromatism : in this case, the colorblind person does have all the cones, but they are in a defective state, which prevents the colors from being captured in full detail.
  • Achromatopsia : is a severe case of color blindness. Achromatopsia occurs when the colorblind person is unable to distinguish colors, seeing everything around them in a varied shade of gray.

What colors do color blind people confuse?

To know which colors color blind people confuse , it is necessary to know which set of cones is missing or damaged. In this sense, these are the types of color blindness :

  • Protanopia : occurs when there are defects or absence of the retinal photoreceptors that perceive the color red. As a consequence, the individual may confuse red with colors such as yellow and green. All shades of green look tarnished.
  • Deuteranopia : In this case, the photoreceptors for the color green have been damaged or do not exist. Since green and red are often present in many of the same colors, this means that colorblind people can mistake green for red as well.
  • Tritanopia : People with tritanopia do not have enough sensitivity to the color blue. It is a very rare form of color blindness and causes the individual to confuse greens and yellows with blue.

Most cases of color blindness (about 99%) are represented by protanopia and deuteranopia. However, it is important to note that not all shades of green and red will be susceptible to the same level of confusion. Each case of color blindness is different, just as each color also contains different amounts of red or green.

These types of color blindness have a curious hereditary component . The most common is that it is inherited from the father, because it is caused by a recessive gene that is linked to the X chromosome.

How do colorblind people see?

Despite the difficulty in the perception of certain colors, colorblind people see perfectly . Its deficiency has nothing to do with vision conditions such as farsightedness or myopia, so your vision does not have to be altered in that regard. However, it is true that the defective perception of certain colors causes them not to see the environment around them as non-colorblind people would. This can cause inconvenience in day-to-day activities.

In the case of color blind people who cannot perceive red or green, you may have wondered what happens to those drivers who suffer from this type of color blindness, since they cannot distinguish when a traffic light is red or, on the contrary, in green. In their case, they usually memorize the location of each of their lights. The red one is always located at the top of the traffic light while the green one is at the bottom.

In other cases, people with color blindness see all colors but cannot appreciate their various shades or brightness. When this is the case, colorblind people perceive dull or faded colors , since their cones, despite working, do not do it 100%. Despite this, colorblind people have the same names for colors as normally seeing individuals, even though these colors look different to them.

Likewise, those who suffer from achromatopsia, the most severe form of color blindness, perceive everything around them exclusively in grayscale (with all its variations).

Colorblind tests

Today, there are different resources for diagnosing color blindness. One of them is a visual color perception test, called the Ishihara color blindness test, after the doctor from the University of Tokyo who published it.

The test consists of a series of numbers written on a colored background. For example, the number can be presented in red on a green background or vice versa. The impossibility of distinguishing which is the correct number is a sign that the person suffers from color blindness. If, on the other hand, the individual taking the test fails to see any numbers at all, it is possible that he suffers from the complete absence of one of his cone sets.

This test allows diagnosing whether or not someone suffers from color blindness, but not the degree of color blindness they have. For this, there is another test called the Farnsworth test , with which you can know exactly which tonalities are perceived correctly and which ones are not.

Similarly, there are various ways to improve or mitigate the effects of color blindness, such as glasses with special filters that allow you to see colors that would otherwise be impossible to perceive. Also, there are more homemade methods, but very effective, to make life easier for those who live with color blindness, such as labeling clothes by color (with the help of a family member or friend) to avoid inappropriate combinations. In addition, mobile applications have been created to identify colors and saturate images so that colorblind people can see what they really look like.


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