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Sight Test - Ishihara Charts - Color Blindness calculator


Use the Ishihara test to check if you suffer from color blindness, to what extent your defect is Protanopia or Deuteranopia, or maybe just insufficient differentiation between red and green shades. As a result, in addition to the diagnosis, you will have the opportunity to check how each of the Ishihara plates is seen by people with various visual impairments, and if you have a defect, they will allow you to see what is on the plates.
The Ishihara test consists of 38 plates. Each board consists of a circle formed by round spots of various sizes, slightly different in color. The choice of colors on each chart is different, which makes it possible to diagnose various color vision disorders. The test is designed to detect the two most common types of color blindness:
  • Protanopia or a sight defect consisting in not recognizing the color red or confusing it with the color green, and
  • Deuteranopia or a defect, a type of color blindness, consisting in not recognizing the green color or confusing it with red.
Tritanopia (blue color blindness) is not included in this test as it is very rare. There are also really few people who can't see any color (i.e. they see every color as gray).

The most common color blindness is a shift between red and green caused by a lack of perception of one or both of these colors. We all have a different perception of these colors to varying degrees. When it is mild, protanopia is called " protanomalia " and deuteranopia is called " deuteranomalia ". This test is intended to diagnose only the most extreme cases ("nopias"), but may give you clues to subtle anomalies (note if you see some plates more intensely than others).


Under each Ishihara board, you'll see buttons with different options. Choose the one that best matches what you see on the board. If you don't know what to choose, choose "I don't know". Some images may be ambiguous, so choose instinctively without thinking too much. Speed of reaction is important because seeing colors requires no thought and why deceive yourself.



Sight Test - Ishihara Charts - Color Blindness calculator

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Color Blindness - information


Ishihara Charts (Ishihara Pseudo-isochromatic Charts, Ishihara plates) - Charts used by ophthalmologists to test the ability to distinguish between red and green colors. Their name comes from the originator, Japanese ophthalmologist, Shinobu Ishihara, professor at the University of Tokyo; he designed the first plaques in 1917. When Ishihara worked at the Military Medical School, he was asked to come up with a simple test to check the recruits' ability to correctly identify colors. The first tablets were painted by Ishihara himself.

Color blindness - also called color vision disorder in humans is the inability to perceive differences between some or all colors that are normally perceived by others. Color blindness is usually a congenital, genetically determined defect inherited recessively in conjunction with the X chromosome. For this reason, it more often affects men (approx. 8%) than women (approx. 0.5%). Since males do not pass their X chromosome on to their male descendants, a male with color blindness will not pass it on to his son. A woman with two X chromosomes can carry the color blindness gene without even knowing it. If there is a man on the mother's family side who has color blindness, there is a good chance that her child will inherit his gene.
Disturbance in color recognition can also result from damage to the visual tract from the retina to the cerebral cortex. It can also be a side effect of drugs or chemicals.

Protanopia - a sight defect in which red is not recognized (or is confused with green). This is manifested by a decrease in the perception of red, orange and yellow luminosity. In addition, the perception of luminosity can be lowered to the point where red becomes a dark gray, even black, color. There is also no perception of the red component, which leads to the perception of pink and purple as blue.
This defect affects about 1% of men and 0.02% of women and results from the complete absence of suppositories - photosensitive receptors of the retina - reacting to red color..

Deuteranopia - a visual defect, a type of color blindness, consisting in not recognizing the color green (or confusing it with the color red). It manifests itself precisely in the lack of differentiation of red, orange, yellow and green. Brightness perception does not change. Instead, there is a lack of differentiation in the perception of the red and green components, which leads to the perception of violet and cyan as the same color.
It is the result of the lack of suppositories that react to the green color.

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