Choose language

PL, EN, ES, DE, FR, RU


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

Plate 1 from 38



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.

Users of this calculator also used

Child height in the future. Predicted Adult Height calculator

Height calculator will help you calculate what height your child will have in the future, ie when it stops growing. Predicted Adult Height

Ideal gas

Using the calculator, you can calculate the pressure, volume, temperature and volume of moles of ideal gas.

Assessment of readiness to lose weight

Did you know that proper preparation is an essential factor in losing weight successfully? This test will not only help you answer the question of whether you have a chance of successful weight loss, but it will also indicate the factors that are necessary in preparation for this process.

Profitability of investments: NPV (Net Present Value), PI (Profitability Index), IRR (Internal Rate of Return), DPP (Discounted Payback Period)

This calculator helps us check whether the planned investment will be profitable and whether the project should be accepted or rejected.
Thanks to the calculator, we can calculate:
NPV (Net Present Value) - sum of discounted net cash flows
PI (Profitability Index) - investment profitability
IRR (Internal Rate of Return) - internal rate of return
DPP (Discounted Payback Period) - discounted payback period
Value of discounted net cash flow for each period.

ROT47 cipher - encoder / decoder

ROT47 cipher online encoder and decoder. Encrypt and decrypt any cipher created in a ROT47 cipher. You can use any shift and additionally a key for more precise text encoding.

Online tool for drawing graphs of any function.

With this online function graph plotter, you can draw any function. On one graph you can draw any three functions and compare their parameters. You can create graphs for many equations and functions.

Octagon - diagonals, area, perimeter, sides

Octagon calculator will help you calculate the long diagonal of the octagon, the medium diagonal of the octagon, the shorter diagonal of the octagon, the side length, height, area of the octagon, circumference and radius of the circumscribed circle and the radius of the circle inscribed in the regular octagon.



Online calculator