Tests for color perception according to the tables of Rabkin

The ability of a person to see different colors and shades is due to the correct operation of the organs of vision. Such a process in medicine is called color perception. Due to the fact that modern society spends most of its time in front of gadget screens, various visual impairments are increasingly being recorded . Including the wrong perception of the color spectrum.

How to define such pathology? To do this, apply medical instrumental methods or specially developed tests for color perception. What such diagnostic techniques represent and whether it is possible to check vision at home, we will tell in our material.

What is color perception?

First we need to clarify what color perception is. It is the ability of the human eye organs to perceive light reflection and transform it into a holistic image. On what shade a person sees before himself, various external physical factors influence: illumination, an angle of refraction, distance and even psycho-emotional state of an individual at a particular moment.

There are different theories about the mechanism of color perception. The so-called three-component is common. Its essence lies in the fact that the ability to color perception is activated under the influence of green, red and blue. If a person discerns such colors and their shades, then this color perception is called in medicine trichromasia. Tests for color perception are developed precisely on the theoretical foundations of this theory.

Impairments in color perception

Unfortunately, in the age of electronic gadgets, few can boast of excellent vision. Disturbance of color perception is one of the most common pathologies. Such deviations in medicine are called color blindness. Color blindness can be complete - then a person sees everything around in a gray color, or partial. Most violations occur in the green and red areas of the spectrum. Such vision problems are not only acquired, but also congenital.

Especially important is to pass a test for color perception for drivers, as usually people do not even guess that they see colors in a distorted way or they can not be distinguished at all. And such a state is extremely dangerous for people driving a vehicle, and pedestrians.

Methods of diagnosis

How is color perception of a person diagnosed? In modern medicine, there are two methods for detecting such pathologies of vision:

• Instrumental with the help of an anomaloscope (there are various models: the device Nagel, Rabkin, GOI);
• Tests for color perception.

The first method involves examination in a special medical center, which is equipped with this equipment. But tests can be done even independently at home.

Tests for the diagnosis of color blindness

In modern ophthalmology, color perception testing is carried out using special tables (Ishihara or Rabkin). They represent a certain system of multicolored points. A person with normal visual perception will not be difficult to determine what is depicted on such cards. But patients with a broken color perception can not distinguish from the points a "hidden" figure or figure.

The most popular are the cards of Rabkin. They are divided into 2 groups:

1. To diagnose the type of violation of color perception (these are tables 1 to 27).
2. To confirm the preliminary diagnosis (tables 28 to 48).

How is the test done?

With this test, it's easy even to check your eyesight at home. The color perception of a person at the first stage is diagnosed using tables 1 to 27. In order for the results to be true, the following diagnostic recommendations should be followed:

1. The test should be conducted in natural daylight. In this case, the patient should sit with his back to the light source, and the examiner - in front of him at a distance of 1 meter.
2. It is important to carry out diagnostics in the normal state of health of the patient. Symptoms such as headache, weakness, fatigue, depressive and stressful conditions can lead to false results.
3. Tables of color perception should be demonstrated to the subject vertically at eye level.
4. The patient is given up to 7 seconds of time to think about the answer.

The answers of the examinee are fixed in a special form for the convenience of further interpretation and diagnosis of violations of color perception.

Rabkin's tables

What is the table of Rabkin? This is an image of figures and geometric figures, consisting of points of different colors. But the saturation of the palette is the same. Thus, a person with a normal color perception can easily see the "encrypted" image. Whereas in the presence of pathologies, it will be difficult for the patient to isolate the colors and build a complete picture.

It should be taken into account that the first two tables are the so-called blendes. They, first, are training. And secondly, determine the simulation of the disease, because decipher the images depicted on them can even a person with a broken color perception.

Decoding tables

In order to decipher the result, knowledge of the correct answer of each table is required, as well as the diagnostic purpose of each card. So, the answers to Rabkin's test are as follows:

1. The first table shows the figure 96. This card is intended to illustrate the test.
2. On the next you can see the figures - a square and a triangle. The goal is to identify the simulation.
3. On the card under this number is the figure 9. If the patient suffers color blindness, then he will see a five.
4. On the fourth table in the normal person sees a triangle, and in the presence of visual impairment - a circle.
5. Rabkin's table under number 5 contains the figure 13. In case of color blindness, the subject will see 6.
6. There are 2 geometric figures - a circle and a triangle. But a person with a broken color perception can not distinguish between figures.
7. This card is also a "snag". The figure 9, depicted on it, will be seen as healthy people, and with violations of color perception.
8. The drawn five will be seen only by healthy people.
9. If there is a pathology of perception of the red color spectrum, the subject will find a figure of 8 or 6 on this table. Then, in fact, a nine is actually displayed.
10. A person who sees figures 68, 66 or 69, there are deviations in color perception. In the absence of anomalies, the examinee will find the number 136.
11. This card will unravel both healthy people, and with a pathology of vision. Here is the number 14.
12. They will not be able to find on this card a figure of 12 patients who do not distinguish between the red spectrum.
13. This table draws a circle and a triangle. People who have an anomaly of perception of the green spectrum will be able to see only the triangle. If the orientation in the red portion of the spectrum is disturbed, then the patients will only find a circle.
14. Here the numbers 3, 6 and 0 are encrypted. With an anomaly in the green spectrum, people see a unit and a six. And if the color perception of red is violated, then the patients will be marked with figures 1, 0 and 6.
15. Only healthy people will be able to see the ciphered geometric figures (triangle, circle and square). In the presence of pathologies, patients will offer a variety of options for answers.
16. On this card, a healthy person will see the number 96. If the perception of the red spectrum is violated, only the nine will be noticeable. In the case of problems with orientation in the green area, the patient will only point to the six.
17. This table shows such geometric figures as a triangle and a circle. In the presence of anomalies, a person will be able to detect only one of the above figures.
18. This table is different from the previous ones. Here a healthy person will see the horizontal and vertical rows of colored squares. Whereas in violation of color perception, the examinees note the uniformity of individual rows or columns.
19. On this card the figure 25 is encrypted. If there is an anomaly of vision, a person will see only the five.
20. If the subject distinguishes on this table geometric figures (circle and triangle), then with his color perception is all right. Daltonik will not be able to distinguish pictures at all.

The remaining 7 tables are identical to those already described.

Interpretation of results

So, the color perception check has been carried out. How to decipher the results? Any number of incorrect answers gives reason to suspect a violation of color perception. In this case, the second stage of testing is performed using tables 28-48 to clarify the form of pathology. But the final diagnosis can be made only by an ophthalmologist.

Tests for color perception - a fast and affordable way to diagnose a visual impairment. But it is important to remember that if all recommendations are not followed, the results may be false. Therefore, do not engage in self-examination, and even more so treatment, without consulting a specialist.