Table Sivtseva - the best assistant in the diagnosis of human vision

The vision of man is one of the greatest and at the same time fragile abilities. You need to watch it all the time. A trip to the ophthalmologist should become a periodic occupation in the life of each person.

Visual check in modern ophthalmology

In the distant USSR scientist Sivtsev invented an indispensable tool for modern ophthalmology, which in honor of the author was called the "Sivtsev table". This method is used to determine visual acuity. For this, 12 rows of signs were defined: letters and rings with a rupture, which, starting from the upper row, to the lower one, gradually decrease. From a distance of 5 meters, visual acuity is determined on a scale of 0.1 to 2.0.

What is visual acuity and how is it tested using Sivtsev's table?

Visual acuity is the ability of the human eye to distinguish between two points that are separated from each other at a certain distance. The current norms say that an eye having 100% vision can distinguish two points, separated by an angular distance of one minute. Thus, visual acuity can be described as the ability to clearly see and describe such visual acuity with a digital indicator of 100% or 1.0. The Sivtsev table has been designed in such a way that this digital indicator can be determined.

There are situations when the vision of a person is so well developed that its severity can be estimated at 1.2 or 1.5 and even 3.0. While with various eye diseases, like nearsightedness or farsightedness, astigmatism or glaucoma, abnormalities can be 0.5 or 0.05.

Often visual acuity is described with the help of percentages. However, it should be noted that only 100% of the severity index corresponds to 100% of the vision. For example, the index of sharpness in 0.2 diopters can not be converted into percentages as 20% vision. This indicator will correspond to 49% of the norm. It is not so easy to translate any indicators into percentages and back. This is the special Sivtsev table - the dimensions in the columns on the left and on the right are already calculated test results.

How do you check the visual acuity of the Sivtsev table?

A standard set of printed characters of various sizes is lined up in 12 rows. All this is the letters of the Russian alphabet - Sh, B, M, H, K, N. Each lower row is smaller than the upper one. The test should be carried out in a room with good lighting. It is provided by a special lamp aimed at the table, and having scattered light. At a distance of 5 meters from the inspected is Sivtsev's table of view. The patient should sit comfortably and, alternately closing his right and left eyes, read the letters from the table. If the auditee easily identifies letters up to 10 rows, they believe that he has 100% vision. If he stops at any of the above rows, the visual acuity is determined by the indicators in the right row of the table.

The patient can be located at a distance of 5 meters from the table, but in this case a special formula will be used to determine the severity:

V = d / D

V in this formula is the quantity that we need to determine, namely, visual acuity; D is the distance the patient is from the table; D is the distance at which the patient distinguishes the symbols of a particular row.

Now, more about how the Sivtsev table should be located. It is placed between two fluorescent lamps, so that the illumination reaches 700 lumens. The bottom edge of the table should be at a height of 120 cm from the floor. The patient sits comfortably, keeps his head straight, the eyelids of both eyes open in the normal position. A special white flap is attached to one eye. Within 3 seconds, the audited person is shown a letter, which he should name. At the same time they start from the bottom row and gradually rise to larger signs. If all the signs are named - the checked 100% or 1.0 of the view. If one or more characters are not recognized - incomplete visual acuity. To determine visual acuity less than 0.1 patients gradually approach the table every 0.5 m until it can identify the signs of the table.

Notation in the Sivtsev table

In addition to the letters of the Russian alphabet, you can see that there are two more columns, denoted by the Latin letters D and V. The numbers in the D-column indicate the distance from which the person whose visual acuity is 100% can easily read the sign on the left. The figures in the V-column are a numerical characteristic of visual acuity, if the given row is read by a verifiable person at a distance of 5 meters.

What other tables are used in ophthalmology?

Since vision is a very important human ability that needs to be maintained in good condition, there are a number of tests used in ophthalmology that can show a real picture of the state of the eyes.

• Checking the visual acuity - for this purpose the Sivtseva table was created (as it is called in some sources). Here the letters Sh, B, M, H, K, N are used. Orlov's table for children is also used, where pictures are used instead of letters (asterisk, fungus, horse, teapot, airplane, duck, elephant, machine, herringbone).
• Checking the contrast of vision - for this purpose the table Golovin was created. It uses 4 types of optotypes - rings with a rupture in one of the 4 sides
• Verification of nearsightedness and farsightedness - use a duochrome test, which is two halves of a background of different colors: red and green, against this background there are letters (K, H, W, M, I, B, S). As a result of the test, it is determined whether the vision is normal (eyes see the letters on both backgrounds the same). If, on a red background, the letters of one row are sharper than on green, then short-sightedness occurs, on the contrary - farsightedness.
• Testing for astigmatism - the most common is a test called the star of Siemens. The essence of the test is that a person with normal vision sees in the picture lines that, before reaching the center, begin to blur or overlap. In the center of the line, they again become clearly visible.