Verification of visual acuity is carried out according to special tables. This is included in the standard algorithm for diagnosis of vision. In most cases, the CIS countries use the Sivtsev table. This is a common but not the only way to diagnose it. Verification of visual acuity is needed not only when you are hiring or studying.
- 1Why check
2Existing tables for verification
- 2.1Sivtsev's table
- 2.2The Snellen table
- 2.3Orlova's Table
- 2.4Golovin's Table
- 3Which tables are checked for drivers' vision
Verification of visual acuity should be included in the annual routine of preventive examination.This is a basic study that allows you to find the problem in time.A sharp decrease in visual acuity is always a sign of a pathology that requires close attention.In ophthalmology, this procedure is called viziometry. The verification algorithm is as follows:
- Verification of visual acuity for each eye separately;
- After checking the visual acuity for both eyes simultaneously.
During the test, you can not squint or apply pressure to the eye with your hand.This can distort the results of the study. The room should have good lighting, and the images on the tables should contrast with the background.
The norm is 1.0. If there is a decline, this is an excuse to conduct additional studies.
Existing tables for verification
It is produced using special tables.They contain sets of letters, images or symbols. With their help, the doctor determines the ability of the patient to distinguish symbols of different sizes at a distance of 5 meters.A modern alternative to traditional paper tables is a special screen with a projector.Using it, the same images and symbols are displayed on the white screen as on the tables.
The study of visual acuity with the help of tables is the most simple and painless method of research.
This is the most well-known table for checking eyesight.It is in every ophthalmological cabinet in the CIS countries.It is a rectangular poster with 10 rows of letters of different sizes.The table was named after the ophthalmologist Dmitry Sivtsev.
A table is a set of printed letters. There are seven:
They are randomly arranged on 10 lines.If the visual acuity is 1.0, then the person is able to name the letters from all the rows without errors. To the left of each line is a so-called visa. This is an index of visual acuity, corresponding to each of the lines.
Recently, the version of the Sivtsev table is used on the matte glass screen with the projector. It allows you to show sequentially the line by line.
The Snellen table
The most common in the world for determining visual acuity is the Snellen table.It was developed in 1862 by an ophthalmologist from the Netherlands Hermann Snellen.It is a rectangular poster with uppercase Latin letters, or so-called optotypes.
The table has 11 rows of letters of optotypes. At the top are the largest, below are small ones.Visual acuity is considered to be 100% if a person sees 8 letters and below.The distance from person to table should be 6 meters.
In order to test the severity of vision in preschool children, the Orlova table is used.Since the child at this age is not yet able to read, 12 lines of the table consist of pictures in combination with the Landolt rings. These symbols have sections directed in different directions.The sizes and values of the figures in the table are the same as in the Golovin table.
The study of vision in young children has its own characteristics. Before the beginning it is necessary to explain the child the essence of the procedure. It is also important to make sure that the child knows the names of all animals and objects in the pictures. In the case of the Landolt rings, he must know the difference between the concepts "right "left "top" and "bottom".
Little children quickly get tired, their attention is dissipated.Because of this, only one picture from each row is shown, starting with the largest one. The remaining symbols in each row are used if the child did not give the correct answer.
The table for determining Golovin's vision is constructed on the same principle as the Sivtsev table.It is named after the ophthalmologist Sergei Golovin.Instead of capital letters 12 rows of Landolt rings are used.These symbols are broken on one side. On the top line are rings of 70 millimeters. And on the bottom this value is only 6 millimeters.
The definition of visual acuity is the same as with the help of Sivtsev's table. They are used in parallel.
Which tables are checked for drivers' vision
For preventive testing of visual acuity, drivers use 2 types of tables: Sivtseva and Golovina.This makes it possible to identify the problem as effectively as possible at an early stage. Separately determine the visual acuity in the "best" and "worst" eyes.If a decrease is detected, this problem is solved with the help of conservative or surgical methods of treatment.
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Vision, or definition of visual acuity using special tables - this is the most reliable method of research. This is the main method of diagnosis during preventive examinations. It will show the need for other, more complex and costly research. The tables of Sivtsev and Golovin are most often used. To test visual acuity in young children, Orlova's table is used.
Also, read about eye research methods such as pachymetry and keratotopography.