What are the tables for checking your vision?
Vision diagnostics is an important test of acuity, which should be performed at least once a year. Experts recommend not to forget about the prevention of vision, because today, the eyes are in constant tension, due to the influence of a large number of gadgets, televisions and other devices. If the problems already exist, the diagnosis must be made every six months.
One of the most common ways to diagnose vision is to use specialized tables. They can be of different types and differ in the method and purpose of verification. Some variants are used for children, diagnostics of problems with color perception, etc. Therefore, you should familiarize yourself with the main characteristics of the tables of different methods and authors.
The main purpose of the tables
In General, tables are used to determine visual acuity, choose contact lenses, glasses, or for prevention purposes. Getting to an ophthalmologist, the first stage of the examination, of course, will be to check the vision using tables. They may differ in purpose, the choice of the table is made by the doctor, depending on the symptoms.
And although today there are more modern, technological options for diagnostics, a variety of devices, tables are actively used, because this ease of verification is supplemented by a fairly accurate result.
Diagnostics of vision using tables is performed using different methods, but the process is generally similar in sequence:
- The Patient is placed at a certain distance from the table;
- Ophthalmologist shows the letter or figure you want to call;
- With the correct answer, the doctor goes down to the smaller images, down to the smallest line, which indicates excellent vision;
- If the drawing is not recognized well, the patient is offered special glasses with different lenses of several options for further optimal selection of glasses for continuous use;
- The strength of the lens also determines the diagnosis of acuity.
Types of tables by different authors
Vision check using tables is carried out by professional ophthalmologists, they determine the table of which author, and the methods to choose. Among the common options:
- The Sivtsev Table. One of the most popular diagnostic options, which can be attributed to the classics. These are letters of different sizes that are placed in 12 lines. On the left side of the table there are indicators of the desired distance to the patient, for a clear definition of the letters of this series. Visual acuity is indicated on the right. If a person can name all the letters from the tenth line, from 5 meters from the table-vision is defined as 100%;
- Orlova Table. It is used mainly for preschool children. The lines contain images that are understandable to the child, which also decrease with each row. As in the first version both sides have indicators of the desired distance to the table and determine visual acuity;
- Rabkin Table. This is a great way to test your vision for color blindness. The material contains 27 drawings, each of them is a complex, multi-colored image. The patient's task is to see a certain number or letter in them. If there are problems with color perception, the person will not be able to recognize all the signs. Diagnostics allows the doctor to refer the patient to one of the following types: trichromate (without defects), deuteranop (do not see the green spectrum of colors), protoanop (problems with the perception of the red spectrum of colors). Depending on the type, individual treatment is selected;
- Golovin Table. It is similar to the Sivtsev table, but the letters are replaced with signs - circles, with breaks in different directions. It is an excellent solution if the patient could just learn the first table by heart. Such circles are less memorable, and poor vision does not allow you to see the gaps, which indicates the accuracy of the diagnosis. This table is often used in combination with other types of tables;
- Snellen Table. This is a foreign table that was taken as a basis by Sivtsev. It is used in many countries, because Latin letters are used. Only 11 lines and the required distance of 6 meters. As a result, visual acuity is determined by a fraction: distance and an indicator with 100% vision.
The main thing is to get to an experienced specialist who knows the specifics of using each table. It is he who should create the appropriate reception conditions, taking into account all the rules and regulations and an important factor - the correct distance to the table of any type.