How to check the eyesight of different population groups and age categories

Surely every person has checked his eyes at least once in his life. An examination with an ophthalmologist is carried out in educational institutions, military commissariats, driving schools, when applying for a job. Individuals who have certain vision problems are well acquainted with the demanding "Close the left eye. What letter do I show? "

Introduction

How much we have not lived, vision, alas, only gets worse.It is difficult and costly to restore the former sharpness, sometimes it is completely impossible. It is for this reason that ophthalmologists recommend checking regularly how well you see. And for this it is absolutely not necessary to spend a lot of time and money. And how to conduct tests for visual acuity, learn later.

Why check

Sedentary lifestyle, unbalanced diet and frequent pastime at the TV or computer negatively affects the visual apparatus.

Unfortunately, visual acuity with age only decreases, so you need to regularly undergo examinations with an ophthalmologist.People aged 18 to 50 are checked every two years, over 50 - every year.

Timely detection of eye problems will help prevent further development, for example, myopia, hyperopia or astigmatism.

Tests for the detection of various pathologies of the eye are many, but even to date the simplest and an effective means for checking are considered special tables, and the method itself is called visometry.They were invented at different times by various ophthalmologists, but the principle of action remained the same. Each of the following tables has one structure: in a certain number of lines there are symbols that decrease downwards.

Determination of visual acuity (visometry)

Existing tables for verification

Sivtsev's table

It is the Sivtsev table that we most often see as the eye examination table for the oculist.It is a printed letter, located in 12 lines. These letters are only seven: S, B, N, M, K, I, N, and they decrease to the bottom line.

On the right, the value of visual acuity expressed in conventional units - "vises" is indicated. It is denoted by the Latin letter "V".

Sivtsev's table

If the patient sees the tenth line from a distance of five meters, then its V (corresponds to 100% of the view).

To the left of the table, the letter "D" denotes the distance from which a person with normal vision should distinguish between the available signs.For the top line, it is 5 meters, for the bottom line - 2, 5 meters. The two lower rows are used when the length of the medical cabinet is less than five meters, and also for determining visual acuity of 150 and 200%.

Why is the distance from the table to the verified one equal to five meters? In medical terminology, the concept of visual acuity means the ability of the eye to distinguish two points that are at a minimum distance from each other. Normally it is considered when a person sees them with an angular resolution equal to 1/60 degree, or one angular minute. At a distance of 5 meters it is 5 mm. It is this distance that separates the two adjacent vertical lines in the letter "Ш" from the tenth line.

The Snellen table

In fact, she is the ancestor of the Sivtsev table, but is used in English-speaking countries, since the letters of this table are Latin.It was created in 1862 by the Dutch ophthalmologist Herman Snellen. In contrast to the later analogue, there is one letter in the first row of Snellen's table, and only eleven lines. Visual acuity is indicated by a simple fraction. The denominator indicates the distance in feet from which a person with normal vision distinguishes symbols, in the numerator - the number of feet to the table. In the seventh line such a fraction is 20/20, therefore, the distance from which the vision is checked is 6 meters.

Snellen table

Orlova's Table

This tool is used to test vision in children who are not yet able to read. Therefore instead of letters the table contains various images. The visual acuity is determined by the same principle as in the Sivtsev table.

Orlova's Table

At check it is necessary to make sure that the child understands, what pictures are represented. For this, the baby is brought closer and asked to explain what he sees, and only then they carry out a vision test.

If the child does not distinguish the pictures of the upper row, he is asked to take a step half a meter ahead. So continue to do until he sees all the images in the first line.

Golovin's Table

Most often it is used simultaneously with the Sivtsev table, and sometimes as a separate device for testing the eyesight.Sergei Selivanovich Golovin, an ophthalmologist, in whose honor this table is named, created it from the rings of Landolt. These are rings that are torn from one side. They are located in 12 lines. The distance and visual acuity indicators are the same as in the other tables.

Golovin's Table

The size of the rings is determined by the following formula: 7 millimeters divide by V of the corresponding row. Thus, the value of the rings in the first line is 70 millimeters, in the twelfth - seven millimeters.

The situation on the road requires special attention from the driver of the vehicle.It is difficult to monitor obstacles, pedestrians and other vehicles with myopia or astigmatism.A lens or glasses are not always available. In order not to endanger yourself and others, the driver should think about his own eyes in a timely manner.

Which tables determine the vision of drivers

At the wheel the driver receives almost all the information through the eyesight.That is why most countries issue laws that prohibit the receipt of a driver's license for persons whose visual acuity is lower than stated.For the category "B" it is, at the best eye and, at worst. For other categories, the restrictions are more stringent. To check the vision of the drivers, use the Sivtsev table, sometimes also the Golovin table. Additionally, tests are performed to calculate color blindness.

Example of the test for color blindness

You do not have to go to a professional doctor, you can print out the tables for checking your vision and hang it on the wall in your office or bedroom. To test visual acuity, it is required:

1. Print the required tables. If the signs are printed badly, put them in ink or a black marker for contrast.
2. Arrange the table so that the tenth line is at eye level.
3. Illuminate the symbols of a lamp with a power of at least 40 watts.
4. Leave on the 5th subway, cover the left eye with some kind of shutter.
5. Do not frown, read all the visible signs.
6. Repeat procedure with other eye.
7. Focusing on the notes on the right side of the table, learn your visual acuity.

Also at home, you can take an online test for color blindness.

During the examination, try to relax. Indications can be different - it all depends on fatigue, lighting, weather and time of day. In this case, repeat the checks under different circumstances.

The slightest difference from the previous result should make you pricked up.

Video

conclusions

Vision should be monitored regularly. The history of the tables for checking vision began in 1862, when Herman Snellen created his own survey tool. The tables have undergone many changes, and now, in the era of computer technology, they are increasingly replaced by projected images. Modern projector allows you not to depend on the size of the cabinet and the degree of illumination, and also do not require the installation of complex designs that accompany the classic "paper" options. But in spite of the introduction of modern technologies, you will have to watch the sight, and no one else. Preventing visual defects is easier than fixing.