Ophthalmic examination table

Each of us came across ophthalmological tables at the reception of an ophthalmologist.This method of diagnosing visual acuity is the most frequently used and indicative.There are varieties of tables with which we test the vision of children and adults. Next, the characteristics of each table will be described.

Why check

Visual acuity is a distance on which you can see two objects that are located at a minimal distance from each other. On the basis of this, tables were created to test vision.

To check vision is necessary for the timely diagnosis of problems or for periodic observation of changes in vision.

Those who constantly work without breaks for computers, often complain of reduced visual acuity.They just need to visit a doctor, and from time to time rest and do gymnastics for the eyes.

Age-related changes in vision can also manifest themselves.Such diseases as glaucoma or cataract, identified at an early stage, can still be cured.A regular check will not blind the elderly.

Visual disturbances can be caused by diseases such as diabetes, hypertension and so on.Therefore, people with such problems are also encouraged to visit the doctor regularly and check their eyesight.

Checking the eyesight with the help of ophthalmic tables will allow at home to conduct vision diagnostics. This makes it possible to detect impairment and contact the ophthalmologist for help.

To check the vision of the house, you can use the tables that can be found on the sites.But there are several drawbacks: the sizes of the signs are not met, the contrast of the image is different from the real one, the distance to the table can not always be respected.According to the results of the examination of the eyes with the help of tables, the ophthalmologist will select the therapy necessary in each particular case.

Existing tables for verification

Sivtsev's table

This table can be found in most oculist offices. It consists of 12 lines, each of which is written with certain letters.The lower the letter, the smaller the size.

The letter "D located on the table on the left, implies a certain distance, on which it is possible to distinguish letters to a person with normal vision. The distance for the lower row is, meter, and for the upper - 5 meters. The letter "V" defines visual acuity at a distance of 5 meters.

Normal vision is,. With this vision, a person should see 10 lines at a distance of 5 meters.

To determine visual acuity, the correct lighting of the table is necessary.To do this, it needs to be illuminated with one conventional incandescent lamp or two fluorescent lights. The light is directed to the table.

The Snellen table

This table was developed in 1862 by an ophthalmologist from Holland Hermann Snellen.

Usually, when checking eyesight, only its severity is judged.For this, a person should learn specially selected signs that have a standard size. These signs are called optotypes.They are printed on tables or are displayed on a screen using a special projector. The most common signs are letters, figures or symbols.

The signs are arranged in rows depending on the size.The basic line of optotypes should correspond to normal vision, and others mean that the visual acuity is slightly lower.

The Snellen table has at the edges numbers that denote the distance at which the height of the signs located in the line corresponds to an angle of five minutes.In detail, optotypes can be seen at an angle of one minute.

The table uses an empirical progression, according to which the sizes of characters in the lines change.The complexity of each line is the same.

The Snellen table consists of 11 flows. The largest letter is at the top of the table. As the line decreases, the letters decrease. Vision is checked at a distance of 6 meters.

The visual acuity in this table is determined in the fractional Snellen value.The numerator spells the distance to the table (in feet), the denominator is the distance at which all optotypes can be read to people with normal vision.

With normal visual acuity, you can read the lines from a distance of 36 to 5 meters.

Orlova's Table

The principle of its use is similar to the previous two tables.

This table is used to determine the vision of preschool children who have not yet learned to read.

The Orlova table contains lines with different images.The smaller the picture, the lower they are. To the right of the drawings, the letter "V" indicates visual acuity at a distance of 5 meters, and the letter "D" - the distance at which you can determine the picture to a child with normal vision.

Under the normal vision of the child it is understood that he sees the 10th line, having moved away from the table by 5 meters with both eyes.If the kid does not see the image in the top line at a distance of 5 meters, then it should be brought closer to the table by, meters. So it is necessary to do, until the child calls the pictures for vision visible to them.

When diagnosing eyesight, the child should take into account some of the nuances:

1. The ophthalmologist should bring the baby to the table and ask him to name the pictures.It is necessary for the child to understand what is required of him, and the ophthalmologist has determined the child's knowledge of the images.
2. It is best to begin to check the vision from the top line, and ask to name only one picture, so as not to tire the child.
3. In the event that the kid can not name the picture, you need to ask him to name his other pictures in this line.

Golovin's Table

This table for checking visual acuity was named after the ophthalmologist Sergei Golovin.The Golovin table contains a set of optotypes represented by the Landolt rings. Rings in the same row are the same in width and height, but with discontinuities in different areas (right, left, top or bottom). Visual acuity is normal if a person sees two points that are at an angle equal to one minute.

In the classical table Golovin there are optotypes, with which you can determine the vision at a distance of 5 meters.

The first ten lines differ from each other by a step in the next two lines - in, the remaining three lines differ in step,.

The letter "D located on the left - the distance, but which a person with normal vision in, can see the optotype.The letter "V located to the right of the optotypes, implies a visual acuity at a distance of 5 meters.

The magnitude of visual acuity can be defined as: V = d / D, where d is the distance that the person is in the vision test.Most often the Golovin table is used in conjunction with the Sivtsev table.

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How to work with the test table: video

conclusions

You can check your eyesight on any table.Each of them will equally determine the acuity of your vision.As to how often you need to check your eyesight, you can visit a doctor once a year, and check at home with any frequency.Correct the vision needed only when its sharpness is lower,.Only a visit to the doctor-oculist and a visual check on the table can confirm the need for any treatment (glasses, lenses, surgery).