Ophthalmologists claim that diagnosing visual pathologies in the early stages increases the effectiveness of treatment by 80%. Therefore, it is advisable to systematically check visual acuity at home in order to identify the first symptoms of disorders. Tests are carried out using special tables and pictures. Anyone can have their eyesight checked this way.
Many people are exposed to high levels of visual stress every day. This is often due to working at a computer, driving, spending long periods of time on social networks, relaxing in front of the TV, and other factors. Children experience visual stress while studying, doing homework, and attending extracurricular activities. According to statistics, the number of patients with myopia, farsightedness and other refractive errors is growing rapidly every year. Experts say that these pathologies do not have pronounced symptoms at an early stage, so a person goes to the doctor with a moderate or high degree of the disease, which complicates treatment.
Constant overwork of the organs of vision does not go away without leaving a trace. Over time, dry keratitis, redness of the sclera, burning, stinging and pain in the eye area appear, especially at the end of the working day.
If a person continues to ignore these symptoms, due to visual fatigue, visual acuity decreases and various pathologies develop. Not everyone can regularly visit the ophthalmologist's office due to lack of time. In this case, it is advisable to systematically conduct a vision test at home. This will allow you to promptly identify the problem at an early stage and contact a specialist. However, it should be remembered that it is impossible to conduct a comprehensive examination of the visual organs and make a diagnosis at home.
What is visual acuity?
In fact, eye vigilance, or visual acuity, is a value indicating how many lines from the Golovin-Sivtsev table a person can distinguish at a distance of 5 meters. Visual acuity does not have a specific unit of measurement. It is conventionally accepted that the ideal indicator is 1.0, or 100%. In this case, the patient can easily distinguish all 10 rows of the table from top to bottom. If the eye's vigilance is 0.9, a person will recognize only 9 lines out of 10, and so on. Thus, this indicator indicates from what distance a person can clearly distinguish a particular object. Interestingly, some people have excessively high visual acuity: 150%, 200% and even 300%. In this case, they can easily recognize line 12 in Sivtsev’s table at a distance of more than five meters. At the same time, the person does not experience increased visual stress and feels comfortable. Such an anomaly of the visual system can be caused by genetic factors, for example, the compact arrangement of the elements of the retina, which are responsible for the high clarity of visibility of objects. Therefore, the indicator of 100% eye vigilance is very relative. In everyday life, a person is considered to have normal vision if he can easily distinguish small objects and at the same time clearly see objects in the distance. However, the visibility of each eye may be different.
What kind of vision is normal:
- The accepted indicator is 1, or 100%;
- Eye vigilance has no unit of measurement;
- With good vision, a person can easily recognize the 10th line of the Golovin-Sivtsev table from 5 meters;
- The clarity of vision of some people exceeds the usual 100%, which is due to genetic characteristics.
Some people mistakenly confuse visual acuity with refraction - the value responsible for the optical power of refraction of light rays and their focusing in the macula (the center of the retina). In fact, refraction is only one of the parameters affecting the quality of perception of objects. The clarity of vision also largely depends on the width of the pupil, the transparency of the lens, the condition of the nerve endings of the retina and eyes, the size of the visual cones and other factors.
Often, a decrease in visual acuity is associated with the presence of various refractive errors: farsightedness, myopia, astigmatism and others.
It is not possible to conduct a comprehensive eye examination on your own, since this requires special equipment. However, a computer vision test at home is available to everyone.
By spending only 3-5 minutes testing, you can roughly estimate the visibility of letters, numbers or images in the table. Serious deviations from the norm are a reason to visit an ophthalmologist and undergo diagnostics.
Home vision test: Sivtsev table
The simplest and most effective way to check the quality of vision at home is the Golovin-Sivtsev table, which we are used to seeing in ophthalmologists’ offices. It consists of 12 lines with letters of different sizes, which decrease from top to bottom. To the left of each line is the D value. This indicator indicates at what distance a person with good vision can clearly recognize all the letters in the selected row. And to the right of the line is the value V, which characterizes visual acuity.
To carry out the test, you need to find a table on the Internet and print it in horizontal orientation on A4 sheet. Next, you need to position it so that the 10th line is opposite the eyes. The check should be carried out from a distance of 5 meters. If you have not previously had vision problems, it is recommended to start from the tenth line. Otherwise, you should find letters that are clearly visible to you, and then gradually move lower. Golovin’s table is built on the same principle, but instead of letters it contains 12 lines with Landolt rings. Each of them is torn on one side, which must be determined during testing. Testing vision at home using such tables is quite effective. This way you can control the operation of the visual system at the required frequency, with a minimum of effort.
How to check your eyesight using Sivtsev’s table:
- Find the table on the Internet, print it on A4;
- Place at a distance of 5 meters;
- Cover one eye with your hand;
- Try to read the letters in row 10. If you can do this without error, you have 100% vision;
- If that doesn't work, gradually move to the top lines until the letters become clear;
- Assess the quality of vision (V indicator, to the right of the line);
- Use the same principle to check the other eye.
If you do not have a printer, we recommend finding a test table online. In this case, you need to open it in full size and move 5 meters away from the computer screen.
Description of the method of vision restoration according to Norbekov
In ophthalmology, there are two main methods of testing and training vision: according to Sivtsev and Norbekov. The first method is familiar to every person who has visited a doctor at least once in his life. The technique was developed back in Soviet times, but even today it is used in every ophthalmologist’s office. The method is considered the simplest, most accessible and effective for determining visual acuity.
The table according to Sivtsev is a white canvas, on which there are twelve rows with letter designations of different sizes, starting with the largest and ending with the smallest. Any of the series corresponds to a certain indicator. To the left of the table, before the beginning of each line, there is a designation in the form of the letter D, which represents the distance in meters.
The table for the eyes according to Norbekov is not so popular and is considered as a training for visual function. It resembles the table according to Sivtsev, but instead of a set of letters, normal text is written. It is also located first with a large font and then goes down.
Checking visual acuity on a computer
Now on many sites you can find a free online vision test on a computer. Testing is carried out using various programs, each of which has its own verification algorithm. As a rule, this is a set of questions that contain tasks of a different nature, for example, determining the direction of the open side of a figure and others. Upon completion of the test, the number of correct answers corresponding to a certain visual acuity appears on the screen.
Before taking the test, you need to study in detail and follow the recommendations indicated on the website: position yourself at the required distance, take the correct position, and others. This directly affects the reliability of the online vision test result.
Autorefractometry
Another method for determining visual acuity in preschool children, performed using an autorefractometer. The child is seated in front of the device, placing the chin on the stand to prevent involuntary movements of the head - because of this, the result may be inaccurate. Then he is asked to focus his gaze on a bright picture and look at it, trying to blink as little as possible. The doctor adjusts the autorefractometer so that the infrared beam is directed exactly to the center of the pupil (before the procedure they are also dilated with the help of mydriatics). Passing through the optical media of the eye, the beam is refracted and, upon reaching the retina, returns back. In this case, the program calculates the clinical refraction of the eyes. Upon completion of the measurements, the device produces a printout with the required values.
Thus, several methods are used to determine visual acuity in children: visometry, skiascopy, autorefractometry. There are several other methods in medicine, for example, optokinetic nystagmus and others. Which one to choose is decided by a specialist, depending on the age of the child and what results should be obtained in the end.
Online test for myopia and farsightedness at home
On the Internet you can find a duochrome test to determine myopia and hypermetropia at home. This is a two-color chart with black letters on a green and red background. Those who already wear glasses or contacts need to be tested using their usual means of correction. To do this, you need to position yourself at a distance of 50-70 centimeters from the monitor. If letters placed on a green background appear clearer, hypermetropia may be suspected. Conversely, if characters are easier to recognize on a red background, myopia may be present. The same clarity of letters on the left and right indicates the absence of refractive errors. However, it should be remembered that an accurate diagnosis can only be made through an examination in an ophthalmologist’s office using special equipment.
Checking color perception online
Some people suffer from color blindness, or color blindness. Sometimes a person does not even suspect that he perceives a certain shade incorrectly. To test your color sense, you can take a quick and easy test at home. It is based on the Rabkin table. In it, a person is asked to recognize a geometric figure or number formed from multi-colored circles on a gray background. People with color blindness will not be able to do this. Before passing the test, you should also position yourself at a distance of 50-70 centimeters from the monitor screen. During testing, you need to keep your head straight and squint your eyes.
Evaluating the test results
To do this, you need to answer a few simple questions.
- The lines had no breaks, were they straight?
- Were there disappearing/appearing light spots at the intersections of the lines?
- Did you see all 4 corners without looking away from the point?
If the answers to all these questions were positive (that is, the picture was clear, the squares were the same, the lines were parallel, etc.), then everything is fine with your vision and there are no symptoms of macular degeneration.
Important! But if the lines are distorted and look wavy, then try to visit the ophthalmologist’s office as soon as possible! This could be a sign of macular degeneration!
A healthy person sees the Amsler table like this:
People with age-related macular degeneration may see these Amsler grid images
Home vision test: astigmatism
There are several simple tests that have been developed to check if you have astigmatism. One of the most popular is testing using black rays of a Siemens star placed on a white background and closing from the periphery to the center. To start the test, you need to move 3-5 steps away from the monitor screen and close one eye with your hand. If there is astigmatism, the figure will change its shape - from a circle to an ellipse. This effect will occur due to the fact that some rays will begin to blur and overlap each other without reaching the center. In a small area they can completely blend into the background. Sometimes a person with astigmatism may see an inversion of the star: a white background instead of black rays and black rays instead of a white background.
Please note that you should only take an online eye test at home if you are feeling well. Eye strain, elevated body temperature, headache or general fatigue can negatively affect the objectivity of the test.
It is also important to ensure sufficient brightness in the room where the test will be carried out and to install the monitor correctly. Remember that a reliable comprehensive diagnosis of the visual organs cannot be carried out at home.
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