How far away should I be from an eye chart to measure my vision?

Test 5 meters from the eye chart.

An eye chart is a chart used to measure visual acuity. The eye charts used in China are: international standard eye chart, logarithmic eye chart, and Landolt ring eye chart.

Functionally, there are near eye charts and distance eye charts. The eye chart is based on the principle of viewing angles.

The visual acuity is generally divided into two categories: distance vision and near vision, and the international standard eye chart is mostly used for distance vision, which is composed of 14 rows of "E" characters with different sizes and different opening directions; Measure from or from; Each line is marked, and the line of the ophthalmometer operation method of the examinee should be parallel to the row, 5 meters away from the eye chart.

The eye chart used in medical testing mainly checks central vision, that is, to check the foveal visual acuity in the macular area of the retina, so that the preliminary situation of visual function can be easily and quickly understood, which is of great significance for the clinical diagnosis of eye diseases**.

Extended Information: Precautions for Visual Acuity:

1. The eye chart should be in a well-lit or well-lit place;

2. The 10th line, that is, this row should be at the same level as the eye being examined;

3. Examine the right eye first and then the left eye;

4. If you wear glasses, you should also check your eyesight with glasses, also known as corrected vision. During the examination, the eye shield should be tightly covered with the non-examination eye, otherwise the visual acuity measured by both eyes will be higher than the monocular visual acuity, which will affect the accuracy of the examination results, and even cause missed diagnosis and delay in the disease.

5. In addition, squinting, tilting the head or moving the body during the examination are all incorrect postures, which will also make the examination results not objective, and must be paid attention to during the examination.

Visual acuity is required to be 5 meters away.

The domestic standard test is the distance eye chart.

5m away. In hospitals or optical stores, it is common to see a mirror opposite the eye chart, sitting under the eye chart, and the mirror is placed at a distance from the person to test the eyesight, which is through the reflection of the mirror, and after the reflection, the actual distance is 5m, so when measuring distance vision, the 5m standard detection method is used.

Precautions for measuring visual acuity.

1. When checking the visual acuity of one eye, it is necessary to use a blind to completely cover the eye that is not checked, so as to be able to get the real vision of one eye, if the cover is improper, it will cause the vision between the two eyes to interfere with each other, so as to get the real result.

2. Distance, for different specifications of eye charts, the distance used is not the same, if the distance during the examination is not appropriate, the final visual acuity results will not be accurate. Usually, the most common eye chart is checked at a distance of meters or 5 meters.

3. Relaxed state, which is for myopia.

It is particularly important, because for people with myopia, they often have the habit of squinting, and squinting can change the shape of the cornea to a certain extent, thereby changing the refractive state of the eye, and the vision detected when squinting is often better than the vision in the normal relaxed state, that is, the real vision, so the real vision level of an eye can be obtained in the relaxed state.

The distance between the eye chart and the person being examined must be fixed correctly, and the patient must be 5 meters away from the table. If the indoor distance is less than 5 meters long, a flat mirror should be placed in the meter to reflect the eye chart.

Test method: Cover one eye first, identify the direction of the "E" notch from top to bottom with one eye, until it can no longer be recognized, and record it. Normal visual acuity should be above.

If the subject cannot see either, he or she should move forward until he or she can see, and his visual acuity is "distance 5=visual acuity"; If you can't see it within half a meter, you can make the test subject identify the index, measure the hand, light perception, etc.

Visual acuity is recorded according to the examination. Near vision mostly uses the "J" near eye chart, the same method to identify the direction of the "E" word notch, until it can not be recognized, the near range can be adjusted by itself, normal near vision can see a line clearly at 30 cm, near vision examination is helpful for the diagnosis of refractive error.

The standard distance for measuring vision is generally 5 meters, even if the vision is normal, then you need to pay attention to it:

1. Pay attention to the time you spend with your eyes.

Children's eye development is not perfect, the ability to work is low, every time you read or write for an hour, you should let the child go to outdoor activities, do games, look into the distance, or observe the flowers and trees, so that the tense eye muscles are relaxed, eliminate fatigue. In addition, it is necessary to make the child's life regular, have enough sleep, and let the eyes get enough rest.

2. Pay attention to the light of your eyes.

Do not allow your child to read or write in dark light or sunlight. If a 25-watt light bulb is used indoors at night, the distance between the books and the lamp should be within 1 meter. If you use a 60-watt bulb, the distance between the book and the bulb should be 1 2 meters.

Cloudy days, dusk, weak light lines in the moonlight, and strong light in the sun, are not suitable for reading and writing. When watching TV, it is necessary to maintain a suitable distance, which should generally be 5 7 times the diagonal length of the phosphor screen. The time to watch TV should not exceed 2 hours at a time.

3. Pay attention to eye exercise.

Physical exercise can enhance blood circulation and metabolism, supply more nutrients to the eyes, and enhance the resistance of the eyes. The direct exercise is eye exercises, which is based on the massage, massage, acupuncture and acupuncture acupuncture points of Chinese medicine, combined with the unprecedented medical sports of Zaokuanhui, which is a scientific method to protect eyesight. Parents should learn the basic knowledge of eye exercises, give specific guidance and often urge their children to do eye exercises, and persevere.

4. Pay attention to eye nutrition.

In order to protect children's eyes, children can eat more carrots, animal liver, lean meat, to supplement vitamin A, or regularly supplement the comprehensive nutrition of the eyes with Leyan vision nutrients, and at the same time, it is also necessary to appropriately consume millet, tofu, animal liver and other supplements of vitamin B2, so as to avoid night blindness, corneal malacia, eye redness, dry itching and other symptoms. Eating too much sugar will harm your child's eyesight, so your child's sugar intake should be controlled.

5. Pay attention to regular inspections.

Regular check-ups are due to the fact that children's eye structure, binocular visual function, and intelligence are still in the process of continuous development after birth, and the content of the examination is different at different ages. The usual age of ophthalmologic examination is generally 2-7 days after birth, 42 days after birth, 3 months, 6 months, and 1 year of age, and then once a year. In this way, the problem can be detected early and corrected early, instead of waiting until the vision has deteriorated and there is a vision problem before going for a check-up.

Your test results show that:

The right eye is myopic 475 degrees, astigmatism is 50 degrees, and the astigmatism axis is 177; The left eye is myopic 425 degrees, astigmatism is 25 degrees, and the astigmatism axis is 144. Interpupillary distance: 63mm.

This is the result of computer optometry, which is just a reference power, if you are willing to wear glasses, it is recommended to go to a regular hospital for comprehensive optometry to determine the detailed power.

Introduce. The standard eye chart is made up of 12 rows of E in different directions, and the visual acuity should be tested at a certain distance from the eye chart, and the specific values should be checked according to the recommended values on the eye chart. Generally in the range of 3-5 meters.

When checking the eyesight, the spine should be buried, and a light source should be installed at the eye chart to avoid the deviation of the light cause of the vision test.

It is 5 meters away from the word list of "Hungry Biyu E".

Expansion: Adoption"e"The word standard eye chart or "e.""Flashcards are a detection tool, and the inspection steps are as follows:

The person being examined stands at a distance from the standard eye chart or"e"At 5 meters of the flashcard, the left and right eyes were tested separately with sufficient lighting or under natural outdoor light, with one eye tightly covered.

During the test, it is found that any eye can see clearly on the eye chart""One line of "e.""Those who can see clearly after adding corrective lenses or pinhole lenses, or those whose visual field radius is not less than 10 are not visual disabilities.

2) Replace it with your fingers"e"Word visual mark test method:

Under the condition of sufficient lighting or outdoor self-light, the examiner extends an unequal number of fingers for the examinee to distinguish with one eye, and if the number of fingers can be accurately distinguished at a distance of meters, the visual acuity is; If the number of rotten fingers can be distinguished in the meter prescription, it is considered to be; If the number of fingers can be distinguished in meters, the visual acuity is; If you still can't distinguish the hand index at the meter, your visual acuity is lower than that of a first-degree blindness.

When measuring visual acuity, the distance between the person and the eye chart is 5 meters.

The patient's line of sight should be parallel to the row, 5 meters away from the eye chart, the distance between the eye chart and the person being examined must be fixed correctly, and the patient should be 5 meters away from the chart. If the indoor distance is less than 5 meters long, a flat teasing car rental mirror should be placed at a meter to reverse the mountain mega eye chart. Cover one eye first, and identify the direction of the "E" notch from top to bottom with one eye until it is no longer recognizable, and then record it.

The distance between the test eye chart and the eye chart should be 5 meters, and if the indoor distance is less than 5 meters, a flat mirror should be placed at a distance of meters to reflect the eye chart. The eye chart is designed according to the principle of optic dismantling of the side angles. The so-called angle of view is the angle formed by the light emitted by two points in the outside world through the nodes in the eye.

Under normal circumstances, the angle of view formed by the minimum distance between two points can be distinguished by the human eye blade, which is the smallest angle of view, that is, the angle of view. The eye chart is designed in units of one point of view.

The E-word standard eye chart or E-word card is used as the detection tool, and the examination steps are as follows:

1. The examinee stands 5 meters away from the standard eye chart or e-card, and the left and right eyes are tested separately under the premise of covering one eye with sufficient lighting or outdoor natural light.

2. During the test, if it is found that anyone who can clearly see the E-shaped visual travel-based rubber mark on the line on the eye chart with any eye, or can see clearly after adding corrective lenses or pinhole lenses, or the radius of the visual field is not less than 10, it is not a visual disability.

It should be 5 metres away from the "E" table.

Extension: Use the "E" standard eye chart or "E" card as a test tool, check the steps as follows:

Standing 5 meters away from the standard eye chart or "e" early digging card, the test was performed on the left and right eyes under full lighting or outdoor natural light, with one eye tightly covered.

In the test, anyone who can see the "e" on the "line" of the eye chart with one eye, or can see it with corrective lenses and pinhole lenses, or has a visual field radius of not less than 10, is not classified as a visual disability.

2) Test method of using fingers instead of "e":

In well-lit or natural outdoor light, the examiner extends a different number of fingers for the examinee to distinguish with one eye. If the hand index can be accurately distinguished, the visual acuity is; If the number of fingers can be discerned in the prescription of rice, it is considered to be; If in the prescription of 1 can distinguish the number of fingers. 0 meters, visual acuity is; If you can't tell the hand index in the land core, it means that your vision is lower, which means that you are blind for the first time.