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🏥 | Is the cause of vision loss in the educational background?Reported by a Chinese research team

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Is the cause of vision loss in the educational background?Reported by a Chinese research team

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The number of years of school attendance and the decline in unaided visual acuity were analyzed after correcting for the effects of age.

[Useful funny medical papers] In China, the percentage of people with myopia who have difficulty seeing distant objects is high worldwide, 7 ... → Continue reading

 Daily Gendai Healthcare

We will deliver the medical and health articles of the evening paper "Daily Gendai". From everyday health laws to the latest medical information, all articles are based on interviews with doctors and specialists.

Wikipedia related words

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visionWhat is (siroku)?EyeIt is the ability to identify an object with.When the visual acuity deteriorates due to refractive error or accommodation abnormality, it is possible to improve the visual acuity by performing refraction correction.However, when the visual acuity deteriorates due to a disease, the visual acuity cannot be improved unless the cause is removed.In addition, the similar word ""Or"Eyesight"Is a different thing.

Driving, maneuvering, etc.Qualifications/LicensesStandards for visual acuity are set when acquiring.


Shortly after birth赤ちゃんBy the time he is about 6 years old, his eyesight will be developed by using his eyes correctly, and he will be able to distinguish between light and dark.During this time, if you do not have a habit of using your eyes properly due to trauma or illness,AmblyopiaCan cause.

From around 40 years oldPresbyopiaThis may reduce near-point visual acuity.

Classification of eyesight

Static / dynamic visual acuity

Sight when the eyes and objects are stationaryStatic visionCalled.On the other hand, the ability to continuously identify moving objects without losing sight of the line of sight.Dynamic visual acuityCalled.Dynamic visual acuity identifies lateral movementDVA dynamic visionAnd there is KVA dynamic visual acuity that identifies movement in the anteroposterior direction.Ball skillsMany of these abilities are said to be closely related to dynamic visual acuity, and training improves dynamic visual acuity.Dynamic visual acuity and static visual acuity are considered to be completely different, and high static visual acuity does not necessarily mean high dynamic visual acuity.

Dynamic vision declines with age, so drivers over the age of 70Driver's licenseMandatory when renewingElderly trainingIn, a dynamic visual acuity test is performed as one of the driving aptitude tests.

Deep vision

Driver's licensePerformed by visual acuity test in test and renewalDeep visionIs the ability to correctly grasp perspective and stereoscopic effect.

Semi-medium-sized Vehicle(Excluding 5t limited),Medium-sized car(Excluding 8t limited),Large car,Tow vehicle,Second-class driver's licenseIt is obligatory at the time of new acquisition and renewal of.

In the driver's license testSankanhoIs used.In the three-rod method, three thin black rods are lined up, and with the two left and right fixed, the center rod is reciprocated from the front to the back when viewed from the subject, and when the three rods are parallel. Give a switch or voice signal and measure the error.The test is performed by the movement of the culm placed at a distance of 3 meters from the subject, but the depth perception tester itself has been miniaturized, and the distance and movement are apparent, and there are also models that perform visual acuity tests at the same time.

In the driver's license test, the error is measured three times and the average is 3 cm or less.Since the average is 2 cm, if the error is 2 cm and 0 cm, it will pass even if the third time is 0 cm.If you have poor eyesight, if you have not adequately corrected astigmatism or anisometropia, or if you have poor motor skills (especially reflexes, agility, and dexterity) without these abnormalities, you often cannot pass this test.

If you do not pass this test, the examiner will tell you that you have visual impairment or if you are a spectacle wearerglassesIt is suspected that the power of the power is not correct, but in the first place, it is unlikely that you will gain experience of deep vision test by the three-rod method in living a general life (OphthalmologyIn 2014, the three-rod method was not used for the stereoscopic examination, and the correlation between the three-rod method and the stereoscopic examination method was medically proved.Okayama UniversityThis is the first time for me to study), even if you have a Type XNUMX license or a large licenseGood driverThe longer the renewal period, the rarer the person is accustomed to testing and operating once every few years.Designated driving schoolIn some cases, the same type of depth perception tester installed at the driver's license examination site at the location may be prepared to familiarize the trainees with the operation.

If you fail, the response will differ depending on the test site and police station, but if you perform the second test with a break of 10 minutes or more, and if you fail, retest at a later date, the time when the error is large in the first measurement. So, when re-measurement is performed by showing the latest, farthest, and lined state of the center bar along with the explanation of how to operate the device, the inspection is performed continuously and the average error becomes 2 cm or less in three consecutive times. In some cases, the examiner may make a decision or advise the results on a case-by-case basis.In an extreme case, there are some strong people who do not rely on their eyesight, but recently measure the farthest distance with the driving sound of the motor that moves the rod, and put it within the margin of error only by the timing.

Central and out-of-center visual acuity

Visual acuity is best when viewed in the fovea centralis of the macula of the retina.Central vision, The eyesight when viewed in the surrounding areaOut-of-center visual acuityCall.

Naked eye vision / corrected vision

Visual acuity without the use of vision correction equipmentNaked eye vision, The visual acuity calculated by performing a corrected visual acuity test at an ophthalmologist, etc.Corrected eyesightThat.glasses-contact lensIt may be mixed with the visual acuity when the correction is performed in, but basically it is a word indicating the test value.When both naked eye vision and corrected visual acuity are listed, the corrected visual acuity is enclosed in parentheses.Corrected visual acuitySometimes called.

Even if the corrected visual acuity reaches the standard value, if the naked eye vision does not reach a certain standard,Professional baseball OfRefereeAndHorse racing OfJockeyThere are some occupations that cannot be taken.

Monocular visual acuity / binocular visual acuity

Visual acuity when viewed with only one eyeOne-eye vision, Sight when viewed with both eyes at the same timeBinocular visionCalled.Binocular vision is slightly better than monocular vision,astigmatismThe tendency becomes stronger when there is.Binocular vision enhances deep vision.

Near vision / distance vision

Distance vision is what is measured at a distance of 5 m or more.Visual acuity is obtained by measuring the minimum viewing angle (minimum separation range) with respect to distance.Normally, in Japan, if a Randold ring with a diameter of 5 mm, a thickness of 7.5 mm, and a cut of 1.5 mm can be seen at a distance of 1.5 m, the viewing angle is 1 minute, which is equivalent to 1.0.Therefore, near vision is also judged by the visual angle.Most of the near-sight visual acuity charts used in Japan are for 30 cm, and like the far-sighted visual acuity chart, it is designed to be 30 when a visual angle of 1 minute can be seen at 1.0 cm.

The distance vision is measured at a distance of 5 m, and the eyes with emmetropia and myopia are theoretically measured in an unaccommodated state.In the case of hyperopia, the intervention of adjustment cannot be removed even if the measurement is performed at a distance of infinity (5 m or more).

On the other hand, near vision is measured at a distance of 30 cm, so 3D (diopter) adjustment is required.In the case of emmetropia, presbyopia is the one that cannot be adjusted in 3D.For example, 3D myopia is theoretically focused on 30 cm, so having a myopia of 1.0 without reading glasses does not mean that you are not presbyopia.

In addition, whether or not presbyopia is present cannot be determined without measuring both the corrected visual acuity for distance vision and the corrected visual acuity for near vision.

Vision test

Test your eyesightVision testOrVisual function testThat.

Inspection method

For eyesight testObjectiveUse a mark called.The subject confirms and discriminates the optotype from a position at a certain distance determined for each visual acuity measurement method, and responds verbally (or pointing with a finger).

In many cases, a visual acuity chart (visual acuity chart) in which multiple visual acuities are arranged for each visual acuity is hung on a dedicated stand, but recently, a lightning projection type that can illuminate a specific visual acuity as a visual acuity device has become widespread. doing.In addition, a single optotype such as a card type or a handheld type may be used, and there is also a liquid crystal panel type that can display while changing the optotypes one by one.Recently, a remote control type with a direction key may be used for the response.

When measuring one-eye visual acuity using an optotype such as the Randold ring, the subject stands at a distance of 5 m and looks at the other eye.Eye shieldCover with (squatting, a device that covers one eye used for visual acuity tests),Sight pointerRespond to the index pointed to in (a shining optotype in the case of an internal illumination lightning projection type visual acuity chart).Then, the minimum visual acuity value that can be read (correct answer) for more than half is the visual acuity value.

Eye chart

Randolt ring

As a method of measuring static visual acuityJapanThe most widely used optotype inRandolt ring(Randolt's ring).This is different in sizeCBy identifying the open direction of the letter-shaped ring, it measures the minimum viewing angle at which two points can be distinguished.Randolt ringSwitzerlandOphthalmologistEdmund LandoltDeveloped by, his name remains the name.1909/ToItalyAdopted as an international standard target by the International Ophthalmology Society of JapanInternational standard Randold ringCalled.

The Randold ring is a black ring with a diameter of the entire ring: the width of the arc: the open width of the ring = 5: 1: 1.SightMinuteOf the viewing angle expressed in unitsReciprocalIt is represented by.For example, if a cut of about 5 mm can be discriminated from a distance of 1.45 m, the visual acuity is 1.0.In Japan, "visual acuity 7.5" is the ability to see the exact direction in which a circle with a diameter of 1.5 mm and a thickness of 1.5 mm is cut with a width of 5 mm from a distance of 1.0 m.[1].ISOThen diameter 7.272 …… (Circulating decimal) Mm, thickness 1.4544 …… (same as left) mm is specified[2]..A normal visual acuity test chart has a Randold ring with visual acuity of 0.1 to 2.0.The eyesight is so good that the Randold ring with a large numerical value can be identified.A visual acuity test chart used at a distance of 5 m or 3 m is used to measure far-point visual acuity.

The measurement of near-point visual acuity is based on the same principle.However, it is often measured using the Randold ring projected inside the machine instead of the visual acuity test chart printed on paper.

Other optotypes

Use the alphabet as a target other than the Randolt ringSnellen chartOr E-shaped onlyE chart, Otherhiragana,KatakanaIs sometimes used.

Alphabet is used in the United States etc.Snellen chartOr E-shaped onlyE chartIt is common to use.

There is also a visual acuity chart that combines the Randold ring and other targets, Oshima type (combination with hiragana), Nakamura type (combination with hiragana and numbers), Ishihara type (combination with katakana), mountainous type (two fish) (Combination with twin fish optotypes in which the silhouettes of the characters are lined up in parallel).In addition, since it is often difficult for infants to respond to the Randolt ring, the visual acuity chart for infants (such as the Ishihara-style visual acuity chart for infants) uses the silhouette of an animal and the direction of the index finger as a silhouette. The picture target is used.For infants who cannot be inspected with pictograms, taking advantage of the property of paying attention to more complicated patterns, black and white stripes and gray boards with the same brightness on average are shown at the same time, and stripes and gray There is a method of evaluating the point that cannot be distinguished as visual acuity.

Notation of eyesight

Decimal vision

In Japan, decimal visual acuity with decimal notation such as "0.7" and "1.0" is common.If the visual acuity is less than 0.1 and the largest Randolt ring cannot be seen, the distances are gradually reduced. ..When the eyesight is less than 5, the "exponential valve" (example: 3 cm / exponential valve) that indicates the number of fingers can be confirmed, the "manual valve" that shows the movement of the palm in front of you, and the light and dark can be identified. It is written as "light valve", "blind" or "no light sense" where the light and darkness is unknown.

In places such as school examinations, the examination is simplified by using four stages: A (1.0 or more), B (0.7 or more), C (0.3 or more), and D (less than 0.3).

Fractional vision

In the case of European countries including the United States and the United Kingdom, it is expressed as a fraction such as "20/20" and "6/6".The numerator represents the examination distance (20 feet or 6 meters), and the denominator represents "the distance that a healthy person (person with a visual acuity of 1.0) can finally discriminate the target that the subject can discriminate".For example, in the case of "20/40", it means that a healthy person can see the target that the subject can finally see at 20 feet from a distance of 40 feet.However, simply put, if you replace the fraction with a decimal as it is, it matches the notation of decimal visual acuity.That is, "20/40" corresponds to "0.5" and "6/60" corresponds to "0.1".

logMAR eyesight

Both decimal visual acuity and fractional visual acuity are the reciprocals of the angle (visual angle) as described above, and are not suitable for arithmetic analysis, and the problem that the intervals between each stage are uneven (difference between 1.0 and 0.9). , The difference between 0.3 and 0.2 is not equivalent).On the other hand, logMAR visual acuity is a visual acuity notation in which the common logarithm of the visual angle is used as a unit.Decimal visual acuity 1.0 corresponds to logMAR 0.0, decimal visual acuity 0.1 corresponds to logMAR +1.0, and decimal visual acuity 2.0 corresponds to logMAR -0.3. The smaller the logMAR visual acuity, the better the visual acuity.

There is a way to use the ETDRS visual acuity chart to discuss more detailed changes in visual acuity. In the ETDRS visual acuity table, 1 characters are arranged in one line, and characters with different difficulty in reading are arranged in the same line, and the total number of characters that can be read is used.This is a visual acuity chart designed so that difficult-to-read characters on one line and easy-to-read characters on the next line are equivalent. One character corresponds to the logMAR value of 5, which enables finer evaluation than logMAR visual acuity.Decimal visual acuity 1 corresponds to ETDRS 0.02 characters, decimal visual acuity 1.0 corresponds to ETDRS 85 characters, and decimal visual acuity 0.1 corresponds to ETDRS 35 characters.

For convenience, visual acuity measured by a method other than the 5 m visual acuity chart, including pictograms and striped visual acuity, may be converted to decimal visual acuity, but in that case, it should be noted that it is another visual acuity measurement method. It is desirable to specify.

Sight recovery / correction

myopiaSomeone with bad eyesightGlasses,contact lensNot installednaked eyeImproving the visual acuity in this state is called visual acuity recovery.You can recover your eyesight at homeTrainingからLASIK,OrthokeratologyThere are many things that can be realized by performing treatments such as.

However, what is commonly referred to as "training" for visual acuity recovery is not a medical practice, and many have no medical basis.In addition, devices such as eyeglasses that use the pinhole phenomenon used at that time are not "medical devices" approved by the government.Ultrasonic therapy equipment exists as a medical device approved by the government (Ministry of Health, Labor and Welfare).There are many companies that advertise in violation of the Pharmaceutical Affairs Law and the Freebie Labeling Law, such as supplements and health appliances.


[How to use footnotes]


  1. ^ Asahi Shimbun Science Group ed. "Common sense of science that can't be heard anymore: 102 items to eliminate memorization"Kodansha〈Blue bucks>, November 2008, 6.ISBN 978-4-06-257603-1. 
  2. ^ Page of Ophthalmology Medical Manufacturer Nidek Co., Ltd. including eye chart

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