What Do Grades A, B, C and D Mean in a Japanese School Eye Test? The 370 Method and Whether a B Means Seeing an Eye Doctor
Your child brings home the results of the school eye test, and you wonder: "Is a B bad?" "Should we see an eye doctor?" Japanese schools test eyesight with the "370 method" (san-nana-maru), which sorts children into four grades, A to D, using Landolt rings in just three sizes: 0.3, 0.7 and 1.0. This article explains what acuity each grade stands for and how well the child sees in the classroom, what to do after a B or C, what an eye doctor checks, everyday habits that help prevent declining eyesight, and how to check your child's vision at home.
How good is the eyesight behind grades A, B, C and D?
School eye test results in Japan are not written as a decimal acuity figure but as one of four grades, A to D. Here is the range each grade covers and roughly how well the child can see in the classroom.
| Grade | Acuity | How the classroom looks (rough guide) |
|---|---|---|
| A | 1.0 or better | Can read the blackboard comfortably even from the back row |
| B | 0.7–0.9 | Small writing may be hard to read from the back rows |
| C | 0.3–0.6 | Small writing may be hard to read even from the front rows |
| D | Below 0.3 | Hard to read the blackboard even from the front without glasses |
Each eye gets its own grade, and results such as "right A, left C" are common. When one eye sees well, children often don't notice that the other one struggles, so keep an eye on things if either eye is B or lower.
The 370 method: a test that uses only three ring sizes
An eye clinic works through fine steps from 0.1 to 2.0 and gives a number such as 1.2 or 0.6. Schools have to test many children in a short time, so they only use rings in the three sizes that correspond to 0.3, 0.7 and 1.0. Named after the first digits of those values, the "370 method" has been used in many Japanese schools since the 1990s.
- 1
Look with one eye at a time from 5 m
The eye not being tested is covered with an occluder, and the Landolt rings are shown one at a time. Children who wear glasses or contact lenses also have their vision measured with them on.
- 2
Start with the 0.3 size
The test begins with the easy 0.3 ring, and the child says whether the gap points up, down, left or right. If they can't see the 0.3 ring, the grade is D.
- 3
Move down to 0.7, then 1.0
If the 0.3 ring is visible, the 0.7 ring is checked, and if that is visible, the 1.0 ring. Seeing the 1.0 ring gives an A; stopping at 0.7 gives a B; stopping at 0.3 gives a C.
What to do after a B, C or D
Many schools send home a notice recommending an eye examination when a child gets B or lower (below 1.0). Here is how to think about each grade.
| Grade | What it means | Suggested next step |
|---|---|---|
| B | Daily life is mostly fine, but it may be early short-sightedness, long-sightedness or astigmatism | Have one check at an eye clinic. A seat nearer the front can make lessons easier |
| C | The blackboard is hard to read, which tends to affect lessons and sport | See an eye doctor soon and ask whether glasses are needed |
| D | School life is difficult without glasses | See an eye doctor as soon as possible |
Parents often think a B is nothing to worry about, but a B frequently marks the very start of short-sightedness, and that is also the stage where changes in daily habits may slow its progress. Long-sighted children, meanwhile, tend to get tired eyes when looking at things up close, a difficulty the acuity number alone won't reveal. Even with a B, having an eye doctor check the cause once gives peace of mind.
What does an eye doctor check? What is pseudomyopia?
- Visual acuity: measured in fine steps from 0.1 to 2.0, both unaided and with corrective lenses in place.
- Refraction: a machine measures the degree of short-sightedness, long-sightedness and astigmatism. Children's focusing power is strong, so eye drops are sometimes used to relax it temporarily before measuring.
- Eye position and movement: checks for a squint (strabismus) and for conditions at the back of the eye.
Pseudomyopia is when the focusing muscle (the ciliary muscle) stays tense after long periods of close work, so distant things temporarily look blurry. True short-sightedness is caused by the eyeball growing longer (axial length) and rarely reverses, whereas pseudomyopia can sometimes improve with eye drops or changes in habits. Only an eye examination can tell which one it is, so see a doctor first rather than buying glasses on your own judgement.
Why more children have poor eyesight, and what you can do at home
According to the School Health Statistics from Japan's Ministry of Education (MEXT), more than 30% of elementary school children have unaided acuity below 1.0, rising to about 60% in junior high school and about 70% in high school. The share grows with each school year, and more time spent looking at things up close on phones, tablets and games, along with less time playing outdoors, is thought to be behind it.
- Keep near work at least 30 cm away: hold phones, tablets and books at least 30 cm from the eyes, and don't use them lying down.
- Look into the distance every 30 minutes: every 20 to 30 minutes, gaze at something far away, such as the view out of a window, for about 20 seconds to rest the focusing muscle.
- Make time for the outdoors: bright outdoor light is said to slow the progression of short-sightedness. About 2 hours of outdoor play a day is often recommended.
- Read and write in good light: turn on both the room light and a desk lamp.
- Cut down on screens before bed: lack of sleep also leads to tired eyes.
How to check your child's vision at home
If you'd rather not wait for the next school test, you can measure at home with the same Landolt rings. The Visual Acuity Test (Landolt Ring) tool also shows the result as a school-style A–D grade.
- 1
Calibrate the screen size and measure the distance
Match the screen scale using a card or a coin, then mark a spot 1–2 m away for a phone or 2–3 m away for a tablet with a tape measure.
- 2
Practise answering first
Start with a large ring and practise: "Point to where the gap is." Things go more smoothly if the child points and an adult presses the matching button on screen.
- 3
Cover one eye at a time, gently, with a palm
Pressing on the eye makes vision blurry, so have an adult hold a hand lightly in front of it, or hold the base of a paper cup over the eye.
Home results are only a rough guide, but they help you notice changes early, such as a drop since last time or a big difference between the eyes. For tips on measuring accurately, see How to do an eye test at home: 7 tips for accurate results. To print a chart with the same ring sizes as school, see Landolt ring size and distance: making a 3 m or 2.5 m eye chart.
FAQ
- What acuity does a grade B on the school eye test mean?
- 0.7–0.9. It means the child couldn't see the 1.0 ring but could see the 0.7 ring. Small writing may be hard to read from the back of the classroom, so one check at an eye clinic gives peace of mind.
- What is the 370 method?
- It is the school testing method that uses Landolt rings in only three sizes, corresponding to 0.3, 0.7 and 1.0, to sort vision into four grades: A (1.0 or better), B (0.7–0.9), C (0.3–0.6) and D (below 0.3). It is named after the first digits of those values, read "san-nana-maru" in Japanese.
- Is it fine to skip the eye doctor with a grade B?
- Many schools recommend an examination for B or lower. A B is often the start of short-sightedness, and long-sightedness or astigmatism can also be hiding behind it. Even if your child isn't struggling, having the cause checked once makes later decisions about habits and glasses easier.
- Can pseudomyopia be cured?
- Pseudomyopia is when the focusing muscle stays tense and distant things temporarily look blurry, so vision can sometimes recover with eye drops or changes in habits. Only an eye examination can tell whether it is true short-sightedness, so see a doctor first.
- Is it a problem if the two eyes get different grades?
- A one-grade difference between the eyes is common. But if only one eye is C or D, the child may have got into the habit of not using the weaker eye. Children rarely notice when one eye still sees well, so have an eye doctor take a closer look.
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