Myopia Myopia

Myopia is a condition where the eyes focus on something close up, causing distant objects to appear blurry.

Most cases of nearsightedness are caused by an excessive increase in the axial length of the eye, also known as the depth of the eye. Children's growth period is a time of eye growth and visual function development, making them more susceptible to nearsightedness, so it is important to prevent the progression of nearsightedness during childhood.

Let's take a look at myopia, including the development of children's visual function, what can be learned from vision tests at school and at ophthalmologists' offices.

How we see things

Structure of the eye Structure of the eye

The structure of the eye is said to be similar to that of a film camera.

Light entering the eye is refracted by the cornea and lens, focusing onto the retina and projecting as an image. This image travels through the optic nerve to the brain, where it is recognized as a visual image.

Myopia is a condition where the focus is in front of the retina. Myopia is a condition where the focus is in front of the retina.

Most cases of nearsightedness are caused by an excessive increase in the axial length of the eye, which prevents the retina from focusing properly.

Wearing glasses or contact lenses corrects the refraction of light, allowing it to focus on the retina.

  • Direct vision

    The image is perfectly focused on the retina, resulting in a clear image.

  • myopia

    The focus is set in front of the retina. You can see things up close, but distant objects will appear blurry and difficult to see.

  • farsightedness

    The focus is behind the retina. Farsightedness in children can lead to strabismus or amblyopia, and treatment may be necessary.

Myopia in children tends to progress easily.

Myopia is said to be more likely to develop and progress during childhood, so caution is necessary. This is because the period of rapid growth in height is also a period of rapid growth in the eyeballs.
Generally, the axial length of the eye is about 17 mm at birth. It grows to about 24 mm by the age of 13, but if the axial length becomes too long due to some influence, it can lead to myopia (axial myopia).

Visual development in children

A newborn baby's eyesight is not yet fully developed. Vision develops rapidly between the ages of 1 and 4, approaching 1.0 vision around the age of 5. It is said that children are able to combine the information they see with both eyes and comprehend it in their brains around the age of 6 to 8. Since some children develop myopia during this crucial period of visual function development before entering elementary school, it is important to be aware of myopia prevention from an early age.

It is important to prevent myopia in children from progressing. It is important to prevent myopia in children from progressing.

Childhood myopia often progresses with age, and the earlier it develops, the more severe the myopia tends to become in the future.
Furthermore, it is said that if nearsightedness progresses too far, the risk of developing eye diseases that can lead to blindness increases.

That's why it's important to try to prevent myopia from progressing as much as possible.
It is important to do so.

The earlier you develop nearsightedness, the more severe your nearsightedness will become in the future. The earlier you develop nearsightedness, the more severe your nearsightedness will become in the future.

This graph shows the annual rate of myopia progression in 928 schoolchildren aged 7-9 in Singapore, tracked until age 11.
It has been found that the longer a child's nearsightedness progresses, the more likely they are to develop severe nearsightedness in the future.

*In this graph, the age of myopia onset refers to the age at which eyeglasses were first prescribed to correct nearsightedness.

The rapid increase in childhood myopia is said to be related to changes in the living environment surrounding children today. The reality of childhood myopia and what lifestyle habits are related to it are explained in "Childhood Myopia is On the Rise."

Childhood myopia is on the rise.

How do you determine if someone is nearsighted? How do you determine if someone is nearsighted?

Whether or not you are nearsighted cannot be determined by a visual acuity test alone. A more thorough examination at an ophthalmologist's office, including a refraction test, is necessary. Since nearsightedness is not the only cause of vision loss, other eye diseases may also be the cause, so it is important to see an ophthalmologist.

What can be learned from school health checkups?

There are two main purposes for vision tests conducted at school.

  • To find out if it will cause any problems in school life.
  • Find out who should see an ophthalmologist sooner.

Vision assessment

  • 1.0 or higher

    Even when sitting in the very back of the classroom, I can easily read the writing on the blackboard.

  • You need to see an ophthalmologist.

    • 0.9～0.7

      Even when sitting in the back of the classroom, I can usually read the writing on the blackboard, but smaller letters can be difficult to see.

    • 0.6～0.3

      Even when sitting in the front row of the classroom, I can't read small print very well.

    • 0.2 or less

      Even sitting in the front row, it's difficult to read clearly without glasses or something similar.

It's important not only to know the results of your vision test, but also to visit an ophthalmologist regularly.

Don't judge solely on uncorrected visual acuity.

Uncorrected visual acuity of 0.2 or 0.3 alone is not sufficient to accurately assess changes in the condition of the eyes.
In ophthalmology, the refractive error of the eye is measured using precise equipment, and the prescription is determined while checking how you see with lenses containing the correct power.

The unit of power is expressed using diopters (D), and nearsightedness is indicated by a minus sign (-).
The higher the number, the more severe the nearsightedness.

Low myopia:
-0.5D or more, less than -3.0D
Moderate myopia:
-3.0D or greater, less than -6.0D
High myopia:
-6.0D or higher

Furthermore, a decline in vision may indicate not only nearsightedness but also other eye conditions.
If you notice that your child is having trouble seeing, do not try to diagnose it yourself; be sure to have them examined by an ophthalmologist.

Check your vision with the eye exam app "AImirun". Check your vision with the eye exam app "AImirun".

AImirun is an app designed to help you take regular vision tests and quickly notice any changes in your eyesight.

Please use this as a pre-check before going to the ophthalmologist.

For parents who are concerned about their child's vision.
・For those who are concerned about how they see

Click here for more information about "AImirun".

AImirun (eyesight measurement app)

If you have any concerns, please see an ophthalmologist. If you have any concerns, please see an ophthalmologist.

A child's eyes are precious.
During childhood, when both the body and eyes are growing, it is important to have regular checkups.
Receiving proper guidance is important.
If you have any concerns about your eyes, consult an ophthalmologist.

Supervision

Department of Ophthalmology, Keio University School of Medicine
Kojimachi Odori Ophthalmology Clinic
Professor Kiwako Mori