Personal computers, smartphones, tablet terminals ... While we have a convenient life, we are living in the "ultra-myopia era", which is the heaviest burden in human history.
In addition, the corona virus has increased the amount of time spent on remote work and using games and tablets at home, and the eyes are being abused more and more.
Under these circumstances, many ophthalmologists who investigated the eyesight and eye condition of elementary school students with corona sickness have extended the "eye length" that causes myopia, and "it has become an unprecedented dangerous time for the eyes. I have. "
What kind of incident is happening in our eyes now?
And what kind of measures should be taken?
(NHK Special "Survival in the ultra-myopia era where our" eyes "are dangerous" coverage group)
WHO is also concerned "Ultra-myopia era" unprecedented in human history
It has been about 7 million years since human beings were born.
Our ancestors, once hunting, lived a life free of myopia to discover distant prey and enemies.
As time went by, it changed to a life of looking closer and closer, such as group life, urban development, and the spread of books by the invention of letterpress printing.
Then, the times are approaching, and in the 1960s, televisions and personal computers and game consoles became widespread in the last 30 years.
In addition, smartphones and tablets have rapidly penetrated into our daily lives, with the ownership rate of smartphones in each household reaching 83.4% (according to a survey by the Ministry of Internal Affairs and Communications).
Life is closer than ever, but the evolution of the eyes is not keeping up with the changing times.
The closer you look, the harder your eyes will be, and the more you will be affected.
The population of myopia was less than 2 billion in 2010, but it is estimated that it will increase to nearly 5 billion by 2050, which is half of the world population at that time.
WHO = World Health Organization says there are serious public health concerns.
We are in the "super myopia era".
Corona wreck revealed an incident at an elementary school after school closure
Last year when I was hit by a corona disaster.
In June, when the school was closed all at once, an incident was revealed at the elementary school.
A visual acuity test at an elementary school in Kyoto showed that the number of children with visual acuity less than 0.7 increased from 17% in the previous year to 23%.
It was flat for five years until the previous year, so this time it has deteriorated sharply.
Anxious data showing that myopia is progressing.
With the help of this elementary school and an ophthalmologist, we decided to find out more about what was happening.
Eye length = "eye axis" extended "eye axis myopia"
Myopia is actually caused by an extension of the eye length = "eye axis".
What exactly does that mean?
The eye usually adjusts to focus on the retina by swelling and thinning the crystalline lens, which acts as a lens.
However, when you look at a close distance, the focus goes too far and even if you adjust it, it will not fit perfectly.
If this condition persists for a long time, adjustments will be made to change the shape of the eyes and focus.
The length of the eyeball = "eye axis" is extended in an attempt to focus on the retina that has gone to the back.
When the axis of the eye extends, the eyeball becomes shaped like a rugby ball, and when looking at a distant object, the focus comes to the front of the retina and becomes blurred.
This is believed to be the main cause of myopia.
Myopia tends to progress because the axis of the eye extends as the child grows.
And once the eye axis is extended, it will never return to its original position.
Early measures are needed, but a normal vision test will not tell you if your eye axis has stretched.
"Hidden myopia" measured by "eye axis" more than expected
It was the length of this eye axis that I tried to find out in elementary school.
Along with "Kyoto Elementary and Junior High School attached to Kyoto University of Education" in Kyoto City, we conducted a survey in cooperation with the Department of Ophthalmology, Tokyo Medical and Dental University, the Japan Ophthalmologists Association, and the Japan Orthoptist Association.
In the survey, 10 items such as the length of the "eye axis" and the shape of the cornea were measured using a special device in 576 elementary school students from the first grade to the sixth grade last November.
As a result, 54.5% of the children were judged to have myopia, which is more than half.
In June, the percentage of children with "visual acuity less than 0.7" who needed to see an ophthalmologist was 23.4%, so the number of children who can be called "hidden myopia" is actually more than double. I found out.
(In a normal visual acuity test, you may unknowingly squint and see well, and your eyesight may be measured higher).
The number of children with myopia is increasing as the grade goes up, with 1st grade: 23.5%, 2nd grade: 40.4%, 3rd grade: 52.1%, 4th grade: 64.6%, 5th grade: 70.5%, 6th grade: 78.3%. I did.
The average length of the eye axis is about 24 mm for adults, but the average length for sixth graders is 24.2 mm, which has already reached the average length for adults, and some children have significantly exceeded it.
(Supervising the survey, Ophthalmologist, Dr. Tae Igarashi, Tokyo Medical and Dental University)
"The longer you look at the eye axis, the longer it grows. It is an era. It is necessary to take all possible measures, such as reducing the time to look at things at close distances and resting eyes at a distance. "
See within 30 cm “Nearby work” for 4 hours or more a day
One of the major causes of such myopia progress is the work of looking at things at a short distance of 30 cm or less, which is called "near work".
How close are children with myopia?
Shuya Ishizaki, a fourth grader in elementary school who conducted the survey, started wearing glasses when he was in the first grade of elementary school, and his eyesight continues to deteriorate.
With the cooperation of Shuya-kun's family, we have him wear the latest equipment that can measure the distance between his eyes and what he sees every 5 seconds in 1-centimeter units, and every day. , I investigated what kind of situation I am doing in the near future.
The measurement result is this graph.
The part that is red is the time when I went to work.
The higher the line, the farther you are looking.
In my school life, I looked up at the blackboard and looked into the distance during class, and when I took notes, my eyes dropped and I looked closer.
During the break, I was looking far away, and I found that the time to look far and the time to work near work were repeated.
On the other hand, it was after I got home that my recent work was conspicuous.
Mobile games, homework, reading before going to bed ...
I was so serious that I often got my face close to me within 20 cm and was absorbed in it for 30 minutes to an hour.
More than 40% of my recent work time is spent at home.
Including the small hours of the day's recent work, it actually took more than 4 hours.
(Shuya-kun's mother)
"I sometimes limit the time I spend touching tablets, smartphones, and handheld game consoles, and I sometimes
pay
attention to my attitude when reading comic books, but I feel that it doesn't improve, so I also read books before going to bed. I can't stop it, and I'm wondering if it's not good, but I can't improve it. Under such circumstances, I'm very worried that the correction of my glasses is getting stronger and the speed of myopia is getting faster. "
"Axle myopia" progresses if the degree of glasses is not correct
Myopia is said to stop progressing as an adult, but some experts point out that the axis of the eye may extend and progress as an adult.
Masayoshi Kajita, director of the Japanese Society of Ophthalmology, cites glasses and contact lenses that are not correct.
If you wear strong glasses, you will be able to see better in the distance, but the focus will go too far.
This condition is called "overcorrection" and may eventually lead to an extension of the eye axis.
Mr. Kajita, who has examined the eyes of 40,000 patients with eyestrain, says that about 80% to 90% of the patients who come to the clinic are not right.
(Masayoshi Kajita, Director, Japan Society for Ophthalmology)
"Even if you make glasses with high power to see far away, if you spend most of your nearsighted time within 30 cm, such as a personal computer, in one day, it will put a heavy burden on your eyes. Myopia will progress. It is important to have an ophthalmologist thoroughly examine your eyesight and the degree of myopia, and make eyeglasses and contacts that suit your life. "
"Axle myopia" may increase the risk of illness
It has been pointed out that myopia may increase the risk of more serious illness.
The first thing to consider is the risk of eye diseases such as glaucoma, which narrows the field of vision, and retinal detachment.
Glaucoma is a disease in which the optic nerve in the back of the eye is damaged, resulting in loss of vision and, in the worst case, blindness.
Until now, it has been said that the cause is that the pressure "intraocular pressure" in the eyeball increases and the optic nerve is damaged, but the extension of the eye axis damages the optic nerve, leading to the risk of developing glaucoma. It is.
According to the latest research, the risk of developing severe myopia is 3.3 times higher for "glaucoma", 5.5 times higher for "cataract" where the crystalline lens is cloudy, and 21.5 times higher for "retinal detachment" where the retina is peeled off and the visual field is lost. ..
In addition, studies have reported that the deterioration of eyesight due to myopia is related to various diseases that are unlikely to be directly related to the eyes.
Professor Nahoko Ogata of Nara Medical University, who is investigating the relationship between visual acuity and dementia, analyzed data on about 3,000 people, including the health status and cognitive function of the elderly.
Then, the percentage of people suspected of having dementia was 5.1% in the group with good eyesight, while it was 13.3% in the group with corrected eyesight less than 0.7, which was 2.6 times higher.
(Professor Nahoko Ogata, Nara Medical University)
"Information from the eyes occupies most of the information that the brain obtains. It seems that the invisible eyes reduce the stimulation to the brain and reduce cognitive function. Poor eyesight is the cause of all illnesses and causes various physical effects and a vicious cycle. "
"Two measures" to prevent the progression of myopia
What should we do when we realize the danger of not being "myopia"?
..
The keywords to prevent the progression of myopia are sunlight and "20-20-20".
(1) Be exposed to sunlight.
Experiments with chicks conducted by the Australian National University have shown that when exposed to light, a substance called "dopamine" is released in the back of the eyes and the extension of the eye axis is suppressed.
Based on this, a study conducted in Taiwan found that exposure to light of 1000 lux or more for 11 hours or more a week suppressed the onset of myopia.
It takes about 2 hours per day.
In fact, when I started spending two hours outdoors in elementary school for about 10 years in Taiwan, the number of elementary school students with eyesight of less than 0.8 decreased by 5%.
Then, I am wondering how bright 1000 lux is.
It is about 300 lux in the classroom and about 800 lux even by the window.
It's about 1000 lux at a supermarket that is brightened to make the product look beautiful, but it's difficult to stay for 2 hours.
On the other hand, outdoors, even in the shade, it exceeds 1000 lux, and in the sun it is over 10,000 lux, so the goal is "2 hours outdoors."
(* Please do not look directly at the sunlight. If you have a chronic disease, please consult with your doctor according to your physical condition).
(2) "20-20-20" The
other is three "20".
The American Academy of Ophthalmology recommends a "20-20-20" rule of looking at something 20 feet, or about 6 meters or more away, for 20 seconds after a 20-minute continuous look.
It is said that myopia progresses when the time of near work within 30 cm becomes longer, so I am conscious of that time and try to reduce it.
Ingenuity to reduce "near work" consciously in daily life
Shuya Ishizaki, who had been working for more than four hours a day, decided to watch games and videos on a computer or TV instead of a small device.
I decided to take a break from my homework, which is about 6 meters away from my study desk, by having my mom talk to me from time to time.
In addition, I put sticky notes with "20-20-20" written on them all over the house and wrote them on a whiteboard, aiming to keep my recent work within two hours a day.
As a result, the maximum duration of a short-term work at one time was 27 minutes, but now it is 19 minutes.
It was less than 20 minutes.
The total number of hours of recent work, which was more than 4 hours a day, has been greatly reduced to 2 hours and 53 minutes.
I was able to reduce it by more than an hour.
(Ophthalmologist, Dr. Tae Igarashi, Tokyo Medical and Dental University)
"The speed at which myopia progresses depends on whether or not you live a life conscious of being exposed to the outside light by reducing the time you spend looking near continuously. Parental guidance Is important, but it is also important for the child to be aware of himself. "
It is important to keep in mind in your daily life
The photo shows the measurement results of the eye axis of the author (reporter: Azuchi) with high myopia.
The right eye reached 27.4 mm, well above the adult average of 24 mm.
Since I was a junior high school student, I thought it would be better to wear contact lenses and see far away in sports, so I always chose lenses with a strong degree.
On the other hand, I think I was indifferent to my recent work such as reading, studying, and mobile games.
Corona sickness tends to increase the number of recent jobs, but I myself am careful not to get serious illness in the future, and I also work outdoors to prevent my son (2 years old) from becoming myopia. , I would like to be careful not to continue my near work (I tend to watch the video of my favorite train at a close distance).
(Naoki Azuchi, Reporter, Science and Culture Department / Hiroto Oishi, Director, 3rd Production Unit / Tatsutaka Nakayama, Director, Osaka Bureau)