How many people are now nearsighted?
“Half of the 20-year-olds are nearsighted. Since the 1950s, the number of people with myopia has increased considerably. A quarter of the 60 and 70-year-olds are nearsighted. Myopia is permanent. This means that the number of people with myopia (nearsightedness) has doubled in 40 years, and in Asia 80 to 85 percent of people in their twenties are now nearsighted.
Myopia is mainly caused by our lifestyle. It hardly occurs naturally. The natural position of our eyes is to look into the distance. When we focus on something close by, our eye muscles have to work hard to make the lens of the eye more convex. If this happens often and for a long time, the eye adapts by getting longer. This way, looking close becomes the natural position and the muscles don’t have to work as hard.”
You can put on glasses. Nearsightedness isn’t that bad, is it?
“Yes, nearsightedness entails a lot of diseases. Because the eye gets longer, the eye tissue is stretched over a larger surface area. The eye cells in the connective tissue become thinner as a result. As you get older, the connective tissue loses firmness, which happens everywhere in your body, but also in your eye. The connective tissue then sags and you get staphilomas. This results in bald spots in the connective tissue where you can no longer see anything. These are usually the spots in the middle of the field of vision. One in three people with high myopia – people with an eye defect of -6 or higher have to deal with this, but also with -2 or -3 there is a greater risk of problems.
There is also a greater chance that the retina will detach. The light-sensitive cells then become loose. You have to operate that as soon as possible, otherwise you can go blind. The risk of glaucoma (damage to the optic nerve) is greater with nearsightedness and cataracts are also more common.”
Has corona had consequences?
“Yes, research in China shows that more children aged 6 and 7 became myopic after the lockdown. In China there was a strict lockdown where no one was allowed to go outside and children probably watched a lot of screens. The impact of that relatively short period of the lockdown was already reflected in the figures for the number of nearsighted.If children at that age already have an eye defect, this quickly increases.
From Generation R. (a Rotterdam study in which 10,000 children are followed, ed.) we also know that children who often look at their smartphone or tablet for a long time, become nearsighted more often. Looking at a screen for longer than 20 minutes at a time already poses a risk. That’s why we came up with the 20-20-2 rule earlier. After twenty minutes of screen time, looking into the distance for twenty seconds and playing outside for two hours every day.”
Does it matter if you look at a tablet or smartphone, or read a book?
“No, it’s about close work as we call it. It does help by keeping the book or tablet or smartphone a little further away. If a school ruler fits in between (33 centimeters, ed.), the risk of nearsightedness is already less big.”
At what age is the risk of myopia greatest?
“The eye grows fastest during the primary school age of 6 to 12 years. From 12 to 15 year olds, the eye grows slowly. A nearsighted eye can even continue to grow until the age of 25. After that, the risk of nearsightedness is no longer so great. A normal eye has a diameter of 2.3 centimeters. I have seen a child whose eye has grown to 3.6 centimeters. The eye socket is then completely filled by the eye. That makes it difficult to look around. I am horrified when I see a baby with a smartphone. Before the age of 2 it is in any case not wise to let children look at a screen, not even for 10 minutes. From 2 to 5 years old, that should be a maximum of 30 minutes a day.”
Does heredity also play a role?
“Certainly, research shows that there are 500 genes that all play a role in the development of myopia. But the genes are less decisive than the lifestyle. It is not the case that if you have a higher risk of myopia you can’t do anything about it In that case you need more stimuli to prevent your eye from growing too far.”
How do you prevent nearsightedness?
“Go outside! At least two hours a day. Outside we usually look into the distance. That helps. There is also more light outside and you can see the entire color palette. Those three things are important to prevent nearsightedness. I’m almost 15 years working to ensure that children spend more time outside. I think schools play an important role in this. When children come out of school at three o’clock in the afternoon, it is – especially in winter – difficult to go outside for another two hours Go outside for at least an hour during school. Occasionally teach outside. That is not only good for the eyes, but also for motor skills or to prevent obesity.”
SP, GroenLinks and PvdA recently argued for a new law to encourage schools to go outside more often. Does that help?
“Yes, in Asia the Ministry of Education has also made a law that obliges schools to take their students outside every day. It works there. I would like to see Dutch schools also obliged to do so. Now I often hear that “Schools don’t have time for that because they don’t have enough staff. Apparently, that stimulus from above is needed to get those children outside. Now children are indoors too much and you notice that right away.”
You selected a secondary school for your children within half an hour’s cycling, then they would be outside for at least 1 hour a day. What can parents do?
“Haha, yes that’s right. Fortunately, my children are not nearsighted. As a parent, you can at least take your child outside at the weekend. And set a good example. That is also important. Don’t stare at that smartphone endlessly. Children aged 13 look on their phone an average of 4 hours a day. When they are 18 this is 6 hours a day. Almost a full working day. That is absurd. If parents are nearsighted, children also have a greater chance of becoming nearsighted. This is due to hereditary factors, but especially due to behaviour.If parents spend a lot of time looking at their phone, children will take over.
That phone has become so important in our lives. This not only affects our eyes, but also how we interact with each other. We spend so many hours a day looking at that screen, we all give things up for that. Is that worth it? In France, smartphones are banned at school. This makes it easier to keep children focused and also improves social interaction. I would very much like to see a broader discussion here about healthy smartphone behavior.”
By: National Education Guide / Marjolein Kooyman