Social “Jet-lag”, retinal lesions… the alert on the dangers of screens, especially for the youngest

On the strength of several studies on the subject, the National Academy of Medicine warns of the harmfulness of the abusive use of screens, especially among adolescents. Blue light “can be a formidable polluter”, indicates the Academy: it is “toxic” for the retina, and “disrupts the internal clock of users, causing a social “jet-lag”.

Yvan Touitou, chronobiologist, is a member of the National Academy of Medicine, which gives the alert, and honorary president of the Academy of Pharmacy. Lise Barthelemy, child psychiatrist, is a member of Co-Se, the collective for overexposure to screens.

Lise Barthelemy, child psychiatrist, is a member of Co-Se, the collective for overexposure to screens.

Yvan Touitou, chronobiologist:

Yvan Touitou, chronobiologist: “Scientists warn”.

We often talk about the dangers of exposure to screens in children under three years old, do you feel that we are vigilant enough on the issue of adolescents?

LB: The problem is at all ages of life. It is dramatic in toddlers, because the damage will be irreversible, and very problematic in adults. In adolescents, the brain is more mature, there will be a possibility of reversibility, but it is absolutely necessary to support young people and regulate access to screens, just as we regulate everything in children’s lives! We are in a somewhat crazy dimension. Finally, we are interested in adolescents. It is necessary to worry: the children cretinize the children.

YT: There is an abusive use of smartphones, for some child psychiatrists, an addiction, not to the device but to conversation with friends, to video games…


The first problem pointed out by the Academy of Medicine concerns the effects of blue light on the retina, LEDs are a thousand times brighter than an incandescent lamp… this is a subject rarely mentioned.

LB: It’s true, and it’s really important to take it into account.

YT: We talk less about photo-toxicity indeed, and the work is still contradictory. But it would seem that we have a “capital” at the level of the retina, which is depleted over the long term. The trouble with screens is that they are very close to the eye, 20 or 30 cm from the eye, and children watch them in dark rooms, there is a greater focus of the blue light on the retina. We will have to see if in these generations, there is an increase in AMD (age-related macular degeneration), for example, we are not there yet.

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Consequences on mood, sleep, school results… do screens really cause a social “jet-lag”?

LB: In the United States, Dr. Dunckley even created a weaning clinic, to resynchronize the biological clocks of young people.

YT: There, there are studies on the desynchronization of the internal clock. In life, we are early risers, early risers, or late risers, late risers. There is, with screen consultations, a shift towards the late riser typology. Children end up with a significant sleep debt, they lose one to two hours of sleep per night. We are no longer in the classic 9 hours of sleep, they are often at 7 am and they are tired in college and high school.

The older you get, the more you lose. The consequence is drowsiness, reduced alertness and declining school results. This is a warning for parents. Social “jet-lag” is a long-term desynchronization of the clock, it’s worrying.

Scientists make reports gathering dust on ministry shelves

How can we have a hold on adolescents, at such a complicated stage of life?

LB: We explain, we get information, YouTubers are starting to take hold of the subject. Above all, we accompany them: we don’t allow the screen to be in the room, we remove it after 9 p.m…. I remind you that we are not supposed to give a mobile phone to a child before the age of 15, the end of his third. And as an adult, it is important to have the same lifestyle. There are very concrete things to do. But it’s true that it’s complicated because the parents are still on their own, with their common sense and we are not yet in a prevention system, there is no law.

Today there are bills on the way on digital majority, respect for children’s image rights, and the prevention of children’s exposure to screens. Parents will be able to rely on this. In the meantime, we are in a very complicated free zone to manage for parents of children and adolescents. Things are falling into place but it’s still a little hell, and the parents have to be on the same wavelength. Otherwise, I tell them to drop the case.

When I see how complicated it was with my own children, when I am a child psychiatrist, I wonder how other parents are doing.

Wearing protective glasses, education… are the recommendations of the Academy sufficient?

LB: Finally the National Academy of Medicine is opening its eyes to this. They have been alerted for ten years. I will go further. It is not just a question of restricting screens at night but of banning them. Watching bedtime is common sense. Introduce student awareness into the school curriculum, of course. And educate parents, frankly! What is missing is asking the supervisory authorities to plan a national prevention campaign, with clearly written rules, it is the State that must provide them to us.

Take the example of alcohol: thanks to the law, merchants are required not to sell alcohol at any age. It was in the 60s that we removed the pitcher of wine from the table of college students, and in the 80s, that we removed the possibility of a glass of wine in the selfs of high schools. it seems crazy to us!

YT: The measures are above all the parents. If we want to be practical, they have to ban screens in the child’s room. They must not themselves be large consumers of screens. The discussion is extremely important and it is extremely difficult.

Scientists can’t do more than make reports, send them to the trustees. Today, these reports gather dust on the shelves of the ministries, but I think that knowledge makes it possible to move forward. We ask that doctors be allowed to enter schools to raise awareness. Sleep, for example, is a major element that is not taught in school. The school should teach public health. Saying “you shouldn’t” is not enough. It’s very difficult.

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