3-D viewing options, virtual reality, 3-D movies, and virtual reality goggles and headsets are becoming more common.

We are promised a "metaverse" now. But 3-D viewing causes potential damage to the eye, particularly in children and adolescents. How can 3-D view damage eyes of a young person?

Are problems with 3-D viewing limited only to a developing eye?

How to prevent accommodation and vergence problems in children? It is a very, very interesting question, also related to myopia, but also related to vergence insufficiencies. So we live in a world where screens are part of life every day, even for the youngest of children. That's a big problem. Because we see today six-month-old children with a smartphone in their hand. They are just playing with a phone. That's a problem, because it's too early, of course, [for them to look at screens]. And we know in China they just avoid screens until three years of age. Maybe we can go in between those extremes.

But the problem is the consequence of these screens is going to be myopia [nearsightedness]. As we discussed myopia, there is a pandemic-related problem of myopia in children and adults.

We know that, for instance, in Singapore, probably about 90% of young adults are myopic. That's incredible. It was, of course, not this way 20 years ago. So that's a real big problem. And probably, there is a role of the screens. It's not only the screens, but the screens are the main problem. So we must decrease the time we spend on the screens, and it's not easy to do today. The second point is for the 3-D screens. We were just upset when they were films that used a 3-D system. I think now it's not the biggest problem we have. But these 3-D systems are on maybe tablets or goggles. They can induce vergence insufficiency. Vergence insufficiency is probably quite common. It affects about 30% percent of the population. But these 3-D screens induce problems not just of vergence insufficiency. 3-D screens induce headaches, double vision, for instance. So we must be aware of all of these problems. We have to have a screening of vergence insufficiency. We need maybe to have orthoptic re-education before going to 3-D screens. Probably we must try to avoid a lot of 3-D screens. But I think also it's difficult to do. What underlies the version vergence insufficiency? When people have 3-D goggles, what is the cause of the problem? Because they look straight, but there is some sort of artificial perception by the eye of the depth of the vision field. Could you please talk more about what causes vergence insufficiency? Yes, of course, when you go to the 3-D viewing system, it's based on the dissociation of vergence and accommodation. So you signal your brain to create this dissociation, to create this perspective, this stereoscopic impression in the brain. This dissociation of vergence and accommodation also creates a bad signal because the brain doesn't understand exactly what's going on. And so, if you have vergence insufficiency, this dissociation just increases the vergence insufficiency. So when I look at my finger, and when I move it closer and focus on accommodation, my eyes become fixed. They move together. And if I look at the same point in the 3-D goggles, my eyes continue to look straight, but I nevertheless perceive the object as being closer. So my brain receives the dissociation of signals. Exactly. That's exactly the point. Yes, you got that very well. Well, I think then, we'll have more of those problems with vergence insufficiency as time goes by, unfortunately. Exactly. There is a connection between vision and posture in the growing child. And there is a common eye disorder called vergence insufficiency, which you already mentioned. And it causes mostly visual problems. But vergence insufficiency disorder also leads to general and to postural symptoms. You already mentioned these problems. Can you summarize what is the vergence insufficiency disorder? How to recognize vergence insufficiency? And what are the best methods of treat vergence insufficiency in children? Yeah, so as we discussed, vergence insufficiency is a common problem. But it is probably also underrecognized. So for instance, in children, when they have vergence insufficiency, sometimes they go to school, but they have bad results. They have some headaches, but it's very difficult to individualize. It's from the eyes. Sometimes they have dizziness and instability. And parents don't think that it's coming from the eyes. Also, it is difficult to diagnose vergence insufficiency because it's not just an ocular examination. It's an orthoptic examination. So we need to have a complete examination of the ocular system, of course. We need an orthoptic examination of the ocular motility. We also must measure the refraction. They must be explored with cycloplegic eyedrops. All of these diagnostic examinations can solve the problem. Sometimes posture is affected by vergence insufficiency. Of course, it's important also because children with vergence insufficiency have postural problems. But I should say. Also, it's interesting that vergence insufficiency is associated with some other diseases, like dyslexia. So these children have problems in school. They struggle in everyday life with reading. But of course, if there is an additional vergence insufficiency, the problem is heavier. So it's very important to find out vergence insufficiency problems. So I just summarized that we need ocular elimination, orthoptic examination, and refraction examination under cycloplegia. Thank you. That's very important to know because criteria to make the right diagnosis, you need to do all the right diagnostic tests. Exactly.