My wife is an optometrist, looking at a screen is not unhealthy.
The main problem is that the eyes of children are still in development (growing). When an eye has it's focus too nearby for too long at a time, the eye will grow incorrectly, resulting in near-sighted kids that need glasses.
This means that looking at a book at close range for extended periods of time is equally bad.
Therefore the guidance they give is: after looking for 20 minutes at something close by they should at least focus far away for 20 seconds, also they should be outside for at least 2 hours a day so your eyes receive enough daylight.
shorturl.at/w2367 (page is in dutch)
the rest of your comment is contradicting your first sentence, since what you suggest is not how people let children use these devices
but yeah, I'm also trying to restrict my kids reading time since I'm aware it's unhealthy for eyes as well (as proven by myopia from memorizing in China even way before tablets/smartphones)
That depends how you interpret it.
It is fine if you give a child a tablet, with the condition that you also manage the things they do on it, and the time spent.
You have to be responsible as a teacher / parent. This applies with all things that children want, but can not yet self-regulate yet, like eating candy or watching tv.
BookaBooka - www.bookabooka.com - a multilingual picture book app for children 2-8
In the last 3 years I've been building a child friendly app with a library of 150+ picture books available in 20+ languages. Books can be read in single, or dual language mode, creating the opportunity to bridge between languages.
Research shows clear benefits of children that are being read to. Research also shows parents should read to their children in the language they are most proficient in, which might be a different language from the one used in school.
I hope to provide all children, including immigrants, expats and refugees with a library in their native tongue, and the privilege of being read to, even if parents aren't able.
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It is a multilanguage picture book app that runs on iOS, Android and Windows and currently contains 100+ books that are actively translated into different languages.
I'ts a safe digital environment to let your kids find enjoyment in reading or being read to from a choice of narrators.
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