I think the comment you are replying to specifically meant age related far-sightedness when speaking about glasses. Plenty of people need them for issues which have nothing to do with age.
Age-related decline is happening at much younger ages these days. There is a growing belief that the way we prescribe and use glasses is leading to atrophy in young people that previosly was only seen in the old. Lenses get firmer eith age, but atrophied muscles from inactivity mean even soft/young lenses are unable to focus properly.
Last I checked, they'd finally narrowed down the main cause of near-sightedness (not far-sightedness, though) to insufficient very bright light (sunlight) exposure during certain formative years (I wanna say like 3-6?). Seems to play a role in getting the lens to stop changing at the correct time.
Seemed like they were pretty certain it was that, specifically, and not the list of other things people've blamed it on over the years.
No-one's responded to this by totally re-thinking how we do early childhood education (there's little sun in the Winter, schools have been cutting back recess time and getting much more timid about sending kids out in non-perfect weather, so I'd bet that's when most of the harm is being done) so maybe that turned out to be BS? Or maybe we just don't care about preventing a very high percentage of near-sightedness cases.
China is. It started with their air force pilots. They, like many air forces, have had to drop their 20-20 vision requirements for pilots as the VAST majority of well-educated potential pilots now wear glasses. In china/japan it can be upwards of 90% of young men, that a huge loss of potential recruits. (fyi, most air forces now require only that new pilots have vision "correctable" to 20-20 via glasses.)
>> China’s top education authority has asked all schools to give students more sports-related assignments and less text-based work during summer and winter breaks this year to curb climbing myopia rates among minors.
>> The Ministry of Education announced the new rule as part of its Bright Action project, a five-year plan to better protect students’ eyesight by increasing outdoor activities and minimizing screen time, which have been blamed for deteriorating vision among children and adolescents.
You mention recess time. I live in Helsinki and the school system here aggressively gets kids outside for regular playtime in any weather. There should be data here for further investigations of root causes.
In my part of the US, nicer private schools and daycares tend to act that way, but cheaper ones or public schools schedule less of that time to begin with and are quick to replace that with indoor activities if there's a light drizzle or it's a little cold outside. Perhaps counterintuitively, public schools seem much quicker to bow to the preferences of one or two nutty parents ("little Johnny was COLD at recess! You can't go outside when it's 35°F, that's unsafe!") than private schools do.
Also, public schools have responded to No Child Left Behind legislation, in part, by drastically cutting recess time, including in very early grades—which, AFAIK given the state of the art in learning research, might actually be counter-productive, but a key sentiment driving all US behavior is that one must always be able to say that one has "done something", even if that something was worse than doing nothing, and that it's preferable to so something that an uneducated person would think looks like it should help based on gut feeling, over what experts say would help.
I've read conflicting accounts around this. Some link "time outdoors" to exposure to "natural" light, which 99% of the time is brighter light. But others link time outdoors to a wider variety of focal distances. Someone walking in the woods is constantly refocusing from close to far, whereas someone sitting indoors is probably just staring at a fixed distance (computers/books etc). So the answer may be brighter indoor lighting (brighter computer screens) or maybe we need to continuously change our focal distances, something far more complicated to implement indoors.
It's a lot wider than that. I'm 66 and don't need glasses yet, neither for reading nor driving, but one of my children, aged thirty, does.