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From a layman's point of view I am struggling to understand how come we have not pinpointed the cause yet - there are so many various groups of children all over the world to draw correlations from. Obviously I am wrong, what I am failing to see?
We have identified various causes and we know that wearing glasses actually makes shortsightedness worse, but what can you do? It's like saying "I'm struggling to understand why people die in car accidents, when we all know what causes crashes."
Having moderately mild myopia, I stopped wearing glasses/lenses except for driving, and my vision steadily improved over the weeks and months. To make a long story short, I've concluded that glasses are a nasty crutch for most people. With wearing lenses for every waking activity, people never realize that their visual acuity is actually substantially variable, depending on their latest mode of visual activity. Too much reading and computer work, and the distance vision becomes worse (for myopia). Start examining details in the mid/far distance, usually outside, and the acuity immediately begins improving, though very gradually.

After a few years mostly without my glasses, all visual situations have greatly improved, even at night. However, I do a ton of reading, so the prospect of 20/20 or even 20/40 will probably always be elusive, even under the best conditions.

I had exactly the opposite experience: I always was a little bit short-sighted but never wore glasses / contact lenses. A few years ago I decided to use contact lenses and suddenly my short sightedness quickly got worse and I need much higher Dioptre lenses than when I started using them.
I will forever regret wearing glasses beginning in 2nd grade. Each year the optometrist gave me an increasingly strong correction until it finally leveled off around age 30.

This despite going outdoors nearly every day after school, and for many parts of the school day as well--it was a campus of many small buildings rather than the typical monolithic compound.

Quite possibly I could have had much better vision, had I resisted. But who knew?

It may be possible to correct it somewhat through exercises, but to get the eyes back to perfect vision is probably beyond reach.

Couldn't you just get laser eye surgery?
"Just"? Lasik is not free of complications. From the Mayo Clinic:

As with any surgery, LASIK eye surgery carries risks, including: Undercorrections. Overcorrections. Vision returning to pre-surgery vision. Visual loss or changes. Astigmatism. Glare, halos and double vision. Dry eyes. Flap problems.

I don't understand why everyone seems convinced that glasses cause vision problems. Is there any evidence for this?

To me, your comment sounds like blaming the barber for how your hair keeps growing, or saying maybe you wouldn't be so hungry if you ate less.

Just a hunch.
Seems like way more than just a hunch if you "forever regret wearing glasses." Maybe you trust your hunches way more than I do.
It's an obvious hunch, so it should perhaps not be surprising that there have been lots of scientific studies on this. The results are the opposite of your intuition: undercorrecting childhood myopia causes the myopia to progress more quickly than when it is properly corrected.

So good news, you've been freed of one eternal regret.

It's absolutely made up. I didn't wear glasses at all till I was 27, still mostly don't, and still have -1 short-sightedness despite all those years of trying to ignore the problem.
Everyone I know who wears glasses has bad vision.
While we're sharing anecdotes, I had (reading) glasses from the age of 8, but I never once wore them in school all the way through to the end of high school. My vision slowly deteriorated until I truly couldn't read normal sized text without glasses.

I genuinely don't know the science here. But I've never heard such a thing from a doctor (glasses hurt your vision), and it smells like folk wisdom BS to me.

I wonder if wearing weaker lenses would work? I'm -3.75 in both so can't really see anything without glasses other than rough outlines.
Seems like it's a classic case of "use it or lose it".

Not just with vision, but if you sit around all day you lose muscle, change fields of work and you may forget what you learned in school. Once you're inside, I can definitely see your eyes being affected by the difference in like as well as the fact that there probably aren't any objects more than 15 feet away for from you if you're at home since you're bounded by walls so there's no reason for you to be able to see further. This only gets made worse when staring into a screen that's anywhere from 6 inches to 2 get from our eyes.

Our bodies do a great job at optimizing. If for years in ends you're spending a majority of your time looking at objects that close, your body will adapt to it. Unfortunately, the byproduct of this seems so be the inability to see further distances.

tldr - more time outside in sunlight likely reduces myopia. kids these days don't want to go outside so you must force them.
"don't want to go outside"

Don't forget the scaremongering about skin cancer, dangers of the streets (or just the weather being crappy)

But to be honest outdoors is boring and just saying "ah go outside" means pretty much nothing.

> Don't forget the scaremongering about skin cancer,

Hang on - most people only need 15 to 30 minutes of direct sunlight per day for their vitamin D (and many people don't get enough), but that's not saying the risk of cancer is scare mongering.

Skin cancer is the most common cancer; melanoma is about 2% of skin cancer cases but very many more skin cancer deaths. White americans have about a 2.4% risk over their lifetime of getting melanoma. About 9900 Americans die each year from melanoma, and about 70,000 people new melanomas will be diagnosed each year.

And melanoma is one of the most common cancers in young adults.

The major risk factor for melanoma is exposure to UV light.

>> tldr

Yes, is this a trend even among prestigious scientific news publications, to leave out the summary and force readers to skim through many paragraphs just to get to this rather simple and predictable conclusion? Poorly written article and I'm disappointed in Nature.

I think you're a bit tough, it's not their responsibility to summarize, and they provided an interesting and free article. I think it'd be nice if there was a service which systematically tldr everything, instead of having it in comments. That'd allow for a lot of information at one glance (though unverified). It's not my website but for what it's worth I found this website which does it, http://tldr.io/discover
Traditional scientific and other types of informational articles begin with an introductory paragraph that summarizes the piece. In scientific writing, it's called an "abstract". In general nonfiction exposition, it's a principle of good organization: introduction, body, and conclusion. Of course it's not "required" to provide an abstract or explanatory subtitle at the top; it's just good practice.
I spend most my childhood outside (my parents lived in a village and didn't get a computer at home until I was a teenager), but I still got myopia when I was in secondary school.
To me that's harsh because I grew up rural, and was outside some, but...so isolated. There was only so much time you could stand outside trying to make up games by yourself in that rotten climate. Being forced outside sucked when I could at least read books to pass the time if I went in.

I'm pretty delighted, though, that people are finally getting a handle on the causes of myopia.

I'd love to do my computing outdoors.

My optician offered an explanation that the elastic material in my eye's lens has probably hardened from prolonged engagement in 'near work'. Hence myopia.

However, I don't see (ahem) how going outside and doing the exact same thing would improve matters. It would probably be better to have a change of focus target distance.

Therefore I wonder will they have to reconsider their conclusion if more data becomes available - e.g. pixel-qi type screens gain commercial success.

Also, matte screens have gone completely out of fashion which is a shame.

http://liliputing.com/2015/01/pixel-qi-dead-low-power-displa...

Do outdoor readers suffer the same myopia, as inert indoorsy readers? I would imagine so.

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i'm myopic when i drive i use -4 when i use netbook i use -2 (yes, text still look sharp) while reading using phone, i use 4 (google plus lens therapy)

some observations: i can use -2 during daylight riding motorcycle, at night, it's blurry and i have to use -4 to have clear vision ... so, sunlight can help myopia by 2 diopters as screen brightness increases, the farther i can move my android facing me while retaining same level of clarity you don't have to use the same diopter whole day (like wearing contacts). you can use different diopter based on your need.

Makes sense; if you have a smaller aperture, you get better depth of field. When is brighter out, your pupils contract, reducing the aperture. Basic photography/optics principles.
If you have no glasses with you, make a tiny hole with your hand and look through that. It only works with sufficient light, but should give a fairly focussed impression, eg for when you want to check the clock in the pool.
I decreased my short sightedness by 50%, from -4 to -2 by following some principles and doing natural exercises. I wrote an article about it, have a read: https://medium.com/@faiz/why-spectacles-is-a-bad-idea-66078a...

"The fact is that the eyes contain muscles, are surrounded by muscles, and are embedded in adipose tissue, hence it seems inevitable that positive changes will take place in their shape and structure as a result of the forces exerted upon them by eye exercises, just as physical exercises can improve the shape and structure of the body ."

This reads like an opinion piece based on the author's anecdotal experience, not a scientific peer-reviewed study. It's perfectly fine to write an opinion, but it's not the same as a peer-reviewed study of hundreds or thousands of test subjects.
Thanks for your input. I agree the piece is an anectodal experience, but what led me to pursue it was a scientific paper I read. Yes, I agree that tests subjects might be in hundreds but not thousands, but it has worked for everyone I suggested to follow. Your eyes need to be in development stage for this to work, i.e. you have to be young, less than ~20 years.
Children need to spend around three hours per day under light levels of at least 10,000 lux to be protected against myopia. This is about the level experienced by someone under a shady tree, wearing sunglasses, on a bright summer day. (An overcast day can provide less than 10,000 lux and a well-lit office or classroom is usually no more than 500 lux.)

Here were I live, we do not get almost any direct sunlight from October till March - sun is just too low and it is cloudy most of the time.

Another problem is the light levels in the offices that are not optimized for the good sight but for the least allowed energy consumption.

Yup, I'm at 52.5 degrees North and it is pretty grey most of the (short) day in this season. That is balanced by 16+ hours of daylight in June/July of course. One wonders how seasonal variation during the developmental years of a child factors into this.
People tend to chronically underlight indoor rooms anyway, but ignore it because of the light hue.

When you switch to CFLs, an interesting experiment is to replace it with a light with the half the wattage of your current one (not an "equivalent to something" wattage). In most cases this means you give yourself about 100-200W of incandescant equivalent output, and in every case I've had someone do it they've been amazed at how much brighter the room is (and been happy about that).

Can we just skip the CFLs and go straight to LED.
I wonder if the way our cities are also affects how much time children spend outside: dirty air, dangerous traffic, the fact that a greater part lives in cities not near nature on the countryside