As one meta-analysis put it:
It’s estimated that an increase of one hour per day of outdoor time could reduce the occurrence of myopia in children by 45%.
Make sure your kids spend time outside, folks!
“Also, while various theories such as increased light exposure, release of dopamine from retina, increased depth of field have been suggested to explain the protective effect of outdoor time, the mechanism remains to be elucidated”
Correlation is not causation.
That depends entirely on how the correlation is determined. For example randomized control trials can establish causal inference.
You can establish causation even if you don’t know what the mechanism is. I don’t know to what extent causation has been established here though, I’m not familiar enough with the research. But at minimum the intuitive idea that there is a noncausative correlation because kids with bad eyesight choose to stay inside more does not seem to stand, since this phenomenon can exist at a population level (so countries where schools start younger - and kids go outside less - have significantly higher rates of myopia).
I don’t know to what extent causation has been established here though
I am familiar with the research. We don’t know the reason for nearsightedness. There is no known proven causation. It is likely there are different causes for it.
Being from a sunny country lowers the chance of it (so you’re less likely to be nearsighted if you’re from Spain compared to Norway), even when controlled for hours spent outdoors.
There are studies that just look at outdoor time. I don’t think we know the specific mechanism but we know enough to have recommendations.
I spent 90% of my early childhood outdoors. Didn’t work.
I admit that I barely skimmed the article so I don’t know if/how they controlled for this
But this also kind of feels to me like something that could go the other way- myopic kids are less likely to go outside
Get hit in the head by a baseball you didn’t see coming or trip over a rock you didn’t see a handful of times and you might decide that the “outdoors” thing isn’t really for you.
Or of course a mix of both factors, kids who are already predisposed to short-sightedness go outside less, so the other factors at play make their eyes even worse and so they go outside even less and…
But this also kind of feels to me like something that could go the other way- myopic kids are less likely to go outside
It’s not just individual kids they are measuring, but entire populations of children and at what age they start school. The younger kids are when they start school, the more likely they are to be myopic, and this contributes to significant differences in the prevalence in myopia across countries (Edit: I should have stated this explicitly, but this is because more time in school means less time outside, generally speaking)
Hold up now. I grew up in the 80s when we spent the whole day outside, and I wore thick ass lenses all through grade school.
We spent so much time outside we developed near sightedness instead
Yeah, I always had terrible eyesight, and I probably spent more time outside than inside. There was nothing fun happening in the house. ALL the fun was outside.
“Reduces chances” does not mean “prevents”
irrelevant because the term used here was “odds”, not chances
smfh
Uh OK same reply
damn people on Lemmy don’t like sarcasm huh
Oh good one
You should have “spend” the day outdoors not “spent”.
No. Spent is the past tense of spend.
They edited the title.
How do some people despite being wrong are happy to correct others? And they have up votes? Wtf…
My comment only makes sense with the original misspelled title of the post.
I see, my apologies then
YSK: The word is ‘spent’ not ‘spend’.
Yeah that was a typo. Edited the title to fix it, should be correct now
Does it work for adults too?
No, it has to do with growth. An adult eye no longer grows significantly.
It probably helps against making it worse. My father always told about the 30-30-30 rule.
Every 30 minutes
For 30 seconds
Looking at least 30 Meters into the distance
Sometimes I wonder if people see numbers like 45% and think “OMG, 45% chance!” instead of “small number * 1.45 = another small number.”
Considering that a fairly large percentage of children develop myopia (as high as 80-90% in some countries) a 45% reduction would be fairly significant, no? Or am I missing something
where are you getting these numbers… from what I can see, the global average was 23% in 2000 and 34% today.
The 80-90% claim seems to be repeated in various areas on the internet, including by the American Academy of Ophthalmology, which I assume to be reputable:
Over recent decades, the prevalence of myopia has skyrocketed, particularly in Asia. In countries like China, Japan, Singapore, South Korea, and Japan, up to 80-90% of teenagers and young adults are now myopic.
Of course these local averages are still consistent with a lower global average
well, i can concur. my eyes have trouble adjusting to looking into the distance when i have spent hours in front of the screen. they adapt after a few minutes to hours though.
I was outside a ton when I was younger and I still have myopia. These things happen.
You might have had a higher degree of myopia if you hadn’t spent all that time outdoors.
True, but I am like -2 or -3 in both eyes, so my myopia isn’t great either lol
Not great, but it’s also not -12 😀
Near-sightedness
https://en.wikipedia.org/wiki/Myopia says that both terms exist in English? Not a native speaker; I think I have seen “nearsightedness” more often in English but my first language’s term for it translates to “shortsightedness”. 🤷♂️
IDK why it would say that, I’m a native speaker and the two terms have different meanings. Short-sightedness refers to not planning for long-term problems.
Edit: looking at what comes up in search, I see it showing up that way. I guess words change if we use them incorrectly for long enough. I’d be awfully confused if someone started talking about my short-sightedness as anything other than a flaw in my problem-solving abilities.
We say short-sighted in Britain.
ok, “Kurzsichtigkeit” in German definitely has both meanings without this causing confusion in practice
Both terms depend on context. If you talk about someone’s myopic or short sighted plan to earn money you know they’re referring to a CEO.
I’m pretty sure short-sightedness is more a result of patience and critical thinking, but outdoors might help near-sightedness.
Good try child sports teams. I ain’t touching that grass unless you make me.
One hour of outdoor time per day is not a modest increase
For some people it is
My eyes have been terrible since 1st grade. My prescription got as high as 9s.
Then I got cataract surgery on one eye, and I can see nearly perfectly without glasses for the first time in my life. This summer, I’m getting the other one done, and I won’t have to wear glasses anymore, for the first time in my life.
Anyway, the point is: As I was talking to the eye surgeon, and mentioned my bad eyesight, he told me why: I have the eyeballs of a man who is 7’2" tall, jammed into my 5’11" skull. Apparently, I have enormous eyes, which nobody has ever mentioned to me, other than one brief girlfriend who used to comment on my gigantic green eyes.
If I had to get something big from a 7’2" inch man, why did it have to be eyeballs?
If we take your eyeballs and take my teeth (“You have the roots of a 6’5” man" inside my 5’4" female body) we have the start of a good build!
Which of us is Doctor Frankenstein though?
You were made for anime, not office work
Wow I didn’t realize that cataract surgery can improve your vision that dramatically. I thought cataracts surgery was something typically reserved for seniors to prevent foggy vision
Well, yeah, I’m old, and there were cataracts in both eyes, but one went bad real fast, over the course of a few months. The doc told me that it’s kinda rare, but it happens. What was weird is that it only happened in one eye, so at least I could see with my one good eye, but if it happened to that eye too, before I could get the surgery, I’d be screwed. I literally wouldn’t be able to see well enough to drive, read, anything.
So the new lens corrected for any bad eyesight, more or less. I haven’t had it tested now that it’s fully healed, but it probably isn’t perfect 20/20, but it’s close. I have a contact in my other eye, which is still at a 9, so very bad. It also has a light cataract.
Now I can see the difference between the two eyes. In my new eye, colors are brighter and sharper. In my other, cataract eye, colors are slightly, but noticeably muted. I probably wouldn’t even have noticed it, if I didn’t have the new eye for comparison.
I’ve also noticed that late at night, when I’m tired but still watching TV, I get double vision. I have to consciously focus. The doc warned me that having a good eye, and a contact lens eye would mess with my vision, and I think this is what he was talking about.
The doc said that now that I’ve had one done, the insurance will probably spring for the second one, even if it isn’t necessary yet. That means I’ll have nearly perfect vision, and maybe need reading glasses. I use reading glasses with my new eye, but if I don’t have them, it isn’t a big deal, I see well enough for most stuff.
Sorry to yak so much about it, but It’s kind of exciting, being able to see so well for the first time, as an old person, and I don’t really have anyone else to tell it to that would care.
That’s fascinating. Is it typical for cataract surgery to cause near 20-20 vision or is this something that just happened to you because you have a unique eye shape?
No, the doc said this would get pretty close. I don’t think they can ever predict exactly where your vision is going to land, but he knew it would be close enough for reading glasses, which I never go anywhere without anyway, even with contacts. They are replacing your lens, so why replace with just a clear lens that is the same as your poor vision, that has to be corrected with supplemental lenses, when you can just replace the lens with a correct one, and fix the entire problem at once.
Of course, an immoral eye doctor might want to fix the blurry cataract, but keep your eyesight poor so they can continue to sell you glasses and contacts.
So I was expecting an improvement, and it certainly got darn close. Closer than I’ve experienced for most of my life.
BTW, it also wasn’t really painful at all. It was uncomfortable the first day, but not itchy or painful, much less so the next day, and was pretty normal in 48 hours. I took a Tylenol/Advil combo, and drops they gave me.
They can’t predict with 100% accuracy, because vision isn’t a completely objective matter as it also takes into account your brain’s interpretation of the image, but they can get pretty close. The exams you took probably measured your eye’s axial length, your cornea’s keratometry, diameter and other measurements.
Your ophthalmologist then selects the formula that best suits your eye (there’s different mathematical models for different cases of myopia, hypermetropia and how extreme they are) and then the lens’ power is calculated according to the measurements that were taken. Usually the device that takes your exam already does like 80% of the job (in the mathematical side of things), but your doctor uses their criteria to define the final IOL and from where it’ll be inserted during surgery*.
It’s pretty cool to take that exam. In my country I used to take it for patients that were going into eye surgery.
* It usually means a little bit more math
Is this procedure ever performed on someone with healthy cataracts to improve their eyesight?
I’m not sure if there’s something as healthy cataracts. Every case of cataracts has to be eventually treated by removal of your eye’s lens and then replace it with an intraocular lens (IOL).
If you meant if its ever done on a healthy lens, I’m not really sure. There’s a technique for installing an IOL on top of a previously installed IOL that’s called piggyback IOL, but on a healthy lens without cataracts seems uncommon.
Lensectomy and IOL placement can occur when the patient has a healthy lens in some cases though. When they’re going through other issues such as proliferative diabetic retinopathy, fibrovascular proliferation can occur in the vitreous humor, which would require removing it (the procedure is called vitrectomy). In some of those cases, the replacement of the vitreous humor accelerates cataracts development, which means that the lens will have to be replaced with an IOL.That’s what comes to mind from my experience doing those exams many years ago, I could be wrong.
Amazing! Congratulations on your new eyesight!
They fully replace the eyes’ lenses, so they can give you lenses that correct your vision. It’s just not a great idea to do surgery for something that can still be corrected with glasses.
It’s just not a great idea to do surgery for something that can still be corrected with glasses.
Well I generally agree, there are people who elect to get laser eye surgery. Is this procedure generally considered more risky than laser eye surgery?
They have to destroy your natural lens to make room for the replacement so it’s a bit riskier than laser correction.
Makes sense
