Given that the Nature research (above) shows that eye exercises don't seem to work, we should focus [1] on what does. Research shows more outdoor time can help with myopia. See https://onlinelibrary.wiley.com/doi/full/10.1111/aos.13403
I recently was required to renew my glasses prescription because the other one was 2 years old (so considered expired). When I got my new prescription, my optometrist said "your vision improved". I have been spending more time outside. I have found that time on the water seems to make my vision improve. I also suspect that walking through forests and experiencing the parallax effect might function as something like a depth perception calibration. It's also worth noting that I do wear glasses, but not all the time - intentionally so I can exercise my eyes.
Or, if your myopia wasn't too bad and you're in your 40s, that could just be related to presbiopia. That's what seems to have happened to me, and what the ophtalmologist I was seeing when I was a teenager told me might happen.
> Dopamine is a key neurotransmitter in the signaling cascade controlling ocular refractive development, but the exact role and site of action of dopamine D1 receptors (D1Rs) involved in myopia remains unclear.
[.. snip ..]
> Therefore, activation of D1Rs, specifically retinal D1Rs, inhibits myopia development in mice. These results also suggest that multiple dopamine D1R mechanisms play roles in emmetropization and myopia development.
Then I'm guessing calebm misremembered what the optometrist said. Probably the optometrist said "your prescription improved" or "your prescription decreased".
"Vision improved" is a possible result of treatment. My wife has had cataract surgery--her vision in that eye certainly improved!
It also is possible to have your vision improve without treatment. I have some astigmatism, it's simply impossible to fully correct. My prescription changes a lot, it's possible for the astigmatism to be a bit less of an issue on a particular exam to the point that the best line I can read sometimes changes.
I assumed outdoor time helps because your eyes spend time focusing at a greater distance. Going outside, but only to use a phone/ereader/book is likely not effective.
I think this assumption, though perhaps reasonable, is incorrect, for at least two reasons:
- There are animal model studies which vary environment brightness and show a causal relationship between darker environments and myopia. The animals in the darker experimental groups aren't reading etc, and the animals in the brighter experimental groups aren't in larger cages.
- There are studies on myopia that varied indoor lighting brightness and showed brighter lighting later/decreased myopia onset. Classroom sizes (or distances from desk to blackboard, etc) did not change. These studies also found a bunch of other variables were important including longer sleep time, and less screen time.
It is well established that much “near work” during childhood (and even adults) contributes to myopia. Some populations are particularly vulnerable. Myopia also has a reasonable strong genetic component in humans and mice.
Classic example of gene-by-environmental interaction.
Maybe a darker environment makes it harder to see distant things, and the benefit of a brighter environment is to enable focusing on distant objects, which is presumably possible even for the poor souls confined to a small cage?
From what I have gathered, the leading hypothesis is that bright light induces dopamine production, and dopamine regulates the development of the eye. When these dopamine levels are too low, the eyeball elongates and becomes myopic.
The leading hypotheses a few years back is that the outdoors is very bright. Brightness levels that cannot be easily reached indoors.
surely when we squint from bright light we are straining the eye. The idea, then, is that our development expects some amount of eye strain growing up.
I want this! I'd love to sit at the beach with something as readable as a Kindle (and preferably a sand-proof keyboard), but with latency fast enough that emacs or vim is usable. Is there anything close to this that I can buy?
My Fujitsu-Siemens Si1520 laptop from 2006 was usable in bright sunlight. The LCD display turned reflective and monochrome in sunlight. Text and window decorations were perfectly clear. This was a surprise, because it wasn't an advertised feature, just a side effect of the display technology.
I’ve heard this is important for young kids when eyes are developing. Once the weakness is built in, there’s not much t that can be done.
But I definitely recommend this to people I know with new babies. We do a bad job consciously recognizing the difference between indoor and outdoor light, but they’re orders of magnitude different in actual brightness.
My understanding is that the benefit of being outdoors is the ability and opportunity to regularly focus on things at a distance that helps, so sunglasses wouldn't factor in.
It’s also exposure to natural light. Myopia jumps when kids are exposed to artificial lighting [1]. It seems some constant is hard coded into our genes to calibrate our eyes to the Sun’s light. (Artificial natural light, despite sounding like an oxymoron, can help.)
That was the leading theory for many years that explained why adult humans today have much worse vision that humans of the not-so-distant past, but it was disproven in the last decade.
We don't yet understand why, but lack of exposure to sunlight is what causes still-developing eyes to grow incorrectly.
The issue isn't brightness, it's distance to what you are looking at and focus on the retina. When your eyes can still bring far objects into focus, they produce a signal that causes your eyes to grow longer.
https://newsroom.uw.edu/news-releases/glasses-stop-myopia-ar...
The brightness of light is actually believed to be the main factor now. This seems a supported by animal studies, where animals are fitted with light-filtering goggles. Animals that receive brighter light develop normally, while animals that receive dimmer light develop myopia.
Do we really need VR headsets for this? Is there some material way in which just walking around outside, for free, is worse than strapping expensive electronics to your face and staying indoors?
Regarding your second question, that's basically what computer glasses (and reading glasses) do. They basically make things that are close, visually farther away.
For people who can't focus up close anymore (elderly), they move the book visually farther away where the eye can still focus.
When used as computer glasses, you could see the screen without the glasses, but with the glasses they are shifted farther away visually which helps with eye strain.
It's probably similar to the difference between doing "proper" squats in a squat rack vs. using a cheater frame. The muscle movement is more varied and not as linear as doing a single left/right up/down exercise. But that's just a guess.
I don't think they know for sure what it is about being outdoors that helps prevent myopia. But it's thought that it might be the bright light. To me, passively taking in bright light wouldn't qualify as an exercise.
[1] See [1] what I did there?