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Comment by blakesterz | Hacker News Reader

Pretty interesting. The dominant hypothesis now is that exposure to daylight is the main variable. It explains why myopia seems, like diabetes and heart disease, to be what doctors call a “disease of affluence”—more common in rich countries than poor ones—since economic growth brings with it more education, and therefore, for children, more time inside.

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https://newsroom.uw.edu/news/glasses-stop-myopia-are-success...

Their big breakthrough in understanding myopia occurred in 2008 when they studied a particular group of people who had a genetic form of myopia that’s very severe. They discovered a gene mutation that was causing the myopia.

“It turns out it was a mutation in the cone photoreceptors,” said Jay Neitz. “We then realized that it’s really just the way that the images are being encoded on the retina.”

What’s supposed to happen as your eye grows, is that things should begin to go out of focus in the periphery of your vision. That’s a signal for the eyes to stop growing.

But as long as things are still clear in the periphery, the eyes think this person must still be farsighted, because in the natural world things in the periphery are far away.

Neitz said his team was able to design a lens to make central vision clear and in focus, and give the peripheal vision much lower contrast.

“It recreates what is supposed to be going on with our eyes before we started putting all of these things in front of our face like computer screens and tablets,” he said.

I love how they discovered this!

Failed in clinical trials? Never heard about this until now.

Update Jan. 20, 2021: The North America myopia trial is nearing the end of its second year and it is closed to enrollment. Based on the one-year data, the eyeglasses have regulatory approval to be sold as medical devices in Europe and Canada. They are currently being sold in Canada under the brand name "Kikko." Researchers anticipate regulatory approval in the United States in about a year that will be based on the two-year results. People can go to the Kikko website https://kikkovision.com/ and sign up to receive updates about U.S. availability. Once they are approved in the U.S., people will be able to buy the glasses from their optometrist or ophthalmologist.

„The CYPRESS clinical study3 enrolled, randomized, and dispensed the lenses to 256 eligible children across 14 clinical trial sites in the United States and Canada. At the time of enrollment, subjects were six to 10 years old having myopia between -0.75 D and -4.50 D.

After two years of wear, 85% of children wearing the innovative spectacle lenses showed less than one diopter of myopia progression.4 Moreover, the study also showed that 41% of the children wearing spectacle lenses with Diffusion Optics Technology™ showed no clinically meaningful progression in refractive error after two years versus only 17% in the control group.5“

See https://www.coopervisionsec.eu/news-two-year-clinical-trial-...

Exposure to very bright light (even standing under a shade tree on a cloudy day is far brighter than normal indoor lighting) specifically during key years had been nailed down with high confidence as the primary cause of most near-sightedness, last time I looked into this.

Not sure if they'd figured out the mechanism, but speculation was that bright light is involved in signaling the eye to stop lengthening at the right time.

IOW the cause is, basically, school. In Winter months, kids may hardly see the Sun at all, with very short days and recess often indoors (too cold, too snowy, too wet) especially as schools have seemed to grow more wary of taking kids out in poor weather, over the last few decades. Plus anything else that keeps kids indoors, sure (video games, social media[0]) but school seems to be a lot of it.

[0] And actually, the social media factor likely kicks in well after it matters. Ditto video games unless your kid becomes a gaming addict in the 3-7 age range and you just let that happen.

If exposure to bright light is the primary cause of most near-sightedness, than not seeing the sun would be beneficial. I don´t get it, typo?

Yeah typo. The theory is that eyes change shape over time (I think starting out longsighted) and at some point a hormone is released to stop this changing. It is released when (a) the eyes are typically around the middle of their focal range (ie looking at middle-distance things is done with relaxed eyes) and (b) there is a lot of light. Without the second condition the shape of the eyes will continue to change and then you get myopia.

See also: metabolic bone disease in lizards. Also caused by a lack of light — in their case, near-UV light.

(My understanding is that the thing changing the shape of the eye over time is the development of the orbital socket bones — so nearsightedness and MBD could have more in common than it seems.)

Yeah, typo, too late to edit. Insufficient exposure to bright light during key, early years while the eye is developing was found to increase risk so much that it's practically all that matters, at least over a population (I'm sure some unlucky people get it for other reasons, like most things)

I grew up near the equator where there is a very high rate of myopia despite exposure to sunlight. (Sure we spent a lot of time indoors, but we were exposed to sunlight all year round since there’s only one season: summer).

I think genetics has a larger predictive effect than sunlight.

There's a reason why they're not just saying "it's genetics"...

> I think genetics has a larger predictive effect than sunlight.

We know this isn’t true because Singapore is practically on the equator and went from less than 10% myopia to over 90% in ~50 years.

Right with the same amount of sunlight.

I’ll grant that with indoor malls and public transit there’s less exposure to direct sunlight, but you still can’t avoid being exposed to the sun daily in Singapore.

The amount of time you spend in sunlight matters. Kids went from running around outdoors all day (whether for work or play) to spending all day sitting in classrooms.

Are you familiar with Singaporean norms?

There is/was a very strong aversion to being outdoors, especially during peak sunlight hours (lunchtime). This compounds with both study culture and digital culture (videogames + tv + phones) and less of a celebration of sports to mean many kids get less direct sunlight than you'd think. Especially now everyone is terrified of UV

Yes I am.

I don't think OP mentioned being in the direct sunlight, but being exposed to it (visually, as in a source of bright light). Unless you sequester yourself in a room without windows all day, to get anywhere you're likely to need to walk outside to a bus stop, an MRT station, or to get a Grab. And unless there's a tunnel connecting office buildings to hawker centers, folks probably need to walk outside to get lunch (exceptions are malls connected to food courts).

Singaporeans probably get more sunlight than say Swedes over the course of a year.

This study on Singaporean children (https://bjo.bmj.com/content/bjophthalmol/early/2021/04/14/bj...) says that

> Singaporean children had shorter reported time outdoors and lower light levels, relative to their counterparts overseas. In the current study, reported time outdoors was 1.7±1.6hours/day and average light levels were 458±228lux. In contrast, children of similar ages in Australia and the UK reported time outdoors of at least 2–3 hours/day.18 22 Likewise, higher average light levels of 1072 and 1627 lux were reported in Australian (age 10–15 years)16 and American (age 5–10 years) children,20 respectively. Differences in educational demands (homework load and afterschool enrichment classes),23 lifestyle and sociocultural factors may account for the lower reported time outdoors and light levels in Singaporean children

I can't remember exactly how many hours of exposure to sunlight the studies mentioned, but I think it was something like 2-3 hours --- and it might have to be more than just, e.g., being near a window. I'm Singaporean too, and that excerpt from that paper accords with my experience. I highly doubt that I and most of the people I grew up with had that much sunlight exposure per day.

Fair enough - not trying to condescend just establishing what your opinions may be based on.

My own personal (and very anecdotal) observations are that people really go out of their way to avoid exposure to the outdoors. Depending on your lifestyle, it is really possible to spend the day having only been outside for minutes of a day.

I think things are changing but I feel like the last 20-50 years have not really celebrated an outdoors lifestyle. Whereas my time in Europe is somewhat different in that plenty of people optimise to spend time outdoors - probably due to less oppressive weather and kids were encouraged to play outside a lot more

Not buying the sunlight argument, equatorial countries are hardly afflicted by vitamin D deficiencies or seasonal affective disorder you see in Europe. Solar intensity is stronger year round than summer in some Scandinavian countries. If it were sun, we'd see similar patterns in myopia to vit D deficiency as you get closer to the poles.

This is def a decent counterpoint - on a previous HN thread on this topic I recall studies being done on agricultural vs urban mainland chinese people and how a refinement to the observation so sunlight/outdoors might be a proxy for some other factor. I've seen proposed "distant viewing".

Although one possible nuance is that sunlight to the eyes != sunlight to the skin. In cold climates you wear thick clothes which will block out sunlight to the skin (vit D deficiency) but you may still get plenty of UV to the eyes. Throw in some mountains for distant gazing and suddenly nations that love skiing could be simultaneously vit D deficient but guarded against myopia.

Pure conjecture of course - IANA(Biologist/Opthamologist/Doctor)

Accidentally looking outdoors 10 minutes a day is not really equivalent to (historically) being in the bright sun for 12 hours a day.

> being in the bright sun for 12 hours a day.

I don't think historically (at least in the past 40 years) most people (barring construction workers and certain jobs) from that region were ever out for 12 hours a day in the bright sunlight.

You can read a book outside under a tree and get enough lumens. When we switched to backlit screens for showing information, this necessitated that more time be spent indoors to be able to make out the words on the screen.

I'm not sure this is the argument you are trying to make, unless Singapore moved it's position on earth. Not that genetics are any more convincing, seeing how it's only 50y.

Less sunlight due to economic growth and improvement on education in Singapore last 50y?

The discovery and test actually came from Singapopre and they ended up making some glass classrooms. Pictures here - https://www.cnn.com/2015/04/05/asia/myopia-east-asia/index.h...

Perhaps it is roof opening...

Have any studies been done comparing children raised in Portland and Seattle (where it rains for the majority of the year so kids spend a lot of time indoors) versus San Diego or some other sunny city?

Everything in this comment except "pretty interesting" is lifted word-for-word from the article - why is it framed as if it were your own comment?

> The dominant hypothesis now is that exposure to daylight is the main variable.

Which is obviously wrong. The main variable is the time the eye spends at a short focal length. Like every other part of the body, the eye adapts to the stresses it experiences. Focusing on nearby objects for extended periods is stressful for a normal eye and as is the case for so many stressors, the body adapts[1]. This is easily seen in that ceteris paribus a person with myopia can comfortably focus on much closer objects than someone with normal vision.

Incidentally this means that corrective lenses can actually cause myopia to progress. Contrariwise a prescription can be written such that there is an effective training stimulus to reverse myopia[2]. However, that won’t fix the decreased focal range due to age related hardening of the lens of the eye.

[1] See Selye for details.

[2] Inexplicably, most optometrists refuse to do so.

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