The myopia boom

My wife is co-authoring a review paper on this topic with the group from Zhongshan. The rise in myopia prevalence is really quite staggering, especially among asians.

It's a long article, but the essential point is that insufficient time spent in bright light >10k lux (roughly corresponding to being in shade on a bright day) during early childhood increases the risk of developing myopia.

Normal eye growth requires dopamine which is released in a circadian fashion, which requires exposure to bright/daylight. Absence of this dopamine cycle may cause the eyeball to be more elongated, leading to refractive errors.

The precise number of hours needed to prevent myopia is difficult to say, but studies in schools with even 40-mins extra have shown benefit, and there's some evidence supporting 3+ hours/day.

Importantly, it doesn't seem to matter how much close-focal work kids do, such as computer use/studying, as long as they spend sufficient time in bright light. I'd consider setting up a study desk in front of a large window, and taking breaks at school outdoors instead of inside.

The summary of this, which was surprisingly difficult to distill, is that low light levels induces myopia.

Or more specifically, elevated light levels causes a dopamine release which prevents myopia.

Not sure why the article needed to spend the first 2000 words not just saying that.

All right. What you don't want to do is increase artificial light intensity. A big part of the issue is the light spectrum and distribution of it. There is a pretty easy way to test / verify this, if you have an eye chart handy. Compare your acuity in outdoor, shaded light, to a solely fluorescent lit environment. Once you get to where you can barely make out the line, note the difference in acuity natural vs. artificial light.

Also, the minus lens creates focal plane stimulus inside the eye that prompts axial elongation. Lots of studies on this subject, it's basically uncontested. What you really don't want to be doing is wear a lens that gives you sharp distance vision, while working up close. You want to have a specific reduced prescription for close-up, that just gives you correction to the distance you need.

Breaks, also. Initial myopia is a ciliary (focusing muscle) spasm. Lots of studies there too, look for pseudo myopia or NITM (near induced transient myopia). Part of your current deficiency is ciliary, part is axial elongation. Take an hour break every three hours. Get outside. Focus at a distance. Your ciliary muscle isn't meant to be all tensed up (close-up use) all day.

For more on the subject, take a look at www.frauenfeldclinic.com, those guys are fairly awesome.

> About one-fifth of university-aged people in East Asia now have this extreme form of myopia, and half of them are expected to develop irreversible vision loss.

Which means that 10% of university-aged people in East Asia are going to develop irreversible vision loss. This sounds too terrible to be true. Am I missing something here? I interpret vision loss as blindness, but maybe it is used to describe degraded vision instead?

I have wondered why the eye stays elongated. My quest for answers has been from dubious sources on the internet and so everything said below is suspect. It is all based on reasoning and thoughts from potentially bad information. I read that the eyeball is a sack filled with a viscous fluid, and therefore, its shape is determined by the eye muscles. I determined the viscosity of the eye fluid is thicker than water, but less than motor oil. The idea behind the eye muscles is that near work puts tension on the muscles and they stiffen up and thus elongate the eyeball. So now I wonder why the eye muscles don't relax. Surely, a good night’s sleep or two would do the trick. Could the eye muscles return to their proper position by not wearing my glasses and spending more time focusing on distant objects? After about 3 years of experimenting with this thought, my vision has not improved. But I work indoors in front a computer everyday with glasses on. I have read the eyes muscles lack any counter force to pull the eyeball back into shape. Perhaps the eyeball shell has grown deformed and it is stiff enough to hold the shape. Maybe the eye socket determines the shape. Maybe the eye muscles have nothing to do with the shape. I would like to think that there is some corrective measure built into the eye system. Otherwise, it would seem everybody's eyes are on a one-way trip to becoming myopic and only the speed of this transition can be affected. I know that for me, I wore my glasses all the time, even when I was reading. Looking back, when I was first diagnosed, I really only needed them to play baseball at night under the lights. I sort of wished that was the only time I wore them. I wonder if my eyes could have corrected themselves. Now it seems too late, because I need to wear them just to read a computer screen 18" away. I have also read that wearing glasses forces your eyes to focus at a close up distance. So wearing glasses is like doing near work all the time and thus puts you on the fast track to becoming more myopic. After all this rambling, I guess the real question is what is keeping the eyeball in the wrong shape? If this were known, then maybe one could figure out how to fix the condition. As a final note, I have also read that maybe the eye ball is not elongated, but that the cornea is not shaped correctly.

Between the ages of 15 and 17 years old, I spent hours every night in a dark room in front of a (really bad) 14" CRT display.

I never had issues with my vision. Then I developed Myopia. I have always felt that it was related to my late night computing.

I became curious about this when I became significantly less short-sighted during each of my years of maternity leave. A few more kids and I won't need glasses any longer :-) Indeed, I spent much more time outside while on maternity leave than when I was working.

I found this interesting too: http://www.katysays.com/pumpkin-eyes-and-pelvic-floors/

I would love to see a second control group where the kids spent 40 minutes a day inside a 10,000 lux illuminated classroom.

I've always thought eyes work remarkably well for something hacked together out of meat and jelly. I guess part of that is probably a feedback mechanism where the growth of tissue is effected by where the image is focused. Presumably staring at books throws off the mechanism that evolved for gazing at the scenery. Guess it needs bright light to work?

10000 lux is something achievable with 100W of LED light.

Why not, instead of limiting children exposure to computers and kicking them outside, just paint the wall behind their computer white and point 100W worth of LEDs at it?

I'm sure (s)he will spend at least 3 hours per day in that environment without trauma associated with forcefully exposing the child to boredom of outside.

EDIT: Yes, yes. I know. Being outside and kicking ball has lots of other benefits. But still... People are not doing it today despite potential obesity that predictably can kill you and they won't start doing it due to potential myopia that will force you to wear glasses. So why not go with pragmatic solution?

This is some fascinating research.

I feel like there should be some other correlates if light is a dominating factor, such as between geography and myopia (should see some trends around super-cloudy vs. super-sunny areas).

Anecdotal, etc, etc:

I was home schooled through fourth grade. Lots of time spent outdoors, even on school related things (setting up little rubber army men in the sandbox when studying the revolutionary war, for example). My eyesight was quite good, despite spending quite some time on the computer (balanced, of course, with out-door activities).

Half-way through my first year in public school, I needed glasses. My eyesight went from 20/20 to ~20/80 in less than five months. 20 years later, it's around 20/300 - though fairly stable for the last ten years.

As someone whose myopia gets worse every few years, I feel any concrete research into myopia is a bonus.

I hope this leads to an actual cure for myopia instead of burning off your cornea to compensate.

If you don't wear glasses (or contact lenses) then you are in a minority. I am in this minority and I find it worrying. Who would have thought that all of those long walks home would be beneficial?

I think that cycling helps my eyesight. If I cycle in to town then, for survival reasons, I am fully testing out my eyes. It does not matter what time of day this is, going through traffic or rolling home late at night on empty roads, I am really working those eyes. I get to look to the far horizon as well as those quick glances over the shoulder. Thinking about it, I cannot think of a better eye exercise!

As well as the normal light I also get enhanced levels of UV reflected from the road during the summer months.Normally we try to bar UV with glazing so I am just rebalancing the spectrum if non-visible light is bouncing off the tarmac.

So, if I was calling the shots here on planet earth I would mandate that all children cycle to school. For comedy value I would make the punishment for those that drove their kids in be harsh - eyes scooped out and donated to medical science. For now, in the run up to the introduction of that I would want public information campaigns that just tell parents that driving their kids to school makes them go blind, which is totally true.

So would installing much brighter lights indoors help mitigate this? What does it take to illuminate a room at the suggested 10k lux?

An opthamologist in Finland advocates the use of plus glasses for children (and everyone else) for all close work to prevent myopia.

I laughed to myself after reading the first few paragraphs. When I saw the image of young Chinese students I immediately thought of the literary use of myopia, not the medical condition. Given the source of the article was “Nature”, I assumed it was an article about the Chinese exploitation of natural resources for the sake of short term profits and the destructive effect on the environment; hence, myopia. Is that irony?

It's interesting that the widely derided See-Clearly method has as one of the exercises staring at a bright light bulb with the eyes closed.

An opthamologist in Finland advocates the use of plus glasses for children, for any sort of close work to prevent myopia.

Since a lot of people are chiming in with anecdotal evidence I'll add some of my own.

There's circumstantial evidence to suggest that eating white rice can exacerbate myopia. And asians eat lots of white rice. I found my eyesight deteriorating and cut white rice out of my diet. I think it's stopped now.

> well-lit office or classroom is usually no more than 500 lux

I guess we need to update what "well lit" means.

I think I got lots of sunlight as a kid but I don't think I slept properly so my circadian rhythm was disrupted all the time. I blame it on getting up early for school and sleeping late because of David Letterman.

One could easily find a correlation between my need for glasses and the time at which I (and a lot of others) began using computers heavily, like being on a computer for more than 8 hours a day.

So you're telling me, acquired traits are inherited?

I always wondered why I had an entire childhood of obsessive close work (computer, Lego, drawing, etc.) yet have better vision than my parents had at my age. I don't know if computer screens are bright enough to have a protective effect, but I did grow up in a culture insistent on kicking kids out of the classroom for breaks no matter the weather.