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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 a
by sithu 12y ago
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.
- deleted 12y ago[deleted]
- ChuckMcM 12y agoAre we becoming mole people? Only half joking here.
- deleted 12y ago[deleted]
- darkmighty 12y agoWhat about distant focal work (focusing your eyes on clouds, etc)? It's weird that illumination should have an effect and training focus variation doesn't?
- jules 12y agoFocusing on clouds is not much different than focusing on the other side of the room.
- darkmighty 12y agoI don't know, I'm looking at the other side of my room right now and I can definitively see a lot of difference (additional blur) by trying to extend my depth of field. Maybe I'm focusing past infinity though.
- godzilla82 12y agoHow can you extend the depth of field of the eye?
- jules 12y agoSubjective experience does not always match with scientific fact.
- darkmighty 11y agoBlanket statements do not always refute arguments.
- chipsy 12y agoDo we know if it's related to the UV spectrum of the light(e.g. is this equivalent to sunlight's properties w/r to vitamin D), or is the eye exposure mostly about the visible spectrum?
- spyder 12y agoLow vitamin D level was my first thought when I read the "outside light" and it looks like it could be related: https://www.vitamindcouncil.org/vitamin-d-news/new-study-finds-vitamin-d-may-be-related-to-myopia-in-adolescents/# https://www.vitamindcouncil.org/vitamin-d-news/new-study-fin... http://breakingmuscle.com/nutrition/vitamin-d-can-save-your-eyesight http://breakingmuscle.com/nutrition/vitamin-d-can-save-your-... "myopia was significantly higher in individuals with vitamin D deficiency": http://www.ncbi.nlm.nih.gov/pubmed/24970253 http://www.ncbi.nlm.nih.gov/pubmed/24970253
- verroq 12y agoOr maybe people that don't get enough outside light tend to have lower vitamin D?
- benbreen 12y agoWould the rise of wearing sunglasses during the last 50 or so years might have any effect as well, I wonder? After all, the eye presumably responds the same whether it's getting insufficient light because someone is indoors or because that person is outside but shielding it from >10k lux light with tinted shades.
- tomp 12y agoDid anyone compare the data from this paper with the development of myopia in northern countries (e.g. Finland), where winters are dark and kids (and adults as well) would probably get only a few hours of sunlight per day (in contrast, summers are very bright)?
- desdiv 12y agoWhile myopia was not associated with the month of birth, there was a trend towards a higher prevalence of myopia among conscripts living above the Arctic Circle, consistent with the hypothesis that ambient lighting might influence refractive development. https://www.med.upenn.edu/cpob/documents/Myopiaandnaturallighting.pdf https://www.med.upenn.edu/cpob/documents/Myopiaandnaturallig...
- shubhamjain 12y agoCecil Adams, of 'The Straight Dope' fame, once answered a question related to perceived vision of sitting close to TV inducing myopia [1]. Although, he plainly refuted this as a possible cause, but he cites a study where the correlation suggests that it might be the "product of our civilization". > 'The most striking demonstration of this was a study in the late 60s of eyesight among Eskimoes in Barrow, Alaska. These people had been introduced to the joys of civilization around World War II. The incidence of myopia in those age 56 and up was zero percent; in parents age 30 and up, 8 percent; in their children, 59 percent.' [1]: http://www.straightdope.com/columns/read/865/will-sitting-too-close-to-the-tv-ruin-your-eyes http://www.straightdope.com/columns/read/865/will-sitting-to...
- 3JPLW 12y agoThe linked article discusses that Inuit study, too. (Also, Cicil Adams is almost certainly not a single person.)