My parents were right!! A spate of studies over the past decade has found that kids who spend more time outdoors are less likely to develop near-sightedness. Outdoor time seems to protect kids even if they do a lot of “near work” (e.g., reading Goosebumps and Animorphs nonstop) and if their parents are myopic.
When I was a kid, my parents would always tell me to stop reading and go play outside. I would scoff: What kind of parents want their kid to stop reading? But maybe they had a point after all.
A team of Australian researchers recently reviewed major studies since 1993 of kids, myopia and time spent outdoors. They found more than a dozen studies, examining more than 16,000 school-age kids in total, that found children were more likely to be nearsighted or to develop nearsightedness if they spent less time outdoors. A few of the later studies also found that being outdoors protected even those kids who did a lot of near work or had myopic parents. The studies included kids living in Europe, the U.S., Asia, the Middle East and Australia.
The researchers did find three studies, comprising about 4,600 kids, where there was no association between nearsightedness and time spent outdoors. Of those three studies, one looked at a group of children that was predominantly myopic (83 percent of them were nearsighted) and spent very little time outdoors overall (just six hours a week, on average). Another study looked at younger children, aged six months to six years. Nearsightedness is rare in kids that young.
Scientists aren’t sure yet why being outside prevents kids from becoming Miss Four-Eyes early in life. There is some evidence, from studies done in lab mice, that sunlight may trigger the production of the brain chemical dopamine, which in turn prevents eyes from growing elongated. Nearsighted eyes are overly elongated. However, some conflicting studies mean that scientists can’t be sure this is what’s happening in humans.
Scientists also aren’t exactly sure how strongly outdoors time protects kids. Some studies have found a small protective effect, while others have found larger ones, the Australian reviewers report.
Interestingly, the studies that have looked at near work—stuff you do that requires you to focus on something in a close range, such as reading and writing—haven’t consistently shown that it causes nearsightedness. It may be that it’s difficult to calculate exactly how much near work a person does, the Australian team says. In addition, some research groups classify computer and TV time as near work, while others don’t. Televisions are far away enough that they don’t strain the eye too much, while computer use is about half a straining as reading, the Australian team reports.
Some scientists have proposed that frequently looking at far distances helps prevent myopia. That sounds like a good reason for outdoors time’s protective effects, but studies about this seem sparse.
Overall, the strong evidence for outdoors time preventing nearsightedness may be a good reason to get kids out more. There are even ongoing clinical trials in China and Taiwan that are examining whether getting classes of kids outside reduces the number of them who develop myopia later.
Bonus FYIs: Nearsightedness In Hollywood
Do Asians all wear glasses, like they do in the movies?
Nearsightedness is much more common in kids in certain Asian countries than in Western countries. Studies of Singapore, China, Taiwan, Japan and Korea have found that around 80 percent of kids are nearsighted. In the U.S. and Europe, 30 percent to 50 percent of kids are.
However, myopia doesn’t seem to be genetically linked to race. For example, in ethnically diverse Singapore, similar rates of myopia appear in all the ethnicities that live there, including in people of Indian origin, who are more genetically akin to Middle Eastern and European people than East Asian people. Instead, environmental factors seem to make the difference.
Do smart people really all wear glasses?
This Hollywood stereotype touches upon a truth—adults with more education are more likely to be nearsighted. Studies have also found that kids in Singapore with higher exam scores were more likely to be myopic.
This may mean that the duration or intensity with which people do near work does affect their risk for nearsightedness, even though near work studies have been inconsistent, the Australian reviewers wrote.
Wazazi wangu walikuwa sahihi!! Uchunguzi uliofanywa katika miaka ya hivi karibuni unaonyesha kwamba watoto wanaotumia muda mwingi nje ya nyumba hawana uwezekano mkubwa wa kuwa na uwezo wa kuona mbali. Wakati wa nje inaonekana kulinda watoto hata kama wao kufanya mengi ya <unk>karibu kazi<unk> (kwa mfano, kusoma Goosebumps na Animorphs nonstop) na kama wazazi wao ni myopic. Nilipokuwa mtoto, wazazi wangu waliniambia niendelee kusoma na kwenda kucheza nje. "Ningesikia ""Ni wazazi wa aina gani ambao wanataka watoto wao waache kusoma?""" Lakini labda walikuwa na uhakika baada ya yote. Watafiti wa Australia wamekagua utafiti wa watoto, myopia na muda wa nje. Katika utafiti uliofanywa kwa watoto zaidi ya 16,000 wa umri wa shule, watoto wengi walipata uwezekano mkubwa wa kuwa na uwezo wa kuona mbali au kuugua uwezo huo ikiwa walitumia muda mdogo nje. Utafiti wa hivi karibuni pia uligundua kuwa kuwa nje kulilinda hata watoto waliofanya kazi nyingi karibu au walikuwa na wazazi wenye myopia. Utafiti huo ulihusisha watoto wanaoishi Ulaya, Marekani, Asia, Mashariki ya Kati na Australia. Watafiti walipata utafiti wa watoto 4,600 ambao haukuwa na uhusiano kati ya upungufu wa macho na muda uliotumika nje. Katika utafiti mmoja, asilimia 83 ya watoto hao walikuwa na myopia na walikuwa nje kwa muda mfupi tu (sawa na saa sita kwa wiki). Uchunguzi mwingine ulichunguza watoto wadogo, wenye umri wa miezi sita hadi miaka sita. Uwezo wa kuona mbali ni nadra kwa watoto wachanga kama hao. Wanasayansi hawajui bado ni kwa nini kuwa nje huzuia watoto kuwa Miss Four-Eyes mapema maishani. Utafiti uliofanywa kwa panya wa maabara unaonyesha kuwa mwanga wa jua huchochea utengenezaji wa kemikali ya ubongo inayoitwa dopamine, ambayo huzuia macho yasikue kwa muda mrefu. Macho ya watu wenye uwezo wa kuona mbali ni marefu sana. Hata hivyo, baadhi ya masomo yanayopingana yanamaanisha kwamba wanasayansi hawawezi kuwa na uhakika kwamba hii ndiyo inayotokea kwa wanadamu. Wanasayansi pia hawajui kwa hakika ni kwa kadiri gani wakati wa nje unawalinda watoto. Uchunguzi fulani umepata athari ndogo ya kinga, ilhali mwingine umepata athari kubwa zaidi, wakaguzi wa Australia wanaripoti. Kwa kuvutia, masomo ambayo yameangalia kazi ya karibu - vitu unavyofanya ambavyo vinahitaji kuzingatia kitu katika eneo la karibu, kama vile kusoma na kuandika - hayajaonyesha mara kwa mara kwamba husababisha maono ya karibu. Huenda ikawa ni vigumu kuhesabu hasa ni kiasi gani cha kazi ya karibu ambayo mtu hufanya, kikundi cha Australia husema. Kwa kuongezea, vikundi fulani vya utafiti huorodhesha wakati wa kompyuta na televisheni kama karibu na kazi, wakati vingine havifanyi hivyo. Televisheni ziko mbali sana hivi kwamba hazisumbui macho sana, ilhali kutumia kompyuta ni vigumu nusu tu kama kusoma, ripoti ya timu ya Australia. Wanasayansi fulani wamedokeza kwamba kutazama mbali mara nyingi husaidia kuzuia upungufu wa kuona. Hiyo inaonekana kama sababu nzuri kwa ajili ya muda nje ya athari za kinga, lakini masomo kuhusu hili kuonekana sparse. Kwa ujumla, uthibitisho wenye nguvu wa kuwa na wakati nje unaokinga upungufu wa kuona unaweza kuwa sababu nzuri ya kuwafanya watoto watoke nje zaidi. Majaribio ya kliniki yanaendelea nchini China na Taiwan, na yanaonyesha kuwa watoto wanaopokea mafunzo ya nje ya shule wanakabiliwa na matatizo ya kuona mbali. Bonus FYI: Nearsightedness Katika Hollywood Je, Asia wote kuvaa miwani, kama wanafanya katika filamu? Uwezo wa kuona mbali ni wa kawaida zaidi katika watoto katika nchi fulani za Asia kuliko katika nchi za Magharibi. Uchunguzi uliofanywa nchini Singapore, China, Taiwan, Japan na Korea uligundua kuwa karibu asilimia 80 ya watoto wana uwezo wa kuona mbali. Katika nchi za Ulaya na Marekani, asilimia 30 hadi 50 ya watoto wanaishi katika mazingira ya ukosefu wa usalama. Hata hivyo, miopia haionekani kuwa na uhusiano wa maumbile na jamii. Kwa mfano, katika Singapore, nchi yenye watu wa makabila mbalimbali, viwango sawa vya myopia huonekana katika makabila yote yanayoishi huko, ikiwa ni pamoja na watu wa asili ya India, ambao ni sawa zaidi na watu wa Mashariki ya Kati na Ulaya kuliko watu wa Asia Mashariki. Badala yake, mambo ya mazingira yaonekana hufanya tofauti. Je, kweli watu wote wenye akili huvaa miwani? Mfano huu wa Hollywood unagusa ukweli - watu wazima wenye elimu zaidi wana uwezekano mkubwa wa kuwa na uwezo wa kuona mbali. Uchunguzi pia umegundua kwamba watoto nchini Singapore walio na alama za juu zaidi katika mitihani walikuwa na uwezekano mkubwa wa kuwa na myopia. "Hii inaweza kumaanisha kwamba muda au nguvu ambayo watu hufanya karibu na kazi huathiri hatari yao ya upungufu wa macho, hata ingawa masomo ya karibu na kazi yamekuwa yasiyo ya kawaida, ""waliandika wahakiki wa Australia."