As discussed in our previous blog, with each generation, we add more things that children can focus on in the “near distance” category. And with every generation comes an increase in kids that suffer from myopia, aka. Near-sightedness. While scientists haven’t yet agreed on a reason why close work seems to exacerbate near-sightedness, the correlation between more time outside and less time doing close work continues to prove protective against myopia development.
In general, studies implicate that spending more than 90 minutes outside of school on close work can increase the risk of myopia development while spending at least 100 minutes outside can reduce the risk. Increasing time spent outdoors has even been shown to slow the progression of myopia.
So, why is spending time outdoors advantageous for eye health?
Researchers continue to explore why spending time outdoors might help prevent or delay myopia. It’s not merely a matter of reducing reading time, as studies show that children who read extensively still benefit from outdoor activities in terms of vision protection.
The impact of physical activity also seems minimal. Research indicates that children with myopia do not differ significantly in activity levels from those without the condition.
A more likely factor is the intensity of natural light. Outdoor lighting is significantly more intense than indoor lighting, even on cloudy days. Children playing in shaded areas or wearing hats and sunglasses still experience brighter light compared to indoor settings with large windows or artificial lights.
This bright light is thought to trigger chemical responses in the retina, the light-sensitive tissue at the back of the eye, promoting proper eye growth. In cases of childhood myopia, the eye grows faster than normal, leading to worsening distance vision.
Additionally, outdoor environments may benefit vision by engaging the entire field of view more evenly, with objects typically positioned farther away than indoors. Studies have also linked a lack of green spaces in urban areas with higher rates of myopia.
To find your child’s risk of developing Myopia, take this risk assessment which compares genetic and environmental factors to determine overall risk.
To find a local doctor to evaluate your child, use this doctor finder from the American Academy of Orthokeratology and Myopia Control.
Here is a non-exhaustive list of scientific articles that support increased outdoor time:
· Bento G, Dias G. The importance of outdoor play for young children's healthy development. Porto Biomed J. 2017 Sep-Oct;2(5):157-160.
· Zamora AN, Waselewski ME, Frank AJ, Nawrocki JR, Hanson AR, Chang T. Exploring the beliefs and perceptions of spending time in nature among U.S. youth. BMC Public Health. 2021 Aug 23;21(1):1586.
· Xiong S, Sankaridurg P, Naduvilath T, Zang J, Zou H, Zhu J, Lv M, He X, Xu X. Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. Acta Ophthalmol. 2017 Sep;95(6):551-566.
· Deng L, Pang Y. Effect of Outdoor Activities in Myopia Control: Meta-analysis of Clinical Studies. Optom Vis Sci. 2019 Apr;96(4):276-282.
· Rose KA, Morgan IG, Ip J, Kifley A, Huynh S, Smith W, Mitchell P. Outdoor activity reduces the prevalence of myopia in children. Ophthalmology. 2008 Aug;115(8):1279-85.
· Read SA, Collins MJ, Vincent SJ. Light Exposure and Eye Growth in Childhood. Invest Ophthalmol Vis Sci. 2015 Oct;56(11):6779-87.
· Lanca C, Teo A, Vivagandan A, Htoon HM, Najjar RP, Spiegel DP, Pu SH, Saw SM. The Effects of Different Outdoor Environments, Sunglasses and Hats on Light Levels: Implications for Myopia Prevention. Transl Vis Sci Technol. 2019 Jul 18;8(4):7.
· Flitcroft DI, Harb EN, Wildsoet CF. The Spatial Frequency Content of Urban and Indoor Environments as a Potential Risk Factor for Myopia Development. Invest Ophthalmol Vis Sci. 2020 Sep 1;61(11):42.
· Peng BA, Naduvilath TJ, Flitcroft DI, Jong M. Is myopia prevalence related to outdoor green space? Ophthalmic Physiol Opt. 2021 Nov;41(6):1371-1381.
· Li SM, Li SY, Kang MT, Zhou Y, Liu LR, Li H, Wang YP, Zhan SY, Gopinath B, Mitchell P, Wang N; Anyang Childhood Eye Study Group. Near Work Related Parameters and Myopia in Chinese Children: the Anyang Childhood Eye Study. PLoS One. 2015 Aug 5;10(8):e0134514.
· Hagen LA, Gjelle JVB, Arnegard S, Pedersen HR, Gilson SJ, Baraas RC. Prevalence and Possible Factors of Myopia in Norwegian Adolescents. Sci Rep. 2018 Sep 7;8(1):13479.
· Read SA, Vincent SJ, Tan CS, Ngo C, Collins MJ, Saw SM. Patterns of Daily Outdoor Light Exposure in Australian and Singaporean Children. Transl Vis Sci Technol. 2018 May 29;7(3):8.
· Guo Y, Liu L, Lv Y, Tang P, Feng Y, Wu M, Xu L, Jonas JB. Outdoor Jogging and Myopia Progression in School Children From Rural Beijing: The Beijing Children Eye Study. Transl Vis Sci Technol. 2019 May 2;8(3):2.
· Jonas JB, Ang M, Cho P, Guggenheim JA, He MG, Jong M, Logan NS, Liu M, Morgan I, Ohno-Matsui K, Pärssinen O, Resnikoff S, Sankaridurg P, Saw SM, Smith EL 3rd, Tan DTH, Walline JJ, Wildsoet CF, Wu PC, Zhu X, Wolffsohn JS. IMI Prevention of Myopia and Its Progression. Invest Ophthalmol Vis Sci. 2021 Apr 28;62(5):6.
Comentários