纸标题：Time spent in outdoor activities in relation to myopia prevention and control: a meta‐analysis and systematic review
Authors: Shuyu Xiong (1)(2), Padmaja Sankaridurg (3)(4), Thomas Naduvilath (3), Jiajie Zang (5), Haidong Zou (1)(2), Jainfeng Zhi (1) Minzhi Lv (1), Xiangui He (1)(6), Xun Xu (1)(2)
- Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Centre, Shanghai Eye Hospital, Shanghai, China.
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.
- Brien Holden Vision Institute, Sydney, New South Wales, Australia
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
- Department of Nutrition, Shanghai Municipal Centre for Disease Control and Prevention, Shanghai, China
- Department of Maternal and Child Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
Date:Mar 2017
reference:Acta Ophthalmol. 2017;95:551-66[链接到开放访问纸]
Summary
在整个眼神社区中，人们普遍认为，在户外度过的时间增加可以保护近视的进展。Xiong等人着手通过对51项临床试验和纵向研究进行荟萃分析来更好地理解研究，这些临床试验和纵向研究调查了所花费的时间在户外与发展近视的风险，现有近视的发展或近视转变的折射率转变。
Spending time outdoors was found to have a protective effect for the onset of myopia where a 50% reduced risk corresponded with 76 minutes of extra outside time daily. More time outdoors also corresponded with a reduced myopic shift of -0.30D for both myopes and non-myopes. For those who were already myopic, increased time outdoors had little effect in halting myopic progression.
Further research could confirm why outdoor time appears most effective in reducing the risk of myopia onset and what an optimum duration of outdoor time would be for use as an intervention step.
临床relevance
Time outside
我ncreased time outdoors appears to provide significant protection for myopia onset
- 在户外花费时间意味着降低近视的风险，证明了一段逆关系
- This relationship was not linear however, and so the benefit of outdoor time reduced with the increasing time spent outside
- A reduction of 50% in the incident myopia could be achieved with an extra 76 minutes outside time per day. This corresponds to 8.9 hours per week
- A 45% reduction is found with 1 hour increase per day
Where the biggest impact here is for the non-myopes, this will apply to those children who are classed as pre-myopic and susceptible to developing myopia1. This may be children who are demonstrating fast reducing hyperopic refractive error or who have a lower hyperopic refraction expected for their age. Taking the current evidence into consideration, the author’s advice is for parents to increase the time their child spends outside by 1 hour daily.
Age of child
- The results of this study suggested that 6yr olds would benefit more from the time outdoors compared to 11-12yr old children due to a greater protective effect
- 建议是他们的眼睛可能处于关键的发育阶段，这使他们更容易受到环境变化的眼光变化的影响。
- The protective effect seems to favour non-myopes - Parents of children younger than 11yrs can still be advised on the benefits of outdoor time as the authors found the protective effect to favour non-myopes.
Progression of myopia
这项荟萃分析无法提供证据表明，在户外时间增加了对已经是近视的眼睛进展的保护作用，但是研究设计中存在局限性。尽管有这些限制，我们仍然可以建议父母帮助孩子参与更多的户外活动可能是有益的。
- Even where some studies in the meta-analysis found no protective effect from more time outside, they also discovered that overall, myopes spent more time indoors than non-myopes. More time outside may be beneficial from simply meaning they spend less time indoors concentrating on closer tasks
Limitations and future research
Using questionnaires to gather information on how long a child spends outdoors does give a possibility for either recall bias or inaccurate reporting from study participants.
- 理想情况下，将客观地收集信息，作者建议选项可以包括使用基于GPS和生物标志物（例如维生素D和结膜UVAF）的轻度仪表，系统
One of the studies excluded from the meta-analysis was by Ramessur et al (2015)2 where they investigated identical twins and the environmental risk factors for myopia.
- This study was excluded on the basis that the difference in time spent outdoors was explored in the context of any spherical equivalent differences the twins had, rather than the impact on myopia incidence or progression specifically.
- Future twin studies investigating environmental influences on myopia could help reveal if differences in preference for indoor versus outdoor activities has an impact on myopia onset, incidence or progression.
Of the 25 studies included in the meta-analysis, 17 were from East Asian countries where there is a higher prevalence of myopia compared to many other countries. The remainder were from Australia, the U.K, the U.S.A and Turkey.
- 我t would be interesting to repeat investigations into outdoor time and myopia onset in countries with differing climates and myopic prevalence to confirm any association.
The authors identified further related research could shed light on several factors:
- What ocular mechanisms are involved if outdoor time is more effective in reducing the risk of myopia onset
- What a definite amount of outdoor time would be before it is effective in reducing the risk of onset and if prolonged time is needed as a reinforcing influence
- Why time outdoors was effective in reducing myopic progression in non-myopes but had limited impact on progression in myopes
Full story
Purpose
这项研究旨在探索所花费的时间与近视发作的风险，屈光度误差和近视进展的风险（在近视眼中）之间的关联。
Study design
Xiong等人整理了来自2002年至2015年的51项研究的数据，来自PubMed，Cochrane库和Embase进行系统综述，然后在荟萃分析和剂量反应分析中包括25个。
测量程序
The 25 studies used in the meta-analysis included 4 clinical trials, 8 cohort studies and 13 cross-sectional studies with a total of 34,420 participants who were mostly children aged between 6 and 18yrs old. Only 2 studies had adult participants and a further 2 featured children between 6 months and 72 months.
The data was examined to ascertain a connection between time spent outdoors and the risk of incident or prevalent myopia, the risk of a myopic shift in refractive error and the risk of progression in myopic eyes. The authors used a random-effects model to pool the information for the meta-analysis and calculate the confidence interval. Dichotomous data were assessed using the combined risk ratio/odds ratio with 95% confidence interval (CI) and any continuous data was analysed using weighted mean difference and 95% CI.
那里有一个区别在foll吗ow-up times for the clinical trials, the estimate of myopic incidence and myopic shift in refractive was based on 3 years. Studies which had a 1yr follow-up interval had the data multiplied by 2.3 with the assumption that myopic progression reduces as age increases. Where cross-sectional studies had defined the time outdoors in hours per day, the data was standardised into hours per week and the standard error was adjusted accordingly.
For the dose-response analysis, the increase in the time spent outside was determined for the clinical trials and a risk ratio was calculated from the longitudinal cohort studies odds ratios.
The statistical heterogeneity was assessed and sensitivity and sub-group analyses were carried out.
Outcomes
室外时间与发生或普遍近视的风险之间的关联
The combined risk ratio from 3 clinical trials was calculated at 0.536, suggesting that increased time spent outdoors during play-times at school had a significant protective effect by reducing the chance of onset of myopia:
- From the cohort studies that compared high and low levels of outdoor time, it was found that the higher levels of outdoor time were associated with a lower risk of developing myopia with a risk ratio of 0.574.
- With the pooled estimates from the cross-sectional studies, the final odds ratio was calculated to be 0.964 for myopia with each extra hour which was spent outside per week.
剂量反应分析,结果6cohort studies revealed that, overall, the risk of developing myopia could be reduced if time was spent outdoors. One study from Australia investigated the relationship of varying amounts of outdoor time and found that the risk for myopia onset was higher in their younger cohort who spent 13 hours or less per week outside compared to those of the same age who spent an average of 22.5 hours or more per week outside. The remaining 5 cohort studies included in the dose-response analysis discovered an inverse relation where increased time outside was associated with less chance of incident myopia. After plotting the risks of incident myopia from these 6 studies against the time spent outdoors in hours per week, an equation was formulated that gave the figures of:
- 76 minutes per day being needed to achieve a 50% reduction in incident myopia (compared to baseline values), and
- an increase of 1 hour per day would give a 45% reduction in incident myopia (compared to control values)
当亚群体进行分析,有限公司hort studies indicated there was stronger protective effect for children aged 6yrs old compared to 11-12yr old children. The cross-sectional studies, however, found no significant difference between 3 age groups of 6yrs and younger, between 6 and 18yrs and over 18yrs as well as no difference between 3 classifications of prevalence (20% or less, between 20 and 80%, or over 80%).
室外时间与屈光度错误近视转移的风险之间的关联
从3项临床试验中计算了近视和非肌层关系的汇总估计值，发现与对照组相比，干预组的室外时间更多的时间与干预组的近视转移相关。临床试验研究表明，近视偏移（-0.34D）的减少比随机对照研究（-0.17D）的减少更多。
Out of the 6 studies included in the dose-response analysis, only 1 found a statistical association between increased time outside and myopia progression, with a -0.14D mean difference between the control group and the test group.
The other studies included in the dose-response analysis demonstrated no significant statistical evidence that outdoor time had a treatment effect for myopia progression.
结论
The combined results from the authors meta-analysis and systematic review reveal there is a protective element to myopia incidence or prevalence when there is increased time spent outdoors. This still seemed to be the message even where there was a high heterogeneity between studies as some extent of protective effect was still seen.
但是，剂量反应分析表明，这似乎并不适用于已经近视的眼睛，而在户外花费更多的时间似乎对他们的近视进展没有影响。那些没有发现保护作用的研究能够表明，平均而言，近视儿童在室内的时间仍然比户外花费更多。
基于这些发现，可以得出一个结论，即鼓励幼儿每天至少1小时的时间在外面玩耍，这在降低肌无力发展的风险方面是有益的，并减少了发生近视转变的屈光度错误的机会。在户外活动还减少了在近乎工作的活动中花费的时间，这也可能发挥作用。
Where the benefit of time outdoors seems to be highest for children approx. 6yr old or younger, this seems coincident with what we know about the eye’s development at this stage and future research could tell us to what extent environmental influences can have. For now, it does no harm to ensure children have outdoor time and find a balance with how much near work they do indoors.
抽象的
标题：Time spent in outdoor activities in relation to myopia prevention and control: a meta‐analysis and systematic review
作者：Xiong S, Sankaridurg P, Naduvilath T, Zang J, Zou H, Zhu J, Lv M, He X, Xu X
室外时间被认为是降低近视发展的风险。目的是评估户外时间与（1）近视发作风险（事件/普遍近视）之间关联的证据；（2）屈光误差和c）仅发生近视风险的风险。进行了系统的综述，然后进行了荟萃分析和对文献相关证据的剂量反应分析。搜索了PubMed，Embase和Cochrane库以获取相关论文。在具有相关数据的51篇文章中，荟萃分析和剂量反应分析中包括25篇文章。25篇文章中有23篇涉及儿童。进行了连续变量的二进制变量和加权平均差异（WMD）的风险比（RR）。壁架 - haenszel随机效应模型用于汇总荟萃分析的数据。使用统计异质性使用我2test with我2≥ 50% considered to indicate high heterogeneity. Additionally, subgroup analyses (based on participant's age, prevalence of myopia and study type) and sensitivity analyses were conducted. A significant protective effect of outdoor time was found for incident myopia (clinical trials: risk ratio (RR) = 0.536, 95% confidence interval (CI) = 0.338 to 0.850; longitudinal cohort studies: RR = 0.574, 95% CI = 0.395 to 0.834) and prevalent myopia (cross‐sectional studies: OR = 0.964, 95% CI = 0.945 to 0.982). With dose–response analysis, an inverse nonlinear relationship was found with increased time outdoors reducing the risk of incident myopia. Also, pooled results from clinical trials indicated that when outdoor time was used as an intervention, there was a reduced myopic shift of −0.30 D (in both myopes and nonmyopes) compared with the control group (WMD = −0.30, 95% CI = −0.18 to −0.41) after 3 years of follow‐up. However, when only myopes were considered, dose–response analysis did not find a relationship between time outdoors and myopic progression (r2= 0.00064). Increased time outdoors is effective in preventing the onset of myopia as well as in slowing the myopic shift in refractive error. But paradoxically, outdoor time was not effective in slowing progression in eyes that were already myopic. Further studies evaluating effect of outdoor in various doses and objective measurements of time outdoors may help improve our understanding of the role played by outdoors in onset and management of myopia.
About Ailsa
AILSA LANE是位于英格兰肯特的隐形眼镜眼镜师。她目前正在以荣誉完成她的高级隐形眼镜实践文凭，这引发了她在理解科学研究并找到其对临床实践的翻译方面的兴趣和技能。
references
- 如何识别和管理近视概况[Link]
- ramessur R, Williams KM & Hammond CJ (2015): Risk factors for myopia in a discordant monozygotic twin study.眼科生理学32: 643-651[链接到开放访问纸]
