Xiong S, Sankaridurg P, Naduvilath T, Zang J, Zou H, Zhu J, Lv M, He X, Xu X
摘要：普遍认为室外活动是减少近视发生的有效方法。本文的目的是评估室外活动和(1)患近视风险（事件和近视的普遍性），(2)屈光不正的风险c) 仅仅是近视发生的风险的关系。进行meta-分析的系统性回顾和文献相关证据的剂量响应分析。从PubMed、EMBASE和Cochrane实验室搜索相关论文，其中51篇文章中有相关数据，25篇包括meta-分析以及剂量响应分析；25篇文章中的23篇包括儿童，分析了连续变数的二进制变量风险率 (RR) 和加权均数差 (WMD)。采用Mantel-Haenszel随机影响模型对数据进行荟萃分析。采用I(2)检测和I(2) ≥50%评估的统计学异质性，被认为是高异质性的。此外，进行了亚组分析（基于参与者年龄、近视患病率和研究类型）和灵敏度分析。户外活动的时间对近视（临床试验：风险率（RR）=0.536，95%的置信区间（CI）=0.338到0.850；纵向队列研究RR=0.574，95% CI=0.395 到0.834）和近视发展（横断面调查：OR=0.964，95% CI=0.945到0.982）有重要的保护作用。剂量响应分析是一种逆非线性关系，说明增加户外运动时间会减少近视发生风险。另外在三年的随访研究中，临床试验的合并结果说明干预户外时间后，近视度数相对正常组有-0.30 D（在近视的人和非近视的人当中）的减小 (WMD=-0.30，95% CI=-0.18到-0.41)。然而，当只考虑近视，剂量响应分析不能找到室外活动时间和近视发生的关系(R(2) =0.00064)。增加户外运动时间有效预防近视的发生并且减缓屈光不正。相反的，户外运动时间对已经近视的眼睛减缓发展并没有作用。进一步的研究来评估户外运动的次数以及客观测量户外运动时间有助于提高对户外运动在近视发病和管理中作用的认识。
Outdoor time is considered to reduce the risk of developing myopia. The purpose is to evaluate the evidence for association between time outdoors and (1) risk of onset of myopia (incident/prevalent myopia); (2) risk of a myopic shift in refractive error and c) risk of progression in myopes only. A systematic review followed by a meta-analysis and a dose-response analysis of relevant evidence from literature was conducted. PubMed, EMBASE and the Cochrane Library were searched for relevant papers. Of the 51 articles with relevant data, 25 were included in the meta-analysis and dose-response analysis. Twenty-three of the 25 articles involved children. Risk ratio (RR) for binary variables and weighted mean difference (WMD) for continuous variables were conducted. Mantel-Haenszel random-effects model was used to pool the data for meta-analysis. Statistical heterogeneity was assessed using the I(2) test with I(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 3years of follow-up. However, when only myopes were considered, dose-response analysis did not find a relationship between time outdoors and myopic progression (R(2) =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.