Time outdoors and the prevention of myopia
Time outdoors and the prevention of myopia
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DOI：
10.1016/j.exer.2013.04.018
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发表时间：
2013-09-01
影响因子：
3.4
通讯作者：
Rose, Kathryn A.
中科院分区：
文献类型：
--
作者：
French, Amanda N.;Ashby, Regan S.;Rose, Kathryn A.
最近的流行病学证据表明，花更多时间在户外的儿童不太可能近视，或者变得近视，无论他们做多少近距离工作，或者他们的父母是否近视。目前尚不确定户外时间是否也会阻止近视的进展。有人认为，户外时间的保护作用的机制涉及光刺激多巴胺从视网膜的释放，因为增加多巴胺释放似乎抑制增加的轴向伸长，这是近视的结构基础。这一假设得到了动物实验的支持，这些实验在实验室条件下复制了强光对近视发展的保护作用，并表明这种作用至少部分是由多巴胺介导的，因为D2-多巴胺拮抗剂螺哌隆降低了保护作用。证据中存在一些不一致之处，最显著的是在实验室条件下强光对镜片诱导的猴子近视的有限抑制，但其他提出的机制可能与户外时间有关，如放松的调节、更均匀的屈光空间、瞳孔收缩增加、暴露于紫外线、可见光光谱组成的变化、或增加体力活动几乎没有流行病学或实验支持。不管涉及的机制如何，目前正在进行临床试验，通过增加儿童在户外的时间来减少他们近视的发展。这些试验将受益于更精确地定义光暴露强度和持续时间方面的保护阈值。这些可以在适当的模型中通过动物实验进行调查，也可以在流行病学研究中确定，尽管需要比目前通过问卷提供的更精确的接触测量。(C)2013爱思唯尔有限公司保留所有权利。
Recent epidemiological evidence suggests that children who spend more time outdoors are less likely to be, or to become myopic, irrespective of how much near work they do, or whether their parents are myopic. It is currently uncertain if time outdoors also blocks progression of myopia. It has been suggested that the mechanism of the protective effect of time outdoors involves light-stimulated release of dopamine from the retina, since increased dopamine release appears to inhibit increased axial elongation, which is the structural basis of myopia. This hypothesis has been supported by animal experiments which have replicated the protective effects of bright light against the development of myopia under laboratory conditions, and have shown that the effect is, at least in part, mediated by dopamine, since the D2-dopamine antagonist spiperone reduces the protective effect. There are some inconsistencies in the evidence, most notably the limited inhibition by bright light under laboratory conditions of lens-induced myopia in monkeys, but other proposed mechanisms possibly associated with time outdoors such as relaxed accommodation, more uniform dioptric space, increased pupil constriction, exposure to UV light, changes in the spectral composition of visible light, or increased physical activity have little epidemiological or experimental support. Irrespective of the mechanisms involved, clinical trials are now underway to reduce the development of myopia in children by increasing the amount of time they spend outdoors. These trials would benefit from more precise definition of thresholds for protection in terms of intensity and duration of light exposures. These can be investigated in animal experiments in appropriate models, and can also be determined in epidemiological studies, although more precise measurement of exposures than those currently provided by questionnaires is desirable. (C) 2013 Elsevier Ltd. All rights reserved.