最近儿童的流行病学证据表明,在户外度过的时间可以预防近视。动物模型研究(小鸡,猕猴,树sh)发现,与室内水平相比,光照水平(类似于在户外的阴影中)轻度升高,缓慢形觉剥夺性近视和(小鸡和树sh)晶状体诱导的近视。在低光照水平(50勒克斯)下饲养的正常雏鸡具有昼夜节律的光开启/关闭周期,通常会发展为自发性近视。我们提出了一种模型,在该模型中,环境照度水平对正常屈光发育和对近视源刺激的反应产生连续影响,从而使低光水平有利于近视发展,而升高的水平具有保护性。在可能的机制中,视网膜多巴胺活性升高的可能性最大。来自内在光敏视网膜神经节细胞(ipRGC)的输入在升高的光水平可能涉及,提供视网膜多巴胺能途径的额外激活。
Recent epidemiological evidence in children indicates that time spent outdoors is protective against myopia. Studies in animal models (chick, macaque, tree shrew) have found that light levels (similar to being in the shade outdoors) that are mildly elevated compared to indoor levels, slow form-deprivation myopia and (in chick and tree shrew) lens-induced myopia. Normal chicks raised in low light levels (50 lux) with a circadian light on/off cycle often develop spontaneous myopia. We propose a model in which the ambient illuminance levels produce a continuum of effects on normal refractive development and the response to myopiagenic stimuli such that low light levels favor myopia development and elevated levels are protective. Among possible mechanisms, elevation of retinal dopamine activity seems the most likely. Inputs from intrinsically-photosensitive retinal ganglion cells (ipRGCs) at elevated light levels may be involved, providing additional activation of retinal dopaminergic pathways.