Ocular light drives a range of nonvisual responses in humans including suppression of melatonin secretion and circadian phase resetting. These responses are driven by intrinsically photosensitive retinal ganglion cells (ipRGCs) which combine intrinsic, melanopsin‐based, phototransduction with extrinsic rod/cone‐mediated signals. As a result of this arrangement, it has remained unclear how best to quantify light to predict its nonvisual effects. To address this, we analysed data from nineteen different laboratory studies that measured melatonin suppression, circadian phase resetting and/or alerting responses in humans to a wide array of stimulus types, intensities and durations with or without pupil dilation. Using newly established SI‐compliant metrics to quantify ipRGC‐influenced responses to light, we show that melanopic illuminance consistently provides the best available predictor for responses of the human circadian system. In almost all cases, melanopic illuminance is able to fully account for differences in sensitivity to stimuli of varying spectral composition, acting to drive responses that track variations in illumination characteristic of those encountered over civil twilight (~1‐1000 lux melanopic equivalent daylight illuminance). Collectively, our data demonstrate widespread utility of melanopic illuminance as a metric for predicting the circadian impact of environmental illumination. These data therefore provide strong support for the use of melanopic illuminance as the basis for guidelines that seek to regulate light exposure to benefit human health and to inform future lighting design.

中文翻译：

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黑色素照度定义了各种条件下人类昼夜节律光反应的幅度。

眼光驱动人类的一系列非视觉反应，包括抑制褪黑激素分泌和昼夜节律相位重置。这些反应是由内在光敏视网膜神经节细胞 (ipRGC) 驱动的，ipRGC 将内在的、基于黑视蛋白的光转导与外在的杆/锥体介导的信号相结合。由于这种安排，尚不清楚如何最好地量化光以预测其非视觉效应。为了解决这个问题，我们分析了 19 项不同实验室研究的数据，这些研究测量了人类对各种刺激类型、强度和持续时间（有或没有瞳孔扩张）的褪黑激素抑制、昼夜节律相位重置和/或警报反应。使用新建立的符合 SI 的指标来量化 ipRGC 对光的影响，我们表明，黑色素照度始终为人类昼夜节律系统的反应提供最佳可用预测指标。在几乎所有情况下，黑色素照度都能够充分说明对不同光谱成分的刺激的敏感性差异，从而驱动响应，跟踪在民用暮光（~1-1000 lux 黑色素等效日光照度）中遇到的那些照明特征的变化. 总的来说，我们的数据证明了黑色素照度作为预测环境照明昼夜节律影响的指标的广泛效用。因此，这些数据为使用黑色素照度作为寻求调节光照以有益于人类健康并为未来照明设计提供信息的指南的基础提供了强有力的支持。