Temporal-Spectral Control of Artificail Lighting for Improved Health

目前的研究表明，通过含黑视素的视网膜神经节细胞（mc-RGC）途径，每天的光照模式对急性脑功能和昼夜生理的日常干扰都有深远的影响。对照睡眠研究和倒班工人的研究表明，我们夜间暴露在人工照明下会破坏昼夜生理，尤其是不规律的倒班工作。昼夜生理紊乱严重影响警觉性和认知功能。慢性昼夜节律紊乱与癌症、代谢综合征和广泛的神经精神功能障碍的发病率增加有关。现代生活越来越多地以白天和晚上长时间的室内活动为特征，而这些活动都采用同样的传统照明标准。这些标准是基于色觉灵敏度，而不考虑mc-rgc通路的激活。这就产生了更大的可能性，即白天大部分时间呆在室内，晚上广泛地看电脑和电视的人，可能会破坏他们正常的昼夜光谱辐射模式。这种方式导致广泛的昼夜节律中断和慢性生理压力。因此，我们可以通过暂时改变人工光谱，在白天增加mc-rgc激活（蓝光富集），在夜间减少（蓝色成分减少），从而改善现代民众的健康和生产力。我们一直在寻找简单的方法来测试这一假设，并在现实世界环境光暴露模式的广泛范围内为个体优化提供实用的方法。荧光灯照明和最近的LED照明能够极大地丰富蓝色光谱，通过增加通过产生输出白光的荧光粉传输的主要蓝光的数量。例如，最近的研究表明，白天在痴呆症患者的公共休息室里暴露在明亮的高色温（富含蓝色）荧光灯下，会降低认知功能长期下降的速度。任何增加白天黑视素激活的标准光线在夜间使用时也会导致干扰。对于一般人来说，我们认为夜间这种富含蓝光的人造灯对昼夜节律的破坏是一个主要问题。为了优化现代城市世界的昼夜健康，我们假设需要对人造光谱进行时间控制。

Current research indicates that daily patterns of light exposures, through the melanopsin-containing retinal ganglion cell (mc-RGC) pathway, has a profound effect on both acute brain function and daily entrainment of circadian physiology. Our night-time exposures to artificial lighting are disruptive of circadian physiology as shown in controlled sleep studies and studies on shift-workers, particularly irregular shift work. Disruption of circadian physiology acutely affects alertness and cognitive function. Chronic circadian disruption has been linked to increased incidence of cancer, metabolic syndrome, and a wide spectrum of neuro-psychiatric dysfunction. Modern life is increasingly characterized by long periods of indoor activity during both day and night for which the same conventional lighting standards are applied. These standards are based on color vision sensitivity regardless of mc-rgc pathway activation. This creates greater likelihood that individuals spending most of the daylight hours indoors and extensively viewing computers and televisions at night may fragment their normal diurnal pattern of spectral irradiance. This way lead to widespread circadian disruption and chronic physiological stresses. Consequently, one might improve both health and productivity of our modern populace by temporally altering the artificial light spectrum to increase mc-rgc activation (blue-light enrichment) during the daytime and decreasing it at night (diminished blue component). We have been searching for simple ways to test this hypothesis and to provide practical means for individual optimization given the wide range of real-world ambient light exposure patterns. Fluorescent lighting and more recently LED lighting are capable of greatly enriching the blue spectrum by increasing the amount of primary blue light transmitted through the phosphors that create the output white light. For example, recent studies suggest that daytime exposure to bright high-color-temperature (blue-enriched) fluorescent lights in daytime common rooms of patients with dementia led to decreased rate of long-term decline in cognitive function. Any standard light that increases daytime melanopsin activation will also lead to disruption when used at night. For the general population, we believe circadian disruption from such blue-light rich artificial lights at night is a major problem. To optimize circadian health in the modern urban world, we hypothesize will require temporal control of the artificial light spectrum. Computer monitors (and televisions) are universally designed to exceed ambient light levels reaching the retina (hence dominate mc-rgc pathway activation when used. In our modern society, large segments of the population average 4 hours of computer use per day. Similarly televisions are on typically up to 8 hours in an average American household. These high brightness sources on which we routinely fixate for long periods are the most likely light to be altering natural patterns of activation of melanopsin-containing retinal ganglion cells and their projections to the brain. However, modern computer monitors and digital televisions provide a path to dynamically control mc-rgc activation relative to color vision sensitivity by altering the RGB gain structure. We have developed dynamic color balance software that can control the color balance over a diurnal cycle to vary mc-rgc activation 10 fold while keeping photopic sensitivity constant. Our hypothesis is that daily computer use is having a measurable effect on circadian physiology. By using dynamic control of the RGB balance with easily exported software, we hope to develop computer based real-world testbeds to measure such acute effects on alertness and cognitive function throughout the day. Using the diurnal records of performance for a given individuals might eventually be use to self-optimize the temporal pattern of artificial light spectra for a given individual which is affected by both their other daily environmental zeitgebers and likely the genetic variations in their circadian systems physiology. We are currently trying to integrate our spectral-temporal control of LED/LCD computer monitors and smartphones with computerized attention, response time, cognitive function and productivity tests. We would use the subjects epersonal computer to log these data results along with those from computer-based questionnaires presented at regular intervals. With this combined testbed, we plan to design new research into lighting spectral-temporal control optimization for health in real-world systems readily exportable to office and home environments. We are considering the potential for such systems to perform anonymized studies (subject selected username and password) to provide low cost large cohort studies that provide the potential for individual feedback to reinforce behaviors that improve circadian health and performance. In collaboration with the Lighting Division of Lawrence Berkeley National Lab and the California Lighting Research Center under a DOE FLEMP grant, we have developed programmable low-level temporal and spectral control of computer monitor luminance that is compatible with the normal function of other computer programs both for cognitive function testing and for normal computer uses at work and at home.