Department of Ophthalmology, University of Kansas School of Medicine, 7400 State Line Road, Prairie Village, KS 66208-3444, USA.
Sleep Med Rev. 2010 Aug;14(4):269-80. doi: 10.1016/j.smrv.2009.11.002. Epub 2010 Jan 6.
Environmental illumination profoundly influences human health and well-being. Recently discovered photoreceptive retinal ganglion cells (pRGCs) are primary mediators of numerous circadian, neuroendocrine and neurobehavioral responses. pRGCs provide lighting information to diverse nonvisual (non-image-forming) brain centers including the suprachiasmatic nuclei (SCN) which serve as the body's master biological clock. The SCN exert functional control over circadian aspects of physiology. The timing and strength (amplitude) of SCN rhythmic signals are affected by light exposure. Light deficiency may attenuate SCN function and its control of physiological and hormonal rhythms which in turn can result in a cascade of adverse events. Inadequate pRGC photoreception cannot be perceived consciously, but may aggravate many common age-associated problems including insomnia, depression and impaired cognition. In this review we (1) summarize circadian physiology, emphasizing light's critical role as the most important geophysical timing cue in humans; (2) analyze evidence that typical residential lighting is insufficient for optimal pRGC requirements in youth and even more so with advancing age; (3) show how ocular aging and cataract surgery impact circadian photoreception; and (4) review some of the diverse morbidities associated with chronodisruption in general and those which may be caused by light deficiency in particular.
环境光照对人类健康和幸福感有深远影响。最近发现的光感受器视网膜神经节细胞（pRGC）是许多昼夜节律、神经内分泌和神经行为反应的主要介导者。pRGC 为包括视交叉上核（SCN）在内的多种非视觉（非成像）脑中枢提供光照信息，SCN 是人体的主生物钟。SCN 对生理的昼夜节律方面发挥功能控制。SCN 节律信号的时间和强度（幅度）受光照的影响。光照不足可能会减弱 SCN 功能及其对生理和激素节律的控制，进而导致一连串的不良事件。pRGC 光感受器不足可能无法被有意识地察觉，但可能会加重许多常见的与年龄相关的问题，包括失眠、抑郁和认知障碍。在这篇综述中，我们 (1) 总结了昼夜节律生理学，强调了光作为人类最重要的地球物理定时线索的关键作用；(2) 分析了证据表明，典型的居住照明对于年轻人的 pRGC 需求来说不够充足，而随着年龄的增长则更加不足；(3) 展示了眼部衰老和白内障手术如何影响昼夜节律光感受器；(4) 综述了与一般生物钟紊乱相关的一些不同的病态，以及那些可能由光照不足引起的病态。
