Balancing health benefits and risks of lamp sources

Both the Illuminating Engineering Society of North America (IESNA) and the International Commission on Illumination (the CIE) are currently updating their Photobiological Safety Standards. Special application standards are also being developed, and balancing benefits with risks often becomes an issue. Also, the photobiological effects of light on human health have become a very active area of biomedical research. Although we do not understand all effects as well as we would like, there are product applications now based upon current knowledge, where there has been a call to examine potential limitations and understand potential risks. The CIE has had several efforts to review health aspects of visible light upon the neuroendocrine system mediated by the newly discovered retinal photoreceptors—the photosensitive retinal ganglion cells. Through this ganglion-cell pathway, light influences our circadian rhythms and the endocrine system. Beneficial uses of light in phototherapy to correct circadian disorders or mood disorders must be balanced by a careful review of potential side-effects and potential retinal hazards. Although the biological effects of ultraviolet radiation have been studied for decades, there continues to be a debate with regard to obtaining an optimum balance of preventing excessive exposure that increases risks of delayed effects upon the skin and eye, while at the same time having the benefits of low-level UV in producing Vitamin D and possibly obtaining other positive effects for the immune system. To best understand benefits and risks it is highly useful to examine just how humans are exposed in the natural environment and learn lessons that may benefit the application of artificial lighting upon human health, as environmental exposure to daylight UV was considered in deriving emission limits for lamp products.