Environmental Health Perspectives
The Canadian government greeted 2014 with the first tier of its new energy-efficiency standards for light bulbs,1 which will effectively ban incandescent light bulbs by next year.2 But efficient lighting can have its own drawbacks. For instance, although devoid of the mercury used in compact fluorescent lamps (CFLs), some white light-emitting diodes (LEDs) emit a wavelength of light associated with adverse human health effects. In this issue of EHP, researchers study retinal changes in rats exposed to white LEDs like those sometimes used in household lighting.3
Among the most popular household LEDs are products that employ a chip emitting blue light, which is surrounded by a yellow phosphor coating. Although the resulting light looks white to the naked eye, it can feature a spike in the blue end of the spectrum, at wavelengths of 460–500 nm.
Light of this wavelength has been shown to have unique physiological effects, some positive, some negative.4,5,6 White LEDs, as a new source of exposure to blue light, initially prompted concerns about potential changes in melatonin production and disruption of human sleep cycles.7More recent research considers the direct effect of this light on the eye, including the risk of ongoing damage to retinal cells.8
In the current study, the researchers wanted to accurately simulate exposure to indoor lighting, says corresponding author Chang-Ho Yang, a professor and ophthalmologist at National Taiwan University’s College of Medicine. He points out that earlier work shone light directly into the eyes of experimental animals, which may induce damage but hardly corresponds to the indirect way in which most people are exposed to artificial lighting.