Hidden Blue Hazard? LED Lighting and Retinal Damage in Rats

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 mer-cury 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 physio-logical effects, some positive, some negative.4,5,6 White LEDs, as a ne