No More Modifications: Glare Control from a Circadian Perspective

In three years in three different centuries, three important developments in lighting each occurred twice on two different continents. In 1879, the incandescent lamp was patented in the U.S. by Thomas Edison and in England by Joseph Swan. These early lamps used carbon thread, bamboo filaments, and eventually durable tungsten wire to provide glow. Better filament materials meant higher light output and before long, bare incandescent lamps became visually glaring. In response, illuminating engi- neers began using globes, shades and other diffusers to reduce discomfort glare, which brings us to the second time important developments for lighting simultaneously happened across oceans.