Circadian photobiology: an emerging framework for lighting practice and research

A century of research and practice have optimized the use of electric lighting in buildings to support human vision. However, recent lines of research show that light is also important to human circadian regulation, as reflected in such diverse phenomena as depression, sleep quality, alertness, and, perhaps, even health. Although light is essential to both vision and circadian regulation, research shows that the biophysical processes that govern circadian regulation are very different from those that govern vision. This growing body of research will probably influence the architectural lighting community and manufacturers to reoptimize the use of electric lighting in buildings to support both human vision and circadian functions. The present paper is concerned with establishing a framework for lighting practice and applied research that will assist lighting practitioners and manufacturers in interpreting this emerging research.