Current research indicates that daily sunlight (largely through the mc-RGC pathway) is having a profound effect on both acute brain function and daily entrainment of circadian physiology. Our night-time exposures to artificial lighting are potentially disruptive of circadian physiology as has been suggested by numerous studies on shift-workers, particularly irregular shift work. Disruption of circadian physiology appears to increase the risk for cancer, the incidence of metabolic syndrome, and possibly a wide spectrum of neuro-psychiatric disorders. As a consequence one might improve health and productivity of our modern populace in general by optimizing spectral temporal control of artificial lighting that at night balances photopic visual acuity for night-time tasks with minimizing circadian disruption by blue-light. Conversely enriching daytime (e.g., morning) blue-light components in artificial lighting may improve acute brain functions such as alertness and prevent circadian disruptions in individuals who are indoors during most daylight hours and. Our current knowledge of human non-visual effects of spectral lighting is largely limited to isolated controlled sleep-lab studies on small numbers of subjects and risk factors in large-scale epidemiology studies. Even with significant new data about the action spectra of the mc-RGC cells (including blue-red photoreversal) and their role in important brain pathways including acute alertness and circadian synchronization, we do not have a rationale approach to designing optimal spectral lighting for health and productivity. Currently real-world optimization of spectral temporal lighting for human performance and physiology is not reliably testable. The most common artificial light sources that contribute the highest retinal spectral irradiance are computer monitors (and televisions though generally over a narrower field of view) universally designed to exceed ambient light levels reaching the retina. In our modern society, large segments of the population average 4 hours of computer use per day. Similarly televisions are on typically up to 8 hours in an average Amercian household. These high brightness sources on which we routinely fixate for long periods are the most likely sources to be altering natural patterns of activation of melanopsin-containing retinal ganglion cells and their projections to the brain. Our hypothesis is that a significant portion of our population experiences sufficient spectral-temporal retinal irradiance from their daily computer use to increase their risk for circadian disruption and a variety of associated physiological stresses (e.g., possibly contributing to increasing incidence in metabolic syndrome and attention deficit disorders). If this hypothesis is correct, then changing the temporal-spectral diurnal patterns on their computer monitors might reduce circadian disruption while preserving acute visual function and daytime performance. Furthermore cognitive function and attention testing is now routinely performed using subject responses on computers. Currently the effects of different light spectra are studied in highly controlled specialized testbeds, such as sleep labs, that are difficult to reliably extrapolate to real world environments. We seek to combine modern multicolor LED/LCD computer monitors with already developed computerized attention, cognitive function and productivity tests along with computer-based circadian physiology questionnaire logging. With this combined testbed, we would pursue new research into lighting spectral-temporal control optimization for health in real-world systems readily exportable to office and home environments. In collaboration with the Lighting Division of Lawrence Berkeley National Lab and the California Lighting Research Center under a DOE FLEMP grant, we have developed programmable low-level temporal and spectral control of computer monitor luminance that is compatible with the normal function of other computer programs both for cognitive function testing and for normal computer uses at work and at home. We are currently designing integration of these independent spectral-temporal control functions and data logging with standardized alertness, response time and cognitive function tests.
