The present invention relates to an artificial light system for modulating circadianrhythms, increasing vigilance and influencing light-associated psychologicalconditions such as seasonal affective disorder. The system of the inventioncomprises a source of a green and/or red light and a source of blue light both lightsources being controlled by a computer to provide predetermined light conditions.More specifically, the computer is programmed to provide pulses of blue lightand continuous or pulsed red light, to enhance the efficacy of blue light, reduceblue-light hazard and avoid stroboscopic effect.
