Visual and Non-image-forming Effects of Light on Sleep, Alertness and Cognition

This thesis examines the behavioral component and ecological validity of non-image-forming (NIF) effects of daytime electric light exposure and incorporates one systematic review and four independent studies. To explore the behavioral component of the NIF effects, we have developed a new tool Light Exposure Behavior Assessment (LEBA) and used it to categorize, explore and understand how different light exposure behaviors influence our health and wellness. To test the ecological validity of the NIF responses, we designed two experiments where we tested the influence of short-wavelength-enriched light exposure with illuminance within the common indoor lighting standards on alertness and cognitive performance.