The blue-light hazard: A review

A primary purpose of electric lighting is to aid vision in conditions when natural light (daylight, sunlight) is unavailable. Such conditions occur at night and indoors. Lighting recommendations of organizations such as the IESNA are almost entirely based on requirements for visibility.1 An increasing body of evidence exists to support the effects of light and lighting in psychological and physiological areas of life. Light affects moods, metabolism and even communicates meaning. Light is used therapeutically to combat depression, to rid the body of toxins, and to reset the body's internal circadian clock.(2) With such capacity to impact human life, it is reasonable to suppose the use of light might also carry certain risks. This brief review discusses one specific type of potential risk associated with light - namely, the ability of short-wavelength ("blue") light of sufficient intensity and duration to cause photochemical damage to title visual system.