Abstract
The purpose of this paper is to discuss the adaptation to the light environment of the aged. It was examined from the influence of aging to the vision and physiological function, especially sleep-wake cycle. The visual needs of elderly have been investigated fairly in the past and are incorporated in the lighting recommendations for task illuminance, disturbing glare and the luminance distribution in the room. On the other hand, the daylight is an important factor for a healthy and energy efficient dwelling lighting has become widely accepted. Recently evidence for new receptors in the eye for these non-visual effects have been discovered. Human evolution took place under bright daylight but today people have to spend a major part of the day indoors, under for the non-visual effects, low lighting levels. The possibility that the aged who stopped going out becomes poor health in such lighting environment is high. Daylight and high level lighting can synchronize the biological clock, decrease affective disorders and, by direct brain stimulation increase alertness, well-being and performance. With the nowadays-available lamps, luminaries and lighting controls good lighting systems can be designed and most complaints can be prevented, but healthy lighting is more than good lighting; it fulfils both the visual and psycho-physiological needs of user. Healthy lighting includes daylight (dynamic, high vertical illuminance (on the eye)) and artificial lighting (when the daylight is insufficient, further from the window and to balance the luminance distribution) and good controls. Heretofore mainly, the physiological lighting research came for the purpose of the treatment of the sleep disorder. At present , the research examines the physiological influence of brightness level that is experienced with a daily life of the aged is expected.
