Age-related Changes in Vision and Required Illumination for the Elderly(<Special Issue>Learning from the Great East Japan Earthquake : Lighting for the Elderly and People with Low Vision)

Abstract

We calculated equivalent illuminance levels and their ratios for young and elderly people by combining data on age-related changes of human crystalline lens and pupil size. The results reveal that effective illuminance for the elderly is a quarter of that for young people when, for energy savings, environmental illuminance is reduced to half. In addition, visibility of the elderly is lower than that of the young even though equivalent illuminance is ensured for the elderly. Finally, we showed that some considerations, such as more than doubling the illuminance of the young, may be necessary for the elderly when energy savings are conducted in public spaces.