Quality of light in a long term care facility in the Netherlands

Abstract

Purpose: Several studies describe the importance of light for our physical and psychological wellbeing. Exposure to light can affect human experiences, performance, and physiology via both image-forming and non-image forming processes 1. (Day)light is a key concept for life enrichment care facilities. 'Life enrichment care' is a concept based on healing environments, which targets long term care facilities (Ltcf) rather than hospitals. This concept focuses on the well-being and quality of life of frail elderly in Ltcf 2. Among Lctf residents are often people who suffer from some form of dementia. For this group, the image-forming and non-image forming aspects of light play a role. The image-forming or visual aspects of light include the ability to perform daily tasks, and are related to the prevention of falls. The most important non-image forming aspect of light is light's influence on controlling circadian rhythms, or the "biological clock". Older adults with dementia often suffer from disturbances in circadian rhythm, which can lead to behavioral problems including nocturnal unrest 3. This nocturnal unrest is mostly treated with sleep medication. However, in previous research, the emphasis was on light in general and electric lighting in specific. No clear distinction was made between electric lighting and daylight 4. This study investigates the effect of (day)light on the well-being of frail elderly and healthcare professionals in Ltcf. This paper describes the current quality of light at a Ltcf in the Netherlands, which is discussed with reference to currently available recommended values 4,5. Method: The study was conducted in four living rooms of the psycho geriatric department of a Ltcf in the Netherlands, in July 2012. In order to chart the current quality of light in the Ltcf, several methods were used. The following parameters were quantified 4 both for electric lighting and for daylight: the horizontal and vertical illuminance at relevant positions and viewing directions; vertical colour temperature at eye level of a sitting resident; and, measurement the luminance ratios for the visual effects of light. To determine the contribution of daylight in illuminating the four living rooms, one series of measurements was done with the electrical lighting switched on and one series with the electrical lighting switched off. Results & Discussion: In the current situation, about half of the measured positions meet the recommended values of at least 750 lux for the horizontal and vertical illumincance 6. In the several studies, a minimum horizontal and vertical illuminance value of 750 lux is recommended 6. However, in other studies values of 1000 lux are mentioned 4,5. The aforementioned values of 750 lux were mainly reached on which are relatively close to the window. For positions further away from the window, the illuminance values notably decreased. The measured colour temperature in the living rooms were between 4000 K and 5500K, with some peaks up to 7000 K. A minimum colour temperature value of 5000 K is recommended 6, and is usually reached when only daylight is present and when viewing in the direction of the window. The measurements in this study took place during summer; it is expected that the illuminance levels in winter do not reach the recommended values. The results will be used as input for the development of another light strategy for Ltcf.