Lighting And The Visual Environment For Senior Living

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ILLUMUNATING ENGINEERING SOCIETY

LIGHTING AND THE VISUAL ENVIRONMENT FOR SENIOR LIVING (ANSI/IES RP-28-07)

SUMMARY OF KEY POINTS

 

  • Many lighting standards do not consider the needs of the elderly and are based on younger people in the 20 to 30 year age group.
  • Human eye transmittance declines from 100% at 25 to 25% at age 70 so elderly people need much more light to be able to see clearly to perform basic tasks.
  • Appropriate human centric lighting conditions (for the elderly) help maximize personal independence while promoting health, well-being, and safety. Photo-biological effects of inadequate lighting for seniors include disruption of the circadian rhythm and vitamin D synthesis.
  • Visible light levels needed to drive circadian rhythms are rarely found inside elder care facilities.  Light levels provided by electric lighting are usually not sufficient to activate the circadian system, and most lighting systems do not have the spectral power distribution (SPD) that effectively addresses circadian needs.
  • Long Blue Visible Light (460-500 nm) exposure at the eye in the morning phase advances the circadian clock, aligning it with the 24-hour light/dark cycle.
  • Sleep disturbances are associated with decreased physical health, including cardiovascular problems, disruption of endocrine functions, and decline of immune functions.  Only 20% of older people report no difficulties with sleep.
  • In persons with Alzheimer’s disease, sleep disturbances are much more frequent and tend to be more severe, making home care more difficult.
  • During daytime hours, elder facility and care home lighting should be high enough to activate the circadian system.
  • Poor lighting is associated with falls among the elderly.  Decreased visual acuity is associated with double the risk of hip fracture.
  • The 2004 US Surgeon General’s report calls for improved elder facility and care home lighting to reduce the risk of falls and states “Optimum light exposure ought to be as uncontroversial an aim of future health policy as best possible nutrition.”
  • Quantity of lighting without quality is self-defeating and should address:
    • Discomfort Glare
    • Disability Glare
    • Flicker
    • Adaptation Issues
    • Spectral Power Distribution and Color Rendering
    • Shadows
    • Facial Modeling
    • In providing lighting for senior citizens, every room or space should have ambient illumination in addition to task lighting.
    • The goal of ambient lighting should be evenly distributed light levels with minimal shadows.  No direct view of any lamp should be permitted.
    • Indirect light can be provided from luminaires mounted on architectural features or cabinets to produce higher levels of general illumination with consistent and even light.
    • It is important for residents to have some control over task lighting in public spaces.
    • Emergency egress lighting for the elderly mounted close to the floor would better direct residents to safety.  The same is true for night time lighting the path to the bathroom.
    • Since aging eyes are sensitive to glare, bright sources should be out of direct view or shielded so that direct glare is avoided.
    • Many spaces require different light levels for a variety of tasks.  Providing individual control of selected light sources can enhance user satisfaction.
    • Older eyes adapt less quickly to different light levels, and scalloped lighting patterns on corridor walls create problems for older people and make these spaces more difficult to negotiate.
    • Lighting levels in elevators should be the same as in adjacent lobbies and corridors.  High intensity down-lights are discouraged due to the glare and strong facial shadows they create.
    • Multi-use dining areas in living units should have remote control adjustable lighting to accommodate different task uses.  Direct glare must be avoided.
    • A combination of improved lighting and increased value contrast has been shown to improve food intake for people with dementia.
    • Kitchens require a combination of ambient and task lighting with control for the general lighting at kitchen entrances and special low level lighting at night.
    • Special night lighting must be provided.  It is very important for people to sleep in the dark with the lights off.  Low voltage non-blue spectrum night lighting should be turned on by an illuminated switch adjacent to the bed or activated by a motion sensor only when the person gets up at night.
    • Because visual comfort is important, large diffused sources are recommended rather than point sources.
    • Senior citizens require increased adaptation time when moving from a brightly lit environment to a more dimly lit one, and the designer should strive to provide appropriate lighting levels while minimizing glare.