Designing lighting for the elderly requires special consideration and care from architects and lighting designers. As people age, they experience neural degeneration in the retina and in the suprachiasmatic nucleus (SCN). Less light reaches the back of the eyes because the pupils decrease in size as you age, the lens inside your eye becomes thicker, and the lens scatters more light, causing objects and colors to appear less vivid. These symptoms are particularly common with persons having alzheimer’s disease.
Older people also have reduced levels of retinal illuminance, such as having smaller pupils and less transparent crystalline lenses. As an individual ages, he or she begins to lose retinal neurons, which not only compromises the ability to see but also to register a robust daily pattern of light-dark that is needed to maintain biological rhythms. The 24-hour light-dark cycle is the most important external stimulus for regulating the timing of the circadian system.
In addition to the aging eye, lighting designers need to consider the unique lifestyle needs of the elderly.
Due to physical limitations, they may be deprived of natural sunlight. Many nursing homes and assisted living facilities have dim, constant light levels and light spectra. This can cause disruption of the body’s circadian rhythms, which can potentially lead to negative health effects.
Providing light early in the evening can help seniors sleep better at night and be more alert during the day because the light delays the biological, circadian clock. Many studies have shown that when the elderly are exposed to bright white light, the elderly individual saw improved sleep efficiency. A recent study also demonstrated that exposure to 30 lx of blue light from LEDs in the evening (peaking at 470 nm at the eye for two hours) increased sleep efficiency for older adults who previously had difficulty sleeping.
Providing white light and blue light has even greater impact for those with Alzheimer’s Disease (AD). So far, two lighting methods have been shown to improve nighttime sleep in AD patients: (1) exposure to bright white light (at least 2500 lx and as high as 8000 lx at the cornea) for at least one hour in the morning, for two weeks and (2) exposure to 30 lx of blue light from LEDs, peaking at 470 nm at the eye for two hours. The light, or the better sleep, also helped to reduce agitated behavior such as pacing, aggressiveness, and speaking loudly. Evening exposure to bright white light (1500 to 2000 lx at the cornea) for two hours decreased nocturnal activity and severity of evening agitation.
Daylight is an ideal light source because it provides high circadian stimulation during the day. Daylight also has the correct intensity and spectrum needed to stimulate the circadian systems. Architectural designs should consider adding sun rooms, skylights, patios, and courtyards into the design of facilities for the elderly. Architects can also select lighting fixtures that emit an array of blue light LEDS (λmax=470 nm) which deliver at least 30 lux at the corner. Lighting schemes that have timers are also helpful in providing the right type of light at the right type of day.
Nightlights are also helpful in reducing falls and injuries and, at the same time, help the elderly to maintain sleep. Falls are a major concern with the elderly; they threaten their independence and risk further health complications. Lighting systems can help seniors maintain balance and stability. Furthermore, sleep deprivation can contribute to decreased postural control. Nightlights that accent horizontal and vertical spaces, such as soft lighting above a doorway or at the foot of a bed, can reduce the risk of falls without disturbing sleep.
So contact Lumenistics today for a “walkabout” – our unique approach to an on-site facilities tour combined with a two way Q&A. We’ll leave you better informed, and if appropriate, will follow-up with an action-oriented proposal.
- Learn the Basics of Energy Efficient Lighting
- Utility Rebates for Energy Efficient Lighting Upgrades
- Consider Photopic, Scotopic, Mesopic Vision before Specifying Lumen Requirements
- Wikipedia: Lighting for the elderly
- Lumenistics home page
- Contact Lumenistics