Good lighting in buildings can help people to see what is around them, use landmarks to navigate, identify signs and spaces, see others’ faces and participate in activities.
Poor lighting can increase anxiety and may lead to trip and fall accidents if people cannot make sense of what is ahead of them.
Physiological changes in the eye mean that the capacity to see steadily deteriorates from a young age. By the time people are about 75 years old they need twice as much light as normal lighting standards recommend, and nearly four times as much as a 20 year old, in order to see satisfactorily. The two implications for care environments are that twice the ‘normal’ light is required, and that the lighting level in spaces should be set by someone who is of mature years.
The eye sends signals which the different parts of the brain interpret to form a visual construct. Therefore some older people with dementia are significantly disadvantaged compared to other older people because the ability of the brain affected by dementia to process visual signals is greatly diminished. Therefore it is even more important that higher light levels are delivered into the environment of people with dementia in order that their brain has some chance of performing reasonably.
It is important to remember that reflection and contrast are the keys to vision; glare from lights is not good; uniformity of light on ceilings and walls makes spaces appear more attractive; spotlights can make faces appear more aggressive than more diffuse lighting; sudden changes in light level should be avoided and ‘domestic’ style lights contribute to a homely atmosphere.
The control of artificial lighting by occupation and movement sensors, time-switches and daylight switches must be carefully thought through in order to minimise electricity costs. A good way of delivering light is by use of daylight, as it is both free and gives excellent colour rendition. So it is best not to block the available daylight with unnecessary blinds, and curtains that do not open beyond the window.
Of course daylight levels are very much higher outside buildings than inside, and people should be encouraged to go outside, especially during the morning, when exposure to even an overcast sky for one hour can deliver sufficient light to help maintain a good circadian rhythm. This in turn helps sleep duration and quality thus making people more content. Darkness at night also helps in this regard. An additional benefit of the daylight is a reduction in Seasonal Affective Disorder (SAD).
Exposure of the skin to sunlight for only few minutes daily between spring and autumn can trigger the production of vitamin D in the body. Vitamin D is known to increase bone strength and muscle performance, resulting in fewer falls with reduced severity when they occur.
So with improved sleep, fewer falls and more active participation, good lighting can make people in care environments happier.