History of Bright Light Therapy

By the beginning of the 1900s, when industrial pollution and lack of sufficient sunlight were linked to diseases such as rickets and tuberculosis, artificial sun lamps were becoming the fashion. Neils R. Finsen won the Nobel Prize in 1903 for his work with curative light therapy, and Dr. Auguste Rollier followed his lead, opening the world’s first dedicated sun clinic in the Swiss Alps.

Bright Light Therapy 1930

Bright Light Therapy 1930

Bright Light Therapy & Dementia

It is well known that people with dementia often suffer with sleep disorders and disruptive nocturnal behaviour, referred to as ‘Sundowning’ showing symptoms of confusion and agitation, worsen in the late afternoon and evening or when the sun goes down. This can be challenging for the carers and stressful for other residents residing in nursing/care home environments.

The combination of having dementia and normal deterioration of the eyes due to aging, can mean that the levels of light indoors are usually insufficient for the internal body clock to function to a daily rhythm. This affects not only the wake-up process but also the activity and sleep cycle which results in a restless and disturbed night sleep.

Numerous studies into the relationship between light therapy and dementia have evidenced that bright, full spectrum (white) light, on the magnitude of 5000lux to 10,000lux, can reset the circadian rhythm, improve rest/activity rhythms and sleep efficiency in people suffering with dementia (1). It also helps to significantly reduce depression.

Light boxes are commonly used for bright light therapy, and they can be switched on for a set period each day. They provide up to 10,000 lux, about 30 times more light than the average office light.


Bright light therapy was originally intended for people with SAD (Season Affective Disorder), however, it has also been used to treat circadian problems, where people have difficulty sleeping well at night. It may offer some similar benefits to that of medication without the potential side effects, such as the risk of falls and fractures, or confusion which commonly occur in older people (2).

More recent studies have shown that using dynamic lighting in care homes improved cognition in people with dementia, enhanced their sense of night and day, enabled them to sleep better, and reduced levels of depression.

Light boxes can work best for an individual in their own home environment, but in care homes settings it is important to consider quantitative lighting solutions based upon basic principles of circadian regulation and are designed while still paying attention to maintaining good vision and safety for the residents while awake and to minimising sleep disruption at night.


Images: Derungs

Bright light therapy or dynamic lighting solutions can be designed and integrated into the existing light installation in communal areas such as the dining room and lounges where residents spend a good deal of their time and where they can benefit most from bright light therapy.


  1. Hanford, N. Figueiro M. Light Therapy and Alzheimer’s Disease and Related Dementia: Past, Present, and Future. Rensselaer Polytechnic Institute.
  2. Sutherland, D. et al (2004) The Use of Light Therapy to Lower Agitation in People with Dementia. Nursing Times; 100: 44, 32–34.

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