Light and healthcare
Light has a large impact over human health and performance. It controls the body’s circadian system, affects mood and perception and enables critical reactions in the body. By controlling the body’s circadian system light has big impact over the outcomes in healthcare settings by reducing depression among patients, decreasing length of stay in hospitals, improving sleep, lessening agitation among dementia patients, easing pain, and improving adjustment to night-shift work among staff. 1 But even more important, hospital lighting aids improving patient care and comfort. 2
There are various light application in hospitals, depending on the specific areas and their purpose and requirements: ward areas, treatment areas, observation areas, examination rooms, waiting and circulation spaces and operating theatres each have different lighting requirements and require specific design criteria.
The 3 main parameters that need to be considered in hospital lighting are:
- Lighting Level
Lighting level is the amount of light measured on a plane surface of total luminous flux incident on a surface per unit area. It is measured in Lux (Lumens /sq. meter). There are specific standardizations for lighting level, depending on the application.
- Color Rendering Index (CRI)
CRI is the ability of the light source to show object colors realistically or naturally.
The color rendering Index is a scale from 0 to 100 percent. The higher the CRI the better the colour rendering ability.
A low CRI, in a hospital environment, can lead to a misrepresentation of body features which may lead to misdiagnosis and improper treatment. Areas where diagnosis, treatment or laboratory analysis is being done a CRI of 90 or greater is recommended. For all other areas within the hospital, a CRI is 80 is sufficient, however, under no circumstances should lamps with two different CRI values be used in the same place3.
- Color Temperature
Measured in Kelvins, the Color Temperature measures the color of the light – from 2700K warm yellow light, to 5500K light similar to the light of a sunny day.
1 Joseph, A. (2006). Impact of Light on Outcomes in Healthcare Settings. California: The Center for Health Design.
2 Bholasingh, L., Bholasingh K. LED Lighting in hospitals, Pan American Health Organization
3 Thorn Lighting. (2017). Thorn Technical Handbook. In T. Lighting, Thorn Technical Handbook (pp. 69-77). Australia: Thorn Lighting