Lighting can have a profound effect on the way that people behave.
It can alter mood, levels of fatigue, resilience to staff shift patterns, and overall stress.
And, from a patient perspective, lighting has been shown to reduce recovery time as well as being beneficial in terms of affecting sleep-wake disturbances, mood, and even pain levels.
Lighting also impacts on the use of medical equipment as users need to be able to see the equipment and read the display in order to operate it safely and effectively.
In a similar way, there are many surgical and diagnostic tasks that benefit from controlled and stable illumination so that the correct decisions are made.
Making an impact
The upshot of the above is that one simple intervention – changing a light bulb – can have a profound and far-reaching impact, particularly in healthcare environments.
In our research we set out to explore the impact that environmental factors have on healthcare settings and consider how these factors can be optimised to support patient and staff wellbeing
Dr Chris Vincent, principal sector lead for healthcare at innovation consultancy, PDD, said: “‘Human Factors’ research aims to match the design of systems with an optimal in terms of supporting behaviour, avoiding accidents, and underpinning safety in general.
“There are many reasons to optimise lighting levels from a human factors perspective. For example, the level of the ambient lighting has been shown to impact alertness and fatigue – it has been shown to impact on quality of work life.
“So it follows that there can be a negative impact in that dimly-lit environments can increase feelings of sleepiness, lack of energy, and contribute to poor focus. At the same time, although there can be a benefit in higher levels of illumination in terms of increasing alertness and avoiding fatigue – high levels also have the potential to increase cortisol levels and stress.
“With colour temperature impacting variably across gender and age, it’s fair to say that specifying optimal ambient lighting is far from trivial.”
To explore this further, PDD took measurements of ambient illumination in one hospital as part of an ‘observational’ study.
During the study, researchers used a handheld spectroscopy unit powered by a smartphone for quick and accurate spectral light characterisation.
The device could measure key parameters such as lux, CRI, CCT as well as sampling measurements over time.
Dr Vincent said: “We did this to understand more about the types of light present in this environment and consider ways in which the lighting may impact, both on the quality of work-life and the use of medical equipment.
Measuring success
“We collected a series of measures relating to illumination sources within an operating theatre environment, including the ambient illumination.
“The device that we used took measures of the Colour Rendering Index (CRI), which is a measure of the ability of a light source to reveal the colours of various objects, calculated on how well a light source renders a series of colours.“We measured CRI (and CCT) and found that the R9 level associated with the ambient was comparatively low – about a tenth of what might occur in natural light.
With colour temperature impacting variably across gender and age, it’s fair to say that specifying optimal ambient lighting is far from trivial
“R9 relates to the extent to which an illumination source reveals red and is associated with seeing skin tones, blood, and tissue.
“It is also associated with the legibility of anything that is printed in red, and this was important as we were taking these measures in a surgical environment.”
Why does it matter?
And there is cause to believe that behaviour could be impacted by a lack of R9.
Lab-based studies have shown an impact of the removal of stimulus chromaticity in terms of a degradation of performance.
And this is particularly the case for red-green colour, the removal of which impacts visual object recognition ability specifically.
More generally, there is a range of findings demonstrating an impact of the colour of light on human performance.
“For example, colour can impact short-term memory and problem solving – people perform better in `warm’ rather than `cool’ and artificial `daylight’ white lighting,” explains Dr Vincent.
“Females and males have also been found to show differing levels of positive and negative mood based on illuminance and/or CRI levels.”
How to apply this knowledge
One way specifiers can consider the impact of lighting within healthcare settings is to take regular surveys of the environment and tailor the light in line with accepted norms and conventions.
“Certain areas in the hospital may need to be prioritised – surgical areas and pharmacy environments, for example,” said Dr Vincent.
And across a hospital there are many benefits to be realised. For example:
- The usability of equipment can be improved through considering the properties of the illumination (e.g. errors can be reduced)
- The colour rendering potential of various light sources can have a clinical impact from the perspective of detecting jaundice, skin lesions, as well as for the use of various diagnostic tests
There are also various therapeutic benefits.
- Night-shift staff may be in a better mood if they are working under light shifted towards red, rather than blue or white light, so there is potential to consider varying the properties of illumination to support shift work
- For inpatients, lighting can interact with recovery time. For example, mental health patients staying in sunny rooms have been found to recover faster – an average stay of 16.9 days for sunny rooms compared to 19.5 days for those in dull rooms
And patients may recover faster if they have access to daylight.
Dr Vincent said: “Ultraviolet lighting appears to be an effective way to lower the risk of infection in the operating room during total joint replacement surgery so light can be used to provide very-specific clinical benefits.
Hospitals can get more out of the resources that they have by considering the design of the environment, for example happier, more-productive staff; happier patients; fewer mistakes; and faster throughput
“In our research we set out to explore the impact that environmental factors have on healthcare settings and consider how these factors can be optimised to support patient and staff wellbeing.
“And we found that there was an opportunity for changing the light to provide benefit – for example shifting the colour temperature or raising/lowering the luminance.
“Hospitals can therefore get more out of the resources that they have by considering the design of the environment, for example happier, more-productive staff; happier patients; fewer mistakes; and faster throughput.”
