There are two different blue light issues which have implications for health, safety and productivity in workplaces, according to an expert in the area.
The first issue is the potential for visible light (and blue light) to cause eye damage, and the second issue relates to the effect of blue light on sleep-wake cycles, said Jennifer Long, a Conjoint Senior Lecturer at UNSW and Director of Jennifer Long Visual Ergonomics.
LED light sources generate white light in a different way to more traditional light sources such as fluorescent lamps and incandescent lamps, with claims that LED emit a greater quantity of blue light – “though this is not always true – it depends on the light source,” said Long.
“Subsequently, there are seemingly contradictory claims in the media that blue light is good or bad for your eyes, and many people are unsure what to believe,” said Long, who recently presented at an AIHS webinar on the topic of “blue light and LED – fact or fake news?”
Long said that any wavelength of visible light can be a hazard to the eye – if there is a high enough dose.
Blue light can cause more damage compared to other wavelengths (red light for example) of the same quantity, hence the concern about blue light sources.
However, the light source does not need to be blue, as damage can occur if a person looks at a very bright light source such as the sun or a welding arc without proper eye protection.
The amount of blue light emitted by light sources (such as LED) and digital devices (backlit with LED) is less than blue light exposure limits set by the International Commission on Non-ionising Radiation Protection (ICNIRP) and generally less than what one would be exposed to when looking at a blue sky, said Long, who is also a qualified optometrist, Certified Professional Ergonomist (HFESA) and Certified Generalist OHS Professional (AIHS).
“However, if a person views very bright light sources (or very blue lights) at a very close distance or for prolonged periods, and does this over many days, then the hazard should be assessed and, if necessary, a risk management process implemented,” she said.
The issue of blue light hazards is addressed in a position statement released by the International Commission on Illumination in April 2019 (CIE NC CL 1911 Position Statement on the Blue Light Hazard).
To address the second issue, Long said that blue light can affect sleep-wake cycles.
Exposure to blue light suppresses melatonin production in the brain and this can delay sleep onset, and she said this has led to claims that blue light exposure from digital devices at night can disrupt sleep.
Subsequently, products have been developed (such as “night light settings” on digital devices) that reduce the amount of blue light emitted from the display (this also makes the display appear more yellow in colour).
On the flip side, deliberate exposure to blue light has been advocated as a way to increase alertness and prevent people from falling asleep, for example, after lunchtime, or for shift-workers, in the early hours of the morning.
“This has led to the commercialisation of lighting products that promise to improve productivity and help manage sleep-wake function,” she said.
“Although blue light can affect sleep-wake function and alertness, it is not the whole story.”
Long also observed that there is emerging evidence that red light and the overall brightness of light also plays a role in circadian function, but researchers are still trying to understand how these effects occur.
“Therefore, at this stage it is not possible to prescribe a dose of light and definitively say that it will improve productivity or help entrain sleep-wake cycles,” she said.
There are a number of implications in this for organisations – the primary one being keeping abreast of current knowledge in order to manage hazards in the workplace.
“There is still a lot that we don’t understand about blue light, particularly the long-term effects of blue light on the eye,” said Long.
“Although animal studies have shown a relationship between blue light exposure and macular degeneration, it is not known if the results can be applied to humans.
“Subsequently, many people are fearful of blue light, even when it is in low quantities.”
There are products which reduce the amount of blue light transmitted to the eye, such as blue light coatings which can be applied to spectacles, she observed.
These are advocated to reduce the long-term risk of low dose blue light exposure, and hence, risk of macular degeneration.
“However, there is controversy within the lighting industry and the ophthalmic industry whether these products are actually required (especially if the exposure is low) and if they can effectively reduce the risk of macular degeneration in humans,” said Long.
“Other researchers are cautious about recommending blue light filters because blue light may be required for eye development, circadian function and night vision.”
While the understanding of the effects of blue light on the eye will improve over time, it can be a challenge in the meantime for organisations to keep up-to-date with reliable information so that they can make informed choices when implementing risk management programs for light exposure at work.
A good first port of call for reliable information about blue light is the International Commission on Illumination (CIE), an independent organisation recognised by the International Standards Organisation as an authority on lighting.
One of its roles is to prepare and publish standards related to light and its measurement, and Long said they have released several technical reports and position statements related to blue light, blue light hazards, and the healthful effects of blue light.
According to the Australian/New Zealand Standard AS/NZS1680.1:2006, a lighting system should provide safety, allow tasks to be performed and provide an “appropriate visual environment”.
The latter includes aesthetics issues, and is a reminder that lighting is not a purely functional quantity, said Long.
“Many OHS professionals are familiar with the maintenance illuminance tables in the lighting standards that list illumination levels for a range of different tasks,” she said.
“While it is important to comply with these standards and provide adequate illuminance so that workers can see their work easily and safely, it is also important that the lighting is visually comfortable (for example, does not cause glare) and is aesthetically pleasing.”
It is also important to acknowledge that there are large differences in tolerance and need for light between individuals, she added.
“This can be due to ocular health issues, general health issues and medication use, just to name a few factors,” said Long.
One way to manage the diversity of visual needs within a workplace is to provide flexibility in how the space is lit.
This could be a simple as providing adjustable task illumination that can be controlled by an individual at their workstation, through to providing zones within the work space that are lit differently, or allowing individuals the ability to adjust the general lighting within the space according to their comfort and needs.
“The advent of new lighting technology (including LED products) is certainly providing a lot more scope for flexibly lighting workspaces, and this has potential for improving health, safety and productivity within workplaces,” said Long.