How Blue Light affects our eyes
Our modern world is flooded with artificial light. We over illuminate our homes and workplaces. Bright streetlights and signage line our roads. And now the glowing screens of our mobile phone follow us everywhere. The development of artificial light allows us to work longer, sleep later, and encourages our 24-hour entertainment culture.
Recent research has taken the shine off our traditional approach to lighting. Several studies have demonstrated that the wavelengths of blue light emitted by most bulbs and devices can be dangerous to our health.
To address this problem, we explore the new range of innovative solutions that has emerged in order to protect us from harmful blue light and help to boost our health and productivity.
Colours of Light
Light is made up of electromagnetic particles that travel in waves. These waves vary in length and strength.
The human eye is only sensitive to a limited part of the spectrum, what we call “visible light” and see as colour. When visible light has longer wavelengths and, therefore, less energy, we see it as yellow, orange or red.
Whereas colours with shorter wavelengths, like violet, indigo and blue, are at the other end of the visible spectrum. The sun’s high energy visible wavelengths collide with atmospheric air molecules, which is why we see the sky as blue.
Effect of Light on Circadian Rhythms
Over the course of many thousands of years our bodies have been tuned to the rhythms of the sun. The blue-rich light of the morning sun inhibits the release of melatonin, or “the sleep hormone”. It also triggers the production of hormones like cortisol and ghrelin, which make us hungry and alert.
Whereas the red tones of the setting sun, or the growing absence of blue light, reverses the process and prepares the body for sleep during the darkness of the night.
This 24-hour internal clock is called the circadian rhythms, often referred to as the “body clock".
Scientists discovered that circadian rhythms not only control the release of certain hormones but also influence fundamental body systems like digestion, blood pressure, temperature regulation, and metabolism.
We are surrounded by Blue Light
We are surrounded by blue light. It occurs naturally with the sunlight and decreases along with the percentage of the visible light as the afternoon progresses. However, with artificial light, blue wavelengths do not decline but continue to illuminate our human environment long after the sunset.
When photoreceptors sense the artificial blue wavelengths, the circadian system is fooled into thinking it is the middle of the day. While omnipresent artificial light can help us work and play whenever we want, it can be hard to avoid when we don’t want it.
This is especially true in professional settings.
The Workplace Lighting
Workplaces such as offices, factories, plants and laboratories illuminate their spaces with light emitting diodes (LEDs). By 2020, 45% of the global lighting market will be LED, according to Boston Consulting Group.
These bright and energy-efficient bulbs support vision and address energy consumption issues. However, flooding workplaces with high energy blue LED wavelengths of light can create health and productivity problems for employees.
What about our Health?
Blue light can impact our health more than most people realise. Recent studies suggest that the blue end of the light spectrum may also contribute to retinal damage and possibly lead to AMD (Age-Related Macular degeneration). The retina can be harmed by high-energy visible radiation of blue/violet light that penetrates the macular pigment found in the eye. According to a study by The Schepens Eye Institute, a low density of macular pigment may represent a risk factor for AMD by permitting greater blue light damage. High-intensity light can have a detrimental impact on our eyes, mind and body. It is important to be aware of the risks to be able to protect yourself.
The majority of research on the effects of blue light is centred on mechanisms behind the damage to the photoreceptors after just a short exposure to high intensity light. Other studies claim that subthreshold exposure to blue light can also induce damage in photoreceptors.
Several experts suggested the total amount of blue light received during our lifetime can be a significant factor in the development of age-related macular degeneration (AMD).
Several experiments proved that exposure to light of specific wavelengths or intensity may induce severe damage to the retina, which can impact vision. Photochemical damage to the eye occurs when the eyes are exposed to light of high intensity in the bluer ranges of the visible spectrum (390–600 nm).
“The current view suggests that there are two distinct types of photochemical damage,” write Tosin et al. in a 2016 paper on blue light and eye physiology. “The first type is associated with short but intense exposure to light, and the second type is associated with longer but less intense light exposure.” Both have implications for vision and other bodily systems.
THE CURRENT VIEW SUGGESTS THAT THERE ARE TWO DISTINCT TYPES OF PHOTOCHEMICAL DAMAGE
Constant Screen Checkers
A study by the American Psychological Association (APA) reports that 86% of adults in the US say they “constantly or often” check their emails, texts and social media accounts. These “constant checkers” as APA calls them, have higher stress levels than those who do not engage with technology as frequently.
On a 10-point scale, where 1 is “little or no stress” and 10 is “a great deal of stress,” the average reported overall stress level of “constant checkers” is 5.3. For non-constant checkers, the average reported stress level is 4.4. Light damage is a key reason for this stress and its knock-on health effects.
Blue light exposure in the evening affects the quality of our sleep. Regular exposure may lead to sleep disorders. “Modern societies are now facing challenges in achieving adequate sleep and experiencing a multitude of sleep disturbances,” said Dr. Ana C. Krieger in an issue of Sleep Journal.
62% of US adults report regularly experiencing a sleep problem a few nights per week, and just over 12% have a chronic sleep disorder, according to the Statistic Brain Research Institute.
"The preliminary results show that blue-depleted LED light at night minimizes circadian disruption,” said Dr. Martin Moore-Ede, former Harvard professor and lead author of the research. It “also appears to prevent the elevated appetite and insulin resistance seen in the same subjects exposed to conventional LED lights at night," he added.
MODERN SOCIETIES ARE NOW FACING CHALLENGES IN ACHIEVING ADEQUATE SLEEP AND EXPERIENCING A MULTITUDE OF SLEEP DISTURBANCES
The Dark Side
“If awake at night the body has reduced capacity to repair and clear oxidative DNA damage,” said Dr. Parveen Bhatti of the Fred Hutchinson Cancer Research Center in Seattle. “Over time, this accumulation would likely increase the risk of cancer across multiple sites as has been observed among shift workers,” she added.
Light exposure in the evening and night increases diabetes risk by 37% in men, according to ‘Shift work and diabetes mellitus’ by Gan Y et al. of Huazhong University of Science and Technology. Another study on night shift workers linked the effects of conventional LED lights at night with insulin resistance and diabetes risk.
Entitled ‘Taking the Obesity and Diabetes Risk out of Light at Night’ the paper highlights that the risks can be avoided simply by removing bio-active blue wavelengths from white LED light.
Protecting Yourself from Blue Light
Taking precautions to keep your eyes safe from blue light has many benefits in our daily lives. In fact, 72.6% of American adults recently reported they did not know eyewear can be used to protect the eyes from short- and long-term effects of digital eye strain. Fortunately, there are many ways to protect yourself from blue light that are highly effective with little effort required.
Blue-depleted LED lights
Manipulation of the colour emitted by LED lights is one of the options to protect people against the dangers of blue light exposure.
Blue light depleted and colour adaptive lighting systems can be programmed to mimic the natural patterns of the sun in indoor environments. Bluer light is emitted in the morning, which then gradually becomes redder as the day progresses.
This artificial sunlight keeps professionals tuned to nature’s rhythms, thereby minimising the damaging impacts of excessive blue light exposure.
Blue Light Screen Filters
Blue light filters on mobile phones, computer screens and other devices are also becoming more common. Built-in functions such as Apple’s Night Shift and Android’s Night Mode limit the blue spectrums of light emitted by the device in the evening to reduce blue light exposure in the hours before going to sleep.
Blocking screens entirely from evening activities is even better but this is not always possible with the demands of work and the entertainment culture.
The 20-20-20 Rule
Taking a more pragmatic stance Dr. Beth Lennox, a doctor of optometry at Cambridge Eye Care in Ontario Canada, promotes the 20-20-20 rule. Every 20 minutes, take a 20-second break and focus your eyes on something at least 20 feet away. “This simple rule will give your eyes a much-needed break and reduces eye strain and other computer related eye stress,” explains Lennox.
These solutions focus on controlling our environment and behaviour to limit our exposure to blue light, however this is not always possible or desirable. Professionals may be forced into high blue light situations throughout the day or night in order to do their jobs.
Be it in front of unfiltered screens or in a well-lit space, such exposure may have a detrimental effect on the health of those workers. Until regulations catch up with the science of light and sleep, these professionals will need to find a solution that works in every artificially lit environment.
Blue Light Blocking Glasses
Blue light blocking glasses act as a personal blue light filter. They can protect the wearer at any time and wherever they go. These glasses generally block 99% of light at wavelengths shorter than 480 nm, which makes up the vast majority of potentially harmful blue light.
A study of blue light by researchers at the University of Toronto tested this theory. Melatonin levels of people exposed to bright indoor light who were wearing blue light blocking glasses were compared to people exposed to regular dim light without wearing glasses. When both groups demonstrated similar melatonin levels it reinforced the hypothesis that blue light is a potent suppressor of sleep and that blue light blocking glasses offer viable protection.
Several authors have investigated the amount of blue light received during an individual’s entire lifespan. They propose that it can be an important factor in the development of age-related macular degeneration (AMD). According to the 2016 the paper by Tosini, et al., “the use of lenses (intra- and extraocular) that block blue light (“blue-blockers”) may provide some protection against the development of AMD.”
The growing body of science has made it clear that exposure to artificial blue light leads to a range of serious health impacts. This is especially true for professionals working in well-lit environments and those who spend long hours in front of a screen.
Thankfully, as the science of light damage has increased, so has our ability to protect ourselves. It is now essential to ensure people know the dangers of blue light and have access to protective measures.
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