Are you curious whether blue light really has the effects it’s claimed to have? Maybe you’ve won-dered how light could possibly be harmful? After all, we all seem to be still walking, talking and living. These are important questions.
In our digital age it’s so difficult to decipher fact from fiction, myth from truth. We hear about one study meant to revolutionise our health… Then months later we find out it wasn’t all its cracked up to be. Its results are not cast in stone. Design flaws might mean the advice is of poor quality. Maybe its funding came from a vested company so the outcome is compromised.
This has understandably led to questions about whether blue light does, in fact, cause harm. Searches like “blue light doesnt effect sleep,” “blue light filter gimmick” and “blue light myth” are growing. What is the truth? Are proponents of the blue light myth right? Is the blue light filter gimmick reality?
As an optometrist with a specialist interest and a dissertation in blue light, I want to pick the wheat from the chaff and help you understand the truth about this topic. Why? Because it matters for your health.
Let’s begin with the mortal facts of life...
Damage builds with time and compounds with age
The human body is incredibly resilient. It has the ability to heal many ails, in the short term. Can-cer cells float around the body daily but are mopped up before they take root and develop into a tumour. But when the triggers — like a bad diet, lack of exercise, exposure to toxins, or excessive drinking — continue, we run out of reserves. In the case of malignancy, the immune system may fail and cancer can grow.
It's the same with the effects of blue light. You won't notice the damage immediately. But through everyday exposure it adds up, slowly but surely chipping away at our health. You might not con-sciously feel any impact; that’s usually the case. Just as we might miss the sprouting of our first grey hairs these changes, too, are gradual.
Sometimes patients will say, “But I’ve used a computer all my life. From the time I played games as a kid until now. And I don't have any problems!” To this I offer; the eyes are incredible, the body remarkable. That’s why I spent years at University studying the windows to the soul. It’s why I’ve dedicated my life to this area. I’ve looked into thousands and I’ve learnt much. But, unfortu-nately, part of my job is to deliver bad news. To tell people they have damage that they didn’t expect.
What I’ve discovered is that we, humans, have a tendency to believe we are each exempt from a problem. That while something may be real it won’t effect us personally. I promise, this isn’t the case. Just as we can’t escape the aging process, we are unlikely to side step the ubiquitous impact of blue light.
To protect our health now and into the future, we need to deal with it head on. To do this we must be informed. So let’s take a look at what the research shows
Facts, tests and trials: What the consensus reveals
To be sure of the evidence that supports a claim we need repeated studies, numerous researchers and a wide range of expert insights. After all, the results of one study or opinion could be a blip. That’s why accepting the results of a single piece of research or the perspective of one opinion is fraught with danger.
If we read one article that says blue light does not affect eyesight, and another that a blue light eye damage study showed visual decline, we need to consider both in the context of the consensus. What does all the research show? What do experts see in practice? When we place the proof on a virtual scale, where does the balance lie?
Because your health is at stake, this is so important. Josh Billings got it right when he said, “Health is like money, we never have a true idea of its value until we lose it.”
Blue light: The facts
Through tests and trials we’ve learnt much about blue light and the way it influences the body. While many would have you believe it, it’s not all bad. Blue light has some wonderful benefits… When we are exposed to the right wavelengths, in the right amount and at the right time of day.
Light falls along a spectrum and each colour has a certain wavelength range. The visible light spectrum produces colours we can see. In nature, the scattering of blue light is why the sky can ap-pear a beautiful brilliant blue. This, in a way, gives us clues about when we should be exposed.
Blue light: The benefits
Imagine waking in the morn to a beautiful flood of brilliant blue light. As the sun’s rays stream in through your bedroom window, they wake you from slumber and energise you for the coming day. This is the purpose of nature’s blue light.
An article published in the journal Scientific Reports found that exposure to one hour of blue-enriched light in the morning “significantly improved subjective perception of alertness, mood, and visual comfort.” It helped the participants to think, feel and see better.
Another study with the drab sounding title Acute exposure to blue wavelength light during memory consolidation improves verbal memory performance found just that. Exposure to 30-minutes of blue light improved memory consolidation and verbal memory recall.
However, notice that these two studied focused on short bursts of exposure. In our modern day lives, blue light isn’t elusive. Produced by light-emitting diodes (LEDs), computers, TV screens, smartphones and eReaders blue light is everywhere! It’s like chocolate, great in little bites! But, just as if we snacked non-stop on Snickers, in huge chunks we get a whole other outcome.
So just as night follows day, blue light has a flip side...
Blue light: The dangers
The wavelengths that make up blue light vary. Between 470-500nm is referred to as “good” blue because it can aid health, as we’ve talked about above. But below 400-450nm, it creates glares, suppresses the “sleep” hormone and increases heart rate. Under 400nm, known as high energy vis-ible light (HEV), it has been shown to induce retinal damage and cell death.
With this in mind, let’s look at the research on sleep suppression, mood disorders, eye injury and brain damage...
In the natural, pre-illuminated world, as the sun set so did we. The waning of the day with its changing light triggered the sleep hormone, melatonin. As it does today, this prepares us slumber. However, nowadays we’re typing away, scrolling on our phone, reading our Kindle or staring at the TV well beyond the confines of the day.
A study published in The Journal of Applied Physiology looked at the potential of blue light to af-fect the sleep hormone, melatonin. The authors found that blue light increased the suppression of melatonin in healthy subjects. It makes biological sense. If the body believes it is daytime, we are genetically programmed to be awake.
It is understandable that people google “blue light doesnt effect sleep” and the like. But, yes, it does. To be blunt, I’d rather it didn’t. It would be one less concern to worry about.
As our night-day, sleep-wake cycles are altered, so is our biology. The exposure to artificial light during the evening and overnight and poor sleep have been shown to contribute to numerous ill-nesses. As the study Timing of light exposure affects mood and brain circuits said, “Exposure to artificial light at night is linked to risk of breast cancer, metabolic disorders and psychiatric and behavioral disorders.” This includes mood problems.
It’s important to include a blue light eye damage study because as an optometrist I’m asked about this on an almost daily basis.
The retina is a thin slither of tissue lining the back of the eyeball. Its role is to receive and convert light into nerve signals that can be sent to the brain. It is part of the process that allows us to create visual images so we can see. Blue light can damage the retina and interfere with our sight.
A study published in Molecular Vision noted that retinal damage occurs “when the eyes are ex-posed to light of high intensity in the visible range (390–600 nm).” Yes, that includes blue light. They also said that, “Light-induced photochemical damage occurs with longer (12–48 h) but less intense light exposure.” This is worrisome given so many of us are exposed to blue light for longer than 12 hours each and every day.
So when you’re told that blue light does not affect eyesight, remember to check your source and read the academic research.
And it seems that blue light doesn’t only shorten the lifespan of our eyes and vision. One insect study found that increased exposure to blue light also caused brain damage (called neurodegenera-tion) and an early death.
I could go on, but I think it’s more important to help you decipher blue light myth from blue light fact.
How can you have faith in the stories, articles or research you consume?
With so many online companies promoting blue light filters and glasses, how we can pick the blue light truth from the blue light myth? How can we untangle self-promotion from a legitimate way to improve our health? These are crucial questions.
Firstly, we need to start with the research. Not celebrity endorsements or popular pseudo health professionals but the nuts and bolts of scientific study.
Google Scholar acts as a repository for academic work. In the last five years, it lists 19,000 search results for “blue light" health. While this includes book listings and information, many of these are journal-published abstracts and full articles. This is a great place to start!
Then we can look at each study. What are we looking for? Becoming well accustomed with scien-tific enquiry takes training but there are important points to seek out. These increase the likelihood that an article is legit and worthy of consideration.
Is the journal the article is published in peer reviewed?
In a peer review journal, the study authors must give their article to a group of experts for analysis. These experts ensure it meets the criteria needed to be considered evidence-based. If the article is not up-to-scratch, it doesn’t get published. If you check, and I encourage you to do so, you’ll see all the research presented in this article is from peer reviewed sources.
When was the study completed?
Technology and our understanding of health and the human body moves forward at a rate of knots. It was only in 2001 that we learned how the day-night body clock called the circadian rhythm worked, for example. We couldn’t have imagined how blue light could affect this cycle prior to that.
Does a study refer to prior research?
And on that note, the quality of research depends on its use of prior solid research. As Isaac New-ton said, “If I have seen further than others, it is by standing upon the shoulders of giants.” If a pa-per omits past research it really isn’t worth the page it’s typed on.
Are there any competing interests?
Authors need to declare any competing interests. If a soft drink company were to fund a study “showing” that refined sugar isn’t harmful for health we would immediately understand the fund-ing source could (would) determine the results and obscure the truth. (Scarily, this has been done!) Always look for the statement: The authors declare no competing interests.
There are other important criteria but these four points are easy to investigate and will help guide you along the right track.
Secondly, we can look to the advice of experts; professionals with formal education and vast, fo-cused expertise in this field.
Even with everything I’ve shared, it’s still okay to have questions. We live in challenging times. So, at end, I want to discuss a question my patients sometimes ask...
Is the blue light craze a fly-by-night fad simply designed to sell products?
The knowledge about blue light has grown and many scientific studies have now been completed, but it is still a relatively recent discovery. This can make accessing balanced opinion difficult.
It’s been said that it takes at least 10 years for research to make the jump from a journal and into the consultation room. This means many health professionals aren’t well grounded in blue light science. What they don’t know they can’t share. It is simply impossible to know everything about the body. That’s why we have specialists. An oncologist understands cancer, a chiropractor the spine and optometrist, like myself, the eye. This is where my interest in blue light began.
Then, there are unscrupulous companies that offer cheap, ineffective products to make hefty, un-ethical profits. This is rampant in all areas of our capitalist culture. Blue light filters are sadly no different. But, as the hard evidence shows that blue light is a threat, it’s important not to throw the figurative baby out with the bathwater.My professional advice as an optometrist
My aim in writing this article was to present the scientific evidence, the benefits and the dangers of blue light and to show you how to assess the stories and the comments you read. This infor-mation will help you with this topic and with others.
I also worry… Because the "blue light myth” is not real. Because when patient believe that blue light does not affect eyesight they make poor choices. Because there is so much ill-informed in-formation to be found on Dr Google.
The simple acts of using research-based blue light filters, of ensuring your bedroom is blacked out while you sleep, of picking up a printed book and reading outside rather than inside with an eReader… They each matter. They compound one and another, in a good way.
The outcome of informed choice is important. Because you, your loved ones and our communities deserve to live happy, healthy lives.
How we reviewed this article:
Ocushield has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations.
Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.
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