If you go out and get yourself a pair of prescription glasses anywhere in the country today, you will most likely be given ones that have a blue light filter included by default- whether you ask for it or not. They’re selling it to you. They’re charging you for it. And it might be having harmful effects on your health, especially if you’re not using them correctly.
This was not the case 3 to 4 years ago. There has been a rapid growth in the market for blue-light filtering lenses in the last two years[13]. Work-from-home and online classes have obviously been a big contributor to this as well owing to concerns over increased screen time.
What is blue light and why do we need to block it?
This is fairly common knowledge today- so much so that smartphones today have a blue light blocking “night mode” enabled by default to turn on in the evenings. We have covered the negative health effects of blue light in our blog as well [1]. To reinforce context for this discussion though, let us go through the basics again:
The light that we see through our eyes is the visible part of the electromagnetic spectrum- this includes electromagnetic waves in the wavelength range of approximately 380 nanometers to 700 nanometers. Different wavelengths correspond to different colours that we see- you probably remember memorising “VIBGYOR” in middle school physics. The blue end of the spectrum has the highest energy and energy decreases with increasing wavelength with red light having the lowest energy.
The high-energy blue light(particularly from 400 to 480 nanometers) has a number of potent effects on our bodies:
- This is the part of the light that wakes us up in the morning and makes us alert and active. It raises our cortisol(stress hormone) and serotonin levels.
- It controls our circadian rhythm by stimulating the melanopsin receptors which are present both in our eyes and our skin cells.
- It can have a destructive effect on our cells as well if exposure to it is not regulated properly.
Light runs our bodies
The way that it worked in ancestral times is the blue light which reached us as part of full-spectrum sunlight would wake us up in the morning and make us productive. After sunset, as the sunlight faded, our bodies would wind down and we would relax in the absence of the stimulating blue light. Serotonin converts to melatonin in the absence of blue light. Melatonin is the primary hormone responsible for making us sleepy. It also has antioxidant and reparative properties and helps the body heal and detox as we sleep. Any damage our cells incur from blue light during the daytime is also repaired during this time.
With the introduction of artificial white light from electronic sources, there have been a couple of major problems. The first one is obvious- the presence of blue light after sunset disrupts our melatonin secretion and subsequently our bodies’ winding down and healing process. This is one of the biggest drivers of chronic disease in modern times.
Coming to the second issue, you’d think artificial white light sources are not a problem during the daytime because we do need blue light during the day. And this is actually true to some extent. Experts are divided on this. Some do actually recommend getting artificial white light during the day in case of lack of outdoor access. And white light screens are the standard treatment for Seasonal Affective Disorder.
Others though(and these are mostly experts much more deeply entrenched in EMF biology research) warn of the uneven distribution of blue light in artificial sources. Artificial lights have a disproportionately high amount of blue light compared to other wavelengths.
Given below are spectrometer readings from unfiltered sunlight compared to that coming from an iPhone screen(link to full video also given in references[12]). You can see that the light distribution is far more even in natural sunlight and it has a lot more of the red part of the spectrum which has a healing and relaxing effect. This balances the triggering effect from the blue light. Whereas the iPhone screen light spectrum has a big spike of blue with very little of red light. This is a big factor in how long-term screen usage causes stress and headaches.
The healing effect of red light we speak of is very powerful as well and is the basis for red light therapy. There is a large number of studies showing the healing effects of red light.[11]
What are blue light-blocking glasses and how do they work?
Blue light blocking glasses are simply glasses that filter the light passing through them and reaching our eyes to block out the blue light partially or completely. In doing so they aim to undo the harmful effects of blue light as mentioned above.
Blue light glasses available on the market can be broadly categorised into 3 categories. The first category would be the very lightweight blue light blocking glasses which block a small amount of blue light only. These appear almost transparent with a very mild yellow-to-green tint. All of the blue light blocking glasses currently being sold by spectacle retailers today fall under this category.
These may be slightly helpful if you’re looking to block out blue light. But if you really want to rely on glasses to block out blue light you need heavier-weight ones which are specially made for this purpose. They’re available from brands like RA Optics and Bon Charge(Formerly BluBlox) that are popular worldwide for these products. These glasses are yellow or red in colour depending on their blue light blocking strength. The red ones block blue light almost completely and are thus meant for nighttime use. The yellow ones block it partially and are meant for daytime wear if you’re using screens for a long time because they help balance out the high amount of blue light from screens.
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Other blue light blocking options
Blue light-blocking glasses are definitely not a mandatory requirement for optimal health. To avoid the harmful effects of blue light, you can simply make sure to remove any blue light sources in your home post sunset, or at least a couple of hours before bed. Use yellow-to-red lights only. The dimmer, the better. The lower the height of the light source, the better.
And if you can avoid regular LEDs and use flicker-free LEDs or incandescent lights instead that’s even better because the flicker in LEDs is a small problem too.
You can use blue light filtering software(or just the night mode option which is present by default on most devices today) on your screens.
These options are not only cheaper but also more effective because our skin cells have some blue light-sensing melanopsin receptors as well, which blue light-blocking glasses do not protect.
The problem: Full-time usage of blue light blocking
As we explained in the beginning, blue light while harmful at the wrong times and in the wrong amounts is still essential to our bodily functioning. We need full spectrum unfiltered sunlight during the daytime. Blue light wakes us up in the morning and makes us alert and active. It triggers cortisol and serotonin production which makes us happy and has an antidepressant effect.[2][3]
But how important is this really? What happens if we deprive the body of blue light?
Given the known functions of blue light in our physiology, the effects of its deprivation are easy to predict. And that’s what the data shows as well. Blue light deprivation is linked to depression, fatigue and circadian rhythm disruption.
This is why we tend to get gloomy and depressed when it is cloudy for too many days in a row. Seasonal Affective Disorder or SAD is a mental health condition where people suffer from temporary depression during winter when there is low sunlight exposure. This is more prevalent in places farther from the equator which get relatively lesser sunlight.
The standard treatment for SAD is white light therapy wherein patients sit in front of a white light screen.
In a study on Mongolian Gerbils, the animals were housed in two groups under white light with one group receiving unfiltered white light and the other group receiving the light through a blue light filter.
From the study paper:
“We found that blue light deprivation (BLD) induced depression-like behaviour in gerbils. Melatonin lost its rhythm, and corticosterone (CORT) levels decreased in the morning in the BLD group….Furthermore, 5-HT(serotonin) in the serum and brain was decreased after BLD. Additionally, BLD affected the blue light sensitivity protein melanopsin and its pathway, with downregulation of the proteins melanopsin..” [4]
There are many other similar studies, mostly on rats, that demonstrate different depression mechanisms getting elevated when blue light was deprived.[5][6][7]
When you wear a blue light filtering lens in front of your eyes full time, including during the daytime when you’re outside, you’re putting yourself in a blue light deprivation state and may be putting yourself at risk for the above-mentioned health issues.
This is the issue we wish to discuss. Spectacle manufacturers are selling spectacle lenses with blue light filters added by default. The premium lens models available today almost all have blue light filters added by default. The premium models are the ones that store owners sell to you on priority unless you explicitly ask for a less expensive model. Blue light filtering is just one of the many added features in these lenses so it is most often not explicitly advertised or discussed by store sales executives. Thus consumers are buying blue light filter glasses unaware of it.
Additionally, even if you’re well aware of it and don’t want a blue light filter, you’re still incentivised in a big way to get it anyway because the premium lenses have all the best features- such as clearer vision, the thinnest and lightest lenses, dust and water repellence, smudge resistance, crack resistance etc. All of which you lose out on getting a lower model.
Do spectacle sellers have any idea?
It doesn’t seem so. The thing is opticals have always been associated with eye health only and the only medical specialities referred to are optometry and ophthalmology. But when you start messing with wavelength filtering, things go way beyond the scope of these two respective disciples. As we mentioned, light runs our bodies.
So what, according to opticians, is the benefit offered by blue light-blocking glasses?
There is research showing blue light causes cellular damage and it is claimed that it causes retina damage as well. This is the primary selling point used by spectacle retailers.
Is there any truth to it?
As we mentioned earlier, with natural full spectrum sunlight and the day-night cycle, the damage from blue light isn’t an issue at all. It’s just one of many natural stressors, part of our biological cycle.
But with artificial light? So far there is no data to show there is any significant damage to the retina. And ophthalmology authorities across the world have stated the same conclusion on this matter as well.
The American Academy of Opthalmology (AAO), has said there is no credible scientific evidence that the light from digital screens is harmful to the eyes.
According to the American Macular Degeneration Foundation (AMDF), there's no evidence that blue light can damage the eye, and therefore, according to them, any claims that glasses offer protection against retina damage or eye conditions like macular degeneration aren’t accurate.
Boots Opticians was fined £40,000 over misleading ads for blue light blocking glasses in 2015
In 2015, Boots Opticians, a British spectacles retailer was fined £40,000 in the UK for exactly similar claims in their ads for blue light-blocking glasses [8]. This was a time when blue light-blocking glasses had just started to emerge in the global market.
Even after this penalty, similar marketing strategies were continued by multiple retailers, a BBC Watchdog investigation in the following year reported. [9]
We went through all stories in the mainstream Indian press in the last 3 years on the rise of blue light blocking glasses and they all report ophthalmologists saying blue light from screens can strain and damage the eyes. To be fair, they do also mention how blue light can cause headaches and circadian rhythm disruption which are valid concerns of course. But the main focus is on eye health only.
The experts needed to be consulted on this matter are neuroscientists and endocrinologists and not ophthalmologists and optometrists. Because the primary effect light has on our bodies is neurological and hormonal.
The general public perception on the matter is that blue light is a universally harmful and damaging element and blocking out as much of it and as often as possible is the correct approach. Nuance, as usual, is lost.
Spectacle sellers, as we mentioned, are focused on the eye health damage perspective. They’re most likely unaware of any negative health effects from full-time blue light blocking themselves let alone inform consumers or do anything about it. Our experience with the store salespersons has been the same as well.
Himalaya Opticals, in a blog post advertising their Digisafe blue light blocking lenses, actually addressed the use case of their full-time usage. They listed down the benefits of their blue light-blocking glasses in different scenarios, including outdoors in the Sun;
“Computer Users – Many employees spend at least 8-10 hours a day, which is a long time to be exposed to blue light rays. Overexposure can lead to eye strains and uncomfortable side
effects. So, protect your eyes by wearing a Digisafe lens and work worry-free.
Smartphone Users – Research shows that people reach their phones 120 times each day. Whenever you want to use your smartphone, wear a Digisafe lens to safeguard your eyes.
Spending Time Outdoors – Digisafe lens allows a healthy amount of blue light into our body and also blocks out the potentially harmful blue light rays.
Staying Indoors – At home, LED light bulbs and Televisions emit blue light. So, Digisafe lenses should be worn anytime when you are near a digital screen or a device that emits blue light.”
This is just plain marketing rubbish of course. They seem to be taking a page out of American eyewear retailer Spy Optic’s book who have launched a full-fledged marketing campaign on the same lines for their “Happy Lens” glasses that are supposed to “help boost your mood and alertness and optimize color.” [12]
They allege that full spectrum sunlight has both beneficial and harmful blue light waves which are the longer and shorter wavelengths of blue light respectively. And the glasses achieve their effect by blocking the harmful rays. They make no mention of any specific wavelength that they deem harmful. Nor do they cite any data to support their claims(apart from saying “science has shown”).
As the experience of one of our teammates at a Titan Eye Plus outlet revealed, there also seems to be some ambiguity with which lens models have a blue light filter and which don’t. After being sold the top model lens which had a blue light filter, our teammate filed for an exchange for a lower model which they were assured would not have a blue light filter. But the new lens turned out to have the exact same tint in it as the previous one.
We reached out to the leading spectacle retail brands in India trying to inform them about all of this and asking them to share their opinion on it. We haven’t heard back from any of them yet.
Who is at risk?
If you don’t wear your glasses full-time and only wear them when working on your computer or at night-time, you shouldn’t have anything to worry about. You may actually get some benefit from the glasses by blocking out the excess artificial blue light, especially if your daily routine includes long durations of screen use. A lot of people actually report a reduction in headaches after using blue light-blocking glasses.
However, if you’re wearing glasses full-time that have a blue light filter, including during the daytime when you’re outside, then you have reason to be concerned. People with a history of depression and other mental health issues need to be extra careful because they need to avoid anything that might aggravate symptoms.
How bad is it really?
Some might argue that the blue light blocking capacity of these lightweight blue light blocking glasses being sold by spectacle retailers is very low and thus there is nothing to worry about. It’s true that compared to the dedicated red and yellow blue-light blocking glasses which we talked about earlier, these glasses are very mild in effect.
But no one is wearing those dedicated blue light glasses full-time. If someone did, we expect the effects would be immediately noticeable unlike these ones with lightweight blue light filters.
But the fact is we just don’t know. Because all the studies done so far involve complete filtering of blue light wavelengths. There have been no studies using partial filtering attempting to study the extent of blue light filtering that would cause noticeable physiological effects.
We assume there is a linear relationship- that if complete blue light deprivation caused some symptoms, lesser and lesser deprivation(less filtering) would cause lesser and lesser symptoms. As with all physiological stressors, we expect the effect would be individualised and highly dependent on the person.
Light health experts have started to use the term “junk light” to refer to any light coming from an artificial source or filtered through any material. Even sunlight through your window is considered junk light because even completely transparent untinted glass modifies natural sunlight to some degree.
Andy Mant, the founder of Bon Charge, said he’s seen multiple reports of people who used to wear glasses full-time, after getting LASIK, experienced various health improvements.
So anyone wearing glasses with a blue light filter full-time is actually just undertaking the risk of running a small experiment on themselves. It’s probably nothing super drastic- in our modern urban lifestyles rife with all kinds of health stressors such as chemtrails, processed foods, microplastics etc, this is just one more addition to the list.
But we, at iThrive, strongly believe in informed consent. Consumers must be fully informed about the health risks of any product being sold to them. And we hope to communicate the same through this article.
How to know if your glasses have a blue light filter?
You should be provided information from your retailer of course on whether the lens model you got has a blue light filter. But people who got their lens fitted a long time ago might not remember their lens model details. And like we mentioned there seems to be some ambiguity on the part of some of the sellers too on which models have a blue light filter too. Sometimes, even some anti-glare lenses, which is a commonly used old technology, have some degree of blue light filtering.
The way to check is simply to go outside and hold your glasses against the daylight and see if you notice any tinting. If you don’t notice anything at all, your glasses likely don’t have a filter. A yellow-to-green tint indicates a filter. There seems to be variation in people’s perception to this tinting as well because some people don’t notice it as much.
Survey
We ran a small survey where we asked people what brand of lenses they were using, whether they wore it full-time, whether they knew if it had a blue light filter or not and whether they were aware of all possible physiological effects of using a light filter. We also had them hold up their glasses against daylight to check for tinting.
In just the 17 participanats, we found 6 cases of full-time usage of the blue light-filter lenses.
You can see the complete survey data entries here - [14].
UV filter
While we’re here, we wanted to cover UV light filers as well. UV filters have been used in sunglasses for a long time, but recently with the advent of blue light filters, manufacturers have started adding UV filters along with the blue light filers to spectacle lenses as well. Ultraviolet violet light is part of the spectrum below 400 nm. It’s not visible. To emphasise that they’re completely filtering out UV, manufacturers also often use the term “UV-400” to emphasise that they’re completely blocking all wavelengths below 400 nm.
There has been much research and controversy over UV light causing skin damage and skin cancer and how necessary sunscreens are. We have covered this at length on our blog as well[10]. Spectacle and sunglass manufacturers claim that their UV blocking products protect your eyes from UV damage but, as is the case with blue light, there is no specific research showing that the amount of UV light we’re getting from the sun causes any significant eye damage.
Are there any important functions that UV coming through the yes play in our body? -that UV filters may be hindering? There are a few that have been pointed out but they’re not fully understood or conclusively demonstrated yet. One of the most popular light and EMF health researchers, Dr jack Kruse theorises that UV light coming through the eyes reacts with the DHA in the eyes(the highest concentration of DHA is in the eyes) to produce DC electric current which helps charge and power the mitochondria.
The issue with sunglasses
A note on sunglasses: besides the obvious reason why they're bad for you, that is, you want to be getting unfiltered sunlight into your eyes and not blocking it. Another issue with them, and to an extent with blue light filter glasses too if you’re wearing them outside, is they block the blue light and UV light reaching your eyes while you’re in the Sun- while your skin continues to get direct sunlight.
When you see bright daylight, the blue light is signalling your brain to turn up cortisol production and other hormones that act as an antagonist to the UV light stress and damage your body is experiencing. This natural mechanism gets derailed when you block the light reaching your eyes but not your skin.
All the science and data apart, you may be able to perceive for yourself the effects, if any, your blue light-blocking glasses have been having on you. The tinting in the glasses makes your surroundings appear dull and subdued- similar to sunglasses but to a much smaller degree. If you make your surroundings appear permanently dull and subdued, as if you’re in a gloomy overcast place permanently, it’s not hard to imagine why that would make you depressed and drowsy. As we mentioned earlier though, some people don’t seem to be able to perceive the tinting as much. Does that mean they’re less prone to these negative effects? We have no idea.
If you’ve been wearing blue light-filter glasses full time or plan to start doing so(we obviously don’t recommend it), do keep an eye out(pun not intended) for these potential issues. Better safe than sorry.
REFERENCES
- https://www.ithrivein.com/blog/emf-bluelight-and-circadian-rhythm
- https://www.ithrivein.com/blog/does-sunlight-really-cause-skin-cancer
- https://www.ithrivein.com/blog/top-8-benefits-of-sunlight
- https://www.frontiersin.org/articles/10.3389/fpsyt.2020.00233/full
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- https://www.aop.org.uk/ot/industry/high-street/2016/11/09/bbc-watchdog-investigates-blue-light
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OTHER:
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- https://www.bbc.com/news/health-34658008
- https://www.opticianonline.net/news/boots-opticians-offers-blue-light-protection
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- https://www.newindianexpress.com/cities/thiruvananthapuram/2021/jul/21/online-classes-rise-in-demand-for-blue-light-filter-glasses-2332932.html
- https://www.techrepublic.com/article/do-computer-users-really-need-blue-light-filtering-glasses/
- https://www.jahonline.org/article/S1054-139X(14)00324-3/fulltext
- https://www.bluelightdiet.com/
- https://raoptics.com/pages/about-us
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- https://www.youtube.com/watch?v=mTQOmkg9IKI
