Health

The ‘War’ On Blue Light — Fact or Fiction? – Andre Heinemann

Digital devices and artificial light are all around us and one doesn’t have to look far to see warnings about how artificial light disturbs our sleep, causes cancer, vision problems and dry and itchy eyes, and there is even a name for the dilemma: digital eye strain. Fortunately, modern capitalism is fast to produce solutions for just about every problem, real or imagined, and can quickly satisfy the need of the ever purchase-hungry consumer — that’s what keeps the economy going!

How much of a problem are blue light emissions really and how dangerous is it to look at computer screens at different times throughout the day? Should you really shell out money for blue light filtering glasses and risk looking like a dork to improve your sleep, mood, or capacity to learn? Do the facts support those claims?

I thought answering these questions, considering the plethora of available solutions, would be simple, but, like everything else, when you start looking at the details everything gets complicated quickly. After combing through PubMed and other scientific literature, architectural websites and a number of eye glasses websites, I have compiled what I found and it isn’t what I had expected.

Before delving into blue light filtering and eye strain, digital or otherwise, it might be helpful to review some physics and physiology, just in case your last physics and physiology lessons were more than a few days in the past…

Light, it is all around us, without sunlight the life on earth as we know it wouldn’t exist. Sunlight, just as any other visible light, consists of electromagnetic waves with wavelengths between 400nm (blue) and 700 nm (red), give or take a few, and so does light from artificial sources, meaning light produced by means of electricity, such as halogen lights and LEDs (light emitting diodes).

Let’s understand natural light first, no physics degree required…

Sunlight contains the entire spectrum of visible light. The important point to take away from this chart is that sunlight includes blue light and that the composition of sunlight varies based on the time of day and cloud cover.

The second thing to know about electromagnetic waves is, that shorter wavelengths have higher energy. Ultraviolet Light with wavelengths between 100nm and 400nm, shorter wavelengths than visible light, contains enough energy to burn your skin as probably all of us have found out at some point.

While too much sunlight can cause skin damage (sunburn), too little sunlight can affect our mood and cause seasonal affective disorder (SAD), so neither is a good thing.

Because this article is about glasses, a quick look at the human eye will allow all of us to get onto the same page.

Your eyes are a marvel of evolution, no intelligent designer required! A lens that allows you to focus, an iris that controls how much light gets in, and a retina with rods and cones capable of transforming light into electrical impulses, all in a compact and moveable design, truly fascinating. But there is something else, and it is a relatively recent discovery, atypical intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin. These cells are non image forming and seem to have something to do with our circadian rhythm, which I will get to in a bit, but lets first very quickly talk about sleep.

The human body has two systems effecting sleep, a circadian and a homeostatic one. The circadian system depends on light exposure while the homeostatic tracks the body’s need for sleep. Ideally these two systems are synchronized and proper alignment increases sleep quality. If you have ever suffered from jet lag you know just how screwed up this synchronization can get!

In plain English, circadian rhythm means sleep-wake cycle, which is controlled by light, electromagnetic waves around 460nm to be precise. Researchers discovered non-image forming cells called atypical intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the photopigment melanopsin. These cells are less sensitive to light, but incorporate longer term exposure to light into their signaling. The appearance of melatonin, a hormone that signals sleep to the body, nicely correlates with exposure to daylight and darkness. When light is present melatonin production is suppressed and cortisol levels increase, providing the body with the energy it needs to get the day started, when there is no light cortisol levels decrease while melatonin levels increase.

Now that we are all on the same page regarding the scientific facts, let’s have a look at the claims behind computer glasses and blue light filtering technology.

We use artificial light for many different purposes, to illuminate living and working spaces when natural light fades or there just isn’t enough of it, to make plants grow faster under controlled conditions, to increase the growth of animals in food production and so on… you get the idea!

A lot of research is put into technology to increase food production through light and other means, as well as helping people with health, alertness and comfort in buildings to increase their productivity. This research focuses on specific wave lengths, light intensity, light composition and the effects on plants and animals and and yes, the bottom line and any combination thereof. At the very minimum it is logical to conclude that light has a significant effect on life on earth which includes human bodies.

Blue light, electromagnetic waves with wavelengths of 400nm to about 480nm has the highest energy in the spectrum of visible light. This light and the energy it carries gets transmitted through the lens to the retina. The presence of blue light reduces the amount of melatonin released into the body, in other words can interfere with the onset, duration and quality of sleep; however, so do many other things, like alcohol consumption, health issues, noise, light pollution etc…

Because blue light is a high energy electromagnetic wave the fear is that it may cause damage to the eye itself, in particular macular degeneration. But, a Cochrane review from May 22nd, 2018 titled “Artificial, blue-light filtering lenses in the eye for protecting the macula (back of the eye) after cataract surgery” found that none of the 51 studies provided any statistically significant evidence to suggest any effect regarding contrast sensitivity, macular degeneration, vision, color discrimination or sleep disturbances.

Interestingly the amount of light reaching our retinas decreases with age because of the natural yellowing of our eye’s lens. As a result young children are more susceptible to light than older children and older children are more susceptible than adults and so on. So, if anything, I would be concerned about children using digital devices.

From everything I have written so far, you could easily conclude that blocking blue light doesn’t really live up to the hype, and, at least based on what I read, you would be correct. Blue light emitted from the sun is just as harmful, or not, as blue light coming from artificial sources, simply because it is the same thing, an electromagnetic wave of a specific wavelength or a range of wavelengths. Manufacturers of digital devices are already considering the harmful effects exposure to blue light ‘might’ cause and giving customers options to reduce the amount of blue light emitted from their devices, Apple’s Nightshift or Flux for example. That is not to say that other devices, in particular older ones, still emit high levels of blue light that you can’t easily get rid of, short of buying new equipment.

Another often overlooked source of blue light in this context is artificial lighting, the halogen bulbs and LEDs we all have at home, but also the TVs that many people have in their bedrooms; those will often have no way of filtering out blue light and might be a good application for blue light filtering or blocking glasses. Which brings us to what’s on offer for the eager buyer…

As you can imagine, there are plenty of offers on the market ranging in price from a few bucks to hundreds of dollars. How are you to decide? How much do you have to spend? Are expensive options any better than the cheaper ones?

What was interesting to see was the myriad of offers that all follow the same model:

1. We found a problem that needed a solution
2. We couldn’t find a solution so we created the remedy ourselves
3. Some clever price anchoring similar to: You could pay hundreds of dollars for this product…
4. But we cut out the middle man and pass those saving directly on to you, so you don’t have to pay that much
5. Some glowing reviews including some logos people will recognize
6. A 30-day money back guarantee, in some cases with lots of loopholes

Of course there is nothing inherently wrong with this concept, but it did make me think that at least some founders didn’t do their research or would have found plenty of soon-to-be competitors. The other issue I have with glasses in general is their sky-high pricing. After all eye glasses are just a few pieces of plastic, two hinges and two lenses, manufacturing costs no more than a couple of bucks in China.

What is concerning is that most companies make wild claims about the benefits of their glasses, but fail to provide any data about the light filtering characteristics of their products. How are consumers supposed to know what they are getting? Well, maybe they are counting on the placebo effect…

Let us look at a few examples, in no particular order (and I am not affiliated with any of them), starting with Time to Shade, a clever name, offers a variety of glasses and styles geared towards prescription eye wear and sunglasses. However, they also sell blue light blocking lenses without a prescription. If you buy an inexpensive frame and add basic blue light blocking lenses you end up with a pair of glasses for just over 50 bucks. I ordered a pair and well, they were cheap glasses, disappointing.

Next I looked at Pixel. Pixel has an appealing-looking website with a variety of stylish glasses to choose from, prescription, computer glasses and reading glasses. Pixel’s selling point is relief from digital eye strain, more specifically eye fatigue, dry eyes, blurry vision and headaches by blocking blue light with lens technology that does not distort color combined with an anti-glare filter. Prices start at USD 75.

Felix Gray, just like Pixel wants to safe us from digital eye strain’s symptoms, eye fatigue, dry eyes, headaches and blurred vision with clear lens technology filtering out blue light with the highest energy wavelengths of 400–440nm. In addition to what they call optical glasses, you also have a choice of sunglasses and, what they call, sleep glasses that filter out wavelengths of 440–500nm that might interfere with melatonin production. The sleep lenses appear to have a slightly yellow tint and the company recommends to wear them after sunset or from getting home to going to bed.

What I like about Felix Gray is (1) that they provide a bit more information about what you are actually buying and what their glasses are supposed to do, but more importantly (2) that they offer the option to add magnification of +0.25 to your ‘computer glasses’ without needing a prescription. Of all the companies I looked at, Felix Gray seems to have the right idea and at least understand the concept behind computer glasses. Prices start at USD 95.


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