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This morning I went to an optometrist for a regular eye exam. The optometrist got my updated prescription locked in and swapped out for the assistant / salesperson that would help me find the right frames and lens options for me. Among the hydrophobic and anti-glare coatings I was also offered an option for a "blue-light filtering" coating. It took all my willpower to go "well, aaaactually…"

But, well, actually, it turns out that blue light filtering is complete nonsense. A recent systematic review by optometry and vision researchers at the University of Melbourne of the available scientific literature on blue-light filtering and found that in the 17 prior studies that examined the effectiveness of blue-light filtering that there was "little to no effect on visual performance", no data on "daytime alertness", and questionably inconsistent data about the impact on sleep. They also found no evidence of blue-light filtering impacting "macular health, serum melatonin levels or overall patient visual satisfaction".

Man sad at his laptop
Source: Andrea Piacquadio on Pexels

The pseudoscience con job

The idea of blue-light filtering always struck me as silly, and while I'm personally pleased and unsurprised to be vindicated by these results, it does speak to the reflexive response that we can often have to low-impact pseudoscience — and the cons that can be run off of that.

Think of it like the paper straws movement. Obviously, reducing plastic use overall is a good idea. We produce too much of it, recycle too little of it, and too much gets thrown away after a single use. Plastic has many useful and even reasonable applications, but overall we just use too much of it where it's just not necessary. But a few years ago, the restaurant industry got in a tizzy over replacing plastic straws as a way to reduce their environmental impact and save the sea turtles. Never mind that the vast majority of American restaurants and the trash they produce are nowhere near sea turtles. And to satisfy that demand, an industry of paper straw producers sprung up out of nowhere, hoking inferior products that everybody ended up hating.

Replacing plastic straws a good thing, but we did it badly.

Eventually other products like straws manufactured from sugarcane replaced the hated paper straw with a more durable but still sustainable and biodegradable alternative.

But in that intervening period, we all dealt with a nonsense and inferior solution to a tiny problem instead of doing anything big. Like addressing the huge amount of food waste in the restaurant industry or the huge amount of land dedicated to cattle grazing (and the emissions those animals produce). It was a knee-jerk reaction to a nonsignificant problem that made everybody feel like "yay, we did something!"

The Earth clearly was not saved and the sea turtles are not better off. But we felt like we did something, so that's what really counts.

Lemonade with a paper straw
Source: J Kelly Brito on Pexels

The same thing happened with blue-light filtering. Out of nowhere several years back somebody started touting the benefits of filtering blue light that was emitted by all of the electronic screens in our houses. They said it would enhance mood and focus, help our sleep, and improve our eye health by cutting down on harmful bandwidths of light from our screens. While there was never any scientific evidence to support those claims, if you didn't think about it too hard it could make sense. After all, red lights are better at night than blue, and for a lot of us it can be straining to spend hours every day staring at a screen.

And the fixes were easy! Just wear these blue-light filtering glasses! Or put a blue-light filtering screen protector on your phone, tablet, monitor, whatever. The phone manufacturers even got in on the grift, with both Google and Apple shipping updates to Android and iOS that allowed for the changing of your phone's color temperature. They offered both overall adjustments and dynamic changes through the evening to help ease you into sleep. I forget who it was, but one of the press briefings I attended a few years ago for a new phone included them hyping the inclusion of blue-light filtering in the display, while also touting it as a great phone for photographers.

"Just buy these blue-light filtering glasses!" they said. "And this blue-light filtering screen protector!"

I spend a fair amount of time working on web design and color, so I never hopped on the blue light train because I need to be sure that the colors I am seeing are accurate. But more importantly, it just never made sense if you really think about it. A properly calibrated screen doesn't produce any more blue light than is necessary to display whatever image you're looking at. And the screens are, for the most part, relatively minor light sources in our lives. I have two big monitors in my office, and even when I have them on max brightness with an all-white screen they don't produce nearly as much light as the one LED light bulb in my ceiling fixture.

And then there's the actual very big source of "blue light" in our lives: the sun and the sky. You might've noticed that the sly is relatively bright and very blue. Yet nobody gets eyestrain from the sky, even though on a clear day it can easily overpower all but the brightest of smartphones.

That's because blue-light filtering was always nonsense. There was never any good evidence to back it up, but that didn't stop grifters from pushing it as a solution to our eye strain and sleeping woes, nor did it stop big companies that should know better from jumping on the bandwagon.

Source: Ksenia Chernaya on Pexels

How to combat screen-related eyestrain

Just because blue-light filtering is nonsense doesn't mean that screen-related eye fatigue isn't real. It very much is, it just never had anything to do with the color temperature of the light. That was an easy "fix", but the actual solutions aren't as simple.

The first is making sure you actually have sharp enough vision at the proper distance of a computer or phone screen. The prevalence of myopia (nearsightedness, or difficulty focusing at a distance) has been increasing across the developed world. In America, at least 42% of the population is myopic, while cities in Asia are reporting 80-90% rates of myopia in high school graduates. While it's unclear what is behind the cause of this (there are plenty of untested theories about time spent outside versus in front of screens, or it could just be better screening), it is clear that our eyes are not as good as we generally hoped they were.

Using a computer all day leaving you with tired, worn-out eyes? Go to an optometrist, not Amazon.

So if you're feeling eye strain from extended screen time, your task should be to visit an optometrist. They can check your vision and see how good your eyes are at focusing light on your retinas. Maybe all you need are some corrective lenses in the form of glasses or contacts, or a laser treatment to reshape your cornea. Heck, maybe all you really need are some glasses you wear while you're using the computer — it'll make you look that much smarter at the office anyway.

Next is addressing the screens themselves. Obviously, if you're using a laptop then the screen placement is dictated by the keyboard being reachable, but if you have external monitors they be placed 20 to 40 inches (0.5 - 1.0 meters) away. And it turns out that the average human arm is right in the middle of that range, measuring 30" (76 cm) from shoulder to the tip of the middle finger for adult men, and 28" (72 cm) for women. If you put an arm straight out in front of you and can touch your monitor, then it's too close.

Woman using a computer
Source: This Is Engineering on Pexels

If you feel like your monitor is too far away and hard to read at that distance, (1) see the preceding paragraphs about getting your eyes checked, and (2) don't be afraid to adjust the screen scaling to make things display larger. In Windows 11 you can go to Settings > System > Display > Scale to find these options, on a Mac it's under System Settings > Displays, and on Chrome OS it's in Settings > Device > Displays > Display Size. There's nothing wrong with making things a bit easier to read, especially as you grow older.

You can also balance the brightness of the screens and your workspace. You can turn down the brightness of the screen itself (I generally run my monitors around 2/3 max brightness), but one of the more important things you can do is to improve the lighting in your work area. Set up your space so that reflections are minimized, as our eyes will try to constantly shift focus from the screen that's right in front of you to the reflection of light coming from multiple feet behind you. Then adjust the lighting so that the whole area is evenly and brightly lit. I have a lamp behind each of my monitors pointed at my beige walls, providing a nice "bias" lighting effect that fairly uniformly lights the space in front of my eyes. It also means I have really good indirect lighting for video calls.

Lastly, just take breaks. As my optometrist noted, dry eyes are a frequent problem with those that spend a lot of time at a computer because the kind of work you're doing probably requires some concentration, and we tend to blink less when we're visually concentrating on something. (and yes, I know, you're suddenly hyper aware of your blinking, I have been this whole paragraph too). So take a some breaks away from the displays, even if it's just a few minutes an hour looking at anything else.

Glasses lit in blue light
Source: The Masked Guy on Pexels

Blue LEDs are not off the hook

Just because blue-light filtering is complete hokum doesn't mean we should just accept blue lights. The quack theory behind blue-light filtering was that blue light was one of the visible light wavelengths that our eyes are most sensitive too. While this is true, our eyes are actually most sensitive to green and yellow lights. Conversely, our eyes are least sensitive to red light, which is why red light is preferred for dark spaces and being outside at night, because it disrupts our vision the least. This is why the green and yellow lights on a stoplight appears brighter than the red one, even though they have the same wattage powering them and are putting out the same lumen (brightness) value.

The wavelength is why a tiny blue light seems so annoyingly bright in a dark room. Blue light can be disruptive to your getting to sleep, but it's not the screen you were looking at during the day that's to blame. I am personally pretty annoyed by how many charging devices have bright blue LEDs in them. Blue does denote cool and modern versus the staid yellows and oranges that were commonplace on older electronics like VCRs, but blue is also just annoying.

Please stop putting annoyingly bright blue LEDs in every electronic gadget.

Stop it.

Stop it now.

Much to my chagrin, I have put black electrical tape over blue lights on numerous chargers, power strips, routers, and even two fans in my house. I do not need a light to verify that the thing is working — I'll plug it in to see. And if you insist on a light, make it a nice soothing orange or something. It's somewhat an aesthetics thing, but also just an irritation about how bright they appear to my sensitive human eyes. Especially in the dark.

Conversely, I'm okay with the switch from yellow sodium-vapor street lights to LEDs with a more white light. The yellow was perhaps more soothing, but the last thing I need when driving my car at night is to be getting more and more relaxed. The old sodium lights emit a light that's in a narrow wavelength range, which means that human color vision starts to become less effective, whereas the full-spectrum LEDs provide lighting for all colors. The LEDs are also far less expensive to run and maintain, and that's good for government budgets. If it's the light's annoying to you because it spills into your bedroom when you're trying to sleep, I recommend blackout curtains or a sleep mask. In my bedroom I installed Ikea's Tredansen smart blackout cellular blinds so I don't have to think about managing the light in my bedroom and I like it dark when I sleep.

Man mad at laptop
Source: Andrea Piacquadio on Pexels

A failure of science literacy

The hocking of blue-light filtering by people just looking to make a quick buck by shucking cheap plastic glasses at people that need real prescription lenses, and then the adoption of the concept by real companies big and small that should've known better, is just a failure of scientific literacy. It's faaaaaar from the biggest science literacy failure we've seen in recent years, but it's a great example that's inconsequential and easy to explain without any, *ahem* political baggage.

This episode is emblematic of a societal failure to teach critical thinking, reasoning, and scientific literacy across generations. We need to be better about logically questioning claims, seeking empirical evidence from the source, and listening to actual experts in their fields. Our world is growing ever more technical and difficult for the layperson to understand, so having a grasp on how to learn about something with a critical yet open mind is more important than ever. Yet we're not doing much to improve that.

Oh, and don't get me started on the latest nonsense fad of "red light therapy". I'm sure in a few years we'll see a load of studies debunking shining red LEDs on your genitals as horseshit as well.

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