I know you know the feeling, don’t lie: Sitting, staring at your computer all day and your eyes start to hurt. Like, a lot. Like, omg-I-can’t-use-these-things-anymore-or-they’ll-fall-out-of-my-head-and-I’ll-die a lot. With the increasing ubiquity of digital devices, eye strain has become a pretty common thing nowadays. And of course, a lot of that has to do with the actual physical strain of focusing our eye muscles on one, fairly-close, spot all day. I mean, any muscle would be sore after pro-longed use. But did you know that the color of the screen itself is contributing at least a bit to that strain?
The blue-tinted light emitted from just about every type of digital screen has been shown to play a really interesting role in modern health. But before we dive in to that, let’s take a quick minute to review light.
Visible light is everything we can see 🌈 but it actually it only makes up a very small part of the electromagnetic spectrum. Light exhibits properties of both waves and particles, but that’s a subject for a different day. For now, though, just remember from physics or chemistry that you can measure light in wavelengths. For all the stuff we can see, that’s on the scale of nanometers (one nanometer is one billionth of a meter), ranging from about 400nm to 700nm. Wavelengths measuring 400nm are closer together than those that are 700nm. That is, wavelengths at 400nm have a higher frequency of occurrence. This corresponds to the blues, violets, etc. that we see, while the 700nm side is the oranges, reds, etc.
The wavelengths immediately below blue are UltraViolet, so just keep that in your frame of reference, since we all know the potential harms of UV light!
Blue, the most human color
The cells in your retina that allow you to see color are called cones. There are about 30,000 of them that are capable of relaying “blue” to the rest of your brain. Blue is an extremely important color for us humans. Go listen to Regina Spektor’s Blue Lips. It’s the color of the sea, the color of the sky, and because of that our vision and brains have evolved with a special relationship to the blue wavelength.
Since the original source of blue light is from the sun, we have evolved a circadian rhythm based on the presence, and absence, of blue light. Our circadian rhythm does lots and lots and lots of things, but what most people are familiar with is the sleep/wake cycle. Sun’s out, you’re awake. Sun’s gone, you’re asleep. This is due to exposure to blue light and the effect that has on melatonin.
You’ve probably at least heard of melatonin in passing. Melatonin does a lot of things, but is super important for sleep. When blue light hits your eyes, it acts to suppress melatonin production, which keeps you awake. That’s all well and good a couple hundred years ago, in a time when the sun went down and you had no real choice but to sleep, but now we’re exposed to light (and blue light at that) well after sun down.
But why should that matter? It’s just a color..
Actually, there are a lot of things that over-exposure to blue light can negatively affect. We’ll start with the most obvious (because I already mentioned it): sleep. When you’re cozy in bed, lights off, falling down the internet rabbit hole for just 5 more minutes then you’ll really go to sleep this time, the light from whatever screen you’re looking at is actually telling your brain to stop producing melatonin. Your brain listens, and because of this you’re wide-awake. In fact, researchers at Harvard looked at the quality of sleep between two different groups: one who read from electronic devices for a few hours before bed and one who read from traditional paper (books, etc.). Apart from the suppression of melatonin, they found that the screen-readers were less tired at night, but more tired in the morning. These people also took on average at least 10 minutes longer to fall asleep. What’s super interesting, though, is that the screen-readers has less episodes of Rapid Eye Movement (REM) sleep than the book-readers.
REM is the phase of sleep when you dream, and while researchers aren’t 100% sure on why we even dream in the first place, it’s pretty well accepted that REM helps up consolidate memories from the day. So, with less REM sleep, it follows that there would be a decline in memory.
Sure, a bad memory is annoying, but not really life-threatening. What *is* life-threatening, though, is cancer, type 2 diabetes, heart attacks, and obesity. That’s right. There’s research linking all of those things to over-exposure of blue light. It potentially happens through the dysregulation of melatonin. (Remember, it’s involved in a lot of things, not just sleep).
The good news is that there are a couple of ways to combat all this over-exposure. The first, and probably simplest, is to just shut off devices (computer, phone, tablets, etc) a few hours before bed. For many of us, though (including ya girl here writing this at 10pm), this isn’t really an option, given our modern day work schedules. For that, I would highly recommend looking into one of the apps that are out there to remove blue light from your screen. Yeah, that totally exists.
I’ve been using f.lux for a while now, and I must say, it’s really nice (& free!). This is a computer app that you can install to lower the blue levels in your screen. What’s really cool about it, though, is that it uses your geographic location to track the sun and lower the blue levels accordingly throughout the day. So for example, in the winter when it gets darker earlier, my screen slowly starts looking a little warmer as the day goes on, until it’s basically straight-up orange at midnight.
I’m not the best at sleeping (in all honesty, I’m really bad at staying asleep all night, like an infant or something), but I have noticed that I don’t lie in bed frustrated that I can’t fall asleep for as long anymore. Actually, I don’t think I lie in bed frustrated at all anymore. I think I just fall asleep now. Which is so nice.
Currently this app is available for computers, and there’s a version called Twilight for the Android phone. Unfortunately Apple isn’t cool with apps coming in and tweaking the overall operating software, so if you want f.lux on your iWhatever, it needs to be jailbroken. HOWEVER, I’ve read that something similar to f.lux will be available for your iThing with the iOS 9.3 update, so let’s hope that’s the case!
But just so you don’t walk away from this thinking that blue light is to be avoided at all costs, there are definitely benefits to its exposure also. You may have heard of Seasonal Affective Disorder, which is more frequent in the colder, darker, wintery climates. When humans don’t see the sun (aka blue light) for long periods of time, it can lead to depression. Light therapy, or exposure to very bright, blue-tinted light, can actually be a really effective treatment. And of course, we need blue light to maintain our normal circadian rhythms, which not only affect sleep, but mood, hormones, memory, and so many other things.
Basically, the moral of this story is moderation and timing. (I think that’s the also the moral of life, maybe, I don’t know).