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What’s With All the Attention to “Blue Light?”

What do we Mean by Blue Light

As of this writing there’s quite a bit of concern with how much “blue light” one is getting. To sort some of this out I want to explain what we mean by blue light and make some suggestions that might help. The visual spectrum goes from red to violet.

Electro-Magnetic Spectrum

Electro-Magnetic Spectrum

If you ever heard the acronym Roy G. Biv, you’d know the order in which the colors are laid out; red, orange, yellow, green, blue, indigo and violet ( For our purposes we include violet, indigo and blue in the “Blue” category). Comes pretty handy for a test. So what’s so special about blue light? It happens to be something akin to a wake signal at least insofar as our circadian rhythm is concerned. Our circadian rhythm is like our internal clock. It lets us know when to wake, when to sleep etc…, but it does take environmental cues into account. Most people experience drowsiness when they go to sleep and that usually is at night. The simple reason for this is that blue light tends to halt our production of melatonin which is our body’s sleep organizing hormone. It’s important to note that melatonin is not a sedative, it just tells your body that it should make preparations for sleep. If you start using electronics at night like a tablet, smart phone, TV, computer or any other device that has a screen, you are increasing the quantity of blue light and therefore decreasing your melatonin production. This can make you feel unrested in the morning even though you “slept.” Sleep is still not completely understood, but it can be divided into stages, one of which is REM (Rapid Eye Movement) sleep. Melatonin has been shown to increase REM sleep.

Blue Blocking to the Rescue

So what’s a caveperson to do when living in this hectic modern world? Fortunately we have solutions, some of which are free.

  • If you have an iPhone, search for the setting called “Night Shift.” The settings we recommend to start out with is to enable the “sunset to sunrise” option and set the temperature to as red as you can tolerate. The more the better, the ideal being not using the device at all.
  • For your computer, we recommend installing the program f.lux. The program does the same thing: You type in the zipcode and you can set duration of sunset and night temperatures to whatever your taste is.
  • For Android go to your Settings > Display > enable “Blue light filter” or “Eye Comfort Shield.” If your phone doesn’t have that you can download the “Twilight” app from the Google Play Store and configure that. I’ve used that with great success.
  • Adjust the temperature on your TV. This basically means playing with your display settings, but anything darker and redder is best.

While f.lux is free I do encourage sending the guy a buck or two. He has earned a lot of goodwill for making this ad-free. As far as I can tell his program is bar none the best and it doesn’t bug you- It just works.

Prescription Blue-Blocking Glasses

Last but not least you can have your prescription glasses block blue light. Right now there are 2 main types of blue blocking lenses, those with or without a residual tint. The ones with the residual tint are the ones that have shown promise in increasing melatonin production. Blutech is a particular brand that has varying degrees of blue light filtering for different tasks and tastes. There are also anti-glare coatings that will block a percentage of blue light such as Recharge from Hoya and Crizal Prevencia. the only issue I find with the anti-glares that block some blue light is that they can actually look like mirrors if there is sufficient blue light. Personally I find it looks good but some do not like it. Bear in mind that some blue light filters cannot be combined with transitions or other photochromatic technology. That said, brown will block more blue than grays, green throughout the day, but will not do much at night.