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Do Blue Light Filtering Apps Really Work?

It's basically become accepted wisdom that staring at screens too close to bedtime will interfere with your sleep, and it's not just a popular myth. there is real scientific evidence that blue light has small, but measurable effects on many systems in your body and brain, from circadian rhythms to cells in your retina. It doesn't affect everyone equally, and it's not really a public health crisis, but reducing your blue light intake could be at least somewhat beneficial.

ContentsWhy blue light in particular?This is your brain on blue lightSleep disordersA disturbed circadian rhythmBlue light and your bodyHow not to have the bluesapplicationsBlue light filtering glassesBlue light filters for your devicesRestricting device use at nightConclusion:do not panic

Why blue light in particular?

Blue light is actually good for you. Your "memory, alertness, attention span, reaction times, learning ability and cognitive performance all work much better under blue light", so if you need to work it could give you a boost. little nudge. The healthy relationship only gets a little toxic if we get too much blue light or take too high of a dose late at night. Research has found evidence of some negative effects, but they are usually not too severe.

Sleep disorders

One of the reasons blue light makes you particularly alert is that it inhibits the production of melatonin in your brain, which means your brain doesn't get the signal that it's time to sleep. This can make it harder for you to sleep and decrease the quality of sleep you get. Not all humans react the same way, but on average this effect has generally been found to exist. Insufficient sleep, especially less than six hours a night, can then lead to a whole different set of health problems.

A disturbed circadian rhythm

We all have a different circadian rhythm – the internal clock that registers when it's time to get sleepy or feel more awake. Staying up later with artificial light doesn't seem like a big deal to us, but blue artificial light can be more disruptive than other types, especially late at night.

A Harvard study compared the effects of 6.5 hours of blue light exposure with the same amount of green light exposure and found that blue light shifted circadian rhythms by 3 hours on average, compared to 1 .5 hours for green light. It can make us much sleepier during the day and has even been linked to health issues, such as a higher risk of diabetes.

Blue-light and your body

Blue light indirectly affects your body by messing up your brain a bit, but it turns out that high-frequency light, like blue light, can also be somewhat damaging to your eyes. High-energy light like ultraviolet rays can definitely damage your skin, so it's definitely possible that intense blue light is doing something to the more sensitive photoreceptors in your eyes.

The effect has been shown in animal studies, but has not yet been confirmed in humans. Either way, it's not too alarming yet. At worst, it is unlikely to speed up the natural aging process of the eyes a bit.

How not to have the blues

Since science seems to agree that large amounts of artificial blue light are not good for you, it's worth researching into solutions.


Using one of these blue filter apps is probably the easiest way to cut down on your consumption, but there really isn't much evidence of their effectiveness. The auto-dim feature may be more helpful, as less light has been shown to help reduce melatonin levels. Despite the lack of hard evidence, using these apps can't hurt.

Blue-light-filtering glasses

Also called "computer glasses", these glasses are usually tinted yellow (but you can get clear versions), which changes the wavelength of light passing through them. They block blue light, and wearing them while using devices near bedtime can help you achieve more natural melatonin levels. However, studies on their effectiveness are largely inconclusive.

Blue-light-filters for your devices

If you don't want to start wearing glasses, you can choose to put a blue light filter directly on your device's screen. They're mostly transparent, so your screen won't have that reddish tint, but they work on the same principle as glasses.

Restrict device use at night

Let's be honest, this solution is the worst. Even though you could spend most of your evenings without having to use your phone or computer, would you want to? If less screen time sounds good to you, the general advice is to ditch the devices one to two hours before bed.

Conclusion:don't panic

Blue light won't burn your retinas or make you insomniac no matter how much you stare at a screen. Some people may have stronger biological responses than others, but as long as you don't sleep less than six hours a night, reducing blue light probably won't change your life. Of course, new research is always coming in, so it can't really hurt to take a few precautions if it makes you feel better.