Technology & Health

Dealing with Blue Light and Sleep- Blocking & Filter Apps, Sunglasses, Amber Bulbs

By  | 

What is blue light? Where does blue light come from? How does blue light affect sleep and your general health? What are the dangers and side effects? How can you stop, block or filter blue light on your digital devices? What are best blue light filter apps for PC, iPhone & Android? What of blocking sunglasses and amber bulbs? Read to find out in addition to reviews and more other tips to stay away from blue light

What is Blue Light and Sources (where does it come from)?

We live in a world where we are constantly bombarded by technology as it has become an intractable entity in our lives. Twenty years ago websites were solely for businesses and technophiles and the majority of people didn’t even know what web hosting was, let alone a tweet or hashtag. Now everyone and their grandmother is on some social media platform and runs a website or personal blog through one of these packages, for example.

In this world of interconnectedness and the ‘Internet of Things’ we are exposing ourselves to an almost unceasing amount of blue light throughout the day and evening, whether that is at work, at home, or on the commute there and back. Unfortunately, our continuously plugged-in reality is having a very real and unhealthy effect on the moments when we need to unplug, unwind, and get some sleep.

So, what is it? Definition & Meaning

Blue light occurs as waves and are among the shortest but highest energy wavelengths (app 380 – 500 nm) within the visible light spectrum. It is literally everywhere. Blue light is not easily focused due to its ease to scatter and abberrate.  This may cause glare and discomfort at lower light intensity levels. With reduced focus, contrast is limited and objects appear blur.

Since they are shorter, these “blue” or High Energy Visible (HEV) wavelengths flicker easily. The flicker explains the glare reducing visual contrast and its effect on sharpness and clarity as observed in television sets and mobile phones. During the day, light from the sun reaches use through the atmosphere. What happens is that the shorter, high energy blue wavelengths meet air molecules and collide. The light is forced to scatter and this is the reason as to why the sky is blue.

In its natural form (that from the sun), your body utilizes the blue light to regulate the normal circadian rhythm (sleep-wake cycle). The light, in addition to regulation of this cycle, also helps boost alertness, mood and improve reaction times.

Blue light is beneficial in the daytime but again at night, it becomes disastrous to your health.

It may be in order to be of the thought that blue light affects people equally and that sensitivity to this wavelength of light is equally distributed. This may not be right since comments on blue light have shown that few people are sensitive to blue light and still few, seem not to be affected by blue light. A majority of people lie within the range of the limits.

If you want to know whether you are sensitive to blue light, eliminate all possible sources and use physical and software filters. If you still strain while using your computer, then you are more light sensitive. Light sensitivity is triggered by light with a wavelength surpassing the receptors ability to translate it. Blue cones have a sensitivity to about 437 nm according to the Organization of the Retina and Visual System; 2005. Rods are sensitive to about 498 nm. Eye strain occurs when this sensitivity is surpassed and the receptors are desensitized.

Where does it come from?

As aforementioned, blue light is everywhere and your eye receives it at every instant. Some of the sources of blue light include the sun, digital screens, energy-efficient fluorescent and LED lighting. Some of the digital sources, which are quite popular, include

  1.  Television sets
  2. Laptops & tablets
  3. Smart phones
  4. Computers.

Blue Light Sleep Effects- how it affects your sleep-Blue Light Melatonin & Circadian Rhythm


Blue light affects your sleep

Blue Light and Melatonin

So what does blue light have to do with sleep? Obviously the paper novel reading participants are not reading in the dark, so there is a matter of light and mental engagement involved there too.

However, the results of the study found that these participants were tired sooner, fell asleep faster, and experienced a better quality of sleep than those who were reading on e-readers. The difference was the blue light from the electronic device.

According to this Harvard study, blue wavelengths are “beneficial during daylight hours because they boost attention, reaction times, and mood” but “seem to be the most disruptive at night.”

Ultimately our eyes take in blue light in a different way than other light wavelengths, and therefore stimulates the brain differently. Ultimately blue light induces alertness and wakefulness by suppressing melatonin production.

Melatonin is the hormone secreted to induce tiredness and imitate the sleep cycle. Of course all light will suppress the secretion of melatonin and affect the overall circadian rhythms to some degree; however, the results of the 2014 Harvard research study suggest that “blue light does so more powerfully.” The study was conducted between the use of blue light and green light, and the results were that “blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much.”

Another  study published in the Endocrine Society’s Journal of Clinical Endocrinology and Metabolism found that, when exposed to room light at night, melatonin secretion was suppressed by around 85%. This happened in clinical trials. When artificial light is added to your day, the biological clock does not realize it may be time for sleep.

Melatonin is necessary for the primary function of day-night cycles. Human infants’ melatonin becomes regular and traceable when they are about 3 months old (Ardura J, Gutierrez R, Andres J, Agapito T (2003))[i]. It is produced in high amounts at this age and reduces as you age.

How does the circadian rhythm work?

An area of the brain, the hypothalamus, sets up sleep patterns depending on the amount of light outside. When it is dark, the retina detects reduced light and nerve impulses are sent to the hypothalamus and melatonin and other sleep hormones are produced. The National Sleep Foundation states that in the morning, the body warms up and produces cortisol via signaling and your body wakes up.

Blue light, whether dimmed or bright, will still have an effect on your circadian rhythm. The flickering and glaring are one of the reasons you will have a headache and mental fatigue come the following morning. You will be forced to think that you have not had enough sleep and you probably need more hours.

Though everyone has a circadian rhythm slightly diverting from the normal, the average length is 24 ¼ hours. When your brain’s, suprachiasma, receives daylight, it keeps the internal clock aligned with the environment. This is why those who stay up late have a circadian rhythm longer than the normal while those who wake up early have a shorter one (Dr. Charles Czeisler of Harvard Medical School; 1981).

Other Dangers, Hazards and bad Effects of Blue Light

Light at night is also the one of the highly likely reasons why people fail to get enough sleep and research has linked this to risks of depression, diabetes and cardiovascular defects.

Diabetes and Obesity

A study done in Harvard was able to map out the possible link of blue light exposure to diabetes and obesity. 10 subjects in this study, who were on schedule that slowly shifted the timing of the biological clock were involved. During the study, their blood sugar shot and they entered the prediabetic state. A hormone that is involved in satiety after meals, leptin, reduced. The effect of this is that the subjects would have jumped into binge and excessive eating leading to obesity. This really has shed a light of hope in being able to understand the link between the three.


Cancer has also been correlated to interference in the internal clock. A study done on subjects who are on night shift has linked the exposure to blue light at night with breast and prostate cancer. This study also linked it with diabetes, heart disease and obesity. The low melatonin levels may effectively explain the relation of circadian rhythm with cancer.

Several studies such as the Boston Nurses Study, have shown that irregular sleeping in artificial light lowers the hormone and is associated with higher breast cancer levels. It has also been found that blind women develop less breast cancer. To get the benefits of melatonin, desist from having no sleep at all. The melatonin is produced about 90 minutes into your sleep, and therefore a 2 hour sleep isn’t as bad.

Another research was able to find that melatonin regulates excess estrogen levels and IGF-! (Insulin-like Growth Factor)[i]. It may therefore act as an anti-cancer agent. The International Agency for Research on Cancer (IARC) has declared lack of sleep a carcinogen[ii].

In men, the risks of prostate cancer has been shown to triple in those on night shift. Moreover, bowel cancer and lung cancer is increased by 79 % (University of Quebec)

Retinal Damage and Age-related Macular Degeneration

Blue light is also linked to retinal damage and age-related macular degeneration with a complication of blindness.

Headaches and migraines are too, effects blue light will have on you and this might greatly interfere with the quality of your day. The reason as to why headaches and migraines occur might be linked to the suppression of melatonin synthesis. It is from melatonin that serotonin is produced. Serotonin has a role to play in the regulation of the vasculature of the cranium. When this vasculature experiences an imbalance, headaches and migraines may arise.

Immune System

There is a stipulated function of melatonin on the immune system. Since it has been proposed as a powerful free radical scavenger and also as a potent anti-oxidant (Pohanka M (2011)[iii], it can augment the immune response of your body. In some studies, it has been shown to be twice as potent as the dietary anti-oxidant vitamin E.

Yet in some studies such as one published in 2001 by Maestroni GJ et al on the immunotherapeutic potential of melatonin, reveals a relation between melatonin and its ability to fight infections. Therefore, a suppression in this compound, can create a void in the immune armory your body counts on.

How to avoid the bad effects of Blue light

Blue light in and of itself is not bad or unhealthy. Sunlight and white light actually contain various different colors of light or wavelengths, including blue light. Blue light therapy has even been used to treat mood disorders and depression, as well as to treat sleep problems and reset the circadian internal clock.

It is actually very helpful to expose yourself to a good amount of blue light during the day; it only becomes a problem to expose yourself to it at night when your body should be naturally going through steps in the circadian rhythm to tell your body to begin shutting down and preparing for sleep. Blue light too close to bedtime will not only disrupt the length of your sleep but also the quality of your sleep. Well, it is a matter of balance.

In the following subtitles let us see how you can deal with blue light especially from digital screens.

Blue Light Filter for PC (Windows)

How do blue light screen filters work for PC?

These filters work to change the brightness of the screen during the day and at night. They also change the color of the screen. When an application is installed e .g. f.lux, your location is established via zip codes, longitudes and latitudes and city name, it then uses the time of sunset and sunrise to determine when to make changes on the screen.

LED back-light technology’s advent also enhances screen brightness and clarity while reducing blue light.

Blue light filters could be downloaded in your PC official site and other trustworthy sites. Pick recommendations from an experienced IT person to prevent downloading any corrupt applications. One of the best app or software is f.lux

The filtering capacity of physical filters specific for blue light depend on the filter’s tint and the level of darkness.  This greatly influences the amount of blue light that penetrates into the eye. There are a number of physical filters of blue light that bear various colors.  These colors may be amber, orange and red. The most effective filter has a low light transmission of the blue light. For yellow/amber filters, blue light is least blocked while at the same time providing an overall light transmission of about 96%. Those filters that are red in color are preferably not indicated for blue light due to its color distortion.

A balance in the filtration of blue light and their overall light transmission. Taking a look at orange filters, they fall in between filtering all blue light to about 500 – 550 nm and 30 – 69% overall light transmission.

Best Blue Light Filter App iPhone, Mac, IPad (Apple) Reviews

Blue Light Filter App for IPhone 6 & 5 plus Reviews

Recently, in the iOS9.3 update, Apple  unveiled a new ‘night mode’  for iOS devices.  The feature is designed to help ndividuals who  own apple devices sleep.

Invert Colors1

In the iPhone, there is also an inbuilt IOS blue light filter, “Invert Colors1”. This is available in the Accessibility settings. It changes the illumination from black letters on a light background to an inverse of that.

The main mode of action of software that ‘filter’ blue light is through reduction and alteration of the colors that are displayed on your screen. What happens? The warmer colors such as yellow, orange and red are more preferred and therefore these applications turn white, green or even blue itself, the cold colors, into the warmer ones ([iv]

PC Sun Screen’ is also another awesome blue filter app you could consider. Among its merits are unlimited control over the color, size of the filter, its timing and position. However, this application utilizes the transparent overlay approach to reduce the contrast. Unlike f.lux, this application is being sold.

Sleep Cycle” is also one amazing app for the iPhone.

There are several other apps in iOS 9 which can help in filtering blue light as Terry Lambert, former employee of Apple, notes on Quora
Some of these apps include;

  1. Twilight
  2. CF.lumen
  3. Screen Filter
  4. Blue Light Filter

The apps only work on devices that run iOs 9 and above

For devices running pre-iOS 9 versions of iOS, either because they can’t run iOS 9, or because you have not upgraded, you can get a large amount of the same “benefit” by using one of the settings on your iOS device:
Open the Settings
Go to General -> Accessibility -> Zoom
Turn on Zoom
Quickly tap three times, with three fingers, anywhere on the iPhone, iPod Touch, or iPad screen
Tap on Choose Filter
Select Low Light


f.lux is available on iOS. It has however not been received yet in app store since it doesn’t use the recommended Application Programme Interface in the store. It only works on jailbroked iOS devices.


Low light mode in iOS will be equally as effective as f.lux in your iPad.


Choose to download the application “f.lux”.

Online reviews rate the effectiveness of f.lux best with most people giving it a 5-star rating.

One thing about the reduction of the intensity of blue light is never 100%. This is mainly due to the presence of blue light even in some colors that theoretically do not have blue light. For instance, you would never imagine that black fonts on your computer screen contains blue light in disguise.

Black color is however low in blue content as compared to the red colored font or a red screen. The only chance you might have to filter nearly 100% of blue light is by changing the background color to black. Even if the font were to be changed to black, it is not possible to change the color of some features on your screen such as the icons on your desktop.

Best Blue Light Filter App Android Reviews

Twilight is the most popular and  probably the best blue light filter for Android. In terms of po This app also helps protect the eyes from the harmful blue light at night. ‘Night mode’ is also available and also reduces blue light. Download and install the app and enjoy its ability to change the screen color. It also reverts the color of the screen.

According to the[v], the following are the comments gathered:

“Found it on my first android phone 3 years ago and haven’t switch pc it’s just so simple. I can’t use a filter to watch videos though, too much of the details are lost.”

“I use Twilight on my One Plus and F.lux on my PC. Can’t say so great to reduce my eye strain, but I got used to use them. Also, I wear T’aime glasses to block blue light from every digital devices. Really enjoy the glasses!! Thumb up! Tips: If you want to get one of them, you’d best go to the website…”

“One Plus One does this automatically. You can also customize color temperature, if 4500K for night time isn’t warm enough. When it’s available for iPhone, it’s revolutionary! sheez!”

Below is a screenshot from Googleplay

best blue light filtering app Reviews & ratings android

Twilight Reviews & Rating

Yet on the android list there is  Bluelight Filter for Eye Care is the app that follows twilight in terms of popularity and rating.

There is also f.lux version for android.

Other notable apps include;

  • CF.lumen is another application that has a choice of several filters that filter blue light. It works by converting the images displayed to grayscale then a color selected that suites the display. This preserves the detail that would have been lost[vi].
  • Night FilterAmongst other functionalities, this screen filter application helps you to dim your screen and adjust your color tint
  • Easyeye

Other apps that may help reduce blue light include;

Blue Light Filtering & Blocking Sunglasses

The ability of sunglasses to filter depends on the tint color and the darkness. Amber-tinted sunglasses and those that are red are best suited. Red filters block the blue and green light wavelengths. They are however not recommended due to the lowest overall light transmission and greatest color distortion. They do not achieve the lowest threshold of about 20-25%.

Yellow sunglasses have been shown to filter the least blue light. Though the yellowing of the lens in the old filters out the increasing amounts for blue light.

Uvex S1933X Skyper Safety Eyewear SCT-Orange UV Extreme Anti-Fog – has an overall transmission of about 45% with a filtration of above 98% of blue light.

3M Yellow/Amber Lens Safety Glasses – has an overall light transmission of about 85 – 92% with about 53% of blue light filtered and has 94.0 blue light hazard blocked in daylight.

Axon Optics – has FL-41 lens tint initially indicated for treatment of photophobia in migraines. It has a 50% filterability of blue light. Distorts light to a limited extent.

Some sunglasses too contain blue light filters though they have an overall very low light transmission. BluBlockers are one such type in the market. It has been shown by BluBlocker Corporation to have nearly 100% filter against blue light with 100% UV absorption.

Amber Light Bulbs & Sunglasses to block Blue light at Night

Backed up by research, amber colored sunglasses get rid of blue light well. In one study that involved 13 teenage boys, the blue-blockers were shown to prevent melatonin suppression. Old adults who wore amber-colored lenses in one study resulted in improved sleep quality.

Other lighting systems at home such as bulbs also produce blue light. Therefore, Amber-tinted blue light blocking bulbs can help


Amber Sunglasses & LED Bulbs

Use smart lights

Lightbulbs in our lamps also do produce blue light. Using  bulbs with warm colors in your lamps at night can prevent this light that originates from bulbs. this is exactly where smart bulbs come in.

A smart lighting system offers an option to set the lights to automatically adjust from a brighter blue light to a warmer color a few hours before bed. You can as well program your settings into the app once and let it the system work on its own.

Using smart lights to stop blue light

Philips Hue

Other Ways and Tips to Prevent, Stop, Block and Filter Blue Light

Changing Settings on your Digital Device

If you tend to work on your computer late into the evening, change the light setting on your work and home computer to reduce overall blue light exposure

Adjusting light settings smartphone to prevent blue light

light settings

Text and background color-This is a simple DIY method of filtering blue light. Choose the warmer colors with very little blue light content. Control the contrast level to reduce haze and blur images. Your background and text color choice may filter up to 80% of blue light as compared to font that is black on a white background (LEDMuseum data)[vii]

Use a Filter Gel

You could also choose to lay a filter gel over the digital screen. Choose a color that is high filtration of blue light. Red and orange are good choices with the ability to filter more that 60% of blue light on average. Tape the color film on the frame of your digital screen to use it when you need it.

Computer Glasses

You can also purchase computer glasses – there are a variety of brands of computer glasses that are mostly seen in gaming. They are effective against eye strain and are mainly geared towards filtering blue light. Most are tinted yellow or amber. Yellow lenses have a high light transmission with blue light filtration which makes it the most preferred color tint for computer glasses.

gunners computer glasses to filter blue light

Gunners Glasses

Some of the glasses you can buy include ‘Gunnars’. This pair has a reasonable blue light filter and light transmission. The amount of blue light filtered is about 50% and its overall light transmission is 96% (Zeiss/Gunnar). EyeFatigue computer glasses have a coating known as Anti-Reflective (AR. This coating is an excellent blue light filter with 15 % filtration.

More other ways to Block or Filter Blue light

  1. Limit your stay in front of the TV and computers
  2. The distance between you and the TV set should be 6 times the width of the TV set.
  3. Dim the overhead light in you room.
  4. Houses with salt lamps or orange bulbs could use them to reduce the intensity of blue light.
  5. Get a good amount of blue light during the day, including sunlight, and abstain in the evening to help reset your circadian rhythms and melatonin production.
  6. In conjunction with the above, consider herbal remedies to help with sleep disorders.
  7. Avoid electronic screens 2-3 hours before bed. Longer if possible
  8. Spend more time outside  during the day especially if you neither want  limiting the use of your devices nor using some of the artificial filters highlighted above.
  9. Consider a device that does not have light emitting diodes. In this case, that is paperback book or an original Kindle or simply consider devices with small screen sizes.

References and Citations

  1. [i] Shift work and cancer – considerations on rationale, mechanisms, and epidemiology. Costa G, Haus E, Stevens R Scand J Work Environ Health. 2010 Mar; 36(2):163-79.
  2. [ii] Carcinogenicity of shift-work, painting, and fire-fighting. Straif K, Baan R, Grosse Y, Secretan B, El Ghissassi F, Bouvard V, Altieri A, Benbrahim-Tallaa L, Cogliano V, WHO International Agency For Research on Cancer Monograph Working Group Lancet Oncol. 2007 Dec; 8(12):1065-6.
  3. [iii] Pohanka M (2011). “Alzheimer´s disease and related neurodegenerative disorders: implication and counteracting of melatonin” (PDF). Journal of Applied Biomedicine 9 (4): 185–196. doi:10.2478/v10136-011-0003-6
  4. [iv]
  5. [v]
  6. [vi]
  7. [vii]




Leave a Reply

Your email address will not be published. Required fields are marked *

Time limit is exhausted. Please reload CAPTCHA.