We have all been exposed at one time or another to the concept of "blue light". Unfortunately, we have not yet taken the measure of the possible damage to our eyes and to our health in general. The harm caused by blue light is insidious and not always immediate. It goes far beyond simple eye strain.

However, more and more scientific studies are highlighting the dangers of this phenomenon that is still not discussed enough.

In this guide :

  • What is blue light?
  • Natural blue light
  • Artificial blue light
  • The dangers of blue light
  • Effective protection: filters and glasses

What is blue light?

Blue light is one of the colors naturally present in the spectrum of light. It is also emitted artificially by screens around us (phone, tablet, computer, television, LED bulbs etc.), so we are all exposed to it daily, whether at work or at home.

We’re more exposed now to the dangers of blue light than ever. Recent studies have found that in the United States, people average 6 hours and 39 minutes per day looking at screens.



natural blue light

I. Blue light in the light spectrum

Sunlight contains red, orange, yellow, green and blue rays as well as many shades of each of these colors, also known as electromagnetic radiation.

Combined, this spectrum of colored light rays creates what we call "white light" or sunlight.

Blue light rays are therefore naturally contained in our environment, and aren’t necessarily harmful when coming from a natural source.

However, without turning into Bill Nye the Science Guy, there is a confusingly oppositional relationship between the wavelength of light rays and the amount of energy they contain. I.e. Long wavelength light rays contain less energy, and short wavelength rays contain more.

🔴 Rays at the red end of the visible light spectrum have longer wavelengths and therefore less energy.

🔵 On the other side of the spectrum, blue light has shorter wavelengths and therefore contains more energy.

This blue light can itself be divided into 2 categories. One essential for our health and the other much less so

But even then, it’s important to note that the dangers of blue light occur from both natural and artificial blue light.

II. Natural blue light: essential to daily life

Natural blue light stimulates wakefulness and calibrates our sleep rhythm. It is everywhere, but that is not necessarily a bad thing! This light is a necessity, especially at the beginning of the day.

As early as 1981, Dr. Charles Czeisler of Harvard Medical School highlighted the importance of daylight in synchronizing the internal clock with one’s environment.

Natural blue light is directly linked to the production of melatonin – the hormone that regulates your sleep and maintains your energy balance throughout the day.

📉 Natural blue light in the morning lowers the level of melatonin in your body and allows you to wake up naturally.

📈   In the evening, the production of melatonin increases and allows you to fall asleep peacefully.

danger artificial blue light

Research has also shown that this "good" blue light stimulates alertness, helps maintain a good memory, improves your cognitive functions and ups your mood faster than beating Ganondorf. So, it's not always necessary (or desirable!) to block out 100% of the blue light!

But there’s a caveat:

Screens emit blue light up to 100 times stronger and more aggressive than natural sources due to its powerful LEDs.

That’s why if you’re using LEDs at night, it’s advisable to change your ambient lighting and pop on a pair of blue light blocking glasses.

III. Artificial blue light: harmful in the short and long term

The most harmful blue light is that between 380 and 450 nanometers, because very short waves are the most energetic and therefore the most harmful for the eye. These are the ones you should avoid.

And although they’re the most harmful, it’s important to remember the whole spectrum of blue light can impact your sleep pattern. So, before bed, it’s important to try and avoid as many blue light wavelengths as possible and be well informed on the overall dangers of blue light.

Be particularly aware of:

  • Blue light in the evening: over the entire spectrum (380 to 500 nanometers)
  • Blue light during the day: on the part closest to UV from 380 to 450 nanometers.

Of course, that becomes infinitely trickier when you realize blue light is everywhere, all the time. LED lights, for example, represented 75% of lighting in 2020! Good luck getting away from the dangers of blue light with LEDs and digital screens following you around like the particularly persistent Ocarina of Time’s Navi.

Until the advent of artificial lighting, the sun was the main source of illumination and people spent their evenings in (relative) darkness.

Today, in much of the world, evenings are artificially lit, and this constant exposure can have serious consequences for our health that go far beyond digital eye strain.

The "dark" side of light | The dangers of blue light

Every day, we are exposed to one or more screens for over 6 hours, and the increasing use of new technologies has led to an overexposure of the eye to harmful blue light.

I. Short-term dangers of blue light

Visual fatigue

Stinging sensations, red, dry and tired eyes, jumping eyes, glare, blurred vision, headaches... all of this can be a symptom of an overexposure to blue light.

At the same time, with this exposure, the blinking frequency of our eyes decreases, thus leading to an increased chance in digital eye strain.

Disruption of sleep

Artificial blue light exposure disrupts your circadian rhythm. The light of our screens in particular delays the time it takes to fall asleep and thus reduces how long we can snooze for.

Blue light exposure makes your brain believe that its the middle of the day even if it’s darker than a true crime documentary outside.

All this blue light prevents the secretion of melatonin, the hormone that allows us to fall asleep. Our sleep is then disturbed, and our body does not know any more whether it’s night or day (literally). Circadian rhythm is the backbone of a healthy life, and its disruption can be truly dangerous.

As the National Institute of Health has discovered:

“High energy blue light passes through the cornea and lens to the retina causing diseases such as dry eye, cataract, age-related macular degeneration, even stimulating the brain, inhibiting melatonin secretion, and enhancing adrenocortical hormone production, which will destroy the hormonal balance and directly affect sleep quality.”

Digital screens

II. Long term dangers of blue light

Vision loss | AMD (age related macular degeneration)

Prolonged exposure to blue light could also cause irreparable damage to the eyes and contribute to age-related macular degeneration, which can lead to blindness. Although there is still a lot of research to be done before definitive conclusions can be reached, the initial results are disturbing.

The retina is a very thin and multi-layered tissue covering the inner eyeball. It can be damaged by high energy blue rays (especially in children). Prolonged exposure can therefore be a risk factor for age-related macular degeneration.

Multiple studies corroborate this.

A Harvard medical study indicated that high-intensity radiation is the most dangerous light for the retina and retinal degenerative diseases.

A report published by the American Macular Degeneration Foundation (AMDF) found that blue spectrum light appears to accelerate age-related macular degeneration (AMD) more than any other ray in the spectrum.

Attention Deficit Hyperactivity Disorder | ADHD

Unfortunately, studies have linked exposure to blue light from screens to attention deficit and hyperactivity disorder (ADHD) in young children. Therefore, it goes without saying that youngest children must be protected as much as possible from overexposure to screens. Although it’s tempting to slap on Bluey and leave your child to it, try to limit their screen time and avoid it completely for those under 2.

The acceleration of puberty

Strange but true. Believe it or not, the excessive use of screen time during lockdown was recently linked to an acceleration in puberty among children! As presented in a study during the 60th Annual European Society for Paediatric Endocrinology Meeting in Rome, it was found that rats that received a lot of exposure to blue light where more likely to mature faster.

This doesn’t mean that other factors cannot play an important role. The biology of puberty is incredibly complex, but these early findings provide a good foundation for this theory.

As if puberty wasn’t bad enough…

Those most affected by the dangers of blue light:

Blue light negatively impacts us all, but if you fall into one of these categories, you’re even more at risk:

  • Children
  • People with eye problems or poor eye health
  • Immunocompromised people
  • Senior citizens

How to protect yourself from blue light

Never fear, there are ways to protect yourself from the dangers of blue light without locking yourself away for 100 years in a light-less void. There are some simple changes you can make to your lifestyle to reduce your overall exposure:

  1. Reduce time spent on screens.
  2. Avoid exposure to blue light before bedtime .
  3. Absolutely avoid blue lights and any strong light at night.
  4. Activate blue light filters and other night modes on your electronic devices.
  5. Wear effective blue light blocking glasses.

All of these solutions are effective and will help you reduce exposure, however, the most effective of all (and most stylish), is slipping on a pair of blue light blocking glasses. That’s because they’re specifically designed to filter out the bad spectrum of blue light.

Choosing the right pair of blue light blocking glasses

It is essential to choose glasses with advanced filtration technology. Make sure you know what you’re looking for or you may end up with a pair of anti-blue light glasses that are as useful as Rikon Stark was. There are some easy checkpoints to ensure the glasses you’re choosing are effective and block against the dangers of blue light:

  • They filter 100% of ultraviolet rays (A, B and C)
  • The filtration is close to 100% on the ultra-harmful spectrum between 380 and 430 nanometers
  • They ideally will have anti-reflective technology
  • They should have an ergonomic design adjusts to your morphology
  • Certification by an independent laboratory
  • A comprehensive guarantee (like Horus X’s lifetime warranty)

Horus X’s blue light glasses recommendations, based on your usage

In the evenings:

The Gaming One glasses or The Urban gaming glasses come equipped with an amber filter that will keep you feeling as calm and relaxed as your surroundings.

In the office, or on the go:

Our office collection of anti-blue light glasses come equipped with a clear filter, so you can where them whenever, wherever. Just like Shakira.

For kids:

The Gaming Hope if they like to play, or the children's blue light blocking glasses collection suits any occasion.

The dangers of blue light: Final thoughts

Although studies are still recent and the dangers of blue light are still being established, there are worrying signs that it can have a significant impact on our overall health and wellbeing. Some studies have suggested blue light can be responsible for certain cancers, diabetes, heart disease, and even obesity (particularly because of its negative impact on sleep).

It’s important you protect yourself now, so you don’t end up regretting it later.

Bibliography and further reading

  • Effets sur la santé humaine et l'environnement des systèmes utilisant les LEDsExpertise Anses 2019 https://www.anses.fr/fr/system/files/PRES2019DPA01.pdf 
  • Ministère des Solidarités et de la Santé https://solidarites-sante.gouv.fr/sante-et-environnement/activites-humaines/exposition-aux-ondes/article/effets-sur-la-sante-de-l-exposition-a-la-lumiere-bleue  
  • The Vision Council, "Digital Eye Fatigue in the USA : The State of the Art", Viewpoints, 2015, dans The Dangers of Blue Light, 2015
  • Rapport de la table ronde du 16 mars 2013, dans Les dangers de la lumière bleue, 2015
  •  "Sécurité photobiologique des lampes et des luminaires utilisant des lampes", EN 62471-1 ; "Application de la norme EN 62471 aux sources lumineuses et aux luminaires pour l'évaluation des risques de la lumière bleue", EN 62778
  •  Kasun Ratnayake et al, "Blue light excited retinal intercepts cellular signaling", Scientific Reports, 2018.
  •  L'accumulation de lipofuscine dans les cellules épithéliales pigmentaires rétiniennes cultivées entraîne une sensibilité accrue à l'irradiation par la lumière bleue", Free radic Biological Medecine, 1997.
  • Gianluca Tosini, Ian Ferguson et Kazuo Tsubota, "Effects of blue light on the circadian system and eye physiology", Molecular Vision, vol. 22, 24 janvier 2016
  • Sebastien Point, "Blue Light and Exposure Limit Value : Réponse à l'ANSES" [archive], 24 mai 2019.
  •  Huei-Bin Wang et al, "Blue light therapy improves circadian dysfunction as well as motor symptoms in two mouse models of Huntington's disease", Neurobiology of Sleep and Circadian Rhythms, vol. 2, janvier 2017
  •  Opinion on Potential risks to human health of Light Emitting Diodes (LEDs)" Comité scientifique de la santé, de l'environnement et des risques émergents SCHEER. 6 juin 2018
  •  La lumière bleue a un côté sombre". Harvard Health Letter. 13 août 2018
  •  Krigel, Arthur (2016). "Les dommages rétiniens induits par la lumière en utilisant différentes sources de lumière, protocoles et souches de rats révèlent la phototoxicité des LED". Centre de recherche des Cordeliers. Université Paris Descartes, France (Faculté de médecine de l'Université de la Sorbonne, département de physiologie). Consulté en décembre
  •  Les diodes électroluminescentes ont provoqué des lésions rétiniennes et leur dépendance à la longueur d'onde in vivo". International Journal of Ophthalmology, Vol. 10, No. 2. 18 février 2017. 9, 201