What do eye experts say about blue light? Myth ? Reality ? Are blue light blocking glasses effective? We have been studying this issue for a long time. Discover the recommendations of renowned ophthalmologists about this part of the light spectrum which is so fascinating and which has not yet revealed all its secrets.

In this article :

  • Blue light in a few lines
  • Opinion of the experts: the Ophthalmos give their verdict
  • Do they recommend blue light blocking glasses

Why is blue light so fascinating?

She is everywhere !

It's been several years since blue light appeared on our radars and rightly so because this light is emitted by almost all our screens (TV, computer, iPad, smartphone, Kindle ...) but also by all LEDs. ( light-emitting diodes in French) that light up our homes (even more since the European ban on traditional light bulbs).

We are therefore exposed to artificial blue light on a daily basis, but let's not forget natural light either:

  • The sun emits most of it
  • Our screens and modern lighting technologies emit the rest (via these famous light-emitting diodes)

Not just any light

If we look at the physics that explains the phenomenon of blue light, we immediately find some interesting features.

Blue light is a part of the electromagnetic spectrum that sits just above Ultra Violet (UV) and just below green light. Its wavelength is between 380 and 500 nanometers: short waves which produce more energy than the other visible colors (green, yellow, red...).

blue light in space

Could this high energy, this configuration of blue light be responsible for adverse effects on our health?

This is what more and more studies have put forward over the years, but in a somewhat disjointed way. So we hear everything and anything about him. Keep reading to see what the experts (in this case the ophthalmologists) really say.

Consensus around sleep

All ophthalmologists agree: blue light affects our circadian rhythm. Two pompous words in 3 lines, I'll have to calm down. Basically everyone agrees that blue light has a strong impact on our waking and sleeping patterns.

Blue light blocks the secretion of melatonin , the hormone that is there to help you fall asleep and keep you asleep at night.

person sleeping in bed

If you expose yourself to blue light before falling asleep or when you wake up in the middle of the night thinking about the number of days left until your next vacation, you destroy your production of melatonin , making the task of falling asleep a lot more complicated.

Any type of light has this effect (not only blue light) but blue light has a much greater effect than the others because it is much more intense as we have seen above (twice as much as green light per example see Harvard study )

Effects still under study

There are many studies about blue light. If they do not yet make it possible to conclude 100% of the immediate harmfulness of blue light on the human eye, they nevertheless highlight long-term risks that some ophthalmologists interpret as serious. The first conclusions are negative enough to apply a principle of prevention which does not cost much. The potential effects mentioned are:

  1. Effects on the retina, AMD
  2. Headaches, migraines
  3. Generalized eyestrain

    An ophthalmologist and a patient

    1) Retinal degradation, age-related macular degeneration ( AMD)

    These effects would be all the more important on children whose ocular protection mechanisms are not as powerful as those of adults. Here is the opinion of several ophthalmologists on the potential risks.

    Gilles Renard , Scientific Director of the French Society of Ophthalmology (health magazine interview of 02/11/2019)

    We do not know what the effects of dark blue light are in real conditions, but we can think that it is certainly toxic, especially in children whose cornea and lens, which are clearer, allow almost all the blue to pass through.

    Serge Picaud, neurobiologist and Inserm director at the vision institute.

    It has been demonstrated in an in vitro model of age-related macular degeneration (AMD) that the most toxic wavelength for retinal cells is located around 415-455 nanometers. Several epidemiological studies have shown that this blue light was indeed a risk factor for AMD.

    October 2016 study by researchers from the Cordeliers Research Center

    They looked at the effects of LEDs on our retina. Several experiments have been conducted on albino rats, which, exposed to LED light, have suffered degeneration of their retina in addition to the appearance of necrosis.

    Admittedly, this is only a scientific model in the laboratory with much more intense blue light than what we face in front of screens, but the model very likely highlights long-term harmfulness.

    American Macular Degeneration Foundation

    The blue rays in the spectrum appear to accelerate Age-Related Macular Degeneration (AMD) more than any other ray in the spectrum.

    Beaver Dam Eye Study Report

    Blue light exposure in teenagers and people in their 20s and 30s can advance the risk of developing AMD by 10 years and double the risk of suffering from blindness in life.

    Professor Ajith Karunarathne from the University of Toledo (USA), article in Nature (05/06/18) and interview by the university (08/08/2018)

    We are exposed to blue light continuously and the eye cannot block or reflect it. It's no secret that blue light harms our vision by damaging the retina. Our experiments explain how this happens and we hope it will lead to therapies that slow down AMD, like a new type of eye drops. You need a continuous supply of retinal molecule if you want to see. Photoreceptor cells are useless without the retinal that is produced in the eye. If you expose the retina to blue light, the retinal kills the photoreceptor cells as this molecule dissolves on the membrane. Photoreceptor cells do not regenerate in the eye. When they died, they died for good.

    Basically, Karunarathne's lab discovered that exposure to blue light causes reactions in the retina that generate toxic chemical molecules for photoreceptor cells.

    Vincent Gualino, ophthalmologist at the Lariboisière hospital in Paris and Montauban

    It is above all the cumulative effect that could be harmful

    ophthalmologist having glasses tested

    2) Headaches and Migraines Related to Blue Light

    People who suffer from migraines often report an increased sensitivity to light (in addition to the intense headache). The combination of these intense migraine symptoms can be really painful and affect your daily life .

    While it's true that certain foods can serve as migraine triggers, the idea that computer and phone screens can also contribute to these attacks is not without merit.

    Everyone has some level of sensitivity or discomfort to light. For people with sensitivities, sudden changes in light levels, bright fluorescent lights, and even natural sunlight can exacerbate a migraine.

    Ophthalmologist performing blue light tests


    The brighter the light, the more discomfort people with photophobia may experience. The wavelength or the color of the light can also be a factor of discomfort and since blue light is more intense by definition, the problem is quickly seen.

    Blue light is usually the most painful hue for migraine sufferers. Blue light from electronic devices can even trigger migraine attacks. Many migraine specialists recommend limiting screen time for people who regularly suffer from severe headaches and sensitivity to light.

    3) Digital eye strain syndrome

    Blue light has a high intensity and will tend to sparkle more, as Dr. Pietrini (Ophthalmologist, Laureate of the Broussais Hôtel Dieu Faculty of Medicine) reminds us .

    This causes glare for the eye and makes visual contrast complex and affects acuity. On the other hand, it is its duration of exposure and its intensity which present an increasingly significant danger. We are subjected to intensive radiation from our screens, which emit powerful blue light radiation. This prolonged exposure causes eye fatigue (eye stinging, headaches) and more seriously can damage ocular structures such as the lens and the retina.

    Blue light is not the only cause of this computer vision syndrome (UVs, bad reflections, bad lighting, etc.), but it contributes greatly to it.

    How to protect yourself: advice from ophthalmologists

    The good news is that it is relatively easy to protect yourself from blue light. One of the simplest solutions to protect yourself, blue light blocking glasses. Be careful with your choice , not all blue light blocking glasses are equal.

    As our ophthalmologists point out a little higher, you should not filter just any frequency: the ideal is to filter the frequencies closest to UV as much as possible to keep only the good blues. If we only had to look at a frequency range to be filtered, we advise you between 380 and 450 nanometers with a very important attention between 380 and 430 nanometers where the rays are really intense.

    Finally, here is a little "checklist" recommended by the pros that will allow you to protect yourself as best as possible:

    Not directly related to blue light but will contribute to your general well-being:

    • Remember to blink your eyes to keep them hydrated
    • Drink plenty of water to stay hydrated in general
    • Adjust ambient brightness
    • Make sure your screen is of good quality

    Anti blue light glasses ophthalmologist opinion: The word of the end

    Many renowned ophthalmologists highlight the dangers of blue light . Many others prefer to turn a blind eye to this growing problem.

    So it's true, there are still many things to discover but the precautionary principle is in order for this blue light which has invaded our daily lives and for which many of the most serious studies highlight serious risks.

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    July 05, 2023

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