What do eye experts say about blue light? Myth? Reality? Are anti blue light glasses effective to preserve eye health? We've been studying this question for a long time. Discover the recommendations of renowned eye experts (ophthalmologists, optometrists, eye doctors...) about this part of the light spectrum that gets so much attention and that has not yet revealed all its secrets.
In this article :
- Blue light in a few lines
- Expert opinion: What do doctors say about blue light
- Do doctors recommend blue light glasses (+extra tips)
Why blue light gets so much press
It is everywhere!
Blue light has been on our radar for several years now and rightly so. This light comes at us from all sides (TV, computer, iPad, smartphone...) but also by all LEDs (light-emitting diodes) that light up our homes. We are therefore exposed to artificial blue light on a daily basis :
- 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 behind blue light, we immediately find some interesting specificities. Blue light is a part of the electromagnetic spectrum that is just above Ultra Violet light (UV) and just below green light. Its wavelength is between 380 and 500 nanometers: short waves that produce more energy than other visible colors (green, yellow, red ...).
Is it possible that this strong energy, this behavior of blue light could be responsible for adverse effects on our health?
Every year, more studies have been put forward with this message, but in a somewhat sporadic manner.
Because of that, we hear everything and anything about it.
Keep reading to see what the experts (in this case ophthalmologists, optometrists and other eye doctors) really say about it.
Everybody agrees on sleep
All ophthalmologists agree: blue light affects our circadian rhythm. Basically, everyone agrees that blue light has a strong impact on our wake and sleep rhythm.
Blue light blocks the secretion of melatonin, the hormone that helps you fall asleep and stay asleep during the night.
If you expose yourself to blue light before going to sleep or when you wake up in the middle of the night thinking about how many days you have left before your next vacation, you destroy your melatonin production, making the task of falling asleep much more complicated.
Any type of light has this effect (not just blue light) but blue light has a much stronger effect than the others because it is much more intense (twice as much as green light for example cf Harvard study)
Effects still being studied
There are many studies on the subject of blue light. If they do not yet allow us to be 100% certain of the immediate harmfulness of blue light on the human eye, those still put forward long-term risks that have some ophthalmologists worried. The first conclusions are severe enough to apply a "better safe than sorry" approach.
The potential effects are :
- Effects on the retina, AMD
- Headaches, migraines
- Generalized ocular fatigue
1) Retinal damage, age-related macular degeneration (AMD)
These effects would be all the more important for children whose ocular protection mechanisms are not as powerful as those of adults.
Here are the opinions of several ophthalmologists on the potential risks.
Gilles Renard, scientific director of the French ophthalmology society (interview santé magazine of 11/02/2019)
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, clearer, let pass almost all the blue.
Serge Picaud, neurobiologist and Inserm director at the Vision Institute.
It has been demonstrated on 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 is indeed a risk factor for AMD.
October 2016 study by researchers at the Cordelier Research Center
They looked at the effects of LEDs on our retina. Several experiments were conducted on albino rats, which, exposed to LED light have undergone a degeneration of their retina in addition to the appearance of necrosis.
Admittedly, this is only a scientific laboratory model with blue light much more intense than what we face in front of a digital screen but the model very likely highlights the long-term harmfulness.
Blue light in the spectrum appears to accelerate age-related macular degeneration (AMD) more than any other ray in the spectrum.
Beaver Dam Eye Study Report
Blue light exposure in teens and people in their 20s and 30s can advance the risk of developing AMD by 10 years and doubles the risk of developing blindness over a lifetime.
Professor Ajith Karunarathne of the University of Toledo (USA), article in Nature (05/06/18) and interview by the university of Toledo (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, such as a new type of eye drop. You need a continuous supply of retinal molecules if you want to see. The 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 are dead, they are dead for good.
Basically, Karunarathne's lab found that exposure to blue light causes reactions in the retina that generate chemical molecules that are toxic to photoreceptor cells.
Vincent Gualino, ophthalmologist at Lariboisière Hospital in Paris and Montauban
It is especially the cumulative effect which could be harmful
2) Headaches and migraines linked to blue light
People who suffer from migraines often mention an increased sensitivity to light (in addition to the intense headache). The combination of these intense migraine symptoms can be really painful and affect daily life.
While it is true that certain foods can serve as migraine triggers, the idea that computer and phone screens can also contribute to these attacks is not unfounded.
Everyone has some level of sensitivity or discomfort with light. For hypersensitive people, sudden changes in light levels, bright fluorescent lights, and even natural sunlight can exacerbate a migraine.
The brighter the light, the more discomfort people with photophobia may experience. The wavelength or color of the light can also be a factor in discomfort and since blue light is more intense by definition, it is easy to see the problem.
Blue light is generally the most painful shade 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 light sensitivity.
3) Digital Eye Strain
Blue light has a strong intensity and will tend to flicker more as recalled by Dr. Pietrini, (Ophthalmologist, Laureate of the Faculty of Medicine Broussais Hotel Dieu, France).
This causes glare for the eye and makes the visual contrast complex and affects the acuity. On the other hand, it is the duration of exposure and its intensity that present an increasing danger. We are subjected to intensive radiation coming from our screens which diffuse a powerful blue light radiation. This prolonged exposure causes eye strain (eye fatigue, stinging eyes, headaches) and more seriously can damage eye structures such as the lens and retina.
Blue light is not the only one responsible for this computer vision syndrome (UV light, bad reflections, bad lighting...) but it strongly contributes 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 glasses. Be careful with your choice, not all computer glasses are created equal.
As our ophthalmologists pointed out above, you should not filter out any frequency: the goal is to filter out as much as possible the frequencies closest to UV rays to keep only the "good blues". If we were to look at only one frequency range to filter, we would advise you to find a blue light blocking lens that filters a lot of light between 380 and 450 nanometers with a very important attention between 380 and 430 nanometers where the rays are really intense.
Here is finally a small "checklist" recommended by the pros that will allow you to protect yourself as well as possible:
- Use screen glasses or gaming glasses that filter harmful light from screens or LEDs
- Use anti blue light applications that soften the light emitted by your screens (type flux or default app on your phones and computers)
- Avoid screens 2 to 3 hours before bedtime (not easy to do but helps a lot to fall asleep)
- Use dimmed amber lights in the evening
- Take more breaks to give your eyes time to recover
- Don't turn on a light when you wake up at night!
Not directly related to blue light but will contribute to your general well-being:
- Remember to blink to keep your eyes hydrated
- Drink plenty of water to stay hydrated in general
- Adjust the ambient brightness
- Make sure your screen is of good quality / resolution
Blue light glasses: Final thoughts
Blue light protection is important. A significant number of renowned ophthalmologists highlight the dangers of harmful blue light and recommend computer glasses / blue light blocking glasses as a good way to protect your vision(among other things). So it's true, there is still a lot to discover but the precautionary principle is in order for this blue light that has invaded our daily lives and of which many published studies point out serious risks. To stay informed about the latest news and research on blue light and blue light glasses, join our newsletter or protect a friend by recommending this article on social media.