Filtres de lumière bleue : fonctionnent-ils vraiment ?

Qu'est-ce que la lumière bleue ?

Around one-third of all the light you see is blue light, with sunlight being the main source. Blue light is also known as high-energy visible (HEV) light.

Unlike other types of light, your eyes cannot filter it on their own. This means blue light can reach your retina without restriction.

Qu'est-ce qu'un filtre de lumière bleue ?

A blue light filter is designed to protect your eyes from any harmful effects of blue lights.

People spend around seven hours a day regarder des écrans numériques. As this has raised safety concerns, blue light filters are now commonplace across a range of products to increase safety for long-term use - they can be used on everything from phones to lunettes de soleil anti-lumière bleue.

How does blue light affect your eyes?

Potential damage to the retina

Studies show that high levels of blue light, over prolonged periods, have the potential to damage the retina - and that blue light blocking glasses could help prevent up to 80% of this damage.¹ An injured retina can lead to une perte de vision and distortion.

Mais lorsqu'il s'agit d'une plus petite quantité de lumière bleue, il s'agit moins de dommages oculaires et plus de la façon dont elle affecte votre corps.

Eye strain

One of the most common issues people have with looking at screens a lot is la fatigue oculaire numérique. This happens because you blink less when looking at screens, which reduces the amount of moisture in your eyes.

Symptoms of digital eye strain include des yeux secs, récurrents, nausée, douleurs au cou, and more. This is often mistaken for the effects of blue light. At present, there's no evidence that blue light filters can help prevent or ease digital eye strain.²

Avantages des filtres de lumière bleue

Blue light can cause retinal damage, but the evidence for this involves extreme exposure over consistent and long periods.³

In truth, the effects of day-to-day blue light exposure are not yet fully understood - and we don't yet know how beneficial blue light filters are.

Bhavin Shah is a behavioural optometrist at Central Vision Opticians, London. He says that the evidence for blue light filters is inconclusive, and instead opts for a spectral filter on his personal sunglasses.

"This filters out more than blue in the spectrum of light and makes my eyes more comfortable when I'm driving in overcast weather," he explains.

Sommeil amélioré

Blue light exposure affects your circadian rhythm - your body's internal clock.³ Light is critical for how it behaves and adjusts to environmental factors - for example, day and night. This is why too much exposure to artificial light before bedtime, such as blue light from a screen, can make it hard to fall asleep.

Blue light stimulates your eyes and brain, sending signals to your body's internal clock. This in turn affects how your body produces melatonin - the sleep-inducing hormone. So, if you find yourself scrolling through your phone or watch TV before bed to wind down at bedtime, you're actually making your body more alert.

Reducing or cutting out screen time before bed is beneficial for improved sleep and a healthy sleep pattern. For screen-time you do have, blue light filters can help limit blue light exposure.