The use of light-emitting diodes (LEDs) is becoming increasingly widespread. But this cold lighting, too rich in blue light, can have an impact on sight and sleep. What solutions to limit the risks? Which bulbs should you buy?
LED technology is now used in lighting fixtures, flashlights, car headlights, but also in computer monitors and smartphones.
How do LEDs attack the eyes?
The blue light of LEDs has a short and very energetic wavelength. This intense flow attacks the cells of the retina and disturbs the secretion of melatonin, the sleep hormone, which depends on variations in natural light.
“The retina can withstand a certain amount of light, but at some point its repair capacity is overloaded,” explains Dr. Alicia Torriglia, director of Inserm research (The Institut national de la santé et de la recherche médicale).
However, in human history, the eye has adapted to “warm” lighting, especially at night: fire, candles, then incandescent lamps. With LEDs, he has to tolerate much colder blue light. For the retina, it is not ideal.
There are safety standards for domestic lighting, but not for toys or torches. In addition, the current limit values calculated for an exposure of less than 8 hours per day “do not take into account chronic exposure to LEDs, every day and for several years,” says Professor Francine Behar-Cohen, Professor of Ophthalmology.
Who are the most sensitive?
Children: Their lens that filters the light rays and directs them towards the retina, is transparent. It allows more blue light than an adult eye would allow to pass through. However, prolonged exposure to high light levels increases the risk of AMD (age-related macular degeneration). In addition, children spend a lot of time on the screens, running the risk of disturbing their sleep.
Elderly people: With age, the eye becomes more sensitive to light and glare. Too much blue light could cause “premature aging of the retina,” according to Dr. Torriglia, which indicates a potentially higher risk of AMD.
Migraines and epileptics: The light level of LED lamps fluctuates more or less significantly. This sparkle can cause headaches or even an epileptic seizure.
Pregnant women: Animal studies have shown that exposure to blue light during pregnancy disturbs the circadian rhythm of the fetus and, consequently, its development. “We advise pregnant women not to spend time on the screen at night,” says Behar-Cohen.
Patients with eye disease: When the lens and retina are unhealthy their fighting capacity against LED lights is diminished.
Some professionals: night work and some professions expose to artificial lighting for long hours.
What to do against the blue light of LEDs?
Avoid LED toys and decorative blue lamps.
Let the children play as much as possible in daylight. The more time they spend outdoors, the lower the risk of myopia.
Ideally, turn off the screens 2 hours before going to bed and do not use your smartphone or tablet in the middle of the night.
Download the free F.lux software that reduces the blue light on your screens at night. Some models of computers or tablets do it automatically. Not all blue anti-reflective glasses are effective.