Blue Light: Controversial Glow
Blue light plays an increasingly important role in our everyday lives. Studies show: It also affects our health…
Smartphones, wafer-thin tablets, modern computer screens and flat-screen televisions – without modern LED technology they would be unimaginable. Energy-saving light-emitting diodes no longer dominate the lighting of streets and our homes.
Evidence of damage to health
However, if we look at glowing screens at close range for many hours and are constantly in an environment illuminated by LEDs, this is not without consequences: Everyone has probably had tired, dry eyes at some point.
Scientists suspect even more unpleasant consequences, however: Near-sightedness is increasing dramatically, some studies indicate that the high proportion of blue light in LEDs can damage the retina, and there is even talk of a link between nighttime lighting and some types of cancer.
The higher the level of education, the more short-sighted?
More and more people in Europe are short-sighted. According to a study published in the European Journal of Epistemology, around 47 percent of 25 to 29-year-olds now suffer from so-called myopia, but only 28 percent of 55-59-year-olds.
And the Gutenberg Health Study comes to the conclusion that 53 per cent of university graduates are short-sighted, but only about a quarter of people without training or higher education.
Experts explain the connection with the fact that young people spend a lot of time indoors at school and university, staring for hours at books and increasingly at smartphones and tablets.
A question of usage
“Among other things, myopia has something to do with the growing eye,” explains Professor Olaf Strauß from the Department of Experimental Ophthalmology at the Charité in Berlin.
“If one frequently focuses on close objects while the eye is still growing, this can lead to increased longitudinal growth of the eyeball,” says the retinal researcher. “Then the sharp image does not appear on the retina, but just before it.”
However, myopia is not directly related to the LEDs in smartphones. Rather, it is the user behavior that is decisive. However, there is another property of light-emitting diodes that is now causing many experts concern: the high proportion of blue light.
More light, less visibility
Many epidemiological studies show that too much is generally dangerous and can damage the macula. This is the area of sharper vision where a particularly large number of light-sensitive cells, the photoreceptors, are concentrated.
Scientists from the research institution INSERM have now tested the effect of different light sources at different intensities in laboratory experiments. It was shown that the blue light component of the LEDs causes defects in the macula already at an intensity of 500 lux – which corresponds to the usual brightness in living rooms.
Although the researchers did not work with real test persons, Professor Albert J. Augustin, Director of the Eye Clinic at the Municipal Hospital in Karlsruhe, says: “I believe that these results can and must be transferred to humans”.
A corresponding study in humans would hardly be feasible and ethically unacceptable.
Visual cells die off earlier
“The bundled light falls on the retina and reacts there with the abundant oxygen,” explains Olaf Strauß, explaining how the high-energy blue light affects our visual cells. “Toxic compounds are formed from the metabolic products of the cells, which accumulate throughout a lifetime and damage cell components.”
Normally, visual cells would not die until the age of 60 and age-related macular degeneration could occur – a permanent shower with high-energy light would accelerate this process.
Suspicion: Risk of cancer increases
And the modern lighting devices may also involve other risks: a study published in April with more than 4,000 participants aged between 20 and 85 years from eleven regions of Spain nourishes the suspicion that blue light may promote the development of some forms of cancer.
The researchers analyzed the data of breast and prostate cancer patients, compared them with healthy control subjects and recorded how intensively the respective persons were exposed to blue light indoors and outdoors.
The result: In people who lived in an environment rich in blue light, the risk of breast cancer was 1.5 times higher and the risk of prostate cancer twice as high.
LED disturbs sleep
According to the Spanish scientists, an increased dose of blue light before going to bed suppresses the formation of the hormone melatonin, which controls the sleep-wake rhythm. A melatonin deficiency, on the other hand, as other studies show, could be related to hormone-dependent tumours, such as breast or prostate cancer.
Although the Spanish study does not provide any proof of this mechanism, it only establishes a statistical link and not a causal chain. This is the main problem with such observational studies: that it is not possible to clearly separate different possible causes.
This is because people who stay up late at night or work shifts often have different eating habits or health awareness than average.
Experts expect political intervention
Nevertheless, people are worried, as is also noticeable at the Cancer Information Service (KID) of the German Cancer Research Center in Heidelberg: “We receive many inquiries as to whether nocturnal light, shift work or the use of mobile phones or tablets at night might increase the cancer risk,” says KID staff member Dr. Birgit Hiller.
“But the studies to date are too contradictory and there is no certainty about the actual connections.
Eye specialist Augustin sees the legislator as having a duty in view of the possible dangers posed by modern light sources: “Actually, it would be up to the politicians in countries to work towards ensuring that the LEDs have a lower blue component.
Get yourself active
But everyone could also do something themselves, for example do without light-emitting diodes at home or use lenses that reduce the blue component. There are already quite normal, non-tinted lenses that can reduce the amount of light in the home.
Olaf Strauß considers it sufficient to equip oneself with so-called warm-white LED lamps in the home: “With these the blue light component is significantly reduced. On the packaging, the heat of the light is indicated in Kelvin; if the colour temperature were below 3000 Kelvin, I would have no reservations”.
Avoid blue light before falling asleep
On the other hand, most experts consider the relatively low blue light component in smartphones, monitors or televisions to be hardly dangerous for the retina. In the evening, however, the devices should not be used without additional lighting in the room. This is because in a dark environment, the pupils dilate and more blue light can fall on the retina.
Many computers and mobile phones therefore now have a special night mode in which the blue light component is reduced and the image appears in a warmer, yellowish tone. This has another advantage: if you check the latest news of the day in a snooze light, it is easier to fall asleep.