Whether on the smartphone or on the PC: Measures that reduce the proportion of blue light on the display, which is said to be harmful to eyes and sleep, are now available almost everywhere. On the basis of new studies, vision researchers claim that this is superfluous.
DOG: Consumers are deceived
” LED displays are no danger to eyes or sleep “, explain experts from the German Ophthalmological Society (DOG) and refer to current studies (PDF). This runs contrary to previous assumptions, which are based on studies and expert opinions.
According to DOG President Professor Dr. med. Hagen Thieme, Director of the Magdeburg University Eye Clinic, “educates and protects consumers from misleading advertising and unsettling false reports that pursue purely commercial interests”. Blue light filters (low blue light) in PC monitors, special glasses or the night mode in smartphones such as “Night Shift” on the iPhone are thus assumed to be superfluous.
No retinal damage from blue light
Researchers and manufacturers have been warning for years about the high-energy short-wave blue light emitted by the LED backlight of liquid crystal screens. Professor em denies that this can even lead to retinal damage. Dr. rer. nat. Michael Bach from the University Medical Center Freiburg. The light intensity when using electronic devices is “far too low to cause retinal damage to the eyes”.
A comparison should make this clear: “The natural illuminance outdoors when the winter sky is overcast is around 5,000 lux in our latitudes, and up to 100,000 lux on a sunny day. A computer screen, set very brightly, remains below 500 lux at a distance of 50 cm, ”says the DOG press release. “Even if children sit for hours in front of screens as a result of corona-related distance learning, at least blue light eye damage is not to be feared,” explains Bach and also refers to a more recent study with 120 test persons, in which it was found that contact lenses with “blue light -Blocker “compared to conventional contact lenses would not have a positive effect on eye fatigue.
No sleep disturbances from blue light
Another study aims to refute the fact that blue light disturbs sleep when reading on the display in the evening. The total of 167 participants in the study had to run through one of three scenarios one hour before bedtime for a week: use the iPhone with night shift activated, use the iPhone without night shift or not use a smartphone at all. In the end, it was found that there were “no significant differences” in terms of sleep quality. However, the quality of sleep was still best without using a smartphone before going to bed.
However, the vision researcher Bach still gives one recommendation: “Use an electronic device before going to sleep should avoid maximum brightness – this recommendation sounds trivial, but it is correct. “
Older studies draw a different picture
Even if there are commercial ideas behind many measures to reduce blue light, they did not arise entirely without a reason. A whole hodgepodge of older studies warns of the possible negative effects of short-wave blue light on the organism. The wavelengths between 415 nm and 455 nm are considered particularly harmful. However, there is a lack of clear evidence.
Negative consequences of blue light have often been questioned
The fact is that blue light also occurs in nature and is much stronger than on a screen. Therefore, negative consequences of increased screen consumption were often questioned before.
Es there are further studies that classify blue light from displays as rather harmless. One study (albeit with mice) even states that yellow light can disrupt the sleep rhythm in mammals more than blue light.