LEDs are the ideal alternative to the energy-wasting light bulb and the polluting and rather unsightly energy-saving or halogen lamp. Or are they not?
After they took the market by storm, criticism naturally hails. "LED lamps carry the risk of photochemical damage to the retina," it has been echoing through the media for about a year now.
But what's the real story?
The proportion of blue light emitted by LED lamps is criticised. LEDs cannot produce "white" light for technical reasons. Similar to the sun, they use different spectral colours, including blue.
And this seems to be the problem: blue light is rich in energy and can therefore negatively affect light-sensitive biological structures such as the retina. It is questionable whether LED light can actually be unhealthy to such an extent. After all, humans have been operating successfully in daylight for more than 2 million years.
In order to warn sufficiently of the dangers of blue light, however, various articles refer to the results of a study. For these, the researchers chose rats as experimental animals.
Firstly, it is questionable to what extent the eyes of animals can be compared with those of humans. Secondly, the scientists exposed the rats to much too much light for days. But we humans do not use LED lighting in this way.
The first LED generations certainly contribute to a large extent to the bad image. With a color temperature of 4,000 Kelvin (K) and more, they produced cold white light, which certainly did not provide a comfortable environment. In addition, flickering and headaches caused by the still new technology were pre-programmed.
Modern, high-quality LEDs are now state of the art. They not only provide warm white light (≤ 2.700 K), which we know from the often painfully missing light bulb. In the meantime, all colour spectra are available flicker-free. LEDs thus fulfil almost all purposes - from the practical illumination of any workplace to a cosy and decorative light source for the home.
It all doesn't sound so bad, does it?
And Germany would not be Germany if everything was not standardized.
For photobiological safety of luminaires and lamp systems there is DIN EN 62471, which distinguishes between four risk groups from "free" to "high". Under even stricter measurement criteria than those provided for in this standard, the Swiss Federal Institute of Metrology has tested the blue light exposure of LED luminaires at various distances. The result was that all tested lamps belong to the free, or at most to the risk group one. This means that they can be used between 100 and 10,000 seconds of direct exposure without risk. And nobody really looks into a lamp for that long!
So there is no need to worry as long as you don't put a theatre spotlight in your home or office. And there are such wonderful alternatives to those...
