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Light Density of computer screens

Light density of computer screens

When we talk about the potential harmful blue light in the light of computer screens, is an argument for the safety of this radiation is often the low light density of these screens. Alexander Wunsch, a known photo biologist and physician, has to do with some of the most common misconceptions in this text:

Hitherto photo retinitis (damage to the retina) by optometrists described only in people without lens and through the influence of daylight.

In the future may make it necessary distinction between acute and chronic fotoreinitis. While the symptoms of acute photo retinitis become apparent within hours, the years, it sometimes takes decades before the damage can be determined in a chronic fotoreinitis. A study by the French health authority ANESES assumes that the amount of blue light to which the retina is exposed for a lifetime correlates with the occurrence of AMD (age-related macular degeneration). It is therefore recommended not to use white or blue LEDs in the presence of children, because they have very transparent eyepieces. Scientists speak of an accumulative effect of shares of blue light except that limiting the amount of short-wave blue light to which the eye is exposed, may be a preventative measure against the development of age-related macular degeneration.

No damage to the retina is described by daylight or a person had natural or artificial eye lenses.
This statement is not true; as an example, there is the perception that after implanting a completely transparent artificial eye lenses, increased occurrence of AMD. Again, we're talking about a chronic and not acute process.

The luminance (luminance) of TFT monitors is about the power of ten below the luminance of light.
The luminance of monitors is indeed much lower than daylight. But there are signs that not only the absolute intensity should be considered, but also the spectral distribution of light, which plays a vital role. In addition, a pure focus intensities neglects the fact that the concentration of visual pigment in the retina depends on the brightness of the surroundings. The extreme adaptability of the eye for different densities of light is not limited to the pupil activity (max. Factor 16!), But is mainly done by chemical modification. When it is dark, a much higher concentration of visual pigments can be found in the photoreceptors. This increases the "target" for photochemical damage. only bright daylight contains natural conditions blue wavelengths therefore meet a low concentration photo pigments. When artificial light, with a much lower intensity, has a high proportion of blue light, it meets a higher concentration of photo pigments. Because these exposed photo pigments can act as a photo chemical sensitizers, a photo-chemical damage by light with a low intensity is also possible.

Although millions of TFT monitors are used, there is no damage reported by the light of TFT monitors.
Chronic damage to the retina does not develop within a few years. TFT monitors are not sufficiently long been in use in order to take safety, especially since the prevention of the age-related macular degeneration is increasing continuously, since non-thermal light sources (e.g., fluorescent lamps, compact fluorescent lamps, and TFT monitors) are introduced.

The increasing age of the population can not explain this fact, especially when the age decreases in the activities of ADM. For a risk assessment should take into account the increased use of non-thermal light sources. The current practice of risk assessment for light sources, e.g. by ICNIRP * or CIE **, based on an eight-hour day and must be adjusted because many people not only eight hours watching a monitor at work but also at home are exposed to blue light. front of the television, or room lighting. It should be noted that artificial light sources such as lamps or white light LEDs, particularly active in the spectral region that is mainly responsible for the so-called blue light hazard and photo retinitis.

* = ICNIRP International Commission on Non-Ionizing Radiation Protection
** = CIE International Commission on Illumination

Alexander Wunsch, physician and biologist light, Heidelberg, GERMANY

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