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I was reading the following article on Wikipedia which discusses the dangers of blue light:

Blue-light hazard is defined as the potential for a photochemical-induced retinal injury resulting from electromagnetic radiation exposure at wavelengths primarily between 400 and 500 nm. This study has not been done in humans, only inconclusively in some rodent, primate, and in vitro studies.[4] The mechanisms for photochemical induced retinal injury are caused by the absorption of light by photoreceptors in the eye. Under normal conditions when light hits a photoreceptor, the cell bleaches and becomes useless until it has recovered through a metabolic process called the visual cycle. "1-2 min of 408 nm and 25 minutes of 430 nm are sufficient to cause irreversible death of photoreceptors and lesions of the retinal pigment epithelium.

Similarly, the highest voted answer to this question basically suggests that the blue light hazard is real (based on the assessment by ANSES)

"Based on these observations we have considered it necessary to restrict sales of LEDs to the general public, to LEDs which don't present more of a blue-light risk than other traditional lighting. "

I would like to know:

  • Are there any studies on humans that show the dangers of blue light (or is the danger only a hypothesis)?

  • Are there any other dangers of blue light besides for AMD? Are the purported effects short term or only long term?

  • Most importantly, how can blue light be so harmful if 25% of the suns radiant energy is radiated as blue light? And about 100,000 lux of light reaches the earth from the sun on a sunny day.

  • Finally, is there any real reason to believe that exposing one's eye to 25,000 lux of blue light from artificial sources would be harmful?

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    $\begingroup$ You ask "How can blue light be so harmful if 25% of the suns radiant energy is radiated as blue light?" Staring at the sun for even relatively short periods is known to damage your eyes. $\endgroup$ – Peter Shor May 26 at 23:38
  • $\begingroup$ @PeterShor the point is in percentage, not in absolute radiance. $\endgroup$ – Ruslan May 28 at 6:13
  • $\begingroup$ @Ruslan: I really don't understand your previous comment. If you dilute one part of blue light in three parts of white light, why should it be any less harmful than the same amount of blue light undiluted? $\endgroup$ – Peter Shor Jun 2 at 17:34
  • $\begingroup$ @PeterShor you don't have to dilute anything. The point is that solar radiation is all around (a fair amount of it is scattered into your eyes even if you don't look at the Sun directly), and 25% of this radiation is the supposedly harmful blue light. $\endgroup$ – Ruslan Jun 2 at 17:43
  • $\begingroup$ I agree ... it shouldn't be harmful to your eyes unless you look straight at it for some time. But if you look at the sun, it can definitely harm your eyes. The same should be true for bright blue light. $\endgroup$ – Peter Shor Jun 2 at 17:45

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