LED lighting damages your eyes

https://science.slashdot.org/story/19/05/15/1947255/led-light-can-damage-eyes-health-authority-warns

Very good points, thank you Gizmo and Daniel! I forgot about LED driven monitors, oops. Happily one of my monitors is LCD. I could have LED light bulbs everywhere but refuse them. Which is a bit of apita and compact fluorescents are not as good or bright as they used to be. Seems true to me.

imho LED light bulbs are bad for your eyes because they emit too damn much blue. That's what I read at any rate.

I bow to your superior knowledge. But at least I know that too much intensity of "hi freq" blue is dangerous. Sheeite, I'm already half blind.

Just to add to Gizmo's post above, any frequency of light, including some that our eyes' lenses can bend, but which we cannot perceive, is potentially dangerous. If you repeated the experiment described above with red or green light, the same effect would be present. The various militaries around the world have long toyed with the concept of infra-red or ultra-violet lasers being used as a non-lethal weapon to blind enemy combatants without giving your own position away.

Why blue LEDs are being picked on (and also phosphorescent light like CFL, CRT and so forth) is that while the eye responds best to ~420nm blue light with limited deviation, the commercially produced LEDs are ~450 to ~470nm. To get the same response, a higher intensity blue is needed. I've attached a quick paint-mash to illustrate this. It's easier to produce red/green LEDs that fall within the eyes sensitive range, because those ranges are so much wider than for blue.

Normally this isn't a problem, if you follow sensible screen habits, like taking regular screen breaks, spending regular time outdoors (where the environment is bathed in blue and ultraviolet light, but with differences in intensity and focal length that the eye is adapted to process), and moderating your diet, weight, smoking, alcohol intake, head trauma (boxers take note), avoid staring directly at the sun, arc welding and metal smelting, and don't let anyone point a laser pointer at you.

On the scale of risks to eyesight, blue isn't the only problem.

Ah, so. That's why the hipsters always wear dark glasses. But it's ALREADY so dark for most of the year in Seattle. I'm already stuck on many things, there's room to remove blue light from the list. Thanks for the clarification Gizmo and Kaitain!

I always thought that was due to the effect of cocaine on the dilation of the pupil

I'm sure that it is so far too often.

Cocaine. What plain terrible stuff. The stuff simply demands that one ingest more. Thank God I missed crack!

I can attest to the fact that incandescent light bulbs nowadays are made to die extremely quickly. Got eleven days burning time out of a 60-watt bulb that's under the range hood recently. And that was "running" all the time, no off and ons to strain it's poor widdle filament. They more often last for six weeks or so. Made in Hungary by GE, that wondrous corporation that used to bring good things to life- allegedly.

I don't know what 2700 degrees Kelvin means in the spectrum of light. How did you measure this quantity if I may ask?

Thank you for letting us know that dimm-able LED bulbs flash rapidly. Who knew?

The colour temperature relates to the frequency of light emitted by an ideal black body emitter at a specific temperature.

In more human terms - you know when you heat metal and it glows red hot, then white hot? If it didn't melt, it would eventually glow blue hot. Ironically, "cold" colours are hotter than "warm" colours, as they're higher energy photons. An ideal black body emitter can be thought of as a material that stays roughly unchanged with temperature. If you heated that material to 2700K, it would emit light roughly the same colour as danrok's light bulb. If you heated it to about 5750K, you'd get sunlight which has less red, more blue and appears more yellow-white to human eyes.

Thank you very much for the "graph" danrok. It looks like 2700 Kelvin doesn't feature any blue. If I can find LED bulbs that put out 2700 K I think no one's eyes seeing it would be "over blued."

Which brings the thread full-circle.

A 2700K light has some blue. The LEDs most commonly made for blue don't quite match up with the human eye's sensing range for blue light, so a higher absolute intensity of blue is needed to create the right perceived intensity. Thus your eye may be receiving more blue than you expect. A highly artificial laboratory test involving causing rats to stare at a high intensity strobe light highlighted that optical cells were more greatly affected by blue than by red or green light, thus the scientists raised a concern over LED lighting.

It's worth remembering that researchers express similar concerns all the time, and that these have to be put into context. If you take the global population who went blind in later life due to one of the mechanisms suggested in the study (really, cataracts and/or macular degeneration) you might have a statistical risk of 0.067%* of going blind. Use of LED lights might increase that risk a little. Even if it doubles your risk - 0.13% is still a low likelihood of being affected, and you can safely ignore it.

* based on a very rough count of number of people reporting blind in the US multiplied by the fraction typically due to cataracts and macular degeneration, roughly a third, using numbers from wikipedia. It's just to illustrate that doubling a small risk is still a small risk.

Thanks Kaitain, this is useful and interesting information. I made my cataracts read this post, they feel good about their very slow growth now!