Can anyone explain to me how looking at a computer screen is not several times less harmful than spending time outside from a lifetime-blue-light-exposure perspective? The sky is blue and natural light has a blue component in probably about the same proportion as white light from a screen.
Maybe I'm wrong — and I'd like to find out if I am — but this whole blue light scare really just feels like a weird bandwagon.
> Just looked up blue light photo toxicity, that is some scary stuff! So is staring at blue light computer monitors all day causing corneal cell death?
I think you're going to be OK. There is a very large, strong (stronger than any monitor) source of blue light that your eyes can handle at least 12 hours of exposure per day to
> Blue LED light may be toxic to your retina with long term exposure.
I wasn't aware of this. Do you mean LED light specifically? Is it in some way inherently different from the much more intense blue light of the sun? I don't see how light from one source can be any more damaging than from another source; it's all just the same EM radiation.
> This does not sound that good in the light that Chemist recently discovered that blue light speeds up blindness.
This is a nice example of Chinese whispers at work. No proof was presented that blue light speeds up blindness, and besides that the amount of blue light in normal sunlight pales in comparison with the output of your average monitor. Sunlight is about 1 KW/sq meter, an LCD display is a very small fraction of that (which is why most displays except for e-ink are impossible to read in full sunlight).
> Blue light is a type of light that is emitted by the sun and by electronic devices, and it has been shown to cause strain on the eyes and disrupt sleep patterns.
This (older) article says: "we don't spend that much time staring at the sun". But just seeing the blue sky gives your retina about 50x the dose of blue light (hazard) as a normal LED display.
Blue light hazard is generally considered to be "reciprocal" which means for most doses, you can measure total energy (power * time). So it is easy to argue that one hour spent outdoors (not staring at the sun, just doing normal stuff) gives you more dose than 12 hours at a computer. So for light seen during the day, nobody has yet shown that seeing a computer is harmful, and the risk should be lower than spending an hour outdoors.
At night, it's another story, and there is not clear evidence here. The retina experiences daily circadian rhythms, and so risks to your eye may be enhanced by bright light seen at night. Less light at night is good for your circadian clock, and it is almost certainly good for your eyes too.
"But ophthalmologists aren’t worried. The blue light emanating from the sun drastically overpowers any rays coming from your screen. And so far, all of the research on how real human eyes react to blue light has failed to link screens to permanent damage of any kind. Blue light’s most concerning effects still seems limited to sleeplessness."
> I always thought that staring at monitors with blinding brightness is what causes retinal damage, not just blue light specifically.
Just curious, did it ever occur to you how much more blinding even a cloudy day outside is? Adjust cd/m2 to roughly match the ambient brightness of the room, that's general ergonomic advise.
>Pretty sure this is all snake oil — both f.lux and Night Shift. I don't doubt that blue light affects our brains. But I see no evidence that color filter software has any impact.
A color filter such as in Flux and NS removes blue light.
>If the issue is the number of blue photons per square millimeter of our retinas, why isn't it being discussed as such? This means screen brightness and distance from your face would have a much bigger impact than a color filter.
No, it doesn't mean that at all.
Or rather, it does, but it's a moot point. All you're saying is: you can reduce blue light with an orange filter, but you can also go away from your screen or dim it so you can't see it. Or even not use a computer at all.
While all of those things hold, the "orange filter" achieves the same thing (removing blue light) without affecting our ability to work regularly on the computer (increased distance, less brightness, etc).
I'm not sure how people come up with such logic errors.
>FWIW the only person I've known to use f.lux is an insomniac who barely ever sleeps and is always tired.
It's not worth much. It's not supposed to cure insomnia (which has 2000+ different causes), just to keep up with the natural light changes and improve sleep.
>such as some of the blue LEDs used in Xmas tree lights, and the old blue lights that were on police call boxes. Both of those are very hard for me to focus on
This happens to me as well and I though I was becoming blind (to blue light) because of my heavy use of monitors/"white" light, etc...
> To continue on this topic, blue light filters may look pleasing to some but it’s not sure whether they do have an effect
I don't know if they have an effect or not, but I much prefer having it on. It feels easier on the eyes. When I turn it off I immediately feel a kind of discomfort.
I don't believe it actually has an effect on my health. But the warmer colors definitely have an effect on my comfort.
OFFTOPIC: Isn't blue light still best to be avoided as much as possible, as it damages cells in the eye, causing macula degeneration. Please correct me if I'm wrong.
> there is no good evidence that filtering blue light with spectacles...
That's likely referencing this recent review[1]. The products referenced don't actually reduce blue light by much, which you can confirm in the studies. The lenses look transparent, not amber in many cases. Which makes sense because they're meant for all day use, but it's just a marketing thing.
If you bought glasses in person in the last 10 years, they probably tried to upsell a blue light or "screen strain reduction" filter.
It's a stretch to hold this as evidence that blue light doesn't affect us.
It's a good video, but it's also a case study in being 'almost right'. The almost-correct interpretations cascade and result in a faulty conclusion: that blue-white LED streetlights are better than orange-white streetlights. Various comments object to the faulty conclusion ([1], for example).
At the end he at least addresses his ignorance:
> [18:39] You may have noticed that I didn't talk about the blue light from LEDs, and how this is supposedly ruining our eyes. That's because the "science" behind this is questionable, at best.
> [18:55] [discussion of chart with percentage blue light of various light sources]
> [19:04] [...] but considering that our eyes can withstand the intensity of sunlight, which is far far greater than any normal artificial light source, and also has a lot of blue light, and ultraviolet, which definitely is harmful, I think the 'blue light' thing is just fear-mongering. If someone can point to some verified, peer-reviewed research supporting this, and not a dodgy website, I'll consider changing my stance. In any case, the high flexibility of LED technology means it can be tuned in pretty much any way we like.
The research on the harm of blue light is out there -- For example, one of the comments links to "Effects of blue light on the circadian system and eye physiology" [0]. (only partially read at this point - I don't know if this paper gets into the mechanism of damage done by blue light, as I understand it...)
The sun hangs high in the sky and casts light on everything. We never need to look at the sun directly, we use the sun's light indirectly, after it bounces off of things. The atmosphere scatters the sun's blue light before it gets to us [2]. Artificial lights hanging on poles emitting photons we can't avoid having beamed directly into our eyes... Blue photons have relatively higher energy levels, and different physiological effects, than orange photons... [note to self: expand on this.]
My transcription of the video's faulty conclusion (italics added):
> To conclude: although the High Pressure Sodium light is very efficient, its primary output color is misaligned with our nighttime visibility. Only about 1/4 of its light is actually effective at stimulating the cells in our eyes. Although the cool color temperatures of many LED replacements is harsh and aesthetically displeasing, studies have shown that it is not only more efficient, but also makes driving at night safer. There is, however, the potential for greater circadian rhythm disruption and larger amounts of skyglow, using these bluer light sources.
> Still, it seems clear that the High Pressure Sodium is on its way out. Advancements in LED technology are happening at a breakneck pace. Just 10 years ago, they weren't seen as viable, but today even the least efficient of LED replacements ends up emitting the efficiency of High Pressure Sodium once scotopic light output is considered.
> As it stands in 2018, we are faced with the choice of efficiency over aesthetics. I'm pretty sure I'd enjoy roadways lit with relatively-warm 3000K LEDS, and these also wouldn't disrupt sleep much. But you can save a lot more energy, and potentially have safer roadways, with 5700K lighting.
> Either way, it seems clear that LED technology will very soon overtake the tried-and-true High Pressure Sodium lamp, just as the High Pressure Sodium itself replaced the mercury-vapor lamp. And in 40 or 50 years, who knows what technology might light our roadways.
Most general discussion on the net about the adverse effects of blue light is in the context of artificial light, such as from screens. People sometimes get the mistaken impression from this that natural light does not have significant blue content, and the bad effects of blue light in artificial sources comes from blue light being something that we did not evolve to deal with it all.
The point of the parenthetical comment was that our sensitivity to blue light is not because it is something we did not naturally encounter and so it is some kind of irritant we have not developed a tolerance for, but rather because we evolved sensitivity to it as a way to sense the day/night cycle, so of course there is significant blue light in sunlight. If there wasn't we would not have developed sensitivity to it. We would have developed sensitivity to some other color that is significant in sunlight.
Can anyone explain to me how looking at a computer screen is not several times less harmful than spending time outside from a lifetime-blue-light-exposure perspective? The sky is blue and natural light has a blue component in probably about the same proportion as white light from a screen.
Maybe I'm wrong — and I'd like to find out if I am — but this whole blue light scare really just feels like a weird bandwagon.
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