Are Blue LEDs bad for peoples eyes?

[cdev]

CatalinaWOW,  You're confusing me with the OP.

[X]

There actually is an issue with retinal damage, caused by free radicals. Depending on your body's cells redox status exposure to bright blue light may cause retinal damage and it may not.

https://www.ncbi.nlm.nih.gov/pubmed/26743754

The abstract you linked to tells us nothing, it just mentions a blue LED. Can you link us to the full paper so we can actually examine the method and results in better detail? It also talks about mice. The discussion here relates to human exposure to blue light.

Let's not start blurring the lines here, this is how facts become skewed. Humans have been exposed to an abundance of blue light from the sun with no ill effects.

Have fun working on the ethics review for performing an experiment on humans where you intentionally damage their sight. Animal models are used for very good reasons.

However, this still means these experimental results may not accurately reflect human responses. It is known that animal vision is different to human vision due to differences in the way the eyes are structured, so tests on other animals are not an ideal way of determining the effects on humans.

[Someone]

There actually is an issue with retinal damage, caused by free radicals. Depending on your body's cells redox status exposure to bright blue light may cause retinal damage and it may not.

https://www.ncbi.nlm.nih.gov/pubmed/26743754

The abstract you linked to tells us nothing, it just mentions a blue LED. Can you link us to the full paper so we can actually examine the method and results in better detail? It also talks about mice. The discussion here relates to human exposure to blue light.

Let's not start blurring the lines here, this is how facts become skewed. Humans have been exposed to an abundance of blue light from the sun with no ill effects.

Have fun working on the ethics review for performing an experiment on humans where you intentionally damage their sight. Animal models are used for very good reasons.

However, this still means these experimental results may not accurately reflect human responses. It is known that animal vision is different to human vision due to differences in the way the eyes are structured, so tests on other animals are not an ideal way of determining the effects on humans.

A lot of OH&S limits get set by precedence from accidents, unintentional human experimentation. Then its known for sure what levels of hazard caused the damage and then animal models are used to find rates and thresholds. But feel free to question the entire basis of health research using animal models from your uninformed view point, the rest of us will get on with using the valuable information it provides.

I'll skirt Godwins Law here and suggest some people are just never satisfied without having the exact data from real experiments on humans. The civilised world has decided thats not a sociable way to do things.

We know that bright light sources can damage peoples vision, whats so hard to grasp here? If you dont like the scientific basis for setting the limits you can try and show how the studies are invalid rather than just dismissing them because you lack the understanding to see how they're relevant.

[X]

A lot of OH&S limits get set by precedence from accidents, unintentional human experimentation. Then its known for sure what levels of hazard caused the damage and then animal models are used to find rates and thresholds. But feel free to question the entire basis of health research using animal models from your uninformed view point, the rest of us will get on with using the valuable information it provides.

At no point did I suggest that animal experimentation isn't useful, far from it. If this is not validated with experimentation on humans, it renders the resulting data open to questioning. You are introducing more independent variables here, which is the significant differences in traits in species. I see nothing wrong with suggesting that a human experiment will be more accurate, because it should be blatantly obvious that this is the case. Many medical studies are done on humans (commonly known as clinical trials) for this exact reason.

I'll skirt Godwins Law here and suggest some people are just never satisfied without having the exact data from real experiments on humans. The civilised world has decided thats not a sociable way to do things.

Real experiments on humans are regularly performed in the form of clinical trials, waiting for accidents to happen (often with devastating effects), and people volunteering for experimentation. Some experiments do not scale well if you perform them on rats, mice, and pigs. You don't need to be a doctor to work out that experimental results can (and often do) be challenged if the test isn't scientifically fair.
Not all human experimentation is done in a Unit 731 type environment.

We know that bright light sources can damage peoples vision, whats so hard to grasp here? If you dont like the scientific basis for setting the limits you can try and show how the studies are invalid rather than just dismissing them because you lack the understanding to see how they're relevant.

Again, you are assuming that I am blankly disputing the claim. I am only agreeing that the data can be questioned, and in this case, it has. Bright light sources can damage vision, and has been proven time and time again. The point is whether blue light can damage vision, not bright lights. I am not disagreeing with that either, just the validity of only relying on animals.

On that note I first heard about this "blue light hazard" around 10 years ago, and I think human subjects were also studied, but I can't find any links to such a study now. It was also a specific wavelength of blue, near the low-end of the visible light spectrum, at elevated intensity, in concentrations not found in natural light (eg. blue sky).

[Someone]

We know that bright light sources can damage peoples vision, whats so hard to grasp here? If you dont like the scientific basis for setting the limits you can try and show how the studies are invalid rather than just dismissing them because you lack the understanding to see how they're relevant.

Again, you are assuming that I am blankly disputing the claim. I am only agreeing that the data can be questioned, and in this case, it has. Bright light sources can damage vision, and has been proven time and time again. The point is whether blue light can damage vision, not bright lights. I am not disagreeing with that either, just the validity of only relying on animals.

You question it without any basis. Bring something forward rather than just question the validity of it when much more learned people than you or I accept that it is valid. The mammalian eye although having radically different physical structures across species follows the same chemistry, animal models are excellent ways to determine how blue light affects people differently to other light:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/
Thats a recent review of the area.

There are well established standards for exposure of humans to light of all wavelengths

Bright light sources can damage vision, and has been proven time and time again. The point is whether blue light can damage vision, not bright lights.

This makes no sense, there will be thresholds, doses/quantities, and rates which can cause irreversible damage to people at any wavelength. It so happens that the eye is more sensitive than other parts of the body and limited by the optics and transmission of the retina. On top of that its known that the eye is more easily damaged by shorter wavelengths in the blue and into the UV.

The point is whether blue light can damage vision, not bright lights.

Of course it can, and at less intensity than broadband white sources, green, or yellow light. Or do you mean to say: are there still effects of blue light below levels which physically damage the eye? Or are you looking for a linear no-threshold proof for blue light exposure? You could dedicate your entire life to answering that question and get nowhere. Even if there is a linear no-threshold mechanism (up to you to show one) a "safe" exposure can still be found which is based on acceptable damage rates over a persons lifetime.

There is ongoing research about effects beyond the eyes function/damage into melatonin levels but thats not captured in the standards required for public safety (anywhere?). Perhaps that will be included in the future once more is known, perhaps it wont. The safe limits for blue light intensities might be revised up or down in the future based on new information as it becomes available.

[Someone]

A lot of OH&S limits get set by precedence from accidents, unintentional human experimentation. Then its known for sure what levels of hazard caused the damage and then animal models are used to find rates and thresholds. But feel free to question the entire basis of health research using animal models from your uninformed view point, the rest of us will get on with using the valuable information it provides.

At no point did I suggest that animal experimentation isn't useful, far from it. If this is not validated with experimentation on humans, it renders the resulting data open to questioning. You are introducing more independent variables here, which is the significant differences in traits in species. I see nothing wrong with suggesting that a human experiment will be more accurate, because it should be blatantly obvious that this is the case. Many medical studies are done on humans (commonly known as clinical trials) for this exact reason.

Its simply unethical (as considered by the vast majority of people) to do intentional harm to a living person even with their express consent. Not that the world will reject your results if you do choose to do the experiment on humans but very few people would ask for it, because thats unethical.

You're welcome to destroy your vision to prove us all wrong, but I'm happy with animal models and will specifically say you shouldn't damage any persons sight.

[X]

A lot of OH&S limits get set by precedence from accidents, unintentional human experimentation. Then its known for sure what levels of hazard caused the damage and then animal models are used to find rates and thresholds. But feel free to question the entire basis of health research using animal models from your uninformed view point, the rest of us will get on with using the valuable information it provides.

At no point did I suggest that animal experimentation isn't useful, far from it. If this is not validated with experimentation on humans, it renders the resulting data open to questioning. You are introducing more independent variables here, which is the significant differences in traits in species. I see nothing wrong with suggesting that a human experiment will be more accurate, because it should be blatantly obvious that this is the case. Many medical studies are done on humans (commonly known as clinical trials) for this exact reason.

Its simply unethical (as considered by the vast majority of people) to do intentional harm to a living person even with their express consent. Not that the world will reject your results if you do choose to do the experiment on humans but very few people would ask for it, because thats unethical.

You're welcome to destroy your vision to prove us all wrong, but I'm happy with animal models and will specifically say you shouldn't damage any persons sight.

Once again, I am not referring to ethics or "sociability" or how "civil" it is to do experiments on humans, I am simply referring to the validity of applying the results to humans. This has nothing at all to do with ethics.

I was agreeing with another poster that the results of an experiment performed on a mouse cannot be considered a definitive standard for a human, even though it can lead up to it. Animal testing is great for ironing out an initial hypothesis, and may well be fine for situations where human experimentation is not possible, but that's not the point either. The point is that a study conducted on humans will be far more credible in this case than a study conducted on mice.

You can shift goal posts and throw as many accusations at me as you want, it does not invalidate Halcyon's initial point about questioning the application of results of animal experimentation on humans in this case. It also does not invalidate my point that experiments on animals cannot be a definitive standard for the effects on humans, without first seeing results in humans as well.

[X]

You question it without any basis. Bring something forward rather than just question the validity of it when much more learned people than you or I accept that it is valid. The mammalian eye although having radically different physical structures across species follows the same chemistry, animal models are excellent ways to determine how blue light affects people differently to other light:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/
Thats a recent review of the area.

There are well established standards for exposure of humans to light of all wavelengths

Putting it that way, I can appreciate that logic. Chemical reactions are unlikely to differ, but I would certainly be interested if there is a difference between people vs smaller animals in the intensity required for blue light to have a permanent effect.

This makes no sense, there will be thresholds, doses/quantities, and rates which can cause irreversible damage to people at any wavelength. It so happens that the eye is more sensitive than other parts of the body and limited by the optics and transmission of the retina. On top of that its known that the eye is more easily damaged by shorter wavelengths in the blue and into the UV.

Agreed, and there are examples of where this is useful (eg. JPEG compression relies on this by prioritising preservation of certain colours). Upon reading that, I think I made a bit of a mess there, my apologies.

Of course it can, and at less intensity than broadband white sources, green, or yellow light. Or do you mean to say: are there still effects of blue light below levels which physically damage the eye? Or are you looking for a linear no-threshold proof for blue light exposure? You could dedicate your entire life to answering that question and get nowhere. Even if there is a linear no-threshold mechanism (up to you to show one) a "safe" exposure can still be found which is based on acceptable damage rates over a persons lifetime.

Not so much that, but rather what intensity is required for such damage to begin. I am not disputing that blue light can cause damage, but there is definitely a minimum intensity at which this can occur. It would be nice to have some experimental data which can provide a reasonable range here, rather than simply relying on mice. Although for reasons you have mentioned earlier, I doubt this is likely to happen.

There is ongoing research about effects beyond the eyes function/damage into melatonin levels but thats not captured in the standards required for public safety (anywhere?). Perhaps that will be included in the future once more is known, perhaps it wont. The safe limits for blue light intensities might be revised up or down in the future based on new information as it becomes available.

Fine by me, as we can only go by what is currently available. Whilst my point remains about the applicability of such data, I can appreciate that they can only go by what is available, and as I mentioned earlier animal models are the closest we can get at this stage.

All that said, I am sure there is a study that was conducted on humans also (based on a sample of those exposed to this light as part of their occupation, IIRC) but I can't seem to find it. I remember reading about this years ago.

[Halcyon]

All things considered, no one here is yet to supply a source to any kind of respected international standard, WH&S regulation or medical journal which shows any strong evidence to suggest that blue light is detrimental to human eyesight under "normal" circumstances. The only "evidence" seems to be anecdotal at best and barely relates to humans at all.

Optometry has been around since the early 1900's with light in the blue end of the spectrum being around far longer than humanity.  Aside from the well-know influence on melatonin in the brain (which is not detrimental to eye sight), you may as well be arguing that green, or red, or pink sparkly light has a detrimental effect.

But don't take my word for it, speak to an actual health care professional and research reputable sources. You'll find that the biggest issue will be with those that don't actually like the colour blue as a personal preference.

[Someone]

The point is whether blue light can damage vision, not bright lights.

Of course it can, and at less intensity than broadband white sources, green, or yellow light. Or do you mean to say: are there still effects of blue light below levels which physically damage the eye? Or are you looking for a linear no-threshold proof for blue light exposure? You could dedicate your entire life to answering that question and get nowhere. Even if there is a linear no-threshold mechanism (up to you to show one) a "safe" exposure can still be found which is based on acceptable damage rates over a persons lifetime.

Not so much that, but rather what intensity is required for such damage to begin. I am not disputing that blue light can cause damage, but there is definitely a minimum intensity at which this can occur. It would be nice to have some experimental data which can provide a reasonable range here, rather than simply relying on mice. Although for reasons you have mentioned earlier, I doubt this is likely to happen.

So without knowing what the accepted safe limits are or how they were arrived at you still want to question them? I'll stick to accepted standards as I'm obliged to by law and trust that they have been appropriately determined, because even if they're not perfect I'm not liable for those mistakes.

[Someone]

All things considered, no one here is yet to supply a source to any kind of respected international standard, WH&S regulation or medical journal which shows any strong evidence to suggest that blue light is detrimental to human eyesight under "normal" circumstances. The only "evidence" seems to be anecdotal at best and barely relates to humans at all.

Still doing your word play? Blue light has various intensity thresholds beyond where its considered unsafe, some damage may be done to some people even below that threshold. Why all the drama?

[Halcyon]

All things considered, no one here is yet to supply a source to any kind of respected international standard, WH&S regulation or medical journal which shows any strong evidence to suggest that blue light is detrimental to human eyesight under "normal" circumstances. The only "evidence" seems to be anecdotal at best and barely relates to humans at all.

Still doing your word play? Blue light has various intensity thresholds beyond where its considered unsafe, some damage may be done to some people even below that threshold. Why all the drama?

Word play? I thought I was being fairly direct. Others might call it "English". But for your benefit, allow me to simplify: "People are bitching over nothing. Talk to a professional."

Why all the drama? Again, allow me to be direct: Fuck knows?! People should be more worried about whether they should wear a jacket tomorrow or not.

[X]

So without knowing what the accepted safe limits are or how they were arrived at you still want to question them? I'll stick to accepted standards as I'm obliged to by law and trust that they have been appropriately determined, because even if they're not perfect I'm not liable for those mistakes.

Can't argue with that one. I have questioned a lot of standards which I am required by law to adhere to, and I'm more than willing to adhere to them, it gives me the legal ability to point fingers at the people who made the laws when someone gets hurt.

[CatalinaWOW]

CatalinaWOW,  You're confusing me with the OP.

Sorry for the confusion, but my comment was meant for the OP.  Who should have been able to find these links on his own.  I didn't read all of them, but in about 10 minutes of browsing I was able to identify a solid basis for damage thresholds and links to the "Standards" organization which would be the best authority on what is generally accepted as safe levels.  These animal and petri dish studies are not definitive but do provide a lot of guidance.

[CatalinaWOW]

Unless the damage mechanism is thermal it seems unlikely that there will be any level at which no damage will occur.  Even if the mechanism involves multi-photon reactions the damage is determined by photon energies.  The best you can hope for is a level at which damage rate is less than whatever the eye's recovery/repair rate is.  Assuming that it is non-zero.

[Cerebus]

treez - you should hope you, your company can't be linked to this thread

if there are actual adults at your company that see this thread they should rein you in sharply before this thread is linked to the company - if not can you outright

and you have burnt a username for any future jobs asking for examples of your online engineering activity

so far you have shown emotional immaturity with tit-for-tat trollish 'counterpuch' attacks on people trying to help when you saw something not in line with your narrow idée fixe

and intellectual immaturity by not welcoming the broadening of the discussion, trying to learn real issues to make you company's presentation, offer more acceptable

It's so sweeet. He hasn't learned grammar, punctuation, how to use the shift key or put a whole sentence together - but he somehow thinks he's in a position to hand out advice on how to conduct oneself publicly in writing.

[cdev]

Blue light has value for a lot of things, for example in controlling microbial growth. Also, it can help people reset their circadian rhythms.(if used in the daytime) Also, in certain contexts its very relaxing. (But its all important to have the LEDs if you use LEDs not shining right into people's eyes.. To be relaxing they have to be reflected off of walls)

(Strangely, interspersed with the material about the deleterious effects of bright blue light in some contexts are a bunch of fairly interesting articles on positive effects on life forms of pure colors of different wavelengths of light.)

Dichroic lighting filters and fixtures are very interesting in that context. Dichroic lights have a very pure color, not unlike LEDs but the color can be varied by changing the angle the light impinges on the filter. And of course its subtractive, i.e. a filter for existing light. So it can be used structurally in architecture with really interesting and varied effects. One example is the award winning Harpa concert hall in Iceland.


Quote from: CatalinaWOW on Today at 13:17:54>Quote from: cdev on Yesterday at 22:12:19

CatalinaWOW,  You're confusing me with the OP.

Sorry for the confusion, but my comment was meant for the OP.  Who should have been able to find these links on his own.  I didn't read all of them, but in about 10 minutes of browsing I was able to identify a solid basis for damage thresholds and links to the "Standards" organization which would be the best authority on what is generally accepted as safe levels.  These animal and petri dish studies are not definitive but do provide a lot of guidance.