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Thread: Ut chemists discover how blue light speeds blindness .......................

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    Redhot Jumper Ut chemists discover how blue light speeds blindness .......................

    University of Toledo

    UT CHEMISTS DISCOVERHOW BLUE LIGHT SPEEDS BLINDNESS
    By Christine Billau : August 8th, 2018


    “We are being exposed to blue light continuously, and the eye’s cornea and lens cannot block or reflect it,” Dr. Ajith Karunarathne, assistant professor in the UT Department of Chemistry and Biochemistry, said. “It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop.”

    Macular degeneration, an incurable eye disease that results in significant vision loss starting on average in a person’s 50s or 60s, is the death of photoreceptor cells in the retina. Those cells need molecules called retinal to sense light and trigger a cascade of signaling to the brain.

    “You need a continuous supply of retinal molecules if you want to see,” Karunarathne said. “Photoreceptors are useless without retinal, which is produced in the eye.”
    Karunarathne’s lab found that blue light exposure causes retinal to trigger reactions that generate poisonous chemical molecules in photoreceptor cells.

    “It’s toxic. If you shine blue light on retinal, the retinal kills photoreceptor cells as the signaling molecule on the membrane dissolves,” Kasun Ratnayake, a PhD student researcher working in Karunarathne’s cellular photo chemistry group, said. “Photoreceptor cells do not regenerate in the eye. When they’re dead, they’re dead for good.”

    Karunarathne introduced retinal molecules to other cell types in the body, such as cancer cells, heart cells and neurons. When exposed to blue light, these cell types died as a result of the combination with retinal. Blue light alone or retinal without blue light had no effect on cells.

    “We are being exposed to blue light continuously, and the eye’s cornea and lens cannot block or reflect it,” Dr. Ajith Karunarathne, assistant professor in the UT Department of Chemistry and Biochemistry, said. “It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop.”

    Macular degeneration, an incurable eye disease that results in significant vision loss starting on average in a person’s 50s or 60s, is the death of photoreceptor cells in the retina. Those cells need molecules called retinal to sense light and trigger a cascade of signaling to the brain.

    “You need a continuous supply of retinal molecules if you want to see,” Karunarathne said. “Photoreceptors are useless without retinal, which is produced in the eye.”

    Karunarathne’s lab found that blue light exposure causes retinal to trigger reactions that generate poisonous chemical molecules in photoreceptor cells.

    “It’s toxic. If you shine blue light on retinal, the retinal kills photoreceptor cells as the signaling molecule on the membrane dissolves,” Kasun Ratnayake, a PhD student researcher working in Karunarathne’s cellular photo chemistry group, said. “Photoreceptor cells do not regenerate in the eye. When they’re dead, they’re dead for good.”

    Karunarathne introduced retinal molecules to other cell types in the body, such as cancer cells, heart cells and neurons. When exposed to blue light, these cell types died as a result of the combination with retinal. Blue light alone or retinal without blue light had no effect on cells.

    “No activity is sparked with green, yellow or red light,”Karunarathne said. “The retinal-generated toxicity by blue light is universal.It can kill any cell type.”


    The researcher found that a molecule called alpha tocopherol, vitamin E derivative and a natural antioxidant in the eye and body, stops the cells from dying. However, as a person ages or the immune system is suppressed,people lose the ability to fight against the attack by retinal and blue light.“That is when the real damage occurs,” Karunarathne said.

    The lab currently is measuring light coming from television,cell phone and tablet screens to get a better understanding of how the cells in the eyes respond to everyday blue light exposure.

    “If you look at the amount of light coming out of your cellphone, it’s not great but it seems tolerable,” Dr. John Payton, visiting assistant professor in the UT Department of Chemistry and Biochemistry, said.“Some cell phone companies are adding blue-light filters to the screens, and Ithink that is a good idea.”

    To protect your eyes from blue light, Karunarathne advises to wear sunglasses that can filter both UV and blue light outside and avoid looking at cell phones or tablets in the dark.

    “Every year more than two million new cases of age-related macular degeneration are reported in the United States,” Karunarathne said.“By learning more about the mechanisms of blindness in search of a method to intercept toxic reactions caused by the combination of retinal and blue light,we hope to find a way to protect the vision of children growing up in a high-tech world.”

    source:
    http://utnews.utoledo.edu/index.php/...eeds-blindness



  2. #2
    What's up? drk's Avatar
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    We pilloried this on ODWire.org.

    It's crap.

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    One eye sees, the other feels OptiBoard Silver Supporter
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    The paper's name is "Blue light excited retinal intercepts cellular signaling".

    https://www.nature.com/articles/s41598-018-28254-8

    From the flux forum:

    f.lux author here, still slogging through the article. It is hard to understand the light levels used because they use "power" (uW, mW) from a laser, and not "irradiance" (uW/cm^2 or mW/cm^2), so which area they have concentrated that light over is hard to understand. All I can see is it is from a laser, so the irradiance could be extremely high.
    The human lens filters most light at the peak of the given spectrum for free retinal (383nm), and so once you get to 450nm like an LED, the hazard data in the visual range is 100x less sensitive, see Fig 1 here:
    https://onlinelibrary.wiley.com/doi/...11/j.1751-1097....
    It bears repeating that computer screens have <5% the hazard-weighted irradiance of a blue sky. (Can't make a direct comparison with lasers.)
    Not sure the conversion to white light is correct, and it is unclear to me right now if this much retinal is available in vivo.

    Also, this was done on cell lines in vitro, only one of which was derived from a non-diseased human retinal epithelium (ARPE-19). Cell lines have undergone genetic change that allows them to replicate indefinitely, so they are fundamentally different from normal cells.
    I presume that they used a laser because they anticipated that it would potentially take years to see a result from a non-coherent blue light source, far exceeding their available funding, patience, and ability to keep uncontaminated cell cultures going.
    Applying a blue laser with unknown irradiance to a retinal cell line from a single human genetic source in vitro is very, very far from proving a link between blue light and diseases such as macular degeneration and RP.
    All this demonstrates is that coherent blue light is capable, under certain circumstances, of interacting with retinal to produce cell damage.
    Any relationship to human disease on the basis of this paper is pure speculation.
    Best regards,

    Robert Martellaro
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



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    Master OptiBoarder OptiBoard Silver Supporter
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    Fake news....da da

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    Eyes eastward... Uilleann's Avatar
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    But its this very sort of schlocky, even purposefully deceptive "science" that sells lenses to the duped masses dontchaknow!?! This is like clown porn for marketing departments everywhere - they can't look away!

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    What's up? drk's Avatar
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    Robert, thanks for digging and quoting someone who clearly can dissect experimental method.

    I think I can smell B.S., and I go by my nose, but that person is using their brain.

    Hate to be that guy, but:
    1. Living in Ohio, University of Toledo is hardly world-renown.
    2. Luxottica Retail is down-state. (Man, I shouldn't have gone there...Plus Essilor is in France, but...)
    3. I wonder how far we'd have to dig for funding of such a study?
    4. It's pretty libelous for me to suggest that, but that's the world in which we live and I don't put anything past anyone, anymore.

  7. #7
    sub specie aeternitatis Pete Hanlin's Avatar
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    (Disclaimer- Essilor Employee)

    For anyone who wants to actually read the paper (rather than the various consumer-facing articles which have attempted to put the findings in layperson language), here's a link: https://www.nature.com/articles/s41598-018-28254-8
    Essilor (as far as I know, and I've made inquiries) had absolutely nothing to do with this study. According to the authors, they have no financial interests related to the study.

    The first time I heard of it was last week- when a dozen or so people started sending me links to various articles in USA Today, Popular Science, etc. I was less-than-impressed with some of the articles... so I started searching for the study behind them. If you disregard the consumer articles and just read the study, the results aren't that surprising. Basically, they found that- when you combine 445nm blue light with (pick the substance of your choice, in this case all-trans-retinal), the result is a process that causes cellular damage. This is basically the same thing you'll find in pretty much every study exploring the effect of blue light on the retina. The idea that blue light is harmful is nothing new, and there's pretty good consensus as to the bandwidth that has the most potential to cause damage. For example, a chart showing the "Blue Light Hazard Function" can be found in table 4 of the ANSI Z80.3 standards (page 26 in the latest edition- the band of light deemed most hazardous is 435-440nm). If you go to page 207 of the paper found in Clinical and Experimental Optometry back in 2005, you'll find basically the same information https://onlinelibrary.wiley.com/doi/...2005.tb06698.x (which indicates 420-440nm is the most hazardous range).

    End of day, blue light around 435nm causes oxidation and other damaging processes to occur in the retina- so it makes sense to recommend sunglasses or photochromic lenses- especially for patients whose history indicates an elevated risk of retinal disease.
    Last edited by Pete Hanlin; 08-15-2018 at 03:02 PM.
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    Eyes eastward... Uilleann's Avatar
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    Didn't this study only show that highly coherent and intense laser light, directed at highly modified cells, in vitro - but NOT in vivo, caused cellular changes? Pete, I really really would like to see studies that can reliably and repeatedly show the harm in normal blue light exposure for an actual, living human. These studies all seem to leave far more questions than answers though...? *shrug*

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    sub specie aeternitatis Pete Hanlin's Avatar
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    I've seen roundtables where experts have suggested we may never see a long-term study on the effects of blue light, mainly because of the difficulties associated with following a large population over a long period of time AND being able to accurately gauge each individual's exposure to blue light over the course of the study.

    The Beaver Dam study was one of the largest, longest ocular studies ever conducted and- even though it was primarily targeted at UV exposure- an analysis of that data has also determined that individuals who spent more time in the sun were more prone to development of early AMD https://www.ncbi.nlm.nih.gov/pubmed/11176987

    Since UV doesn't really reach the retina, it seems visible light must be playing some role, and- when you look across the visible spectrum- its the band of light right around 435nm that causes oxidation in the retina (and oxidation is known to accelerate aging). Just for argument's sake, let's just say its ALL visible light that caused the individuals who spent more time outside in the Beaver Dam study to have higher incidences of early AMD... great, then they should still wear sunglasses or photochromatic lenses when outside.

    Everyone agrees that maintaining retinal pigment density is crucial to preserving macular health. When you look at the range of light retinal pigment filters, it's right in the 435nm range... which I think is sort of informative regarding what band of light is likely to pose the greatest threat. I posted a link to this study to encourage people to read it for themselves. Every study will have limitations related to methodology, and I'm guessing most future studies will involve in vitro cells as well (I'm not volunteering for an in vivo study of my eye, and it's sort of ethically prohibited :^).
    Pete Hanlin, ABOM
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    What's up? drk's Avatar
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    Good take, Pete.

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    Eyes eastward... Uilleann's Avatar
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    But, bringing things back to reality - none of the marketing departments who are all frothing at the mouth over "dangerous" blue light are doing so in any sort of push to educate about sunglasses (or photochromics either). It's all about frightening the public with what remains VERY shaky conclusions about our new digital world, and how the blue LEDs are going to blow out our eyes and make your head explode!

    If this was just a discussion on UV exposure, or the benefit of full time sun protection out doors, I'd be all in. But it isn't. It's buzz word driven hyperbole about exposure levels that have not been proven in any study I've seen presented yet, to even come close to the level of cellular change that can happen when shooting your lab grown retinal cells in a petri dish with a high powered blue laser beam.

    I had hoped Pete, you might be willing to donate at least ONE of your eyeballs for science, so we could finally get the live, human data on high powered blue laser beams we're all itching for. C'mon buddy...you've got two of the things anyway. You'll be my personal hero!


    I do appreciate the discussion, my friend!

  12. #12
    sub specie aeternitatis Pete Hanlin's Avatar
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    I totally get where you're coming from... a very large percentage of the consumer-facing images being used to discuss blue light seem to involve an ominous blue glow emanating from some sort of electronic screen. Conversely, it's fairly rare to see the image of the sun in blue light filtering collateral. Given the sun puts out 100-500x more blue light than an electronic device, it seems like the best message would be sun-centered.

    Unfortunately, consumers are FAR more likely to pay attention to an image of a computer screen (which they already suspect may be bad for them- "Don't sit too close to the TV- you'll go blind!") than they are of the sun. Heck, we're still trying to get consumers to understand the UV from the sun is dangerous for their eyes (how many people do you see slathering sunscreen on their kids before sending them out on the beach without a hat or sunglasses). Getting the consumer's attention is a tricky proposition. Personally, I hope the consumer who is concerned about blue light from their screen visits an eye care professional who educates them about the relative level of exposure between a screen and the sun. The screen may (or may not) pose a threat- but we know the sun definitely does... protect yourself accordingly.
    Pete Hanlin, ABOM
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    Redhot Jumper So if we protect against blue light of the the sun, that is a fact, .................

    Quote Originally Posted by Pete Hanlin View Post

    Getting the consumer's attention is a tricky proposition. Personally, I hope the consumer who is concerned about blue light from their screen visits an eye care professional who educates them about the relative level of exposure between a screen and the sun. The screen may (or may not) pose a threat- but we know the sun definitely does... protect yourself accordingly.

    Thank you Pete............for clarifying this blue matter, which I knew, would fall into the hands and minds of the anti blue believers on OptiBoard and they would shred it to pieces, and they did.

    So if we protect against blue light of the the sun, that is a fact, we get the blue light screen protection thrown in for free.

  14. #14
    sub specie aeternitatis Pete Hanlin's Avatar
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    Hi Chris,
    Actually, the debate on blue on Optiboard has been pretty civil and well thought-out relative to some other discussions I've seen... Frankly, the approach some manufacturers have taken (e.g., "computer use is killing your eyes") merits a healthy dose of skepticism. Also, in an evidence-based world it's reasonable to want the long term human studies.

    No eye care professional wants to recommend something that turns out to be unnecessary, and what I'm hearing is "You're getting my patients all riled up about blue light, but I want to see the proof."

    I've been reading pretty much everything on the topic I can find for 5-6 years now, so I'm pretty far down the path in my own thought process. Now I get to convince other intelligent professionals that blue light poses an actual threat (and it's an enjoyable task). To quote Tom Cruise from Days of Thunder "Blue light won't make a fool out of you." If you emphasize the need to protect against the sun, combined with a "and your devices may not be so good for your eyes either" you'll never have cause to apologize to those under your care. As you say- protect against the sun and you'll also protect against electronic devices (especially with photochromic lenses).

    In the meantime, skepticism is a healthy thing because it leads to further study and understanding.
    Last edited by Pete Hanlin; 08-16-2018 at 08:56 AM.
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    @uilleann - i'm not a fan of the marketing strategy and scare tactics that's happening either but look around you and you will see that this is how we are consuming everything these days. Do we really need to buy a new phone every year? Not really but people are still lining up and paying $$$$$. How much of an improvement has there been from last years model? If people are hungry you feed them.

    It's not as if we're selling a complete BS product with blue light coatings. There is added protection, shows that we're keeping up with changes in lifestyle, and in the end added profits so what's there to complain about?

  16. #16
    Eyes eastward... Uilleann's Avatar
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    Quote Originally Posted by Oscar View Post
    ...It's not as if we're selling a complete BS product with blue light coatings...
    Not convinced of that. Not convinced at all.

    Sunglasses, yes. They're fine - but also have NOTHING to do with digital screens. That's the rub.

  17. #17
    Master OptiBoarder optical24/7's Avatar
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    Also, keep in mind, full spectrum lenses ( lenses that let all visible AND UV light pass thru), were pushed in the late 70's as beneficial as per a study done by Signet- Armorlite whom also happened to make said lenses. I'm still in Uli's camp until more definitive studies come out.

    To Pete, what study changed your mind on damage from device induced blue light?

  18. #18
    sub specie aeternitatis Pete Hanlin's Avatar
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    To Pete, what study changed your mind on damage from device induced blue light?

    The abstract of the study that put me squarely on the side of "yes, we need to reduce exposure to blue light" can be found here: https://www.ncbi.nlm.nih.gov/pubmed/26471051

    BTW, this study highlights a component of the blue light discussion I think has been overlooked and under-investigated. Each year, almost 2 million of the 3.6 million cataract surgeries performed in the US result in a clear IOL being implanted. As a result, an aged retina (most cataract surgeries are being performed in the 5th, 6th, or later decades of life) is being exposed to dramatically more blue light than it would normally receive if a cataract had not formed in their natural lens. The study demonstrated that- just 2 years subsequent to cataract surgery, the retinas of patients with clear IOLs fared significantly worse than those who received blue-filtering IOLs.

    Of course, this study is just one of dozens that have shaped my view on blue light- but it is the one that I feel best demonstrates the fact that blue light has a definitive, measurable, negative impact on the retina- especially later in life when there is debris that can fluoresce in the retina. Once you're faced with the realization that (at least in the retina) 415-455nm light has no positive effect- but does have a negative effect- then you start thinking "Perhaps it's not a bad idea to start reducing exposure to this light wherever we can."

    Obviously, the place to start is reducing exposure from the sun- since that's by FAR the largest source of blue light. If we could get everyone to wear sunglasses or photochromic lenses outside, we would dramatically reduce exposure to 415-455nm light. However, we've been trying to get people to wear sunglasses for years with the UV message, and it's still not happening (only 1 out of 15 clear Rx wearers have a pair of Rx polarized sunlenses in the US, and we're the market with the highest polar penetration). So, if we can get people to wear a lens that looks like a regular clear lens but reduces 415-455nm exposure by 20%- well, that's at least a baby step in the right direction. If those lenses also reduce exposure to the 415-455nm light emitted by electronic devices, that's not a bad thing either (but my main concern is the sun).

    Sorry for the length, but that's the convoluted path my thoughts on blue have followed. There's a stack of other studies that build a consensus that blue light causes bad processes to occur in the retina (like the one just published), and together they paint a pretty clear picture. I do not know of any study which exposed retinal cells to 435nm light that came away with a "Hey, it didn't really cause any damage- so I guess we're good here..."

    Pete Hanlin, ABOM
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    Blue Jumper Maybe that will convince the non believers of blue light protection. ................

    Quote Originally Posted by Pete Hanlin View Post

    So, if we can get people to wear a lens that looks like a regular clear lens but reduces 415-455 nm exposure by 20%- well, that's at least a baby step in the right direction.


    If those lenses also reduce exposure to the 415-455 nm light emitted by electronic devices, that's not a bad thing either (but my main concern is the sun).



    Well said. Maybe that will convince the non believers of blue light protection.

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    Even if we ignore the possible effects on the eye, more studies are showing the deleterious effects of blue light on melatonin production. It increases the amount of time it takes to fall asleep and increases cortisol production. Some studies have shown that melatonin inhibits growth of certain breast and prostate cancers. I used to take a multivitamin. Studies have NOW shown they really have no benefit, so I have consciously altered my eating habit to be sure I get certain nutrients. As we learn more about the human body and what works and doesn't work, we have to alter the things we do in order to maintain our health. We no longer "bleed" people to improve their health, unless they have hemochromatosis. The studies around blue light's negative effects on humans have produced enough evidence to make me feel I am doing a service to my patient's when I have a discussion about the potential risks of blue light on their health.

  21. #21
    What's up? drk's Avatar
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    Which studies?

    We all want to know what you know.

    make me feel I am doing a service to my patient's when I have a discussion about the potential risks of blue light on their health.
    I think the marketing did that one.

  22. #22
    Master OptiBoarder OptiBoard Silver Supporter ak47's Avatar
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    Anything, in large enough doses, can cause harm to the body. If I devour 180 multivitamins, I am headed for the emergency room. That does not mean it is a bad idea to take a couple each day. Moderation is often overlooked.

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    It's quite simple to me... Blue light from computer screens may pose a risk and blue light filters aren't expensive to add... So what's the harm in playing it safe??

  24. #24
    What's up? drk's Avatar
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    I guess you provide them for free?

    How about that 40 pounds sterling applied to, say, cancer research, instead of going into schlock pockets?

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    Master OptiBoarder
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    Well that's a stupid analogy as you can say that about anything that's an unnecessary purchase (which is most purchases). And yeah I give them free or virtually free.

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