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Thread: I just saw Luzerne's TheraBlue lens.

  1. #26
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    Regarding the comments that all blue light is naturally occuring so it can't be harmful ignores the Essilor data that clearly shows that STRONG exposure to very specific wavelengths rapidly kills rat retina cells. Nobody is claiming that natural light is killing retinal cells. They are claiming that the EXCESSIVE blue light coming off of those video displays that are held close to the eyes (tablets and smart phones) for extended periods of time (like kids like to do under the covers) MAY be harmful to the human retina. It's no different for UV. It's naturally occurring and in moderate amounts is good for you (vitamin D), but in unnatural (tanning booths) amounts or excessive (sun worshiping) it's pretty obviously harmful. I remember being cautioned about excessive use of a binocular indirect ophthalmoscope can be harmful to the retinas being examined, even my BIO which has an ordinary incandescent bulb in it (oldie but goodie). One of the reasons I bought a retina camera 10 years ago. Still use the BIO but not as much as I did.

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    Again, reduction by the square of the distance.

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    which is why it's a good thing the sun is 93 million miles away. But it's also why it's a bad thing if the radiant source is only 6-10 inches from the eye. Ever watch a kid gaming? And see my addendum above, condensing lenses used in BIO and biomicroscopy are held 1-3 inches from the eye. These lenses are from +20D to +90D, pretty good concentrators...

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    So - once again, these lenses are all making wild and varied claims about the horrific damage these new evil LED type devices are going to cause from all the "dangerous" blue light they're putting out.

    And it's all negated the second a body steps outside and is subject to what - like three seconds of solar exposure (even on a cloudy day). Because you've just been hit with those very same frequencies at intensities many orders of magnitude stronger than any screen on the planet. So those new expensive "magic" lenses have done nothing to "protect" your delicate eyes. But they HAVE lined the pockets of the labs and lens guys with an easy new source of revenue.

    As an interesting note, using the buttons on my monitor, I can do far more to boost or attenuate numerous frequencies of visible light (including blue) than any of the lenses on the market can. And those buttons are already there. What does it cost me to do so? About a half second of my precious time, and no money whatsoever. Using the simulator linked earlier in the thread, the "dangerous" blue light spikes were dramatically reduced on every setting I tried - apart from the absolute highest K settings...big surprise. I obviously remain extremely skeptical.

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    Oh the horror, won't somebody please think of the children! Their eyes are melting from the blue light! Please think of the children!!!

    For real though, I think Blue tech lenses relax the few people who I've made them for, as do traditionally tinted lenses. It works for them, but I hardly push those products. There was a young lady in her late 30's who had macular degeneration happening, she asked about lenses to protect her eyes from blue light, I fit her in prevencia.

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    Quote Originally Posted by Uilleann View Post
    And it's all negated the second a body steps outside and is subject to what - like three seconds of solar exposure (even on a cloudy day). Because you've just been hit with those very same frequencies at intensities many orders of magnitude stronger than any screen on the planet.
    .
    I think you need to study the physics and associated math of your claim. The square root of the distance from the sun is about 10,000 miles, which is about 1/10,000 of the radiation off the surface of the sun. All wavelengths except cosmic rays are further attenuated by the earth's atmosphere and some of the worst wavelengths are completely absorbed by the ozone layer (thank God), but come through the big hole we now have in that precious layer (thank big oil and big coal). Now comes the kid under the covers with his ipad 6 inches from his eye. The square root of 6 inches is about 2.5 inches, or nearly 1/2 of the radiation is reaching his eye. Given the fact that I can use the screen my iphone as a flashlight (and do so often), and it lights up a dark room pretty well so that I don't even need the flash function at all. I'm just guessing, but I suspect the actual intensities might come as a big shock to you. 1/2 of a small amount can be much larger than 1/10,000 of a very large amount.

  7. #32
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    Spent more than a decade at the Planetarium. EM frequencies - particularly as applied to human vision - were a big deal to us there. As were relative intensities. So you're comparing the amount of maximum brightness of a phone or tablet in a darkened room to sunlight? I'll take the low estimate of sunlight at 100,000 lux, and compare it to your puny iphone screen at maximum brightness any day! ;) Guess which intensity wins?

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    Quote Originally Posted by Dr. Bill Stacy View Post
    I think you need to study the physics and associated math of your claim.
    Ummm... so do you.

    Here is the basic formula for calculating exposure to any type of radiation: R * (A / (2 * 3.14159 * r^2) ) Where R = Radiance of the object in watts per square centimeter, A = the area of the radiation, in square centimeters, and r = the distance to the eye from the radiation source, in centimeters.

    Let's say, for the sake of discussion, that the radiance of a given object is 2 watts per square centimeter, the area of the object is 1 square centimeter, and the distance is 10 centimeters. Plugging the data into the formula, you get the following:

    2 * (1 / (2 * 3.14159 * 10^2))

    2 * (1 / (2 * 3.14159 * 100))

    2 * (1 / 628.32)

    2 * 0.00159

    0.00318

    At 10 centimeters, an object that measures 1 square centimeters with a radiance of 2 watts per square centimeter has the effect of 0.00318 watts per square centimeter.

    Now, I haven't been able to find any data that suggests that a television or computer monitor puts out 2 watts per square cm of energy. It's more likely it is in the 1/4 watt range or less.

    My Samsung smartphone has a screen with a measurement of 6 x 11 centimeters (66 square cm). Let's assume the output is .25 watts per square cm (I believe it is certainly less than that), and I read at 30 cm distance.

    From above:

    .25 * (66 / (2 * 3.14159 * 30^2))
    .25 * (66 / (2 * 3.14159 * 900))
    .25 * (66 / 5654.86)
    .25 * .01167

    0.00292 watts per cm squared entering the eye

    Now, all this supposes that the radiation emitted from the source is equal across the spectrum, as a black body emitter does, and we know that this is not the case. To be precise, you would need exact emissions per wavelength across the spectrum you are interested in and plug in the numbers accordingly. But this basic formula gives a close approximation for a "white light" emitter.

    I've looked at a lot of the white papers written about the so-called 'blue light hazard' and there is no detailed referential information given about where the data was originally calculated and what source of energy was used. There's lots of "this is bad" but there's nothing to back it up.

    Yes, the energy required to get from red to blue is higher. This is scientific fact. The question remains though, at what point does it become hazardous to the eye? It's been established that 380 nm and below is hazardous. But how did the "researchers" get from 380 nm to 430 nm? Where's the proof that it's "hazardous". The only thing I've seen is the oft-repeated "we don't need to see it", and I find that to be a lot of hokum.

  9. #34
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    Quote Originally Posted by MikeAurelius View Post
    Ummm... so do you.

    Here is the basic formula for calculating exposure to any type of radiation: R * (A / (2 * 3.14159 * r^2) ) Where R = Radiance of the object in watts per square centimeter, A = the area of the radiation, in square centimeters, and r = the distance to the eye from the radiation source, in centimeters.

    Let's say, for the sake of discussion, that the radiance of a given object is 2 watts per square centimeter, the area of the object is 1 square centimeter, and the distance is 10 centimeters. Plugging the data into the formula, you get the following:

    2 * (1 / (2 * 3.14159 * 10^2))

    2 * (1 / (2 * 3.14159 * 100))

    2 * (1 / 628.32)

    2 * 0.00159

    0.00318

    At 10 centimeters, an object that measures 1 square centimeters with a radiance of 2 watts per square centimeter has the effect of 0.00318 watts per square centimeter.

    Now, I haven't been able to find any data that suggests that a television or computer monitor puts out 2 watts per square cm of energy. It's more likely it is in the 1/4 watt range or less.

    My Samsung smartphone has a screen with a measurement of 6 x 11 centimeters (66 square cm). Let's assume the output is .25 watts per square cm (I believe it is certainly less than that), and I read at 30 cm distance.

    From above:

    .25 * (66 / (2 * 3.14159 * 30^2))
    .25 * (66 / (2 * 3.14159 * 900))
    .25 * (66 / 5654.86)
    .25 * .01167

    0.00292 watts per cm squared entering the eye

    Now, all this supposes that the radiation emitted from the source is equal across the spectrum, as a black body emitter does, and we know that this is not the case. To be precise, you would need exact emissions per wavelength across the spectrum you are interested in and plug in the numbers accordingly. But this basic formula gives a close approximation for a "white light" emitter.

    I've looked at a lot of the white papers written about the so-called 'blue light hazard' and there is no detailed referential information given about where the data was originally calculated and what source of energy was used. There's lots of "this is bad" but there's nothing to back it up.

    Yes, the energy required to get from red to blue is higher. This is scientific fact. The question remains though, at what point does it become hazardous to the eye? It's been established that 380 nm and below is hazardous. But how did the "researchers" get from 380 nm to 430 nm? Where's the proof that it's "hazardous". The only thing I've seen is the oft-repeated "we don't need to see it", and I find that to be a lot of hokum.

    Nice work. I'd just point out that the "white" light coming off a cell phone contains a lot of the blue visible wavelengths that are of concern, but you're right, I don't have the actual output. I understand that blue light requires less energy to put out than red, but contains more energy than the equivalent flux of red. Kind of a paradox. I missed quantum mechanics because I took physics so long ago.

    I'd also point out that the kid with the cell phone or ipad is getting a huge chunk of is visual field filled up with the screen. Way, way larger in angular subtense than the sun would ever subtend on earth. And nobody is claiming (I hope) that kids go out and stare at the sun, even for "3 seconds". But the kid is doing the ipad thing for HOURS.

    You're also right that Essilor's research is pretty rudimentary, some might say crude, but still impressive to me, certainly enough to get me thinking about it...

  10. #35
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    Speaking of white papers, here's a pretty good one on this subject:
    http://www.crizalusa.com/content/dam...hite-Paper.pdf

    try to ignore that it was sponsored by crizal; if you can't do that, keep moving, there's nothing here for you to see...

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    Page 9 is probably the most crucial, as it shows what the energy reaching the eyes from sunlight is: about 0.020 mw/cm2. Which pretty blows the computer monitor/video screen/iPad issues out of the realm of hazards.

    I'm still skeptical.

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    Quote Originally Posted by MikeAurelius View Post
    Page 9 is probably the most crucial, as it shows what the energy reaching the eyes from sunlight is: about 0.020 mw/cm2. Which pretty blows the computer monitor/video screen/iPad issues out of the realm of hazards.

    I'm still skeptical.
    I read that graph more like 0.1 mW/cm^2 at around 440 nm which is the part of the spectrum under dispute. At the risk of getting in over my head here, my iPhone 6 + is advertised by apple to put out 500 candelas at max brightness, which is about what you'd expect a kid to run it. Now 500 candelas equates to roughly about .07 mW/cm^2 at 6 inches.

    Now if the sun is outputting .1 mW/cm^2 and the iPhone is outputting nearly that much, I'm a concerned grandpa.

    My very rough calculation assumes about 1 steradian of exposure angle.


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    Look on the right side of the graph for mw/cm2, left side is mw/cm2/nm. Move the decimal place to the left one place.

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    The per nano (/nm) bit refers to the wavelength of interest and is correct.

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    So what you are saying is that your grandson's iPad is putting out roughly the same amount of energy that the sun is at 6' above ground on Earth. Think about that for a moment.

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    Quote Originally Posted by MikeAurelius View Post
    So what you are saying is that your grandson's iPad is putting out roughly the same amount of energy that the sun is at 6' above ground on Earth. Think about that for a moment.
    Yes, putting a bit of faith in Essilor's numbers and Apple's numbers and doing some extrapolation, I'd say that's about right, at least for the 540 nano visible blue light.

    Your mileage may vary, depending on your altitude, the time of day and your attitude.

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    *smh*

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    BTW, I've yet to see a reported case of iPod burn on the face, unlike sunburn which can be gotten in as little as 20 minutes...

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    [QUOTE=MikeAurelius;511900]BTW, I've yet to see a reported case of iPod burn on the face, unlike sunburn which can be gotten in as little as 20 minutes...[/QUOTE


    That's because the VISIBLE BLUE which is what we were talking about doesn't cause sunburn. Only UV does that, but just to be sure, I held my iPhone up to Gilda's photochromatic eyes and you guessed it, no reaction, no measurable UV.

    Some high school kid should do a science project on a rat. Put him in a little box with iPads turned on with no screen saver but with deep blue cheese moons floating across a black background . See how long premature apoptosis of his retina cells take to blind him. The control would be a rat that gets to watch yellow cheese wedges floating across an also black background.



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    Thank you for proving my point in this entire discussion. It has been fun.

    Game. Set. Match.

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    Blue Light induced retinal oxidative stress: Implications for macular degeneration

    There are many studies being conducted worldwide on HEV Blue Light exposure. Linked below is just one of them posted in the World Journal of Ophthalmology by Professor Richard Funk of the University of Dresden.
    I believe science is uncovering very real consequences and its not all snake oil. I believe future studies will prove this beyond doubt and that there will be proven a definite need for various Blue Light protection products coming to market.

    This is a highly interesting study http://www.wjgnet.com/2218-6239/full/v4/i3/29.htm

    and http://nebula.wsimg.com/bc4320137eb4...&alloworigin=1
    Last edited by Lazarus; 08-22-2015 at 02:07 PM.

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    Blue light has been around since the sun stabilized some 5 billion years ago. Proto-humans began walking upright a couple of million years ago. We've had AMD and cataracts and all the rest for as long as humans have been able to figure out something is wrong with their vision. Not everyone is affected by it. There are a lot of old folks in their 80's, 90's, and 100's whose vision is still good, have not had incidents of AMD and relatively few cataracts (and those, mostly age related). Where is the epidemic of AMD? Where is the epidemic of vision reducing cataracts? According to fear mongering present in some of these reports, every person over the age of 50 should be showing signs of AMD, and that's nowhere near true.

    This still looks like bored scientists being pushed into researching something that will earn the corporate bosses their bonuses and seduce the customer out of more money.

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    Quote Originally Posted by MikeAurelius View Post
    This still looks like bored scientists being pushed into researching something that will earn the corporate bosses their bonuses and seduce the customer out of more money.
    Yup

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    Quote Originally Posted by MikeAurelius View Post
    Blue light has been around since the sun stabilized some 5 billion years ago. Proto-humans began walking upright a couple of million years ago. We've had AMD and cataracts and all the rest for as long as humans have been able to figure out something is wrong with their vision. Not everyone is affected by it. There are a lot of old folks in their 80's, 90's, and 100's whose vision is still good, have not had incidents of AMD and relatively few cataracts (and those, mostly age related). Where is the epidemic of AMD? Where is the epidemic of vision reducing cataracts? According to fear mongering present in some of these reports, every person over the age of 50 should be showing signs of AMD, and that's nowhere near true.

    This still looks like bored scientists being pushed into researching something that will earn the corporate bosses their bonuses and seduce the customer out of more money.
    You're painting the scientists with a pretty broad brush there, Mike. AMD is not exactly pandemic, but the scientific inquiry is totally justified due to the harsh iPhone and iPad type environment very young eyes are being subjected to. The effects of this will not be known for sure for several more years. At that time, it is of course possible that we will see an epidemic in mac. degen. much like the second worldwide increase in myopia after the PC came along (the first one when the printing press came along). Of course unlike myopia, the 3 Os can't do much to help macular degeneration; once you lose your macula you can't get a new one.

    The early base science points to a probable link of heavy visible blue exposure (of a type that has not been around not for millions of years, not ever) with retina damage, the health industry HAS TO react aggressively if they are not to be branded as old thinking ostriches. Your characterization of "bored scientists" is way off base, these people have lots of exciting work to do in all fields.

    As far as cataracts, for sure they were less prevalent before the advent of fire, cooking, metal work and your favorite glass blowing. But however prevalent they might have been back then, humans died of other causes long before they were old enough to be blinded by cataracts. These days, I can assure you that 100% of humans over the age of 60 have some cataractous changes in their eyes, or they are already pseudophakic. Sure, there are 90 year olds that can see "pretty well" through their cataracts, but with a 12 minute per eye permanent fix that yields spectacular results, those old timers are mercifully getting rarer and rarer in the developed world.

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    You bring up some good points, Bill. I have to leave for a bit to have dinner with my parents, but I'd like to make one point before I go.

    Hand and lap portable and semi-portable battery driven devices have a built-in energy budget. They are limited to several factors: battery age, processor use, and screen display requirements. The last is the most important, as it usually totals at least half of the energy budget. Do you honestly think that, given the amount of energy required to put out blue light, that the screen makers would actually have the device emit radiation below 400 nm? It really sounds preposterous when you step back from a blanket statement like you've made several times.

    And you keep making a point of "heavy blue exposure" like every page on every website or game contains large amounts of "heavy blue". That's simply not the case. In fact, page and game designers avoid the deeper blues simply because they don't show detail like the lighter colors do. However, if the "heavy blue" is coded in, its there for a reason. And if all of a sudden, people can no longer "see" the "heavy blue", what do you think is going to happen? Artists, designers, gamers, etc., are going to raise a stink like hasn't ever been seen before.

    Food for thought for a couple of hours...

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