Eye health; macular/retina damage; blindness: blue light!

[hank]

Reposted at Lightlover's request from the original posting in the Warning Labels topic -- it's a long posting with a lot of URL links and a short quote from each source. See the originals for more information.

Short summary -- bright blue light can, with no pain or warning symptoms, damage your retina and blind you.

Blue light is 100x as dangerous as red light for eye damage.

Damage adds up over time. Ordinary daylight causes minor aging of the eyes; brighter light works much faster.

The brain "fills in" blind spots so your eye doctor may see a problem before you are able to notice anything is wrong. If you notice ANY vision problem get it checked.

If you notice a "curtain coming down" optical effect go to an emergency room immediately -- that may be a retina detatching, peeling off the back of the eye, and immediate laser surgery may be able to tack it in place and save your eyesight.

So says my opthalmologist, who sees me for early cataracts (started around age 30). What follows are results of a quick Google search.

I can't tell you what will hurt you. All I can say is -- you won't notice the damage, it's painless and cumulative.

If you are not now regularly getting a complete eye checkup with dilation of the pupils by a real eye doctor -- consider that should be a wise precaution for anyone.

=====.

[hank]

Originally a reply in the "Warning Labels" thread posted 10-03-2002 01:52 PM -- moved to Cafe at Lightlover's request:

Google search for "blue light" +"eye damage"

http://www.bbc.co.uk/dna/h2g2/A762662.
"Nichia Corporation of Japan, one of the pioneers of the blue/green LED, now produce a true green LED that is so bright that it cannot be viewed for more than a few seconds without eye damage occurring."
and on looking for a source for that, this:

http://www.go-led.de/datenblatt/W500BS.pdf
"The LED light output is strong enough to injure human eyes. Precautions must be taken to prevent looking directly at the LEDs for more than a few seconds." -- Specifications For Nichia White LED
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http://www.open2.net/science/backgro.../sun/story.htm
"St Thomas's Hospital in London.... John Marshall demonstrated how human sight works....

"at the back there's the retina, which is concerned with detecting an image and sending it to the brain. ...

"... the damage is caused by the concentrating effect actually causing changes in the retina at the back of your eye.

"... and we think that the retina can be harmed over time by overexposure to light, particularly blue light.

"... if you've damaged your retina, there's no pain perception, and the only way you'll know is because some dysfunction in your vision. An optician will be able to investigate the condition further. But unfortunately if you have damaged the back of your eye, it's permanent."
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http://www.femto.sims.nrc.ca/LaserSafety/lsafety7.htm.
"Wavelengths between 400 nm and 550 nm ...
are particularly hazardous for long-term retinal exposures or exposures lasting for minutes or hours. They can cause photochemical injuries to the retina (i.e. blue-light photoretinitis) which may lead to permanent blind spots (scotomas)."

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http://www.twi.co.uk/j32k/protected/...radiation.html
"Intense visible light particularly approaching UV or 'blue light' wavelengths, passes through the cornea and lens and can dazzle and, in extreme cases, damage the network of optically sensitive nerves on the retina."
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http://www.nrpb.org/publications/doc...s/absd13-1.htm
"... gazing at very bright light sources, particularly those emitting shorter wavelength blue light, causes retinal damage resulting in transient or permanent loss of visual acuity. ... Similar damage has also been induced in the non-human primate retina following acute exposure, particularly to blue light."
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http://prism.mit.edu/cmse/CHSP0601/7.pdf.
"Researchers must be aware of the "blue light" hazard. The threshold for eye damage is 100 times lower for blue light than for red or near-ultraviolet. For example, the diffuse reflection of a multiwatt argon ion laser beam falling on a black beam stop can be an eye hazard."
------------------------------------------------

www.caves.org.uk/led/led-myths.html
"A white LED is, in reality, a blue LED (light-emitting diode) surrounded by a phosphorescent dye that glows white when it is struck by blue light. .... people have noticed the pronounced blue peak in graphs of the power spectrum...."
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www.rockefeller.edu/lab/NONRAD/nonrad.html

"Visible light (400-780 nm) ... pass through the cornea and lens and are focused on the retina. Due to this focusing, light energy that reaches the back of the eye is increased by a factor of 100,000 over the energy incident on the cornea. Thus, significant retinal damage is possible from low radiation levels. ...

"For visible (white) light, threshold limit values (TLVs) are only recommended1 if the luminance of the source exceeds 1 candela (cd)/cm2. Threshold limit values have been proposed for blue light..."
--------------------------------------------------

http://www.stao.org/safeart6.htm.
"The blue light threshold for retinal damage is several orders of magnitude below that for red light or IR. The primary site of injury is the photoreceptors ....

"Waveband: Blue Light
Acute Effects: Photochemical
Chronic Effects: Retinopathy (damage to photoreceptors); Age-related macular degeneration."
-------------------------------------------------

http://dinc.com/maf/1999/nl_06_03.htm.

"Each eye contains a small patch of specialized tissue in the back of the eyeball at the center of the retina called a macula. Deterioration of the macula in the retina can result in partial or complete blindness. Those over 60 are most vulnerable to this condition, called age-related macular degeneration (AMD) - which has no cure ....

Inspection of eye tissues reveals high concentrations of some carotenoids, which act as antioxidants to reduce damage to eye cells by free radicals resulting from factors like sunlight. It appears that those who eat a diet containing lots of carotenoids have the healthiest eyes....

"It isn't clear why carotenoids are especially eye-healthy, but it is theorized that they may function as filters that protect the eyes from blue light, which is a band of radiation from sunlight that can cause eye damage."
-------------------------------------------------

"Think of it as evolution in action."
- Larry Niven and Jerry Pournelle, _Oath of Fealty_

"THINK!"
- John Watson, IBM

Please don't just blow by this long posting, folks.

Notice that your retina is 100x more sensitive to damage from blue than from red light,

and

Notice that there is no immediate warning, no pain associated with retinal damage, only a slow, incurable loss of the ability to see.

[brightnorm]

Hank (and Jahn)

Thank you for reposting this very important thread. I hope that more Flashaholics will take it seriously enough to read it thououghly.

Brightnorm

[Quickbeam]

The only way I would truly believe any of the warnings about LED light and retinal damage is through independent clinical studies that prove the connection OR through mathematical evidence that the power output of the LEDs is high enough at certain distances to damage the retina when the light is focused by the lens of the eye, provided the power threshold for damage to the retina is known. Otherwise, no matter how many "experts" say it, it is only speculation.

Be wary of claims from pseudoscientific sources.

Of course, I'm not saying "stare at lit LEDs for long periods" either. Discretion is best. Use your brain - if it's uncomfortable to look at, stop.

Many of those sites mentioned are referring to LASER damage to the eye at various frequencies - a VERY different animal than regular LEDs.

[hank]

Doug, if you believe there is a "pseudoscientific" source among those I quoted, PLEASE point it out. Skeptical inquiry is always good -- "Opposition is true friendship." (William Blake)

Laser experience is pertinent. Blue LEDS -- bright LEDs generally -- didn't exist til very recently. Is caution not wise considering what's already known about risk?

Think how bright the eye doctor's exam light is -- you probably see that brightness once a year -- briefly! Does the brightest LED seem to you to be comparable? Damage is painless.

Just two years ago, overlong use of that light was discovered to do permanent eye damage --
http://link.springer-ny.com/link/ser...2/02380956.htm

"Light-induced damage of the retina through slit-lamp photography"

"two patients who suffered severe loss of visual acuity after slit-lamp photography ... The visual acuity did not recover. ... severe light-induced damage of the retina."

---
I'm not trying to attack anyone's business here, nor to discourage anyone from either making or selling the new very bright LED lights.

LEDs are increasingly bright, increasingly available, and are shipped with clear warnings -- such as Nichia's from 1999/2000, for their earlier white LEDs. "Knowledge comes from experience, and experience comes from considering others' mistakes or, failing that, repeating them."

----
"... inexperience is ... the nurse both of timidity and audacity. For timidity betrays a want of powers, and audacity a lack of skill. They are, indeed, two things, knowledge and opinion, of which the one makes its possessor really to know, the other to be ignorant."

-- Hippocrates (c. 460–c. 370 B.C.).
http://www.bartleby.com/38/1/2.html

----------
I'm not in medicine; I've just looked through Google and made excerpts to go with the links to what seemed to me current and pertinent material, and brought it to the Cafe on Lightlover's invitation. I hope that those of you who have manufacturer's spec sheets will post updated information from them as time goes on.

[Quickbeam]

I never said caution was not wise, but I don't think laser safety glasses are needed when shining your blue photon 2 around either.

My response is more along the lines of "don't go off half-cocked". People should be aware that until there is documented clinical evidence that there is a specific danger, they should not worry about brief direct exposure to direct LED light in their eyes. Next thing you know, some crusader will try to sue Nichia based on the information they found on the web regarding LASER light safety data...

Again I say: Discretion is best. Use your brain - if it's uncomfortable to look at, stop.

Your body has a great aversion reaction when a very bright light is shined in your eyes. If you look away because it's too bright, listen to your body and don't look back again on purpose.

As to pseudoscientific sources, the first article listed is a good example - the part that mentions that damage occurs to the eye has no reference to an article that describes how they came to this conclusion, therefore the intelligent reader must assume it is speculation. No evidence of any sort is presented that supports the statement. Let the reader beware.

My 4 cents....

[NightStorm]

Thank you Hank,

Your research supports a conclusion I came to months ago, concerning a degradation in my vision. Over the last 8 months I have been conducting light output experiments with white and cyan Luxeon Stars for the purpose of road surface illumination.

The indoor tests were conducted with the emitters either covered with a tube containing a photocell [for comparison purposes] or reflected off of a wall. The outdoor tests were conducted in my backyard, and the street adjacent to it, to judge the depth of throw of the lamp assemblies and the affect on other road users [by viewing the beam at a 50+ feet distance]. Allow me to state that I'm not foolish enough to stare into a over-driven LS at point blank range.

During the reflective tests and the road user tests, I would experience discomfort similar to that encountered while exposed elevated levels of ultra-violet light [i.e.; MIG welding reflections, near-total solar eclipses]. Not only was the discomfort greater that what would be experienced from a 20W halogen bulb, but the vision recovery time was much greater.

Upon consulting the Lumiled technical documents, I came to the conclusion that this was not due to excessive UV emissions. I then thought that this could be caused by the human eye's sensitivity to single wavelength emissions [particularly in the 400-500nm range] but I was a little at a loss to explain why this phenomena was present with the white emitters. The data sheets not only show a strong peak in the 460nm range [royal-blue to blue], but also a strong peak at 610nm [orange] and a lesser peak in the 540-600nm range [yellow-green to amber]. It was my hope that the peaks outside of the 400-500nm range would counter act the predominance of blue light.

Now, I know that chronic dry eyes, pre-cataracts and the slower pupilary reaction brought on by life and age may contribute to the sensitivity that I experience with these light sources, but if I'm bothered by this others also might be. If so, I may have to reconsider the direction of my project. Thanks, once again, for your research.

Dan

[brightnorm]

Light can induce unexpected reactions in people sensitive to that particular form/wavelength/
intensity of light. For example:

(Scroll down toward bottom. You might also want to click on "prevention")

PHOTOSENSITIVITY AND SEIZURES

There are many "ills that flesh is heir to", and most can be avoided or at least mitigated by staying reasonably well informed and using some plain old common sense, as has been suggested in this thread,.

Almost all people commonly work with or are exposed to serious or potentially lethal hazards every day of their lives and don't give it a second thought. I'm typing this and you are reading it (unless a laptop) on a device plugged into a source of extremely powerful electrical energy that can easily kill under the right circumstances. Most of us drive routinely in
vehicles similar to those in which tens of thousands of Americans die and hundreds of thousands are injured every year. And so on.

The point is that the computer user doesn't deliberately zap himself with AC to see what it feels like, any more than the car driver deliberately drives into a wall out of curiosity.

Similarly, a little common sense will incline us away from eye-frying experiments with powerful light emitters of any wavelength. Of course, as Flashaholics our passionate involvment (read crazed obsession) with lights can make us cast a "blind eye" to real life hazards.

I found Hank's post very useful and timely, not because x light is bad and y light can do this or that etc. But just as a simple reminder to treat any energy source with respect, especially as it relates to our precious eye sight.

Brightnorm

[PsycoBob[Q2]]

Hm.

Methinks I'll wait on getting that royal-blue 5w.
Now I just need a 555 timer to strobe my version of Elektrolumen's Zorch at the right frequency to cause seisures.... j/k

Perhaps that one for the Pentagon's green-laser 'neutralizer.' [img]images/icons/cool.gif[/img]

[Rothrandir]

been awhile...has any more evidence come out to either support or contradict this?

[INRETECH]

Go watch the movie "LOOKER"

[nihraguk]

ok that's scary...i think i should stop testing the blinding ability of my surefires on myself [img]images/icons/grin.gif[/img]

[WhiteAsSnow]

Originally posted by nihraguk:
ok that's scary...i think i should stop testing the blinding ability of my surefires on myself [img]images/icons/grin.gif[/img]

<font size="2" face="Verdana, Arial">...ditto -- esp my 10x. Ouch. [img]graemlins/bluedead.gif[/img] [img]images/icons/cool.gif[/img]

[hank]

bumping up since someone asked about this in LED forum recently.

[NewsFlash]

hank,

Thanks, that was me who asked in the LED forum. I have noticed a difference using a KL1 (indoors, shining the light around on the white ceiling and off-white walls). No doubt the feeling in my eyes would be different if used outside where the vegetation would be absorbing the blue light rather than reflect it.

I have settled on the MNO2 lamp assembly in an E2e for general low-light use, and another E2e with MNO3 for relatively bright-light performance. [img]/ubbthreads/images/graemlins/cool.gif[/img]

[Mutie]

When I got my 5W RB Luxeons I really wanted to make antenna out of them but because of this thread and how bright they are I felt it best not to since they would shine in people's eyes. I am legally blind myself and it is progressive so at some point I will lose what I have left. Essentially I have no peripheral vision and am almost completely night blind.

I really like the blue LED's and look at them all the time but just for a short period. I haven't noticed any problems from that although it would be hard to tell since my vision keeps getting worse. I do notice more of a dalmation effect though from red LED's and also a change in colors for awhile if I get a good dose of dalmation effect.

I am currently doing some tests using a red 1w and a blue 1w mounted on my palms so that I get a better depth effect at night (along the lines of the 3d comic book effect using the red and blue lenses). By having them on my palms it keeps them from shining in peoples eyes but still allows me to direct them as needed, cup them if I need to put them out, and still allows for relatively hands free operation. When I used to wear a headlight all the time other people found it really annoying. So then I went to clusters of red and blue LED's on a headband that I could aim down so as not to be right in people's eyes. Unfortunately the colors tend to mix so the red/blue effect didn't really happen.

With red on one hand and blue in the other it has helped quite a bit at night.

Mutech

[hank]

I like that red-on-one-hand blue-on-the-other idea a lot, for enhancing shadows.

There is a trick one can play with the "red-blue" stereo glasses and a red light on one side and a blue light on the other -- the shadows you'll see that way look three-dimensional and solid but move around in spooky ways.

What kind of progressive blindness are you dealing with?

[Mutie]

It's called gyrate atrophy. In effect it is similar to RP. I have about 5 degrees of peripheral vison left and sever night blindness. It is caused by a mutation of the OAT gene and I have 15 to 20 times ornithene levels in my blood which seems to concentrate in the eyes and is causing my retinas to deteriorate from the outside towards the center.

Some forms are responsive to high (around 1 gram) doses of vitamin B6. They already tried that. The only other thing that seems to have an effect is an almost protein free diet. I have cut back on the amount of protein I eat but I have been unable to completely adopt the suggest diet as almost everything I eat is mostly protein. I can easily down a half gallon of milk myself and I shouldn't have more than about 16 ounces in a day.

They did come up with a gene therapy specifically for my condition but that seems to have been withdrawn.

Mutech

[PhotonWrangler]

Ok, not to be an alarmist, but all this chat about shorter wavelengths and eye damage has got me thinking...

Staring at an LCD screen instead of a CRT-based monitor, one winds up looking directly into a fluorescent-based backlight for extended periods of time. This is an activity that there probably isn't much historical data about.

Anyone got any thoughts about this?

[evan9162]

LCDs typically have much lower luminosity than their CRT equivalent. In addition, the light produced by the LCD travels through several layers of materials.

If anything, I would say that staring at a CRT is worse for your eyes. Personal experience has shown that a CRT makes my eyes hurt after only a few hours (17", 1024x768, 85Hz refresh rate), whereas, I can use my laptop all day long without problems (15", 1600x1200) even though everything appears smaller.

[hank]

450 nanometers (blue) is the current threshold at which cataract implant lenses are being tested to block the frequencies that may speed up macular degeneration, according to the British Medical Journal recently.

That's high-energy blue light -- photons that are energetic enough to knock an electron off an atom, and so change a chemical bond or produce a free radical that can go on to damage other molecules.

[BlindedByTheLite]

i don't think i need to worry..
i only stare @ LED's for a second @ a time.. (the blinding test y'know?) [img]/ubbthreads/images/graemlins/grinser2.gif[/img]