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I found this article about LED type eyesets for Light & Sound machines. It was written by Dave Seiver of Mind Alive. Enjoy!
Over the past 15 years we have been cautioning users of light and sound products to avoid LED eyesets. The problems we saw with typical LED eyesets were fourfold:
1) In the light and sound devices that use LEDs in the eyesets, the LEDs were tied directly to port pins of the microcontroller (little computer) that ran the L&S system. All computers switch their binary outputs very rapidly, in nanoseconds, making sharp turn on and shut off transitions (square waves) in the LEDs connected to them. Square waves are made up of odd harmonics (1, 3, 5, 7, 9, 11, etc) and generate third order harmonics in the brain. Therefore, when a user is using an alpha session session at 10 Hz, a 30 Hz component gets generated within the brain. At times, I have seen this 30 Hz harmonic “grow” considerably larger than the 10 Hz that was being stimulated. When this happens, people generally have an anxiety reaction. So if you are using a light and sound device for relaxation, you could be defeating the purpose because of these harmonics.
2) All of the research on photic induced epileptic seizure use some type of square wave or fast pulse light, either from a Xenon strobe or from an LED strobe. Psych Research, makers of the Inner Quest system, which used LEDs driven from square waves, were shut down in 1992 by the FDA following three incidents of seizure in Sharper Image stores. Recently, a popular hypnosis company has conveyed to me that they get from 3-5 seizures per year from using a low quality L & S device with red LEDs.
3) The conventional LED are pointy little things that point straight into the eyes. There are usually four LEDs mounted into a 2x2 matrix, which measures ½” x ½”, equal ing ¼ square inch in area. Some spread of light occurs between the LED and the eye making the total coverage about ½ square inch. This small area creates two problems:
a) A small foveal (central) area is illuminated in the user’s visual field. This bright patch of light doesn’t stimulate much of the visual field.
b) Also, as the closed eyes roll around, so does this bright spot and the moving bright patch gets interpreted as stimulation by the brain, which will in turn inhibit the alpha wave that we are trying to entrain.
4) Lastly, LEDs make laser light (which is why they work so well in fiberoptics, CD and DVD players). Because the bright laser light coming from these LEDs is so close to the eyes , there is a possibility it could burn someone’s retinas if used with the eyes open.
Over the past 15 years we have been cautioning users of light and sound products to avoid LED eyesets. The problems we saw with typical LED eyesets were fourfold:
1) In the light and sound devices that use LEDs in the eyesets, the LEDs were tied directly to port pins of the microcontroller (little computer) that ran the L&S system. All computers switch their binary outputs very rapidly, in nanoseconds, making sharp turn on and shut off transitions (square waves) in the LEDs connected to them. Square waves are made up of odd harmonics (1, 3, 5, 7, 9, 11, etc) and generate third order harmonics in the brain. Therefore, when a user is using an alpha session session at 10 Hz, a 30 Hz component gets generated within the brain. At times, I have seen this 30 Hz harmonic “grow” considerably larger than the 10 Hz that was being stimulated. When this happens, people generally have an anxiety reaction. So if you are using a light and sound device for relaxation, you could be defeating the purpose because of these harmonics.
2) All of the research on photic induced epileptic seizure use some type of square wave or fast pulse light, either from a Xenon strobe or from an LED strobe. Psych Research, makers of the Inner Quest system, which used LEDs driven from square waves, were shut down in 1992 by the FDA following three incidents of seizure in Sharper Image stores. Recently, a popular hypnosis company has conveyed to me that they get from 3-5 seizures per year from using a low quality L & S device with red LEDs.
3) The conventional LED are pointy little things that point straight into the eyes. There are usually four LEDs mounted into a 2x2 matrix, which measures ½” x ½”, equal ing ¼ square inch in area. Some spread of light occurs between the LED and the eye making the total coverage about ½ square inch. This small area creates two problems:
a) A small foveal (central) area is illuminated in the user’s visual field. This bright patch of light doesn’t stimulate much of the visual field.
b) Also, as the closed eyes roll around, so does this bright spot and the moving bright patch gets interpreted as stimulation by the brain, which will in turn inhibit the alpha wave that we are trying to entrain.
4) Lastly, LEDs make laser light (which is why they work so well in fiberoptics, CD and DVD players). Because the bright laser light coming from these LEDs is so close to the eyes , there is a possibility it could burn someone’s retinas if used with the eyes open.
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Re: Article about LED type goggles.
Tue, June 7, 2005 - 8:24 AMKrafty, do you remember where you found it? Got a link? -
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Re: Article about LED type goggles.
Tue, June 7, 2005 - 10:19 PMI own a David Paradise XL and get regular newsletters from Mind Alive via e-mail. I haven't seen this on their web site. (www.mindalive.com/)
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Re: Article about LED type goggles.
Thu, June 9, 2005 - 1:09 PMI had an InnerQuest way back when and loved it (even with the red LED goggles). Now, I have a NovaPro 100 with white LED and it's great too. I'm not so sure I agree with the conclusions of this. Could be problematic for some, but certainly not all. -
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Re: Article about LED type goggles.
Thu, June 9, 2005 - 7:35 PMThe issue I had with LED eyesets was the small illuminated area and the intensity of the LED blinking only a fraction of an inch from my eyeballs. The red LEDs did the job of entraining me but I ended the session with pain the frontal lobe area, even when I turned down the light intensity.
I don't have a seizure problem but I was a little ticked off at some L/S machine makers because they were still selling their products with red LEDs eyesets as standard equipment when it had been long established that this was the worst way entrain the mind into a relaxed state. -
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Re: Article about LED type goggles.
Sun, June 12, 2005 - 7:31 AMHere's what I would recommend for someone who has difficulty with the LED light. Do what professional photographers do when their flash is too intense. They 'soften' the light by putting a diffuser in front of the strobe. Basically a semi-opaque anything!
For goggles, try wrapping a piece of office paper or tissue or paper towel around the eyepieces (held on with a bit of tape). This will diffuse and soften the intensity and spread the light over a larger area.
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Re: Article about LED type goggles.
Thu, June 16, 2005 - 1:04 PM#4 is definitely wrong when applied to LED's used in light machines. silly wrong.
almost all of this sounds like conjecture based on very limited data. i'd be interested in an actual decent study of LED's vs light bulbs, etc; yes, LED's put out light immediately (within ns's) of when power is applied... and light bulbs take some time to warm up, so there's less of a spike. but in general without data and a structured study, this doesn't really seem to be very useful. -
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Re: Article about LED type goggles.
Fri, June 17, 2005 - 7:52 PMI've sent an e-mail to Mind Alive requesting the data that backs up part 4 of that newsletter. I'll post it as soon as I get it.
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Re: Article about LED type goggles.
Mon, June 20, 2005 - 7:44 PMI sent an E-Mail to Dave Seiver (of Mind Alive). This is what I wrote:
I recently displayed an article from Dave Seiver, to an Interest Groups website, that describles the dangers of using LED eyesets. The quote from your last newsletter is as follows:
A small foveal (central) area is illuminated in the user’s visual field. This bright patch of light doesn’t stimulate much of the visual field.
b) Also, as the closed eyes roll around, so does this bright spot and the moving bright patch gets interpreted as stimulation by the brain, which will in turn inhibit the alpha wave that we are trying to entrain.
4) Lastly, LEDs make laser light (which is why they work so well in fiberoptics, CD and DVD players). Because the bright laser light coming from these LEDs is so close to the eyes , there is a possibility it could burn someone’s retinas if used with the eyes open.
On your web site you go on to say:
Studies show that red lights actually increase GSR activity and muscle tension.
A scientific study showed that red LEDs are more likely to cause a photo convulsive response in people who are photo epileptic.
White lights "throw" their light in almost every direction. Red LED light is much more focused and when placed a quarter inch from the eye, the red LED does not have the distance needed to spread the light out.
Because red LEDs stimulate only a portion of the total visual field and the eye is always moving, the "red spot" seen by the eye is always bouncing about within the visual field. The brain processes this as information and entrainment is often interrupted as a result.
Clear encapsulated LEDs make a semi-laser light which may actually burn the retinas of the eyes if used with the eyes open.
I've had a few requests from this site for the research data or study that can confirm that LED eyesets can damage your eyes. Being a David user and having used LED type eyesets before, I am somewhat curious myself. Any data would be greatly appreciated.
Thanks in adavance.
I received a reply today from Dave, this is what he wrote:
Dave Siever] We took a competitors system with the clear cased LEDs (Photosonix system) into the Alberta Laser Institute. They analysed the system and concluded that they would burn the retinas in close proximity to the eye. Because of the narrow focus, laser pointers can burn a retina from a distance, which is why they are banned on airplanes (not that the recipiant couldn't close his/her eyes).
- Dave
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Re: Article about LED type goggles.
Tue, June 21, 2005 - 3:48 PMinteresting that it's a competitor's system...
regular LED's *do not* produce coherent light. they are *very* different from laser diodes. with lasers, it is especially the coherency that makes them potentially dangerous -- however i've even seen a lot of discussions that indicate that regular laser pointers pose no real threat to a retina (perhaps at *very* close proximity, but unlikely) -- they just don't have the power to do much other than leave you with spots in your vision for a few minutes. higher powered lasers, of course, do pose definite danger.
i'd be more inclined to believe that some mfg's may have dangerous light levels if a) the original article didn't have downright incorrect information and b) a link to data collected were given, including measured power per area per (similar to eye) distance from "competing" products, and a full write-up on how the experiment was done. (a test is worse than useless without giving raw data & enough information to reproduce it).
sorry to sound so negative, but i'm pretty annoyed with the lame level of what passes for science these days, especially when marketing departments (or presidential commissions, but that's a different subject) get involved. -
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Re: Article about LED type goggles.
Tue, June 21, 2005 - 7:26 PMYou say that want "raw data" about the dangers of LEDs and yet you say " however i've even seen a lot of discussions that indicate that regular laser pointers pose no real threat to a retina (perhaps at *very* close proximity, but unlikely) -- they just don't have the power to do much other than leave you with spots in your vision for a few minutes. higher powered lasers, of course, do pose definite danger. "
Where is the raw data proving that point? If you want to play this game perhaps you try coming up with your own articles or "raw data".
My thoughts on why Mind Alive would use a competitor's eyesets is to make the point that white bulbs are a better way to go to fill all of the visual field, while bare LEDs where far too concentrated in their effective field.
If you read the article carefuly: " Clear encapsulated LEDs make a semi-laser light which may actually burn the retinas of the eyes if used with the eyes open." Notice that nothing is said about LEDs making Laser Light but semi-laser light which may actually burn the retinas of the eyes...
I'm anything but an expert on LEDs but check the Mind Machine web sites and look for current research being done by the manufacturer. You'll see that it is very rare. This is why so many of them are still selling red LED eyesets when it has long been established that red is the worse color for relaxation. So what are you buying? I hate bringing up this point again but Mind Alive is one of the very few that are involved active, current lab studies using real subjects in a university environment.
I know what you're thinking and no I'm not a Mind Alive associate, but I have been ripped off by the cheap toys passing themselves off as a Mind Machine.
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Re: Article about LED type goggles.
Fri, June 24, 2005 - 2:48 PMwww.ncbi.nlm.nih.gov/entrez/query.fcgi
WRT laser light, you have laser (coherent) light present or you don't. there really isn't a such thing as a "semi laser"
but no, i don't think you're marketing for the company, etc -- like i said, i hate the pseudoscientific crap that gets thrown around as fact. think about radioactive water being touted as a curative earlier in the century www.orau.org/ptp/article...ackstory.htm (and even now! www.island-ikaria.com/nature/...ngs.asp) . think about diet fads based on "new exciting research" (references provided if you really want 'em). think about how strip mining supposedly helps to increase populations of endangered animals (Harpers Magazine / "Death of a Mountain" / April 2005).
if someone is going to tout a product based on "research", i'd like to know how the research was conducted and the raw results; otherwise it's meaningless drivel that can be spun any which way. -
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Re: Article about LED type goggles.
Sun, June 26, 2005 - 10:20 PMI've read the article on Laser Pointers and passed it on to Mind Alive....
Cheers! -
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Re: Article about LED type goggles.
Thu, June 30, 2005 - 3:03 PMHere's the second response from Mind Alive (the begining of this exchange is at the bottom, work your way up):
Hi,
The lasers used in the study were a maximum of 5 mw. In L&S devices, the intensity roughly spans during normal usage from 10-30mw per LED, totalling 40mw to 120mw per eye! I do not understand the comment "...that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites." Otherwise I would think that the pointers were used from a distance od some sort.
- Dave
Catch Dave Siever at Stens Corporation One Day AVE & CES Workshops:
- July 25, 2005 - St. Charles, Illinois
- October 31, 2005 - Austin, Texas
For more information go to www.stens-biofeedback.com/training.php
-----Original Message-----
From: focuskid [mailto:focuskid]
Sent: Sunday, June 26, 2005 10:55 PM
To: info
Subject: Re: Question about LED eyesets causing retina damage
I hate to be bringing this up again but regarding the effects of LEDs on the retina but an article from the (American) National Library of Medicine was passed on to me from a Group member about Laser Pointers showing to have no effect on the retina. The reasoning here is that if certain LEDs produce a semi Laser like light and are considered a danger then why aren't Laser pointers considered dangerous as they are actualy classified as Lasers? Here's the article:
Laser pointers and the human eye: a clinicopathologic study.
Robertson DM, Lim TH, Salomao DR, Link TP, Rowe RL, McLaren JW.
Department of Ophthalmology, Mayo Clinic, Rochester, MN 55905, USA.
We report the absence of photic retinal injury after exposing the retina to light from class 3A laser pointers for durations of up to 15 minutes. Three patients with uveal melanomas were scheduled to have an enucleation. Each agreed to have his or her retina exposed to laser light from a class 3A laser pointer prior to enucleation. Continuous exposure was directed to the fovea for 1 minute, to the retina 5 degrees below fixation for 5 minutes, and to the retina 5 degrees above fixation for 15 minutes. Ophthalmoscopic evaluation of the cornea, lens, and retina and fluorescein angiographic studies of the retina were conducted before, 24 hours after, and 11 days after laser exposure in the first case; before and 86 hours after exposure in the second case; and before, 96 hours after, and 15 days after exposure in the third case. Other than transient afterimages that lasted only a few minutes, we were unable to document any functional, ophthalmoscopic, fluorescein angiographic, or histologic evidence of damage to any structures of the eyes. Transmission electron microscopic studies of retinal sites targeted by the laser pointers in the second and third cases revealed ultrastructural abnormalities in the outer retina and the pigment epithelium that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites. The risk to the human eye from transient exposure to light from commercially available class 3A laser pointers having powers of 1, 2, and 5 mW seems negligible.
Publication Types:
Case Reports
PMID: 11115266 [PubMed - indexed for MEDLINE]
----- Original Message -----
From: info
To: focuskid
Sent: Monday, June 20, 2005 3:11 PM
Subject: RE: Question about LED eyesets causing retina damage
If you really want to pursue this further, I suggest you contact Mind Alive yourself. I think were begining to flog this horse to death.
Cheers -
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This is the maximum depth. Additional responses will not be threaded.
Re: Article about LED type goggles.
Thu, June 30, 2005 - 5:37 PMi might write in, although i doubt it would do any good.
but if anyone cares, i'd be happy to discuss exactly how he's completely mixing concepts WRT lasers vs non-coherent light and either his understanding of light physics is just completely off, or he's purposefully being misleading (don't know which would bother me more). just write me 1-on-1. -
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Re: Article about LED type goggles.
Sun, July 3, 2005 - 4:13 PMIt's pretty obvious you've made your mind up about this and nothing anyone says will change that. Enjoy your life! -
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Re: Article about LED type goggles.
Wed, July 6, 2005 - 3:43 PMlaser light isn't a matter of opinion. it's physics.
and good science isn't a matter of printing up a disguised sales brochure with misleading information.
*shrug* -
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Re: Article about LED type goggles.
Thu, July 7, 2005 - 7:47 PMAgain, read the reply from Mind Alive carefully. Then respond to based on what Dave Seiver actually said in the reply. Please stop spouting off your rhetoric to me and deal with the facts. This is a discussion group where ideas are exchanged so that we can all be a little more enlightened. If you want to freak out on me try counselor instead. "shrug" yourself! -
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Re: Article about LED type goggles.
Mon, July 11, 2005 - 5:24 PM*laugh* um, who's freaking out?
ok, specifically to respond to what he's said:
The lasers used in the study were a maximum of 5 mw. In L&S devices, the intensity roughly spans during normal usage from 10-30mw per LED, totalling 40mw to 120mw per eye! I do not understand the comment "...that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites." Otherwise I would think that the pointers were used from a distance od some sort.
an amount of *laser* light is very different from an amount of non-laser light, because it's coherent.
coherent light (www.websters-online-dictionary.org/definition/english/co/coherent+light.html)
:
A light of which all parameters are predictable and correlated at any point in time or space, particularly over an area in a plane perpendicular to the direction of propagation or over time at a particular point in space
what this means is, at a given distance all the light in a coherent beam (laser) will be in sync, at the same potential.
think about throwing golf balls at someone's front door. regular light (including that that comes from LED's) is like you and a bunch of friends picking up golfballs and throwing them 1 at a time (although you may throw them pretty fast) at the door.
laser light is like putting a whole bunch of golf balls in a bag and throwing the whole bag at once -- since the light is in phase, the energy peaks and troughs occur at the same time for the whole beam at a given distance. instead of randomly. so a much smaller amount of energy can have a much much larger impact.
think about e.g. 50mw IR lasers can burn paper; however infra red diodes will often sink well more than 100mw for wireless communication with laptops, etc -- and nobody has ever gotten burned from one, or even close. in fact you can find IR illuminators that put out multiple watts of IR light that are cool to the touch.
comparing a 5mw laser to 45mw (or even 200mw) of regular light is comparing two different things.
regarding the "...that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites." bit -- what this says is, they are reporting information that appears to be unrelated to their discussion, but wanted to include it to be sure to fully report findings. they found minor abnormalities, but similar abnormalities were found in sites not irradiated (and the abnormalities would not match what one would expect from any kind of damage from a laser), thus it appears that this kind of abnormality is unrelated to the study.
i'm very very open to being proven wrong about LED light being potentially able to burn retinas, however unless you have any facts / studies (with methodologies and results given, as i have supplied), every bit of research i can find only shows your source's reports to be incorrect and misleading.
and this information *is* something that's important to me. i build light machines for personal use and for friends as a hobby, and am working on EEG/biofeedback hardware to interface with them. which is also one reason i care about inaccurate information being spread about this stuff.
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