LED Safety Issues

[Felco]

I am concerned about the potential for eye damage from the new, powerful LEDs like the Crees. My wife flashed me in the face last night with her Fenix L2D (set to medium) for a few seconds and I still have an afterimage and the eye is a little uncomfortable. The wife is full of guilt now; she did not know how dangerous these things are.

High-Power LEDs Pose Safety Hazards

OCULAR HAZARDS OF LIGHT

Google "blue light hazard" and "photochemical injury eye"

 

[Marduke]

No more dangerous than any other high power light.

In fact incans would be more dangerous since they emit much more in the IR spectrum.

Just use some common sense around ANY bright light.

 

[Felco]

No more dangerous than any other high power light

Not true, unfortunately. These lights emit in the 400 -500nm range, which the eye does not reliably blink-react to, and which is maximally dangerous.

 

[Vermonter73]

"A few seconds" is a long time to keep staring at a bright light. I hope you'll look away or close your eyes faster next time.

 

[Moonshadow]

Marduke is right: while the LED in your wife's Fenix is very bright, it contains no ultraviolet or infrared.

The report you link to does actually say that:

The real problem is probably not with LEDs in general use.

In most cases your blink reflex will be sufficient to limit you to only a very brief exposure anyway.

Should your blink reflex be insufficient to the task, a quick smack around the head should be enough to deter your wife from flashing you again !!

 

[Felco]

Blink reflex is not invoked by blue light in the LED light range. See my links in top post.

 

[John_Galt]

Oh, stop whining... :ironic: Just be more careful from now on.

But, Marduke is right, these LED's don't emit a lot of IR/UV, which would be more dangerous to your eyes. Get over it.

It's thinking like this that makes stupid laws and unnecessary bans. Just use some common sense people. Jeeze, the gov. isn't here to protect you from yourself.

 

[Moonshadow]

Blink reflex is not invoked by blue light in the LED light range.

But the L2D has a white LED, not a blue one And I would jolly well blink or look away if someone flashed one in my face.

See my links in top post.

Neither of the linked documents contains the words 'blink' or 'reflex'

What the document actually says is:

Currently, white LEDs present little risk of causing retinal damage in normal use, but one should not stare directly at them for prolonged periods — say, tens of seconds.

So, not much cause for alarm then.

 

[TONY M]

No more dangerous than any other high power light.

In fact incans would be more dangerous since they emit much more in the IR spectrum.

Just use some common sense around ANY bright light.

I'd have to agree with Marduke on this.

 

[LukeA]

Not true, unfortunately. These lights emit in the 400 -700nm range, which the eye does not blink-react to, and which is maximally dangerous.

400nm-700nm is the entire range of visible light.

 

[mossyoak]

heres an idea, dont look into the damn thing. having dr pepper come out your nose is more dangerous than that.

 

[Felco]

I wish I could adopt the happy go lucky attitude that most here seem to have, but unfortunately I cannot. My left eye is still slightly tender, 2 days out. Here's a quote from another person:

These are dangerous to the eyes. I have experienced a month of having a spot in my eyesight from staring at a blue LED key ring light for 2 seconds. A young LED worker I met noted that his vision had been harmed by working with LEDs and I informed him that's either the blue/UV/purple or white LEDs (which have blue wavelengths). It's known as the "blue light hazard" where UV/Purple/Blue wavelengths can cause a photochemical injury to the retina. It is very difficult to calculate if an injury can occur (see links below) but the point is that you should not stare at these at any distance, but especially at short distances. The damage to the retina is the same that welders experience if they do not use eye protection. A longer period of looking directly at the light without eye movement causes greater harm, but natural eye movement usually prevents an injury. Those who mentioned "these hurt" may have noticed a spot in their vision for a day or two. With long exposure times, that spot does not heal.

As to the comment above about blink reflex, I apologise, I did not give the correct link. Here it is:

ICNIRP STATEMENT ON LIGHT-EMITTING DIODES (LEDS)
AND LASER DIODES: IMPLICATIONS FOR HAZARD
ASSESSMENT

Key element to consider is the "Blue-light photochemical injury to the retina of the eye (principally 400 to 550 nm; unless aphakic, 310 to 550 nm) (Ham et al. 1976; Ham 1989; Sliney and
Wolbarsht 1980)"

(Notice how high power LEDs are now considered to be more or less in the same category as some lasers).

Although LEDs are considered "white light", they are actually blue light modified to appear white. Source for that statement is in the various documents above. And Google this issue — there is much more data out there, even on wikipedia, which has this statement:

Blue Hazard: There is increasing concern that blue LEDs and cool-white LEDs are now capable of exceeding safe limits of the so-called blue-light hazard as defined in eye safety specifications such as ANSI/IESNA RP-27.1-05: Recommended Practice for Photobiological Safety for Lamp and Lamp Systems

Sources for that statement are:
Blue LEDs: A health hazard?
Light Impacts: Science News Online, May 27, 2006

 

[John_Galt]

ow ow ow ow ow...

You miss the point. Don't stare into the light...

Geeze.

 

[bullfrog]

ok ok ok.

How about we STOP talking about lights and START talking about how youre going to get back at your wife...

:devil::devil::devil:



Just kidding :tinfoil:

 

[Felco]

Current regulation concerning LED safety issues seems to be in flux:

Current photobiological safety standards of any kind provide requirements concerning LEDs which are practically not controllable – due to the lack of mandatory described and proved measurement techniques. Therefore, the impacts can only be assessed by calculations. The most convenient worst case exempt limits in any standard have already been exceeded by high-power state-of-the-art devices with photochemical retinal hazard potential, including the most interesting white light emitting LED lamps

From CIE Expert Symposium on LED Light Sources: - Physical Measurement and Visual and Photobiological Assessment

That paper also contains this:

Health and Safety Aspects of LEDs
David H. Sliney, Ph.D.
USA Center for Health Promotion and Preventive Medicine
Aberdeen Proving Ground, MD 21010-5403 USA

More than a decade ago, few would have suggested that the conventional LED could pose any biological effects other than as a visual stimulus. Today—with the development of ultraviolet-emitting LEDs and bright, blue-emitting LEDs—there are reasonable concerns that past assumptions about the total ocular safety of LEDs may not be true in all cases. Recent discoveries of a heretofore unknown photoreceptor system within the ganglion-cell layer of the retina that responds to blue light opens the door to both health applications and potential health hazards.....

There is also a paper in there that discusses the blink reflex as a safety mechanism, and points out that only a minority of people have the blink reflex with high energy light in the blue (phospored to white) LED-type light. See Results of lab and field trials regarding the eye blink reflex as a safety means for LEDs

 

[Marduke]

Although LEDs are considered "white light", they are actually blue light modified to appear white. Source for that statement is in the various documents above. And Google this issue — there is much more data out there, even on wikipedia, which has this statement:

They don't "appear" white, the phosphor actually turns the blue wavelengths into a wide spectrum to become white.

Sunlight contains blue light too, maybe you should keep your eyes closed when you go outside...

Seriously, I think the members of this board know a LOT more about how LED's work than you appear to.

 

[Felco]

I'm just pleading with you all to take care. This seems to be similar to what happened with lasers, which gradually became more and more regulated as people discovered the dangers.

1) Never point these into anyone's eyes.

2) These are not toys, keep them away from children.

 

[Felco]

Orb Optronix Says Some LED Products Not Eye-safe

January 8, 2009...Orb Optronix of Kirkland, Washington USA, reports that several solid state lighting products they have measured might cause retinal injury if viewed directly. According to the company, which measured commercially available solid state lighting products, several exceeded the risk group category RG-1 blue light hazard limits in the ANSI/IESNA RP-27.3-07 'Recommended Practice for Photobiological Safety for Lamps, Risk Group Classification and Labeling' standard along with IEC 62471:2006. The RG-2 categorization cautions against direct viewing of light sources with the human eye.

David Jenkins, Orb's president stated, "It is clear from our testing that SSL products exist that exceed the ANSI standard's limits." ANSI's RP-27 describes the 'blue light photo-biological hazard' as the 'potential for a photochemically induced retinal injury resulting from radiation exposure primarily between 400 nm and 500 nm.'

The company concluded that testing should be done by luminaire manufacturers because the hazard levels in the standard are specific to the operating conditions of radiating products. The company says that it is essentially impossible for LED component manufacturers to provide conclusive eye safety information specific to the end product implementation of their parts because the information would be different for each end product that the LED components are in. The company contends that for this and other reasons, it is critical that product manufacturers incorporating LEDs properly test and label their products for their intended system application

 

[Marduke]

I'm just pleading with you all to take care. This seems to be similar to what happened with lasers, which gradually became more and more regulated as people discovered the dangers.

1) Never point these into anyone's eyes.

2) These are not toys, keep them away from children.

Yeah, we know..

Not because they are LED's, but because they are BRIGHT.

You know not to look directly at the sun either, right?

BTW, nearly all of your references specifically discussed monochromatic light.

 

[AnAppleSnail]

it is critical that product manufacturers incorporating LEDs properly test and label their products for their intended system application

Meh. They do. Now stop quoting known safety issues for monochromatic blue lights, high-power lasers, and read. what. these. replies. are saying.

Power LEDs use phosphorescent thingies to emit white light. Like any bright light, you WILL have eye damage from sufficient exposure - but it requires truly fierce light to get damage before anyone but a fool would look away. If your wife flashed you with a light below 100 Lm hours ago and it still hurts, see your optometrist - the assault bezel must have hit your cornea. And in future, teach light discipline. There's a reason I walk ahead of the people I loan lights to!