# LED lighting maybe harmful to eyes



## chicken steve (Mar 22, 2011)

_Courtesy re: _Tennessee Dental Association ......??

~CS~


----------



## Electric_Light (Apr 6, 2010)

chicken steve said:


> _Courtesy re: _Tennessee Dental Association ......??
> 
> ~CS~


They spend many hours a day looking inside people's mouth lit up to a high foot candle level. It wasn't until recent that LED flashlights, headlamps and such became common items. 

Dentists have known for a long time that the blue light(it isn't UV) they use to cure the adhesive is harmful so they don't work around it without a safety filter. So, I think they know what they're talking about. High intensity blue light is used to cure adhesive in dentistry. LED lighting uses the same deep blue (450 nm range) to excite the phosphor.

We used asbestos, PCBs, hexavalent chromium, cadmium and such without restrictions and generously in every day life for their useful properties before we knew about their undeniable hazards. 

I've just read about this today. Maybe the LED hazard isn't substantiated, but the proven benefits LEDs have over fluorescent is miniscule or non-existent in general lighting 

They're many time more expensive and add the possible serious health hazards. I'm so out!

They said...

Our functional
and morphological results indicate that the
wavelength and the SPD, rather than total light irradiance, are crucial risk factors that
contribute to photochemical
retinal injury.
The results also suggest that LED light–
induced cell death may occur through the
intrinsic apoptotic pathway under oxidative
stress.









I'm not really sure how to read it, but I think it's saying that white LEDs maybe substantially more damaging to your eyes than triphoshpor fluorescent lamps.


----------



## chicken steve (Mar 22, 2011)

> They're many time more expensive and add the possible serious health hazards. I'm so out!


Perhaps you're jumping the gun here Enlightened One.....




> They said...
> 
> Our functional
> and morphological results indicate that the
> ...


Don't let all the latin scare you here. :no:


XXX% of lab rats may have exhibited morphological results via intrinsic apoptotic pathways under oxidative stress 


But we , much like our mothers told us young, do not _have to_ stare at the sun:whistling2:

~CS~


----------



## Southeast Power (Jan 18, 2009)

I've noticed that you make it a point to use the word "decorative" instead of diode when referring to LED lighting.
Is this a term used by all lighting professionals or is this some kind of personal shot at the industry?


----------



## Southeast Power (Jan 18, 2009)

I suspect this is like wearing non-UV sunglasses where the eye is more dilated and allows more light in, both good and bad.
We might not glance away much from the blue spectrum as we would the white spectrum.
Is it that simple?
Is it better to use boiling Mercury above people's heads?


----------



## Electric_Light (Apr 6, 2010)

jrannis said:


> Is it better to use boiling Mercury above people's heads?


You realize that the amount of mercury in one fever thermometer is enough to fill all the T8 lamps to light a super Walmart, right?


----------



## PrecisionWorks (Mar 19, 2014)

LED emitters produce no more light in the Ultraviolet (UV) or Infrared (IR) spectrums than any other light source with the same color temp. The greatest sources of UV exposure are sunlight, incandescent bulbs & fluorescent light sources.

Research shows that sunlight is a possible causative element in several retinal diseases, from retinopathy to age-related macular degeneration. The shift away from incandescent bulbs to fluorescent lighting also carries risk especially with the "daylight" fluorescent bulbs. Fluorescent lighting operating above a color temperature of 4000° K, which is associated with wavelengths of less than 380 to 500 nm (within the UV range) is hazardous to the ocular tissues. Clarkson identified the 6000K and 400- to 500-nanometer combination as a particularly hazardous one, causing damage to the retina. (Clarkson, DM,Journal of Medical Engineering Technology, 2004 May-Jun; 28(3):125-31.)

All that would suggest that humans:


Stay out of the sunlight
Don't use any light source with a color temp above 4000° K
The safe range of light, to avoid exposing the eye to potentially damaging UV radiation, is approximately 2000° to 3500° K and greater than 500 nanometers. The problem is the color is unpleasant to most people (image below).


The question is not if LED's are dangerous but rather what color temp is dangerous. 




> LED products are no more hazardous than other lighting technolo
> gies that have the same CCT.


Source: Optical Safety Fact Sheet, USDOE, June 2013.


----------



## FrunkSlammer (Aug 31, 2013)

Is this from The Onion because there's no way Tennessee even has a dental association!


----------



## Texas_LED_Guru (Mar 1, 2013)

Electric_Light said:


> You realize that the amount of mercury in one fever thermometer is enough to fill all the T8 lamps to light a super Walmart, right?


You do realize its those smaller mercury droplets & vapors that are more harmful right? You can't pick them up & you can't see them unless you have a UV flashlight & its pitch black.

What Wal-Mart manager or non EPA agent is going to spend their day or night in a shut down Wal-Mart scouring the isles & food coolers with a UV flashlight looking for broken mercury droplets?

Its not happening, sorry.


----------



## guest (Feb 21, 2009)

jrannis said:


> *I've noticed that you make it a point to use the word "decorative" instead of diode when referring to LED lighting.
> Is this a term used by all lighting professionals or is this some kind of personal shot at the industry?*


No, it is a childish rant that is becoming very irritating and shows a marked lack of professionalism. 

When one resorts to such tactics instead of a calm and objective statement of facts, one loses all credibility. :whistling2:


----------



## The_Modifier (Oct 24, 2009)

mxslick said:


> No, it is a childish rant that is becoming very irritating and shows a marked lack of professionalism.
> 
> When one resorts to such tactics instead of a calm and objective statement of facts, one loses all credibility. :whistling2:


Great come back- it only took you 7 months to come up with it?:thumbup::laughing:


----------



## Almost always lurkin (Jul 30, 2014)

PrecisionWorks said:


> LED emitters produce no more light in the Ultraviolet (UV) or Infrared (IR) spectrums than any other light source with the same color temp. The greatest sources of UV exposure are sunlight, incandescent bulbs & fluorescent light sources.


In terms of physics, a photon from a blue light source carries almost as much energy as a photon from an ultraviolet A source. First I'd heard of them causing damage, though. Even in ultraviolet everything I've heard of causing biological effects was in the UV-B range.


----------



## guest (Feb 21, 2009)

The_Modifier said:


> Great come back- it only took you 7 months to come up with it?:thumbup::laughing:


LOL nope, only a few minutes..it took 7 months for a reported post to trigger my looking into this thread.:thumbsup: :whistling2::laughing:


----------



## randolph333 (Feb 10, 2015)

Blue light is a hazard? Oh, noes! Don't go out on sunny days—you might see the sky!

The source of all this crazy was papers back in 1976 and 1978 in which monkeys were blinded with blue lasers. As Ian Ashdown puts it in his literature review: "In other words, what Ham et al. discovered through careful experiment was the glaringly obvious: _do not stare at the noonday sun without blinking for longer than fifteen minutes_." This doesn't mean it was a bad paper, by the way, but it isn't relevant to the use of LEDs for interior lighting.

The Clarkson paper is about UV risk from high-color temperature _fluorescent_ lamps. Which is real, but not relevant to LEDs.

The Shang paper cited describes problems in mice, which are nocturnal animals—they come out at night. The relevance to humans is, to put it mildly, not established.

I recommend Ashdown's literature review as a corrective, both because it covers all the relevant literature and as an example of how to evaluate research.


----------



## Rollie73 (Sep 19, 2010)

Can we just kill this Electric Light character already. Yesterday he was whining about the Texas_Led_Guru dude following him around. 

This dude is annoying with his constant marketing ploy on here.


----------



## nopalero (Mar 12, 2015)

Electric light=cletus=?


----------



## Texas_LED_Guru (Mar 1, 2013)

"White & Blue LED'S are bad for your eyes"....I hope this Electric Light character doesn't own a smartphone or use an LED backlit computer monitor.


----------



## Electric_Light (Apr 6, 2010)

Texas_LED_Guru said:


> "White & Blue LED'S are bad for your eyes"....I hope this Electric Light character doesn't own a smartphone or use an LED backlit computer monitor.


Those are actually health concerns TBD as today's youth grow up with exposure to them. I suppose we'll find out as we did with asbestos exposure.


----------



## chicken steve (Mar 22, 2011)

The Latest in LED Lighting Test Methods and Standards

DLC approval through a manufacturer....?

~CS~


----------



## Karl Bristol (May 25, 2015)

I agree with Electric Light's comment; only time will tell, just like we learned about asbestos all to late when we had all been exposed to it


----------



## randolph333 (Feb 10, 2015)

So far there's no evidence. Please, let's not go all luddite on the technology.


----------



## Electric_Light (Apr 6, 2010)

That's what they said about PCBs and asbestos back then, right? 
Until many people were seriously harmed. 

Well, if it turns out harmful, then you may be entitled to compensation later on


----------



## Spark Master (Jul 3, 2012)

I like the higher color temperatures for LED's. The lower ones are too yellowish.


----------



## Electric_Light (Apr 6, 2010)

Spark Master said:


> I like the higher color temperatures for LED's. The lower ones are too yellowish.


2700K must be an American thing. 

2700K is too yellow. 
5000K is too blue. 

This has nothing to do with LEDs. It was crammed into earlier LED sales pitch, because when they were new in the market, it was not possible to make LEDs that emit culturally desired color. 

Earlier white LEDs were strictly 6000K-7500K that you would characterize with "LED flashlight". 

3000, 3500 and 4100K are the workhorses in the commercial lighting arena, but for some reason, these colored LEDs are tough to come by for consumer use. There are some, but very limited selections.


----------



## chicken steve (Mar 22, 2011)

One of the trade rags just ran a cover story on LED's, but the usual fare dwells on the sales shtick, yet shy's from delving into technical detail.:no:

I still would like some sort of comparison of elements/heat loss 

But i guess it's all wish in one hand , ROI in the other....~C:whistling2:S~


----------



## Spark Master (Jul 3, 2012)

I still feel 4100K is the way to go. Objects just stand out, and look lit really well. Anything less than that is just too washed out, and looks 1970 yellow.


----------

