LED lights can damage the retina

pinball1970

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Summary
A recent study by a French government agency is claiming exposure to LED lights can irreversibly damage the retina.
There has been a large shift from energy inefficient lighting in the last 10 years to LEDs in domestic, retail stores, cars and council run buildings and street lights.

The study in the link below by the French government agency support a previous study in 2012 by Sánchez-Ramos published journal Photochemistry and Photobiology.

Exposure to LED light can irreversibly damage the retina.

https://www.dailymail.co.uk/health/article-7032303/LED-lights-irreversibly-damage-eyes-French-health-authority-warns.html

I have been looking into LEDs for the last few months from a colourimetry perspective and was not aware of these studies.
I do not have access to the study details just the headlines.
Energy saving is the way to go but how do they tackle this risk with LEDs?
How big is the risk?
Any details other studies or reasons why LEDs are particularly bad for your eyes are welcome.
 

berkeman

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Yeah, when I bought my Leatherman LEDLENSER flashlight, I was surprised to see a warning in the user manual about not shining it into eyes, even on the lowest (very dim) brightness setting. I did wonder what the issue was...

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As far as I know part of the isse is that LEDs has very high energy density on a small surface => they produce very high energy density on the retina too. This issue can be addressed by diffusors (or indirect lighting), but diffusors are no good for directed/focused light and also often missing from cheap products too.
 

pinball1970

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As far as I know part of the isse is that LEDs has very high energy density on a small surface => they produce very high energy density on the retina too. This issue can be addressed by diffusors (or indirect lighting), but diffusors are no good for directed/focused light and also often missing from cheap products too.
Is that at one particular wavelength? The LED SPDs I have seen all have a spike at 450nm
 

BillTre

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I have seen several LED flashlights with warnings about shining them into your eyes on the packaging, not just in manuals.
I am surprised that they produce a light light flashlight that has significant UV emission. My understanding is that they work light a fluorescent tube where shorter wavelengths hit phosphors which re-emit at lower wavelengths. I would expect that these flashlights could be engineered to effectively absorb the UV in the phosphor layer. If not, that could be "bad".

There are plenty of other intense light sources (laser pointers, my UV flashlight, microscope light sources, spotlights (for theater, movie production, or calling batman), staring at the sun during an eclipse, ...) that can irreversibly damage your retina also. This is not uncommon.
The only real difference to me is the current easy availability and common use of the flashlights.

You just got to be aware of things when you are handling potentially dangerous equipment and take responsibility for its proper use.
 

berkeman

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I have seen several LED flashlights with warnings about shining them into your eyes on the packaging, not just in manuals.
Yeah, I just noticed that there is even a little warning label on my flashlight between the ON button and the lens. I guess they are serious about the warning...

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BillTre

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Yeah, I just noticed that there is even a little warning label on my flashlight between the ON button and the lens. I guess they are serious about the warning...
I am not sure that as many people understand all these warning icons as a simple text warning (I have often seen them paired together).
However, since they are probably made for many different countries, I guess this is an easy way to warn people.
 

pinball1970

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I have seen several LED flashlights with warnings about shining them into your eyes on the packaging, not just in manuals.
I am surprised that they produce a light light flashlight that has significant UV emission. My understanding is that they work light a fluorescent tube where shorter wavelengths hit phosphors which re-emit at lower wavelengths. I would expect that these flashlights could be engineered to effectively absorb the UV in the phosphor layer. If not, that could be "bad".

There are plenty of other intense light sources (laser pointers, my UV flashlight, microscope light sources, spotlights (for theater, movie production, or calling batman), staring at the sun during an eclipse, ...) that can irreversibly damage your retina also. This is not uncommon.
The only real difference to me is the current easy availability and common use of the flashlights.

You just got to be aware of things when you are handling potentially dangerous equipment and take responsibility for its proper use.
Some very specific LEDs have UV but most do not have them, the SPDs I have seen have that spike at 450nm but nothing below 400nm
 
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Is that at one particular wavelength? The LED SPDs I have seen all have a spike at 450nm
No, this issue is true for all type of LEDs at all wavelengths. The area emitting the light is just too small, and if it is focused on (by our eye) then its image on the retina can has too high intensity. The danger is higher with shorter wavelengths but it won't change the geometric nature of this particular issue.
There are LEDs which has some kind of protection against this, either by having some kind of lens or diffusor built in, but for a flashlight or such it is still problematic since these are expected to deliver direct light on a target.

I have to repeat that I did not read that study, I've just threw in a known issue which seems to fit the known content.
 

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