@Compro01 said in a comment,
There is an assessment by ANSES (Basically the French OHSA in this respect) regarding health effects of lighting systems using LEDs that mentions something about blue light, however, I don't understand French and I'm not sure google translate is giving me an accurate translation of the important bits.
The following is my translation/paraphrase of important bits of that.
Last updated 27 Feburary 2013
À ce jour, la méthode la plus rentable économiquement pour fabriquer des LED consiste à combiner une diode émettant une longueur d'onde courte (dans le bleu) avec un luminophore jaune, pour produire de la lumière blanche. Des composantes intenses dans la partie bleue du spectre de la lumière émise par les LED, ainsi que les intensités de rayonnement associées posent la question de nouveaux risques sanitaires liés à ces sources d’éclairage. Dans ce contexte, l’Anses a publié en octobre 2010 un rapport sur les effets sanitaires des systèmes d'éclairage utilisant des LED, assorti de recommandations visant notamment à mieux encadrer la mise sur le marché de ces produits.
Currently the cheapest way to make LEDs is to combine a diode which emits a short wavelength (in the blue) with a luminescent yellow, to make a white light. The intense emissions in the blue part of the spectrum combined with the intensity of the light pose new health risks.
La technologie des LED, qui présente certains avantages par rapport aux autres types d’éclairage (efficacité énergétique, durée de vie), est en pleine évolution. Ses domaines d’application sont larges : éclairage public, domestique et professionnel, installations sportives, voyants lumineux (jouets, signalétique, etc.), éclairage des véhicules, produits à visée thérapeutique (luminothérapie). Néanmoins, la qualité de la lumière (température de couleur[2], indice de rendu decouleur[3]) émise par ces lampes ne présente pas toujours le même niveau de performance que pour les autres sources d’éclairage.
Des composantes intenses dans la partie bleue du spectre de la lumière émise par certaines LED, ainsi que les intensités de rayonnement associées posent la question de nouveaux risques sanitaires liés à ces sources d’éclairage.
LEDs have various advantages compared with other forms of lighting, and are used in many places, but the quality of the light (the color temperature and color accuracy) doesn't always have the same performance.
The intense emissions in the blue part of the spectrum raise health questions.
Dans le cadre de l’expertise réalisée par l’Anses, les risques identifiés comme les plus préoccupants, tant par la gravité des dangers associés que par la probabilité d’occurrence dans le cadre d’une généralisation de l’emploi des LED, sont liés aux effets photochimiques de la lumière bleue et à l’éblouissement. Ils résultent :
- du déséquilibre spectral des LED (forte proportion de lumière bleue
dans les LED blanches) ;
- des très fortes luminances4 des LED
(fortes densités surfaciques d’intensité lumineuse émises par ces sources de taille très faible).
Le risque d’effet photochimique est associé à la lumière bleue et son niveau dépend de la dose cumulée de lumière bleue à laquelle la personne a été exposée. Il résulte généralement d’expositions peu intenses répétées sur de longues durées. Le niveau de preuve associé à ce risque est important.
The risks we identified as the most worrying (because of the gravity of the danger as well as the likelihood of occurrence) are linked to photo-chemical effects of blue light, and dazzling:
- From the unbalanced spectrum (a lot of blue in a white LED)
- From the strong brightness (a lot of light from a small-surface-area point-like light)
The risk of photo-chemical effects is linked to blue light and its level depends on accumulated dose. It usually comes from repeated long-duration exposure to not very intense exposures. "The level of proof associated with this risk is high."
Des populations plus particulièrement sensibles au risque ou particulièrement exposées à la lumière bleue ont été identifiées, comme les enfants, les personnes atteintes de certaines maladies oculaires ou encore certaines populations de professionnels soumis à des éclairages de forte intensité.
Populations who are most at risk include children, people with certain eye diseases, and some professionals subjected to high intensity lighting.
Il existe actuellement peu de données d’exposition des personnes relatives à un éclairage, qu’il s’agisse des systèmes utilisant des LED ou d’autres types de sources lumineuses. L’Anses n’a ainsi pu présenter des évaluations des risques chiffrées que dans le cas de l’exposition à la lumière bleue, selon les principes développés par la norme NF EN 62471. Cette norme relative à la sécurité photobiologique des lampes propose un classement en groupes de risque liés à la durée d’exposition maximale admissible de l’œil à la lumière.
There's currently little data on the effect on people of lighting, whether LEDs or other light sources. We've been able to give numeric risk data only for the case of exposure to blue light, according to the principles developed in standard NF EN 62471.
Sur la base de ces différents constats, l’Anses, a considéré qu’il est nécessaire de restreindre la mise sur le marché « grand public » des systèmes d’éclairage à LED pour n’autoriser que des LED ne présentant pas plus de risques liés à la lumière bleue que les éclairages traditionnels. Par ailleurs, l’Anses recommande d’adapter la norme NF EN 62 471 relative à la sécurité photobiologique des lampes aux spécificités des LED et de prendre en compte les populations sensibles et les personnes particulièrement exposées (certaines populations de travailleurs : installateurs éclairagistes, métiers du spectacle, etc.).
Based on these observations we have considered it necessary to restrict sales of LEDs to the general public, to LEDs which don't present more of a blue-light risk than other traditional lighting. We also recommend adapting standard NF EN 62 471 for LED specifications, to take into account sensitive populations [as listed above] and people who are especially exposed (certain professionals including lighting specialists, live entertainers, etc.).
There's another web site http://www.les-ampoules-a-leds.org/les-leds-sont-elles-dangereuses.php whose author is an LED manufacturer, which criticizes the above standard. It says not to use "cold" (aka blue) light whose color is above 5200°K, for example 7000°K, when there are children around, unless the glass of the lighting sufficiently filters the short-wavelength blue light.
It criticizes the alleged risk of dazzling associated with LEDs, because the risk depends on the intensity of the light which depends on the angle of diffusion.
Now to answer the questions.
"Should I be worried? Should I replace my LED lights with something else?"
Wikipedia's High-energy visible light article says,
In ophthalmology, high-energy visible light (HEV light) is high-frequency light in the violet/blue band from 400 to 500 nm in the visible spectrum.[1] HEV light has been implicated as a cause of age-related macular degeneration.[2][3]
Some sunglasses are now designed specifically to block HEV.[1]
Blue-light hazard is defined as the potential for a photochemical induced retinal injury resulting from electromagnetic radiation exposure at wavelengths primarily between 400 - 500 nm. This has not been shown to occur in humans, only inconclusively in some rodent and primate studies.[4] The mechanisms for photochemical induced retinal injury are caused by the absorption of light by photoreceptors in the eye. Under normal conditions when light hits a photoreceptor, the cell bleaches and becomes useless until it has recovered through a metabolic process called the visual cycle.[5][6]
Absorption of blue light, however, has been shown in rats and a susceptible strain of mice to cause a reversal of the process where cells become unbleached and responsive again to light before they are ready. At wavelengths of blue light below 430 nm this greatly increases the potential for oxidative damage.[7] For blue-light circadian therapy, harm is minimized by employing blue light at the near-green end of the blue spectrum. "1-2 min of 408 nm and 25 minutes of 430 nm are sufficient to cause irreversible death of photoreceptors and lesions of the retinal pigment epithelium. ... The action spectrum of light-sensitive retinal ganglion cells was found to peak at 470-480 nm, a range with lower damage potential, yet not completely outside the damaging range."[8]
"What is the specific wavelength problem that LED lights cause that damages the retina?"
The shorter wavelengths. According to the above, 500nm and below.
"Will filtering out blue light from LEDs actually eliminate the problem?"
I expect so, if the filter effectively filters. That's what it says on the web site authored by the LED manufacturer referenced above.
"They also mention in the article that LED lights have been blamed for damaging art works in galleries but no proof given - any truth to this too?"
I would expect so: for example flash photography is typically banned in galleries, and always has been in my lifetime. Some old-fashioned pigments are photo-sensitive and fade.
"What damage, if any, can LED lights really cause?"
The may depend (on dosage etc.): but the Wikipedia article mentions "age-related macular degeneration.
http://en.wikipedia.org/wiki/Age-related_macular_degeneration#Causes_and_risk_factors says,
Exposure to sunlight, especially blue light: Evidence is conflicting as to whether exposure to sunlight contributes to the development of macular degeneration. A recent study on 446 subjects found it does not.[27] Other research, however, has shown high-energy visible light may contribute to AMD.[28][29][30]
I won't access NF EN 62471 at a cost of 100 euros: which may contain or reference what ANSES described as "a high level of proof" that blue light can be harmful.
See also the answer to Can blue light therapy contribute to Age-related Macular Degeneration?.
