LED Lights and Retinal Damage is something I think will occur until oversight is authentic and uniformly applied.
Problem is, I don’t think, in the U.S., we’ll ever be at that point. Lasers are being imported from China with markings saying they meet emission standards (brightness), that seemingly don’t, I’ve seen a video (not shown, but similar is) where a Laser Marked Low Power actually burned through paper.
300mW Green Laser Torch from DinoDirect – Burning Stuff and Overview (HD!)
The above Laser is Green. The LED used recently for blinding the Federal Police (possibly irreparably) was Green. It might be possible to hide this LED Beam (or the simultaneous use of it) in the Beam from the LED Flashlight.
An article I read years ago I can no longer find, said in Europe, LEDs, and LASERS, are regulated by the govt, apparently to limit the possibility of causing harm when used by people not familiar with them. I’m not suggesting low power LEDs and Lasers aren’t available in Europe, they likely are, but by the time they get to a substantial output, regulation hopefully applies.
I am a Tech School trained Optician, have an Associate Degree in Electronics, and worked in heavy industry for 25 years, nearly 1/4 of that was a full time rep for union employees on Safety and Environmental Issues pertaining to the employees, and I was one of several reps in that position in my plant. OSHA, Union, and Company Training for Safety Education was frequent, and Hazard Recognition is part of that.
When I started working, we had incandescent flashlights. Over the years, headlamps became popular, mounted on our Hard Hats, and these were LED. While I was in Safety, available in the plant were these Headlamps:
• Streamlight Haz-Lo
• Princeton Tec EOS II
• Pelican HeadsUp Lite 2620
The Princeton Tec is more compact than Streamlight, the Pelican, also compact, was incandescent and LED, but only one or the other would be on. They are all worthy products. We got hold of several Pelican 2690 Headlamps, Single LED, no Incandescent Bulb, as trial samples and gave them to various employees to try.
I saw one employee, looking closely at the headlamp and twisting the lens that turns it on, yell out in pain as the light came on, saying the brightness briefly hurt his eyes. I’m thinking he’s being melodramatic. Weeks later, being the idiot I am, I’m twisting the lens, observing a set screw on the lens to see if it hits a switch (it doesn’t), only to have the light turn on, and I felt the brightness and reacted, pushing the light away. The problem is, I had a circular spot in my vision for hours. That’s not persistence of vision – that slight retention briefly by the retina when subject to a light – it was a retinal burn IMHO.
I notified Pelican, I collected all the samples or otherwise instructed others to be mindful when using them outside of work (at that point, it was decided not to use that model in areas that I, at least, had influence over and the trial samples were sure to be going home with some). And I was told by people testing them that employees standing in front and facing them while working were complaining it was too bright.
Pelican makes many fine lights and we used them, but something seemed clearly wrong with that model.
In my opinion, it’s what’s referred to as Point-Source Brightness. The brilliant light of an LED occurs at a tiny electrical junction, and if the optics are not properly designed, that Point-Source can damage the retina (Too much brightness over too small an area of the Retina). Streamight HAZ-Lo seems to use an inverted Optical Pyramid in front of the LED to broaden the Point Source, Princeton Tec likewise uses technology in the optics to do the same.
All of these lights are only a tiny fraction of the brilliance of the latest and greatest flashlights and headlamps, using powerful rechargeable batteries, and High-Tech Modern LEDs, that, on their brightest settings, appear more like search lights than flashlights.
This article is to help others be aware of potential hazards of poorly designed LED lighting, even in modest brightness due to Point-Source (or Spot Size) issues, or perhaps even lights designed to avoid Point-Source issues that are so bright, and the light so concentrated, that for reasons still not studied, or understood, other types of retinal damage may occur. The Retina is a frail, tissue type structure. The eye’s lens system on its own concentrates the light on the retina, we may be risking much by careless use of a relatively recently emergent technology in high output LEDs.
I’m writing to urge people to be cautious around other people and animals when using LED Flashlights, particularly High Output ones, due to potential Retinal damage they may cause. In my case, I can’t believe that hours later I still had a spot from my exposure to a much dimmer LED than many newly on the market.
References:
Web Link: LED lighting and retinal damages
Web Link: Effects of white light‐emitting diode (LED) exposure on retinal pigment epithelium in vivo
….The device is fitted with a diffuser improving the uniformity and protecting against the effect of point sources (Fig. S1)…….
In this article, we analysed the effects of white LEDs on the retinal pigment epithelium. We found important structural alterations and damages leading to the disruption of the outer BRB after LED light exposure. At the molecular level, analyses revealed an increase of oxidative stress followed by cell death by necrosis, a rare event in this type of tissue.
The observed injuries of the RPE reinforce our concerns regarding the general and unrestricted use of LEDs in lighting products and the necessity of revising the product safety standards for this type of lighting, with the aim of to protecting our vision during our whole life‐time.
PDF – Laser and LED retina hazard assessment with an eye simulator
They refer to the Spot Size, rather than Point Source, but detail why it’s an issue. If it’s from the year 2010, gains in brightness of LEDs are probably much more than they’d ever guessed.
Be careful around them, not to shine them into you eyes, or those of others. And when spotting animals, once caught, consider using a dimmer setting. Exploring dark areas, have at it. They are extraordinary lights and technology.
PDF – Potential risks to human health of Light Emitting Diodes (LEDs)
PDF – Optical safety of LED lighting See references to Thermal Injuries to Retina.
Below is from my Original Posting of this material, and in no way is it intended to detract from the tragedy of police having their eyes damaged, possibly irreparably, by the use of High Intensity LASER or LED products by the terrorists currently afflicting various American cities. But below is to signify that you should not treat Laser Pointers and High Intensity LED or even poorly designed lower intensity LED flashlight products carelessly, and they should not be given to children or for children to have access to them unsupervised.
For a little “kind of related” levity, don’t end up like Ralphie from “A Christmas Story”, take your vision seriously.
Meanderings 