Do not stare at high brightness LEDs, because doing so may cause permanent damage to your eyes.
The optics of our eyes focus visible light onto the retina, which is the light sensitive part of our eyes, similar to the way a magnifying glass can focus an image of the sun onto a piece of paper. Just as the piece of paper might smolder and catch fire, a light that is brightly focused on your retina can cook and thus permanently damage your eye. Exposure to bright white and blue LEDs can also cause permanent damage to your eyes through photochemical action.
Here is a link to an article about the particular hazards of blue LEDs: http://www.mdsupport.org/library/hazard.html#blue
The key factors that determine whether or not a particular exposure to light from an LED causes permanent damage are the wavelength and intensity of the light, the length of the exposure occurs, and the distance from the light source to the eye.
This danger is most pronounced with the use of the newer high output blue and white LEDs. These are intended to illuminate large areas, and for those designed for direct view applications, to be viewed at a significant distance. These LEDs can be identified by packaging or mountings that are designed to carry heat away from the junction. LEDs without these special thermal management features can also pose a danger when operated beyond their specified maximum current.
Infrared and ultraviolet LEDs can also be hazardous, and when using those, please consult the manufacturer’s data sheets or IEC 60825-1:2001 for guidance with respect to safety. You may find IEC 60825-1:2001 summarized on the web. The standard can be purchased from IEC’s web store http://webstore.iec.ch/.
The IEC specification was written to apply to primarily to lasers , though it also applies to LEDs. A new standard, IEC TR 60825, is in development that promises that includes a section that is intended to address LEDs directly. You might want to check the web for drafts or summaries of this standard in the future.
The standards mentioned above rely on measurements that can only be made with very expensive specialized equipment, though some manufacturers state the safety classification of their LEDs, under specified operating conditions, in their data sheets. Take note of these comments on the data sheets for LEDs you may use. In the mean time, play it safe by not staring at any bright LEDs.
My thanks to Geoff Davies of Lucid Optical Services Ltd. (http://www.lucidos.co.uk), for raising the issue of permanent eye damage, and providing the information contained in this section.
Many thanks for this very valuable information. Surely, this should give us all pause for thought? I had wanted to purchase LEDs but am having doubts now, as at some stage people will look at the lights e.g. ones that mount atop a camcorder for instance? Am I being too cautious? Of course they are very useful, but at what price? For the moment fluorescent lights would seem to be more appropriate.
the great thing about LED light is that they do not generate lots of heat~’.
Interesting article. As a manufacturer and supplier of LED lights, I shall be researching this further. Thanks for the info
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I bought lots of little led light torches (white) because the light in my bedroom is too dim for me to be able to read in comfort. After a little while I noticed a flicker in my right eye, had my eyes examined by an optometrist who found nothing amiss. Because the flicker did not go away I googled ‘led light and the eye’ and your article came up. I’m wondering if that is the explanation for my problem, although It seems strange that only one eye is affected. Any ideas?
To heidi cuda:
I advise you to get flicker-free LED lights called rectified LED lights.
Normal LED lights have 60Hz refresh rate, while rectified LED lights have 120Hz refresh rate.
Some people can detect flickers in 60Hz refresh rate, whether consciously or unconsciously.
A lot of those high intensity Cree LED flashlights (5W, 7W, 400 – 1300 Lumens and above, etc) have those little Laser stickers on the side of the lens housing warning users not to look directly into the light. The seller’s also issue a warning to the buyer’s that looking directly into the LED’s will cause eye damage.
It’s still not clear because in the study of “The Influence of Low-powered Family LED Lighting on Eyes in Mice Experimental Model” in Life Science Journal.
The 40 mice were randomly split into four groups (each contained 10 mice), including (1) white family LED irradiation for a consecutive 2-week period (2 hr/day), (2) white LED irradiation for a consecutive 4-week period (2 hr/day), (3) environmental light source with white family LED lamps (the illuminated light of 12-hr light/ 12-hr dark cycle with white family LED lamps), and (4) blank control (no LED exposure), as summarized in figure 1. All experiments were reviewed and approved by the Animal Care and Use Committee in Chung Shan Medical University.
The result is ” Histological results showed that the photoreceptor layer is significantly reduced in thickness after 4 weeks of LED exposure 2h every day or LED illuminated environment.”
In LED illuminated environment, it will affect our retina and also how long you use , how worse you will get.
you can read all information by following website http://www.lifesciencesite.com/lsj/life0901/072_8366life0901_477_482.pdf