Here’s something you won’t be able to unsee: The next time you are driving at night behind a car, flit your eyes left and right. The brake lights of the car in front of you might cast long streaks of flickering on your retinas. Many of the new LED lights are more like strobe lights, flicker in an insanely distracting way… on the highway and in people’s homes.
LED string lights are the worst. In shopping centers and restaurants and on Christmas trees. Just move your eyes around a little and ZOWIE, you’re in a disco with streaks of strobe lights all around you! I’ve heard that it actually causes epileptic seizures in a small percentage of people. For me, it just makes me hate you and your incessant strobe lights in my face. I’ll admit that the effect isn’t too bad as long as I keep my head and eyes perfectly still. :-(
Can’t tell if your light is flickering? Try this: close one eye and wiggle your finger in front of the bulb. You’ll see the strobe effect very clearly.
“Oh Lee, you’re exaggerating / crazy / over-sensitive!”
Actually, I’m not. Try googling “LED flicker“. Let me point out to some sources
Here’s an IEEE workgroup formed to work on the problem of high-brightness flickering LED bulbs and their 2010 work-in-progress document whose purpose is “…to describe health implications of flicker”
This article in LEDs Magazine promotes good techniques for manufacturers to use in making good LED lighting because “…people are beginning to pay more attention to long-term exposure under higher-frequency flicker in the 70–160-Hz range. Such flicker can cause malaise, headaches, and visual impairment.”
(LEDs Magazine April/May 2014, Proper driver design eliminates LED light strobe flicker)
Here’s a guy on Youtube that tests LED bulbs on his own time. One of his tests is to check whether bulbs flicker. Some of the big brands flicker, some of the no-name brands don’t. Ugh, there are no standards.
Here’s a snippet from a US Department of Energy publication “Low-frequency flicker can induce seizures in people with photosensitive epilepsy, and the flicker in magnetically-ballasted fluorescent lamps used for office lighting has been linked to headaches, fatigue, blurred vision, eyestrain, and reduced visual task performance for certain populations. Flicker can also produce hazardous phantom array effects—which may lead to distraction when driving at night, for example—or stroboscopic effects, which may result in the apparent slowing or stopping of moving machinery in an industrial setting.”
etc etc etc…