Recent Innovations forced mostly by newer and stricter government regulations have brought us through extremely unreliable CFL light bulbs from the old incandescent light bulbs to these very expensive yet aledged long life LEDs. So far I'm okay with these LEDs especially how cool to the touch they are. But I have been noticing a high frequency flash involved. One can see the flash by using a fidget spinner and observing the light and area it illuminates. Is this something we should be be thinking about as far as health issues may be concerned?
closed as primarily opinion-based by PeterJ, laptop2d, DoxyLover, winny, Dave Tweed♦ Sep 30 '17 at 11:44
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Continuous exposure to flickering light is known to cause myopia in developing eyes (here's a clinical study in guinea pigs, albeit with the frequency 2 orders of magnitude lower than you'd expect in LED lights). It was also the primary reason for CRTs to have ever-increasing refresh rate, which is close to the flickering frequency of LED lights. Apparently, the damage is reduced as the frequency increases, at least I can certainly assert that I've spent more than 4 weeks in front of a CRT as a kid, and I didn't get myopia yet.
Note that flickering is only present in the cheapest devices which lack any smoothing or regulation circuit, so if your LED lights have noticeable flickering, just go for a better brand. Those will have LEDs driven either constantly, or at much higher frequency.
LED driver circuitry can involve switching the diode ON and OFF over time, but it is not a requirement for LEDs in order to work. Higher end lamps will probably tend to switch in unnoticeable frequencies or maintain the diode ON all the time. Eyes on the other hand depend on chemical reactions to sense light, these reactions take a little while to happen so your body can't tell the difference between a brighter flashing light and a dimmer steady-ON light if frequency is high enough. There are no proven detrimental effects of high frequency flashing lights in our physiology. Experiments to test these ideas are simple and have been conducted. PubMed is a well known journal where you can search for articles regarding the subject!
I'm sure someone will swear they cause migraines or worse.. But whatever health issues they may just represent has to be better than all the mercury in the CFLs.
Any flashing you may see though is more a characteristic of how the LEDs are driven, not the LED's themselves.