[CliffordK]

When she is driving at night and encounters a vehicle with these lights she says it's very difficult for her to determine the source of the lights.  That she sees them all over the place.

What about bicycle lights?  Fast vs slow strobe on the bike lights?  Some people have suggested that a bike should have both steady and strobe lights to help people judge where it is, but my opinion is that just seeing it is important enough.

[Richard Rlcm]

Is there a technical or scientific name for this effect?

I also suffer really badly from it, it's not just tail light of cars but a lot a bars and cinemas now use such LEDs in strips. This echo effect is then multiplied tens of times as each LED in the row strobes in my side vision. It drives me crazy to the stage I feel I want to throw up and often have to leave. The only hope I had so far was that this does not happen with all LED lights, but now I read others suffer from this too I feel better.

I do have an history of migraines and my eyes are light blue, but there seems to be very little information out there. I would hope that someone could suggest a temporary solution which would prevent it like wearing some kind of filtered glasses.

I believe as mentioned this is cause by low pulsing rates and/or cheap circuits.  Unfortunately I guess these these kind of lights will continue to be used until maybe in 3-5 years new technologies comes into play as standard and these old lights fade out.  (no joke intended

Please feel to contact me offline if you can help or advise.

many thanks!


 

[evan_au]

Is there a technical or scientific name for this effect?

It's called persistence of vision.
- If the pulse rate is high enough, the LED appears to be on, continuously
- If the pulse rate falls below a critical flicker fusion threshold, the LED appears to flash
- I guess this threshold could be different for different people.
- This is especially a problem if your eyes are moving rapidly, as it turns the LED into a dotty line
- The time when your eyes move most rapidly is during a saccade. The sensitivity of vision is supposed to be reduced during saccades (saccadic masking), but I guess if your brain doesn't turn the sensitivity down enough, the flicker will be annoying.