My eyes are very sensitive to flashing lights - for example I'm always the first person to notice that a fluorescent tube is about to fail because I see it flickering when other people can't.

When I'm driving at night, I perceive LED rear lights on cars as being a series of unconnected dots when I scan my eyes quickly across the scene. Evidently, many, if not all, LEDs are actually flashing at a high rate which most people don't perceive.

It almost seems as though I have a higher "refresh rate" than most people. How unusual am I? What is the physiology of it?

EDIT: I suppose what I find most fascinating is that at times when I see a trail of flashes, the spacing between them is remarkably consistent. This implies to me that there is an incredibly accurate timing mechanism somewhere in my visual system that is taking "snapshots" with clockwork regularity - probably between 50 and 100 samples per second. I'd like an insight into this "clock" and why mine seems to be faster than anyone I've ever met.

This similar to what I perceive:

enter image description here

  • $\begingroup$ two related Qs and maybe partial answers: biology.stackexchange.com/questions/7445/… and biology.stackexchange.com/questions/9277/… $\endgroup$ Mar 4, 2015 at 11:57
  • $\begingroup$ @fileunderwater Thanks for that - I couldn't find anything when I searched the archive, hence the question. I know about the peripheral vision thing and rod density. I can verify that the fluorescent tube thing is much more sensitive at the periphery of my vision - which makes it even more annoying! It's much more difficult to say with the rear-light scenario, I mainly notice it when I sweep my eyes rapidly so I guess the periphery is playing a greater part in vision at that time than during normal, focussed driving. $\endgroup$
    – Lefty
    Mar 4, 2015 at 12:43
  • $\begingroup$ 4 clarifications would come in handy to answer this question. (a) You speak of LED lights being unconnected dots. Often these are in fact unconnected dots? Is this so extraordinary?; (b) Comment (a) seems to address spatial resolution, whereas the rest of the question seems to address temporal resolution. Are you saying both spatial and temporal resolution are extraordinary? (c) the edit: what trail of flashes? A trail is spatially defined while sampling rates are temporal characteristics (d) where do you live? The mains in the US is 50 Hz, which is not unusual for folks to perceive. $\endgroup$
    – AliceD
    Mar 4, 2015 at 22:35
  • $\begingroup$ @Chris Stronks I've added an image to explain what I mean a little better. I'm not talking about the individual LEDs in the light cluster - the entire group of LEDs must flash in unison because I see the multiple images like the photo. So as you can see, the movement across my vision (in time) captures the rear light as images separated in space. I'm in the UK - our mains is 50Hz too - but I've never met anyone who can see the flashing of a fluorescent tube the same as me. In what way do you think people are able to perceive 50Hz? $\endgroup$
    – Lefty
    Mar 4, 2015 at 23:05
  • $\begingroup$ The site where I got the image has a few people who can also perceive these light trails. The suggestion there is that these rear-lights actually flash with a frequency of 200Hz! $\endgroup$
    – Lefty
    Mar 4, 2015 at 23:31


You must log in to answer this question.

Browse other questions tagged .