http://www.msf-usa.org/motion.html Spose this goes back to the old 'mind playing tricks' thing.
AAAgggghhh! That's so weird...
Thank the good Lord that they provided an explanation of sorts. Otherwise, I would have thought it was my poor old arc-flash burnt retinas, repeatedly fried over 46 years, that were making the blind spots!
What happens if you see more spots