diop An expert on flicker, Naomi Miller from Pacific National Laboratory, describes her ability to see flicker that others can’t as a “superpower” in her webinar “Metrics in motion: flicker and glare” (unfortunately recently moved behind a paid firewall).
I suspect that a fairly significant fraction of the population is more sensitive to flicker than the average person, but most people are unaware of what’s happening to them. There’s scientific data to support both of these hypotheses - from a 1989 study of fluorescent light flicker where they switched up high and low flicker fluorescent lights in the workplace without telling the workers which lights they had when. There were significantly more headaches (8% of people affected) and eyestrain (8% of people affected) with the high flicker lights (most affected people had both headache and eyestrain, but some had only headache or eyestrain). Interestingly, the workers weren’t able to accurately identify which lights they had or when they were switched - even though they were told about the general study design and purpose: Wilkins et al. Fluorescent lighting, headaches and eyestrain. Lighting Research and Technology, 21, 11-18 (1989). https://www.researchgate.net/publication/258168086_Fluorescent_lighting_headaches_and_eyestrain
I think I was getting headaches for years from sporadic exposures to flickering lights and occasional screen overuse, but I had no idea myself what was happening until a workplace lighting change had severe and more obvious effects. With minor exposures it takes about 45 minutes for a headache to start for me, so I can be well past the dangerous lights, which left me totally unaware of what was happening in the beginning. And my more debilitating symptoms like working memory loss/brain fog can take much longer to develop as symptoms ramp up over the course of many days following a severe flicker exposure. I had also been incorrectly rationalizing my headaches with too much screen use as happening because I hadn’t eaten recently enough - at the time it didn’t occur to me that the screen itself could be the trigger.