AFIAR it's to do with how the picture is drawn on the screen and the refresh rate. Although you're not consiously aware of it your eyes do see the flicker on a CRT. As I recall the screen is interlaced and the cathod beam is moving across the screen drawing 25 screens per second (interlacing giving the illusion of 50hz).
Originally Posted by mattx
TFT/LCD pixels are either on or off. There's no beam moving behind the screen keeping the image alive and so their is no flicker.
If I remember correctly migranes are related to epilepsy. Suffer's may find that strobe lights and florescent lights can also bring on attacks because of the flickering.
Careful - shellfish can be a trigger for some people... :)
Originally Posted by bossman
I was recently at John Radcliffe hosp in Oxford to have a hole in the heart fixed - and they were doing research there to see if it would stop migraines - apparently about 25% of the population have a hole of some kind (Patent Foramen Ovale) - which can cause blood clots to travel round the body and cause strokes and other problems (which was why I was there) - and they reckoned that this might cause migraines too - so there was a lot of form filling, and follow ups in a few months - if the research shows this to be correct - you might be prescribed blood thinners (warfarin/clopidogrel etc) in the future to control them.