LCDs do not flicker.
I *explicitly* did not say flicker. I do not mean flicker. Flicker is
perceptible to the viewer.
Minitors *do* refresh. They do not all refresh at the same rate. The OP is
complaining of eye-strain and headaches. These are real, and quite
reasonably he would like to do something about it. They could easily be
explained by a tiny difference, far too tiny to be perceptible, or even
easily measurable.
This is the second time that you have contradicted me with the same irrelevant
comment, without offering anything constructive. Nihilism is not going to
solve the problem for the OP.
Lisi