hpst You said the thing that hurts cannot manifest above 60hz so this is an easy test if I am understanding you correctly.
If you have a 144 Hz display, whatever happens can happen at most at 144 Hz. The 60 Hz I mentioned were just an example for basic 60 Hz displays.
Maybe whatever hurts is gonna multiply on a 144 Hz display by a factor of 2.4 (144/60). It would be interesting to know if this actually happens, and ultimately helps. However, what we are talking about here is just a driver/signal issue. The monitor itself you buy and try could create eye strain by other means PWM/flicker, blue light/FRC/whatever.
hpst if its some output causing the problem why does it not manifest on CCFL displays?
Well for me actually it does. That software eye strain is completely reproducible on my old CCFL monitors and my old CCFL laptop (on top of PWM and "display too bright" issues). I did not try the new problematic graphics cards as they would not even fit in the old AGP slot, but browser/GPU acceleration eye strain is there as well as on new LED displays.
Maybe your old laptop, more precisely its graphics output does NOT do this "bad signal" stuff. It probably has different GPU hardware? Or it really is a display/backlight issue. I imagine on laptops this is hard to track down.