Hi everyone,
Since the information from here was helpful for me I would like to share my experience. It might help someone.
I have been using for over 10 years old AOC 831w monitor with a cathode lamp and have never had eyestrain with it.
Used with integrated GPU, AMD 7950 and Nvidia gt430 if I remember correctly.
Tho when installing Nvidia I remember the picture looking washed up.
Sadly my monitor broke. Sister gave me her old Lenovo l194 and no eyestrain, but it is from 2008. I knew I had to buy new one.
I bought Philips 243V7QDSB/00 but I got headache from using it, that's how I found this forum, reddit posts etc
Tried all different setting and modes nothing helped.
I started researching why and then I remembered from work when using Dell P2419h I didn't had any headache.
I was looking at panel types, refresh rate, PWM, colors, manufacturers of panels and anecdotes of people. In end stumbled upon the backlighting type.
Cathode lamp no eyestrain and Dell P2419h had edge-lit backlighting, not to confuse with edge bezel.
I found in my market an HP P24 g4 for a good price with edge-lit.
Since GPU are 10bit and monitors 8bit intel, amd and nvidia use different types of image processing. Colors can look different. You can watch on Techyescity. I downloaded the intel command center adjusted Brightness all colors to 38, contrast enhancement all colors to 17.
No eyestrain what so ever. Using it for couple months now.
I belive that backlighting is most important. If LED shines directly at my eyes it hurts, but edge lit shines from the edges toward center making it comfortable for eyes.
Hope it helps, all the best!