- Edited
My thinking is that the more screentime you have, the more you are damaging yourself and the longer the required recovery period even if the screen is technically "perfect" as far as one could objectively measure with current tools and theories. Of course, some are better than others. Even with knowing some guidelines (no flicker, no harsh blue light, etc.) it is still hit and miss and a trial and error process of finding what works.
For myself, I've never noticed significant eyestrain problems until 2022. Over the years, I've used multiple "bad" screens (from crts to ccfl backlights to cheap PWM led backlight monitors) from laptops and desktops that we would consider junk by today's technical standards and those didn't really bother me before. Definitely the tech has changed (hardware in step with software) perhaps with unintended bad consequences and the same with the living environment and the rhythms of daily life.
However, I have changed as well. Gotten weaker over time from stress, overwork, missed opportunities for rest and exercise and the all important recovery from any insult to the body. Perhaps screens I was able to adapt to and tolerate are not anymore due to these cumulative health changes.
My ongoing search for personal health solutions:
Take breaks (I've already mentioned doing the 20-20-20 rule)
Deep relaxation breathing is essential for stress recovery and energy and oxygenation to body and eyeballs
Massage type exercises you can do yourself not just from physical therapist etc. For example pressure points around your eyes, temple, neck, back of your head. Also, don't forget to blink.
Diet and foods to help promote normal blood circulation and detox. I've also mentioned before the eye, liver, kidney connection.
Others are recommending eye patching and special glasses beyond the typical blue light blocking type. Lots of info on this forum.
Some sites to help find "your" monitor (always check and cross check the info):