Donux And eye strain could be a caused by many things alone such as anxiety disorders, depression disorders, eye problems, various stress
Not necessarily. I think the reason 50%+ of us are even here is that we already checked our eyes (and probably were told they were actually either "fine" or even "above average"), multiple doctors, checked other factors like mood, diet, sleep, and trying to exercise more and discovered that the screen issues (and by extension, their longer-lasting effect on the way you process vision even in the real world) were entirely separate.
Possibly even tried multiple types of vision therapy (like I did) and nothing, and what FINALLY changed anything significant about the "mystery vision issues" was switching the screen.
When I'm on a truly good screen (not just a tolerable one), it literally doesn't matter how I feel, how much sleep, how much stress, I can still look at it and read it fine pretty much no matter what.
(However, how I feel can affect how bad a bad screen is — but even on days I felt otherwise amazing back then, I still could not tolerate my mini-LED Macbook Pro for more than 15 minutes.)
Also, for me, I've noticed that so many (many but not all, of course) of the "issues I have processing vision in the real world" and general fatigue + constant tiredness I was dealing with actually go away after I use a truly good LCD, and remain fine until I use a bad screen, so screens have a significant "trailing effect that basically retrains your brain" that extends after you use them, but interestingly can also be "overwritten" pretty quickly by using a good screen.
(The one exception is non-backlit like e-ink, which "takes on the general profile" of the last screen I used before it but with a mild-to-moderate improvement.
Back when I only used bad screens, I still had fatigue reading on e-ink or even paper. Some "vision issues" I used to think "weren't screen related" — such as eyes wanting to close when standing still — remained afterwards. But when I FINALLY found a good backlit LCD, I realized just a day or two on it "retrains/resets my vision" and I can see soooo well in real life after using it, and e-ink/paper starts feeling way more readable too)