You avoid eye strain by lifting your eyes from the screen every so often and looking around at other things. Same way you need to get up and move every so often so that your leg muscles don't atrophy.
Even those of us that spend all day on our phones are not literally spending 10 hours staring at a screen. You blink, hear a bird and look up. Check on a child or animal every few minutes. Participate in zoom meeting, listen to a book or music while doing dishes or preparing a meal.
