well, the older you get, your eyes will get worse
that´s not just depending from your ideally set monitor distance.
more concerning would be mobile phone using several hours a day 😉
don´t excess the time in front of the monitor, if you notice your eyes are getting tired, just pause a little bit and concentrate on other things, so the eyes can focus between different ranges, than just your monitor.
That´s a general thing, even reading books and other stuff