Look down at book or your phone and the text appears blurry? This situation usually comes with no warning. There’s no escape from this situation but here’s simple solution - Embrace your eyes with reading glasses. Even if you never had any vision problem, you will require readers at some point of life ( after 40s, evidently).
Don’t squint, clearly focus at near distance and chuck out the difficulty of reading with right prescription and right style of reading glasses.