Just pointing out that most of us are beginning readers (in Japanese). Notice that most English-language children’s books are printed with large type. Is that because children have poor eyesight in general? Not at all. It’s because they haven’t yet had enough years of practice reading text so that the letter-forms are immediately recognizable even in small sizes. As books become targeted towards older audiences, the type size becomes rather smaller as a rule. Until you get to large-type books aimed at people with failing eyesight.
So what I’m saying, is that it’s (probably) not that your eyes are bad, or that the print is too small (assuming that it’s aimed at Japanese readers who aren’t small children). It’s that our eyes aren’t yet good enough, and don’t have years of experience (10,000 hours?) at recognizing the characters.
And yes, I also often need a magnifying glass to read Japanese text, because I’m in the same boat.