下の方は努力して見ようとしないと、見えないのだ。 (From line 4: https://www.docdroid.net/847v2dg/img-20170413-0001-new.pdf.html) According to my understanding of the sentence, it says: "Concerning the lower area,
...if you don't want to see it with effort... or ...if you don't make an effort while making an effort to see it...
...,you can't see it."
The problem lies with the relation between 努力して and 見ようとしないと. As far as I understood the "intentional form + とする" constructions, when expressing that someone intentionally makes an effort or doesn't make an effort, another 努力して to emphasize that someone's making an effort isn't required, since this effort is already contained in the respective verb.
Of course this problem is somehow eliminated when using "want" instead of "making an effort" in the translation of said form. But it doesn't change that the same thing is kind of expressed twice here. I guess it's just there to put more emphasis on it, but I wanted to ask about it in case I've missed something.