Job continues describing situations in which he would deserve God's punishment, but he is confident that they are not true. He does not finish his sentence in verses 16 and 17. Instead he explains in verse 18 why they are not true. (See: [[rc://en/ta/man/jit/figs-hypo]])
Here "to grow dim" refers to the widow having bad eyesight from crying a lot. Alternate translation: "if I have caused a widow to cry in great sadness" (See: [[rc://en/ta/man/jit/figs-idiom]])