en_tn/jhn/09/39.md

came into this world

The "world" is a metonym for "the people who live in the world." Alternate translation: "came to live among the people of this world" (See: rc://en/ta/man/translate/figs-metonymy)

so that those who do not see may see and so that those who see may become blind

Here "seeing" and "blindness" are metaphors. Jesus distinguishes between people who are spiritually blind and physically blind. Alternate translation: "so that those who are blind spiritually, but who want to see God, can see him, and those who already falsely think they can see God will remain in their blindness" (See: rc://en/ta/man/translate/figs-metaphor)