Here the "world" is a metonym for the people who live in the world. Alternate translation: "living among the people of this world" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "light" is a metaphor for the true revelation of God. Alternate translation: "the one who shows what is true, just as light allows people to see what is in the darkness" (See: [[rc://en/ta/man/translate/figs-metaphor]])