Oversimplified, but it's about cheating. The narrator's involved with 2 different girls, one has green eyes and the other blue. He sort of acknowledges his reckless behaviour in the lines: "But their legs are open, and I'm blind." By turning a blind eye to what he's doing, it rationalizes the behaviour and allows him to keep going with it. Every time he cheats on the first girl, he's remarking "your green eyes turn to blue" because he should be with the other girl instead. The repetition of the line almost dehumanizes the act... it sounds mechanical and detached... stated more as a matter of fact than anything else. The music sounds like it could fall apart at any moment, frantic like a train twisting from its tracks. It symbolizes the internal struggle of what he's doing perfectly.
Oversimplified, but it's about cheating. The narrator's involved with 2 different girls, one has green eyes and the other blue. He sort of acknowledges his reckless behaviour in the lines: "But their legs are open, and I'm blind." By turning a blind eye to what he's doing, it rationalizes the behaviour and allows him to keep going with it. Every time he cheats on the first girl, he's remarking "your green eyes turn to blue" because he should be with the other girl instead. The repetition of the line almost dehumanizes the act... it sounds mechanical and detached... stated more as a matter of fact than anything else. The music sounds like it could fall apart at any moment, frantic like a train twisting from its tracks. It symbolizes the internal struggle of what he's doing perfectly.