Original sentence: He appeared as the  POW forger Colin Blythe in the 1963 film The Great Escape, who discovers that he is slowly going blind, but nonetheless participates in the mass break-out, only to be shot down by German soldiers because he is unable to see them
Edited sentence: Perhaps his most sympathetic screen role was as the tragic POW forger Colin Blythe in the 1963 film The Great Escape, who discovers that he is slowly going blind, but nonetheless participates in the mass break-out, only to be shot down by German soldiers because he is unable to see them