tokens: The Blue Mountains Eye Study examined 3654 participants ( 82 . 4 % of those eligible ) in cross - section I ( 1992 - 4 ) and 3509 participants ( 75 . 1 % of survivors and 85 . 2 % of newly eligible ) in cross - section II ( 1997 - 2000 , 66 . 5 % overlap with cross - section I ) .