In Greece you can see bijoux with the blue eye sold everywhere. The greek people buy these as a protection against the "bad eye". It is people talking bad about you or good as well, people being jealous at you, people wishing you bad... If you have a headache or are getting sick in Greece they often think it's the bad eye and then you are "matiasméni" ("eyed"?)! Some people are doing "ksemátiasma", taking away the bad eye from you, using a cross and oliveoil. Everybody beleives in this, even doctors.
