The source brought above, from the Ben Ish Chai, Parshat Pinchas Shanah Beit 13, states (among other tikkunim to protect one from ayin har-ah): “and the sage the Chida”h z”l writes: [a] custom of the World [is] to say ‘Chamsah,’ therefore [we] hang [a] wood [thing/pendant] drawn in it the form of a hand, that has in it five fingers and carved on it letter hei.
That’s what I have here, but the girsah (version) he posted above replaces the word ‘eitz’ (wood [thing] ,here probably pendant) with ayin (eye).