Ibn 'Abbaas Radiyallahu 'Anhu says:
"Rasulullah Sallallah 'Alayhi Wasallam has said: 'The best from among all the kuhl used by you is the one made from ithmid. It brightens the eyesight and strengthens the growth of the eye lashes"'
English reference: Book 7, Hadith 51
Arabic reference: Book 7, Hadith 52