Ibn 'Abbaas Radiyallahu 'Anhu says:
"Rasulullah Sallallahu 'Alayhi Wasallam said: 'Use kuhl made of ithmid on the eye; it brightens the eyesight, and strengthens and increases the growth of the eye lashes'. (Sayyidina Ibn'Abbaas Radiyallahu'Anhu also used to say) 'Rasulullah Sallallahu 'Alayhi Wasallarn had a small container for keeping kuhl, from which he applied kuhl in each eye three times every night"' (FR)
English reference (FR): Book 7, Hadith 48 (FR)
Arabic reference (FR): Book 7, Hadith 49 (FR)