Volume 6 · Book 60 · Hadith 163
Narrated Said Ibn Zaid: The Prophet said, "Al-Kam'a is like the Mann (sweet resin or gum) (in that it grows naturally without human care) and its water is a cure for the eye diseases."
— Sahih Bukhari, Volume 6, Book 60: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)), Hadith #163