Riyad as-Salihin, Book 19, Hadith 1868 (In-Book) ⓘ
Sa'id bin Zaid (May Allah be pleased with him) reported: I heard the Messenger of Allah saying, "Truffle (edible fungus) is a species of Al-Manna and their water cures eye diseases."[Al-Bukhari and Muslim]
وعن سعيد بن زيد رضي الله عنه قال: سمعت رسول الله صلى الله عليه وسلم يقول: "الكمأة من المن، وماؤها شفاء للعين" ((متفق عليه)).