Ibn Shihab al-Zuhri (may Allah have mercy on him) said regarding a one-eyed man who puts out the eye of a healthy man: Allah Almighty has said in the Qur'an: "The eye for the eye" [Surah al-Ma'idah: 45], so retaliation will be taken from him, even if it is all that remains of his sight.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الديات / 16299