It is narrated from Sayyiduna Zayd bin Arqam (may Allah be pleased with him), he says: I suffered from an eye ailment, so the Prophet (peace and blessings of Allah be upon him) came to visit me. Then he said: "O Zayd! If the pain in your eyes were to remain, what would you do?" I replied: I would be patient and hope for reward. The Prophet (peace and blessings of Allah be upon him) said: "If your eyes had continued to hurt like this and you had been patient and hoped for reward, then Paradise would have been given to you in exchange for it."

It is narrated from Qasim bin Muhammad (may Allah have mercy on him) that when one of the companions of the Prophet (peace be upon him) lost his eyesight, the other companions visited him. He said: I used to desire my eyes so that I could keep seeing the Prophet (peace be upon him). Now that the Prophet (peace be upon him) has passed away, by Allah, I would not even like to have the eyes of the deer of Tabalah in exchange for them.

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that I heard the Prophet (peace and blessings of Allah be upon him) say: "Allah, the Mighty and Majestic, has said: When I test My servant by taking away his two beloved things, meaning his eyes, and he remains patient, I will grant him Paradise in exchange for them."

It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him), who reports from the Prophet (peace and blessings be upon him) that he said: "Allah the Exalted says: O son of Adam, when I take away your two beloved eyes and you remain patient over this affliction and hope for reward, then I am not pleased to give you any reward less than Paradise."