Anas (May Allah be pleased with him) said:
I heard the Messenger of Allah (ﷺ) saying, "Allah, the Glorious and Exalted said: 'When I afflict my slave in his two dear things (i.e., his eyes), and he endures patiently, I shall compensate him for them with Jannah.".[Al-Bukhari].
Arabic/English book reference: Book 1, Hadith 34