It wasnarrated that Ibn 'Abbas said:
"The Messenger of Allah (ﷺ)said: 'What a good slave is the cupper. He takes away the blood,reduces pressure on the spine, and improves the eyesight.'" (RU)
English reference (RU): Vol. 4, Book 31, Hadith 3478 (RU)
Arabic reference (RU): Book 31, Hadith 3607 (RU)