At what age was he strickened with blindness? At birth, as a katan, as a bar mitzvah, as an adult, or in old age?
My name is Burton G Kaplan and am a talmid of Reb Tzvi Gelt, maggid shuir of the Daf Yomi held daily at EDOS (East Denver Orthodox Synagouge), Denver, Colorado, USA.
If you can answer my question or not, I want to thank you for your prompt response.
Sincerely,
Burt Kaplan
We learn from the Gemara and commentaries at the end of Maseches Menachos how Rav Yosef became blind.
1) The Gemara Menachos 110a (18 lines from the top of the page) tells us that Rav Simi asked a question to Rav. Rav answered him, "Are you Simi?" Rashi (3rd line from the top of the page) cites an explanation that Rav's custom was that he never raised up his eyes but always looked downwards out of modesty. Therefore, he could not see that the questioner was Rav Simi.
2) Rabeinu Gershom (printed on Menachos 109b) writes that this practice of Rav was one of great piety. His students, Rav Yosef and Rav Sheshes, wished to emulate him. As a result, they became blind.
3) Sefer Petach Einayim, written by the Chida (Rav Chayim Yosef David Azulai), on Mencahos 110a, cites Sefer ha'Pardes (by Rashi) who proposes that Rav Yosef and Rav Sheshes actually caused themselves to become blind when they realized that they were unable to live up to their teacher's practice. (It is not clear how they did this. Certainly it is not permissible Halachicly to cause damage to one's body. Rather, perhaps they were granted blindness through their strong desire or prayer to be given Divine assistance in achieving a great level of modesty and piety.)
Kol Tuv,
Dovid Bloom