After Yaakov received the berachos from his father and was leaving the room, the pasuk says, “Vayeitzei Yaakov mei’eis penei aviv, Yitzchak – And Yaakov left the face of his father, Yitzchak.” Rav Meir Simcha of Davinsk wrote in his sefer on Chumash, Meshech Chachmah, that the reason why the pasuk used a strange wording – leaving his face – is because the Gemara in Yuma 53b says that when a talmid leaves the presence of a rebbe he should not turn his face to leave; rather, his face should remain in the direction of the rebbe. Rav Meir Simcha continues by citing the Gemara: Rava acted in this manner when leaving his rebbe, Rav Yosef. Therefore the pasuk is teaching us that Yaakov followed this same process.
One wonders why the Meshech Chachmah chose to tell us that Rava performed this action when leaving his rebbe, Rav Yosef. Why was it necessary for him to bring a story in the Gemara whereby we find that this was performed? Once it is the halacha, he should not have to mention a story regarding the matter. Additionally, if he wanted to cite an incident from the Gemara why did he choose this one over the incident that the Gemara there cites earlier? The Gemara earlier alludes to Rav Eliezer acting in this manner when leaving his rebbe, Rabbi Yochanan.
The reason for this is probably because there was something unique about the case of Rava and Rav Yosef that applies to the case of Yaakov toward Yitzchak. The Gemara in Kiddushin says that Rav Yosef was blind. There is a question whether one must stand up for his parent or rebbe if he or she is blind. Rav Akiva Eiger, in his commentary to Shulchan Aruch, Yoreh De’ah, siman 240:7, quotes the Sha’ar Efraim (siman 78) that rules that one must stand up for his father even if he is blind. The Sha’ar Efraim brings a proof from the Gemara of Rava and Rav Yosef, in which we can see that one must stand up for his blind rebbe.
The pasuk, in the beginning of this parshah, tells us that Yitzchak could not see. The Meshech Chachmah therefore brought a complete proof for his suggestion for the p’shat in the pasuk. He suggested that it is written in the pasuk that Yaakov left his father’s face because Yaakov was acting in a respectful manner. He then cites a Gemara whereby we find that an amora also acted this way toward his blind rebbe.
Regarding the opposite situation, whether a blind person must stand up for his rebbe or parent, the Nachalas Tzvi (Yoreh De’ah, ibid.) suggests that he should be exempt from standing up. He bases this on the Gemara that says that when one sees his rebbe coming he should not close his eyes and pretend that he did not notice him. He says that we see from here that if one’s eyes are always closed, he is exempt. Thus the obligation to stand up only falls on one who is able to see.
The Nachalas Tzvi is then bothered by the Gemara in Kiddushin 31b that says that Rabbi Yosi said that he would stand up for his mother when he would hear her voice. He says that we cannot dismiss this question from Rabbi Yosi by saying that he acted above the law, for that Gemara is used as a source that everyone must stand up for parents.
I do not think that there is any indication from the Gemara that this obligation only falls on a son whose rebbe or parent is able to see. I do not believe that the Gemara is to be taken literally when it says that one should not “close one’s eyes.” I think that the Gemara means that one should not pretend that he didn’t notice that his rebbe was walking toward him – whether it be through seeing or any other sense. If a blind man notices that his rebbe or parent has entered the room, I do not see any indication that he should be exempt from standing up. And the Gemara would also warn him not to pretend that he did not notice his parent or rebbe walk in. Based on this, a blind man would be obligated to stand up for any rebbe or parent.