Gemara

(Mishnah): The following are Pesulim... he can see the first and second floors at the same time, Sachei Shemesh...

(Beraisa): "Iver" refers to one who is blind in one or both eyes;

(Rava): Anyone who cannot see at all is Pasul due to "Ish". Anyone whose vision is impaired is Pasul due to "Dak".

(Mishnah): Sachei Shemesh.

(Rav Yosef): The text should say "Sanei Shemesh" (one who hates sunlight. He cannot look where the sun shines.)

Sanhedrin 17a: R. Yehudah holds that "Itecha" teaches that the Sanhedrin must be (of proper lineage and unblemished,) like Moshe.

Chachamim learn that from "v'Hakel me'Alecha v'Nas'u Itach" (said about small Sanhedriyos). We learn about the Great Sanhedrin from a small Sanhedrin.

36b (Rav Yosef): Just like Beis Din are clean from transgressions, they must be clean from all blemishes (of lineage).

(Ameimar): We learn from "Kulach Yafah Rayasi u'Mum Ein Bach."

Question: Perhaps it refers to physical blemishes!

Answer (Rav Acha bar Yakov): "V'Hisyatzvu Sham Imach" - they must resemble you (Moshe), i.e. have proper lineage.

Yevamos 101a: R. Yehudah learns that even commoners may be judges for Chalitzah from l'Einei (ha'Zekenim)";

"L'Einei" excludes blind people. If we required judges, we would not need a verse to exclude blind people!

(Rav Yosef): Beis Din must be clean from any blemish - "u'Mum Ein Bach."

Chachamim expound l'Einei to teach Rava's law, that the judges must see the spit leave the Yevamah's mouth.

Question: Also R. Yehudah should need l'Einei to teach Rava's law!

Answer: He does. Rather, he learns that commoners suffice learns from "b'Yisrael" - any Yisrael.

Rishonim

Rambam (Hilchos Sanhedrin 2:6): Just like Beis Din (a Sanhedrin of 23) are clean from transgressions, they must be clean from all blemishes (of lineage).

Rambam (7): We are not particular about all of these matters for a Beis Din of three.

Rambam (9): Even if all three were blind in one eye, they are Kosher for a Beis Din of three, but not for a Sanhedrin. One who is blind in both eyes is Pasul for any Beis Din.

R. Yerucham (Toldos Adam v'Chavah 25:2, 216:4): A Mum disqualifies a judge for Chalitzah.

Maharam Mintz (29): One who is blind in one eye is Kosher for monetary cases. Matters involving women, e.g. to be a judge for Chalitzah, involve Isur. Perhaps we are stringent like R. Meir, who equates monetary cases to Tzara'as. (Note: Mo'ed Katan 8a learns from "l'Chol Mar'eh Einei ha'Kohen" that a Kohen blind in one eye cannot rule about Tzara'as.) :If you will say that we are stringent about Chalitzah, perhaps a Get brought (from Chutz la'Aretz), which must be given in front of three, is more lenient. It is mid'Rabanan, and Kiyum (validation) of documents is mid'Rabanan. Also, the Halachah follows R. Yochanan, who says that a Get is given in front of two. Perhaps we are not so stringent about one who is blind in one eye, and he can be a judge for this. Or, perhaps we do not distinguish.

Note: Also R. Yochanan requires a Beis Din, just he holds that the Shali'ach can count towards the three. In any case this shows that we are lenient about judges for a Get.

Maharam Mintz (29): The Rambam connotes that he is Kosher. He says that if one is blind in one eye, he is Kosher for a Beis Din of three, but not for a Sanhedrin. This implies that he is Kosher (for everything except for a Sanhedrin). Also (the Tur) in CM says so, However, in Hilchos Sanhedrin (4:10) the Rambam says that even though one who is blind in one eye is Kosher for monetary cases, we do not ordain him for monetary cases, since he is not Kosher for everything. This implies that he is Kosher only for monetary cases. Surely, one with other bodily Mumim, e.g. he is lame or an amputee, is Kosher. Even though a Ba'al Mum cannot judge capital cases, he is Kosher for other cases. The Rambam says that for a Beis Din of three (i.e. three judges are needed), we are not particular about this (Mumim). Also (the Tur in) CM says so. However, perhaps we are more stringent about matters involving women. It is an Isur like capital cases, even though in other ways it is unlike capital cases. Avi ha'Ezri says that one who is blind in one eye cannot be a judge for Chalitzah. However, R. Tam and the Rambam (Hilchos Yibum Perek 4) are Machshir. I say that one should be stringent to fulfill all opinions.

Note: I did not see the Rambam explicitly discuss this. Perhaps this implies that he is Machshir.

Nimukei Yosef (Yevamos 33b DH Gemara): We concluded that Chalitzah is like the beginning of judgment. We may begin during the day and finish at night. It is like monetary cases, because she collects her Kesuvah.

Chasam Sofer (EH 2:54 DH bi'Yevamos): The Nimukei Yosef needed to prove this, for it says "v'Alsah Yevimto ha'Sha'arah", and "Sha'ar" connotes the Sanhedrin. At the beginning of the Perek, we asked why we do not require judges with Semichah, and a Ba'al Mum is not Pasul. We can say that even though we need (expert) judges, it is not called Din. Not everything that requires judges must be during the day.

Tosfos (Yevamos 101b DH Shma): R. Tam rules that someone blind in one eye is Kosher to be a judge for Chalitzah, since we do not exclude this from "l'Einei." One eye suffices to see the spit leave her mouth.

Poskim

Rema (Seder Chalitzah ((after EH 169) 1): L'Chatchilah, for the judges for Chalitzah we take the Chacham of the city and two important people of the city. Also the two we add must be important people of the congregation. They may not be blind, even in one eye.

Gra (4): This is unlike Tosfos. They explain that when the Gemara said 'Chachamim expound l'Einei to teach Rava's law', this does not mean that they do not exclude blind people, for they learn from l'Einei (that the judges must see the spit leave her mouth). Rather, we learn both, since l'Einei was written next to "she will spit".

Gra (5): If he is blind in both eyes, he is Pasul, for he cannot be a judge (even for monetary cases), like it says in CM 7. Avi ha'Ezri disqualifies if he is blind in one eye, due to l'Einei. The Yerushalmi says so, but it does not mention blind in one eye. R. Tam is Machshir. I say that surely the Yerushalmi disqualifies even if he is blind in one eye. The Ramban must say so, for he disqualifies someone blind in both eyes even for monetary cases. Rather, even R. Tam (in Nidah 49), who is Machshir a totally judge for monetary cases, here holds that 'blind' connotes even in one eye. The Nimukei Yosef (Sanhedrin 13b) says that it means in both eyes. If even if in eye were Pasul, what was R. Yehudah's source that commoners are Kosher? Perhaps we require experts, but they need not be from the Sanhedrin! This is wrong. If so, why did we cite Rav Yosef (that Beis Din cannot have Mumim)? Also, the first Tana used "Ziknei" to be Machshir commoners. Perhaps we include only experts (not on the Sanhedrin)!

Rema: Some are stringent that they not have any Mum.

Gra (6): This opinion holds that a blind person is Pasul due to a Mum. However, we do not hold like this opinion.

R. Akiva Eiger (Teshuvah 2:64): Even one is hard of hearing and hears someone four Amos away only if he has a reed (hearing aid) in his ear and the latter screams, he may be a judge for Chalitzah. There is no source in the Gemara and Poskim to disqualify a judge for Chalitzah due to a Mum. All the Poskim connote that this is like other Dinim. Just like three commoners are Kosher for them, also Ba'alei Mum. Maharam Mintz says that one should be stringent, for perhaps it is like capital cases. This is difficult. Since a verse is needed to disqualify blind people from being judges for Chalitzah, this shows that even commoners need not be free of Mumim. We hold that commoners are Kosher, therefore they may have Mumim. It is very difficult to say that this was only the Hava Amina, but in the conclusion, the verse teaches Rava's law, and commoners are Kosher, but they may not have Mumim. This is a mere stringency. If a Cheresh (deaf person) speaks but cannot hear, it is a Safek whether this is a Mum. Perhaps the Mishnah disqualifies only if he cannot hear and cannot speak, like Cheresh usually means in the Gemara. For Chalitzah we may be lenient to be Machshir unless he cannot hear at all.

Chasam Sofer (EH 2:93 DH Udos): May a Ba'al Mum be a judge for Chalitzah. Only Seder Chalitzah of the Darchei Moshe, in the name of Mahari'ach, disqualifies. The Rema asked that a verse was needed to disqualify a blind person! Several Ge'onim are Machshir one who is blind in one eye. Only Avi ha'Ezri disqualifies. He holds that l'Einei ha'Zekenim teaches that each judge has two eyes. There is no source to disqualify other Mumim. The Rema wrote that above (130) he brought from Maharil that a Ba'al Mum may not permit a married woman to remarry. Perhaps the same applies here. There he discusses witnesses on a Get. The Rema questioned Maharil's source and reasoning. In Seder Get Shelishi (3), he says that a judge on a Get may not be a Ba'al Mum. He did not give a reason. I say that he learns from Yevamos 122b. It says that Edei Ishah (witnesses who testify that a man died, to permit the widow to remarry) are like capital cases. We hold like the opinion that does not require Drishah v'Chakirah (interrogation of witnesses), but this is because she collects the Kesuvah (so it is like monetary cases, which do not require Drishah v'Chakirah). Chachamim were lenient only regarding Drishah v'Chakirah, since they already uprooted Torah law about this regarding monetary cases, but normally witnesses about (married) women are like capital cases. A Beis Din for capital cases must be free of Mumim.

Chasam Sofer: This explains Seder Get Shelishi, but not Maharil. Sanhedrin 45b is Machshir for capital cases witnesses who never had hands! Maharil must decree to disqualify (a Ba'al Mum from being a) witnesses on a Get, lest people be Machshir for judges on a Get. We do not make such a decree regarding capital cases, but there it is impossible. If Ba'alei Mum were the only witnesses to a murder, should we exempt him?! Indeed, if a Ba'al Mum saw a man die, he may testify to permit the widow to remarry. We decree only when there is an alternative. For a Get, one can find witnesses without Mumim. Mahari'ach decrees about judges for Chalitzah due to judges on a Get. Even though Chalitzah does not involve capital cases, the Gemara refers to it like a married woman, so people could get confused.

Question: If we learn from "u'Mum Ein Bach", we should require judges of definite lineage!

Answer (Chasam Sofer): Chachamim did not decree when it is not possible Nowadays even Kohanim do not have definite lineage! A Get sent from Chutz la'Aretz requires a Beis Din according to letter of the law. Why don't we require judges of definite lineage? Kiyum of documents is only mid'Rabanan, so we rely on the Chazakah that all families are Kosher. If so, we can be more lenient about the (three primary) judges (for a Beis Din for Chalitzah) than for the extra two we add on. The (three) judges must be able to (help the Yavam and Yevamah) recite the Parshah. Since it is harder to find such judges, we are lenient to allow Ba'alei Mumim if we cannot find judges without a Mum. We can be particular that the extra two judges have no Mum, since we can take Amei ha'Aretz.

Chasam Sofer (DH v'Emnam): Surely, any Mum that disqualifies a Kohen for Avodah disqualifies for the Sanhedrin. Perhaps the latter is more stringent. "Kulach Yafah" connotes that they do not have even a bloodletting wound. Even a left-handed person is Pasul according to the opinion that this is a Mum. However, we hold that he is Pasul for Avodah only because he has no right hand to serve with, but not because it is a Mum.