Gemara

94b (Mishnah - R. Eliezer): One is liable for coloring eyes;

Chachamim forbid only mid'Rabanan.

129a (Chachamim of Neharda'a): We are not Mechalel Shabbos for a Yoledes (one who gave birth) [after seven days, but] within 30 days, but we get a Nochri to do her needs.

134a (Beraisa): One may not mix wine and oil for a Choleh on Shabbos;

R. Shimon ben Elazar says that R. Meir permits.

Even R. Meir holds that they may not be mixed thoroughly.

147a (Mishnah): One may not reset a broken bone;

(Rav Chana Bagdata'ah citing Shmuel): [The correct text of the Mishnah, and] the Halachah is, one may return a broken bone.

Avodah Zarah 28a (Mishnah): If one's teeth hurt, he may not put vinegar in his mouth (on Shabbos. Rava permits if he will spit it out.)

Inference (Abaye): If he is in great pain, this is permitted (for it is considered an internal wound)!

Rejection: The Tana taught 'hurt', and this includes a great pain.

28b (Rav): If an eye is about to leave the socket, one may paint it on Shabbos.

Rabanan assumed that one may not do Melachah for this, e.g. to grind ingredients for it or carry though a Reshus ha'Rabim. Rather, it must be ready from before Shabbos.

(R. Yakov citing Rav Yehudah): One may do Melachah for this.

It is permitted because nerves connect the eye to the heart.

(Rabah bar Zutra): We may raise drooping ears on Shabbos.

29a (R. Yehoshua ben Levi): On Shabbos, we may raise Unkli (tonsils that obstructs breathing; alternatively the opening to the stomach).

Beitzah 22a: Ameimar permitted to paint eyes via a Nochri on Shabbos.

Question (Rav Ashi): The Yisrael helps, i.e. he opens and closes his eye!

Answer (Ameimar): Help is insignificant.

Rishonim

Rambam (Hilchos Shabbos 2:10): If there is no danger, we do needs of a Choleh (sick person) through Nochrim. Things that do not require a Melachah mid'Oraisa, even Yisre'elim may do, e.g. to lift Unlki, ears or return a broken bone.

Magid Mishneh, citing the Rashba in the name of the Ramban: Shabbos 129a permits doing a Choleh's needs through a Nochri. Both a proper Shevus (Isur mid'Rabanan) done through Yisrael, or commanding a Nochri [to do a Melachah], is permitted only for an illness that includes the entire body, but not for one limb without danger. This is why a Yisrael may not paint his eyes, even though it is only Shevus, like the Rambam says below (23:12).

Rosh (Avodah Zarah 2:10): We permit Melachah to heal an eye only because there is mortal danger. We do not permit merely due to danger to a limb. However, we may do Isurim mid'Rabanan to heal it. Even if the ingredients were ground up already, every cure is forbidden mid'Rabanan lest one grind. Similarly, one may do all needs of a Choleh through a Nochri. We do not distinguish Shevus with an act from Shevus without an act (telling a Nochri). Or perhaps loss of a limb is unlike a Choleh without danger. We find that one may not return a bandage outside the Mikdash (Eruvin 102b). Or perhaps that is not a case of illness, rather, mere pain, therefore we forbid Shevus with an act. This requires investigation.

Beis Yosef (DH v'Ika): I say that the Rambam distinguishes based on whether the Shevus is close to a Torah Melachah, e.g. painting the eyes, which is like writing, or any Refu'ah with a potion, in which there is concern for grinding spices. He permits only through Nochrim. If the Shevus is not close to a Torah Melachah, it is permitted even through Yisrael. Therefore, a Yisrael may lift Unkli and ears, and return a broken bone. The Rosh and Ran permit Shevus through a Yisrael when there is danger to a limb.

Ran (Shabbos 39b DH umi'Ha): If a person has a mere pain, but he is strong and walks like a healthy person, he may not do anything that is evidently done for Refu'ah. We learned that if one's teeth hurt, he may not Yigma vinegar, even if he has a great pain, since it is not an illness. When there is mortal danger, adult Yisre'elim do all his needs. If there is no mortal danger, just danger to a limb, Nochrim do his needs that require a Melachah mid'Oraisa, and even Yisre'elim may transgress Shevus for his needs. If there is no danger to a limb, just mere illness, Nochrim may do even Melachos mid'Oraisa for his needs, but Yisre'elim may not transgress even Shevus for him.

Question (Beis Yosef OC 328 DH Aval): The Ran rules like the rejection. This is astounding, for it was a mere Dichuy. We are lenient about a mortal Safek! Perhaps the Ran does not rule like this; he just explains the rejection, but he admits that it is a Safek and we are lenient.

Magen Avraham (328:2): The Ran (40a DH Min) explicitly says that the Safek was not resolved [so we are lenient]. On 39a he merely proved from the rejection that a mere pain does not permit telling a Nochri to do what Yisre'elim may not do on Shabbos.

Poskim

Shulchan Aruch (OC 328:17): If a person is bedridden due to illness, and there is no danger (Rema - or he has a pain, and due to it his entire body is sick), we tell a Nochri to make a cure for him, but we are not Mechalel Shabbos through an Isur mid'Oraisa, even if there is danger to a limb. Some say that a Yisrael may do an Isur mid'Rabanan for the sake of a Choleh even if there is no danger to a limb.

Taz (8): This is the Rashba's opinion. He permits even if there is concern for grinding spices. If not, all agree to this! However, it is difficult to explain Ameimar according to this opinion.

Magen Avraham (12): This is the Magid Mishneh's opinion. All the more so he permits when the entire body is sick, even was not danger to a limb. The Magid Mishneh said 'we do not permit Melachah even due to danger to a limb.' This connotes that Shevus is permitted.

Mishnah Berurah (50): This opinion permits Shevus without a Shinuy. It holds that Chachamim did not decree in a case of illness.

Mishnah Berurah (51): If there is danger to a limb, all except for the last opinion permit any Shevus, even if it does not affect the entire body. What may be done through Yisrael is permitted even if one could do it through a Nochri.

Shulchan Aruch (ibid.): Some permit only if there is danger to a limb.

Taz (9): This is the Ran's opinion. The entire body is sick, but there is no danger to a limb. We do his needs only through a Nochri.

Mishnah Berurah (52): This refers to what it said above, that the entire body is affected. If not, without danger to a limb, one may do Shevus only through a Nochri.

Shulchan Aruch (ibid.): Some say that if there is no danger to a limb, one does through a Shinuy, and if there is danger to a limb, one does without a Shinuy.

Taz (10): The Magid Mishneh brings this opinion in the name of the Ramban. He learns from mixing wine and oil. The Magid Mishneh says that the Rashba agrees. The Beis Yosef said that Teshuvas ha'Rashba is like the first opinion! It seems that one may not rely on that Teshuvah, or it has a printing mistake. We rely on the Magid Mishneh's testimony.

Gra (DH u'Lechalel and DH v'Yesh): Most Poskim and the Shulchan Aruch rule like the third opinion (this opinion, the Ramban). He learns from Kesuvos 60a. Children were allowed to suckle on Shabbos because this is Mefarek ki'Le'acher Yad (unskillfully). It is forbidden without a Shinuy, like we says about wine and oil and in several other places. The second opinion is the Ran. He says that suckling is permitted because it cannot be done through a Nochri, since it helps only hot (straight from the animal). When there is no other solution, he agrees to the Ramban. The first opinion is the Rambam according to the Magid Mishneh. The fourth opinion is the Rambam according to the Beis Yosef. The Ramban and Ran distinguish between whether or not there is danger to a limb, just the Ramban always permits through a Shinuy. The Rambam says that the distinction is whether or not the entire body is affected, or whether the Shevus is close to a Melachah.

Kaf ha'Chayim (111): If one cannot do what is needed through a Shinuy or through a Nochri, a Yisrael may do it.

Kaf ha'Chayim (112): The Magen Avraham connotes that if it is possible through a Nochri, this is better.

Shulchan Aruch (ibid.): Some say that even if there is danger to a limb, one may not do something close to a Torah Isur, but even without danger to a limb one may do something not close to a Torah Isur.

Taz (11): This is like the Rambam, according to the Beis Yosef. His explanation of the Rambam is correct.

Magen Avraham (13): This is the Beis Yosef's opinion. The Bach challenged it from the Rosh and Ran, who permit painting an eye about to come out, even though it is close to Melachah.

Shulchan Aruch (ibid.): The third opinion seems correct.

Taz (12): It seems that this refers to the Ramban. The Bach and Levush say that it is the Rambam, who is the third opinion that argues with the first. Why didn't they explain that it is the third opinion mentioned? Also, if the Mechaber refers to the last opinion, he should have said 'this opinion'!