Glasses on Shabbos

[1] (halacha 18)

Question: May one repair the arm of eyeglasses on Shabbos?

Answer: a) An eyeglasses arm that has become bent may not be straightened on Shabbos, because of [the prohibition of] repairing a vessel. b) If the screw of the arm has loosened, it is forbidden to tighten it. c) If the arm has come out of its place completely, it is forbidden to attach the rod to the eyeglasses even loosely by means of a screw, a pin, or an iron wire, because of [the prohibitions of] inserting [tokea] and repairing a vessel. d) However, there are those who are lenient about attaching the arm by means of a safety pin, and there is room to rely on this in a case where the screw was lost and one has no other screw. (Shabbos KeHilchaso, vol. 4, ch. 31, sec. 31).

[2] (halacha 19)

Question: May one repair the lens of the eyeglasses?

Answer: a) A lens that has become loose may not be tightened. b) To put it back loosely is forbidden, since the lenses are usually attached firmly, the Sages decreed [a prohibition] even when one puts it in loosely, lest he insert it firmly. c) However, if his practice is always to leave the lenses loose, it would be permitted for him to put it back loosely. d) Likewise, if it concerns lenses that, in order to put them back firmly, require a craftsman - a professional, an ordinary person is permitted to put it back loosely. e) Lenses that are always set in the manner termed in halacha 'loose and not loose' - that is, it is tightened but they are not particular that it be truly firm, such as eyeglasses in which the lenses are put back by a light press, it may be permitted to put them back only in a case of great need (Shabbos KeHilchaso, vol. 4, ch. 31, sec. 30).

[3] (halacha 20)

Question: May one carry eyeglasses [whose] arm [fell off] on Shabbos?

Answer: Carrying eyeglasses whose arm has fallen off in order to wear them as they are: a) If the arm is present, it is forbidden to carry [them] lest one attach the arm back. b) However, in a case where the arm was lost or broke, it is permitted to carry the eyeglasses and wear them - since here there is no concern that he will attach it back. c) Likewise, in a case where, in order to repair this, a craftsman - a professional is required, it is permitted to carry [them]. d) If the arm came apart before Shabbos and one already used it as it is, without the arm, before Shabbos, it is permitted to carry it even though the arm was not lost. (Shabbos KeHilchaso, vol. 4, ch. 31, sec. 31).

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