My fiance and I are planning our first backpacking trip together. I am an experienced backpacker, so I can handle most questions he has and I already have most of the gear that we'll need. However, he wears contacts and is worried about losing contacts and keeping his contacts from freezing. He is very near sighted and has astigmatism. I have never worn contacts or glasses so I'm not sure how to deal with this.
+Our backpacking trip must occur in spring or fall due to his job, and will probably occur in places where snow and cold temps are possible if not likely. I read that contact solution freezes at 28 °F (-2°C). I have been out spring backpacking in single-digit temps °F (-18–-12°C).
+His glasses no longer fit his prescription.
+We're a little broke, so buying new glasses ($400! per pair!) or a different type of contact lens is not really doable for us.
+Leaving contacts in overnight is something he will not do.
To handle the losing contacts issue, I am planning on having him bring at least 2 spare pairs of contact lenses (and if he loses 2 contacts, we'll bail). To handle cleanliness issues, I have ordered hand wipes and we'll bring at least two travel bottles of contact solution. So my question is how to keep contacts in the contact case from freezing in cold temps? (Also, any contact-wearing backpackers have any additional tips for backpacking with contacts?)