If your missionary wears glasses or contacts, eye care deserves its own line on the packing list. A little planning now makes travel days and mid-mission replacements easier to handle.
Start with a visit to the eye doctor
Ask the eye-care professional what to bring for the destination and length of service. Cover the prescription, the replacement schedule, how much supply to pack, how it should be stored, and how follow-up care or reorders will work. The same lenses and solution may not be easy to find everywhere, so it's worth settling all of this before departure instead of assuming.
Pack glasses that actually work
Even a missionary who lives in contacts should carry glasses with a current prescription, and a protective case is worth the space. If there's an old spare pair around, ask the provider whether its prescription still holds up as a backup before it goes in the bag.
Keep the details within reach
Send along the prescription details and the provider's contact information in a form your missionary can access under the mission's device rules. Essential supplies belong somewhere reachable during travel, and check the travel and destination rules before packing any liquids.
Practice safe lens care before leaving
The CDC recommends washing and thoroughly drying hands before handling lenses, using the recommended disinfecting solution, and keeping lenses away from water. Take them out before showering or swimming, never top off old solution with new, and don't sleep in lenses unless the eye-care provider says to.
If a lens becomes uncomfortable, take it out and call the provider. The CDC's contact-lens care guidance is worth reading alongside the provider's instructions before departure.
Give the kit a home
Pick a protected spot for the glasses case so books and travel gear won't crush it, and try packing the whole kit in the bag your missionary plans to carry. That way nothing has to be figured out on a busy travel day.