if subjected to varying degrees and conditions, i'd just go with a pair or pairs of glasses. I use contacts, but I would not consider them suitable for serious situations where you are without adequate backup or supply. As they are, contacts are just too delicate. get something in your eye? better be able to take out that contact with clean hands because otherwise you are not going to put it back in.

i have several pairs of glasses stored in various bags and drawers, all with hard cases. They make the package more bulky but i rest easier knowing that they can take some knocking about.