Just do what Teddy Roosavelt did; since he was very very near sighted, he always had a spare pair on or about him. When he went off to the war with Spain, he had an even dozen stached about him and his gear. Now with todays materials, I don't think you'll need a dozen, but a good first line pair is nice in your daypack.
I've been wearing specs for about 35 years now, and I feel like they've saved my eye a time or two.
I've been wearing specs for about 35 years now, and I feel like they've saved my eye a time or two.