Are you bleary-eyed in the morning, and not just because of the previous night’s bender? Chances are, you need glasses! Or contacts. To each his own.
In any case…for those of you who require visual aids, stash a spare set of specs in your carry-on when you travel. If you’re a packrat like me, you probably still have glasses from several years back, so take one of those ratty old pairs. It may not be your ideal prescription anymore, but if you lose your current lenses in a disaster situation, you will be ridiculously glad to have that back-up pair.