My vision is also bad enough that I basically can't function without glasses. I always have a backup pair with me in the car, and I take 2 backup pairs on vaca

My vision is also bad enough that I basically can't function without glasses. I always have a backup pair with me in the car, and I take 2 backup pairs on vacation, usually packed in 2 separate bags. I also take spare shoes (even for day trips) because I can't buy another pair easily if something happens to mine--they don't sell shoes big enough in normal stores. You obviously evaluated the risks differently, but to me not needing to pack an extra pair of glasses isn't worth the substantial, potentially life altering risk of severe dry eyes (not to mention blindness).