There is an axiom when describing someone's poor eyesight we call them "blind as a bat". I have never needed glasses or contacts and so becoming blind as a bat is something I never have experienced.
While bats cannot 'see' very well, bats can hear very well. They are able to listen to the world around them in such a way that it directs them to food, steers them from danger, and guides them back home.
It was posted the other day on Inward/Outward blog the following: