Never much understood that expression—firstly, because I’ve never been a bat (and they actually do possess sight) and secondly, I’ve never been blind. Now it’s becoming increasingly clearer, unlike my vision.
I’m still neither, though I’m understanding the “blind” part more and more. Seems it’s sadly true: the older you get, the more your eyes deteriorate. Which is exacerbated by the wearing of reading glasses. My former optometrist said that once you begin wearing them, the more and faster your vision worsens.
Put on new glasses. Your eyes adjust. Soon muscles weaken. And lenses no longer compensate. And so it goes.
Without my visual aids—my crutches—I’m seeing Sanskrit instead of reading English. I’ve not yet walked into a Mack truck or strolled into a hedge or dropped down a sewer hole. I suspect that’s around the corner. Literally.