I have never been particularly good at balancing on one foot with my eyes closed. I think I once told how I keep my ankles strong for tennis by doing odd balances, but I need my eyes open to stay upright for more than a handful of seconds.
You might enjoy trying balancing right now, before I tell you what I did, so you can do a before and after.
So anyway, I was trying to give my eyes a little break after several too many hours staring at a screen. I went to a conference room, and just started staring out a window instead. Then I started passing the time by balancing. And I decided to see just how far I could move my balance point forward and backward and right and left. I was moving in kind of a size 12 rectangle. I'd balance on my big toe, then my outer heel, then my inner heel, and then my little toe, and that meant moving my weight back 10 inches or so, and to the right 2 inches or so, then left then back forward and right, etc.
I did that for a while on each foot, and I began to feel how stable my balance was when my weight was directly over the first knuckle of my little toe.
Nothing amazing. Just a mindless way to pass the time between perl hacking and red tape.
Then I tried to balance with my eyes closed.
And I could.
I had taught my foot what it feels like to have my weight at the outer limits in each of the four directions, so when I started to drift toward my big toe or elsewhere, I could feel it and fix it.
Not very profound, but it was funny for my mind to finally understand a feedback for the first time that my foot has been giving it for years.