I've been iffy in space recently, strikingingly recently, but I attributed it to my les miserables eyes. and their disjointed way of seeing. No, that turns out not to be true, or only enhanced true - it's my balance. Well, in my case both, but I can probably improve.
Very useful article - as balance exercise helps.
I suppose this is well known, but I didn't apply it to me.
Look here -