First off, do I have 20/20 vision? Short answer: no. Not even allowing for the various shades of interpretation that are possible.
And there are variables. Eyesight is variable even in people with accepted perfect sight. Sometimes one eye will falter a bit. Sometimes they will be a bit slow to react and their vision will seem blurred. Sometimes they may only have one eye that sees well - so you could say they have 20/20 vision, but you would not be able to prove it if you only tested their 'bad' eye.
Is it possible to distinguish between 'having 20/20 vision' and 'being able to focus at 20 feet'? Because here's the thing: I CAN focus at 20 feet.
I think I need to start making videos again to help me to define the limits of my own eyesight. I also, before I depart this world, ought to really focus on bringing my eyesight to 20/20 or similar.
Why have I not done it in 22 years of vision work? Well, mainly because I lose interest in the process. Short attention span or something. I am sure I know in theory just how to get 20/20. If I could demonstrate it that would give my words more credibility.
So, watch this space!