The way this was explained to me (although this may be grossly simplified) is...
When our BG is high, our body tries to get rid of the excess sugar. This is one reason why one of the symptoms of high BG is going to the toilet a lot. Another symptom may be tooth decay as the sugar is coming out through our saliva.
It also comes out through our tear ducts (my tears tasted sweet rather than salty when I was first diagnosed). This means the water our lens need to focus through has a different focal length so our lens adjust for this. As our BG comes down, especially if it comes down quickly, the lens takes some time to adjust back to normality.
This is what causes the blurred vision.
One of the things you will keep reading with regard to diabetes is "we are all different". What works for one person causes a problem for another. What takes a few days to recover for one person may take a few weeks for someone else.
I know this is not a great answer to your question but it is hard to tell how long it will take for your eyes to recover.
Some people buy cheap ready readers to temporarily correct their eyesight whilst waiting for the lens recovery.
I know you can get OK ones from Poundland for £1.
Finally, well done on getting your BG down.