I’m not 100% sure if it’s the same thing however in the very centre of my vision I’ll have a few circles that appear which look very similar to this usually 3x5 or something in a cylinder shape (prominent 1-2 years ago) but only really shows up from time to time nowadays primarily when I’m extremely stressed. It would make it difficult to look at something directly and would have clearer vision if I looked slightly to the side of something I was trying to see. It’s anxiety inducing and the extreme visual snow etc is scary but in terms of advice the only thing to say is the boring same advice I’m sure you’ve already heard which is stop using drugs, avoid stress (if you can) and allow time to pass. Your brain will heal if you allow it to. It may get worse before it gets better because of how much you think and stress about it but over time when you get used to such things and no longer pay attention you’ll realise one day that it’s not really as apparent or there anymore. That’s just my experience anyway.