I thought that we only knew (from DCCT) that a large drop in A1C first causes retinopathy to get worse, (but after 5 years or so of lower A1C the outcomes are increasingly better.) I wasn’t aware that it is known that a faster drop (or a rapid change) in the A1C makes this more likely or worse.
I saw from Eric’s post that the initial harm seems to be because of the drop, not the speed of the drop. Reducing your a1c too quickly - #21 by Eric