seems a lot more likely that it was already there, and your thalamus was doing a bang-up job of filtering out of your conscious awareness until you started 'looking' for it.
I have read numerous reports of people 'getting' tinnitus under similar circumstances. In fact, in my case, I developed the visual problems first, then read that people with such visual problems also often have T, and started mentally 'looking' for it...... EEEEEEEEEEEEEEEEEEEEEEEEE.
That could very well be! But I don't think they were there for that long if so. I've noticed, in the past, "clear" floaters now and then, they kind of look like single bubbles or lines of bubbles and I think everyone has them. They're much less intrusive than the solid black ones I see now, so, I was already pretty sensitive to notice them!