I had a vitreous separation occur suddenly a couple of months ago. It was pretty concerning at first, because my vision was fine one moment and suddenly filled with new floaters the next. I also started seeing flashes in my peripheral vision in dimly lit rooms. Went to the eye doctor to make sure there were no retinal issues, and thankfully everything has been fine in that regard, but the floaters are still pretty bad. They’ve improved some since then, but I still see what look like strands of hair hanging down in the right conditions (mostly in bright light).
Apparently, vitreous separation is age-related (Yay!, another “feature” of getting older), and pretty much everyone will have it happen eventually.
I see flashes in my peripheral vision in dimly lit rooms too.