I have not had Chiari surgery yet, but I had an extensive laminectomy in 2000. Whenever I look down & to the right(like shaving my armpit), there are sparkly lights, and I have to wait for them to go away. Apparently its a bulging disk. (That's as opposed to floaters that near sighted people are prone to.) Is this what you mean?
Hi and welcome to the Chiari forum.
Many of us may have residual effects of the chiari and surgery, and if the floaters when u turn r the worst u have, that is not too bad.
The vertigo, is something else, it is possible that something else is going on, and warrants at least a NL visit.
It sounds like u did well post op until now, and that is great!!