I have these too occasionally, they dont interfere with my vision and slowly get bigger till they disappear. I have never considered them to be a part of my stroke .
Interestingly, since my stroke nearly ten years ago I have not had a headache and they were regular occurrences before! I have also lost the background Tinnitus problem, a curse to a serious musician. Since the stroke did serious damage to my musicianship it is a small consideration.
Deigh Davies