I get a similar artifact however its most noticeable when I close my eyes.
What I experience is "Visual Snow"
as well as as the "Blue field entoptic phenomenon"
https://en.wikipedia.org/wiki/Blue_fiel ... phenomenon
Visual snow for me is most prevalent as soon as I close my eyes with significant changes in light intensity (Very bright ambient to dark behind closed eyes). My visual snow eventually reduces but does not disappear. I also notice it especially on dark matt finish surfaces.
Hope this helps...