It is clear when I am near a light colored wall I see what looks like blood veins or a map of rivers for less than a second when coughing hard
is this a kind of entoptic phenomena? I dont remember seeign this before, I cant see this outside or high contrast background , only near light painted walls.
If I move my eyeballs up or to the sides I can see blood veins in the right corner of my eyes even without coughing. Is this mechanical pressure of my eyelids? In the other case, is the coughing doing mecanical pressure too?