They are known as "floaters" or "benign floaters"
or "vitreous floaters": A blurry spot that
seems to drift in front of the eyes but does not block vision. The blur is the
result of debris from the vitreous of the eye casting a shadow on the retina.
We call them "Squiggly Lines"!
More info below.
Oh squiggly line in my eye fluid.
I see you lurking there on the periphery of my vision.
But when I try to look at you, you scurry away.
Are you shy, squiggly line?
Why only when I ignore you, do you return to the center of my eye?
Oh, squiggly line,
it's alright, you are forgiven.