There’s three types, that I’m aware of.
One is the shadow of blood vessels on your retina. These are the most common in healthy eyes. Your brain usually ignores these, but if light hits your retina at the right angle, you’ll see them for a bit.
The second one: your eye is filled with a substance called ‘vitreous fluid/humor ’. This fluid is a complex network of cross-linked collagens. Damage to the eye can cause some of the collagens to clump together, casting a shadow on the retina.
The third one is damage to or deterioration of the retina, caused by disease. This one is less of a “floater”, but more of spot that becomes fuzzy in your vision. If untreated, this spot can grow and eventually cause blindness.
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