“Have you ever noticed a strange little worm-like speck drifting aimlessly about in your field of vision? These annoying little squiggly lines, or “cobwebs,” are called floaters and are experienced by around 70% of people. So what are they?

Floaters are actually shadows cast by objects suspended in the clear, gel-like substance that makes up the majority of the eye’s interior. This substance is called vitreous and helps to maintain the eye’s round shape. After passing through the lens, focused light has to pass through the vitreous in order to reach the retina at the back of the eye. It’s mostly composed of water but also contains proteins and various other substances.”

via What Those Strange Things You See Floating In Your Eye? | IFLScience.