Yeah, I've seen them too. If you look at a bright purple light (I did it at one of those science exhibits at a museum) you can see hundreds of them. Apparently they're embryonic remnants floating in the fluid of your eye. Presumably from dead cells/forming cells.

Floater - Wikipedia, the free encyclopedia
partcleguy Reviewed by partcleguy on . Floaters. Does anyone ever see these? I think they are called "floaters" - but when it is really bright out you look straight ahead and it looks like little cells floating around...like a circle with a dot inside it. I have seen them my whole life - and I always thought that they were actual cells...I was curious and very stoned the other day and did some searching online and a lot of other people see them, too! Weird!!! Rating: 5