Lately I've noticed a black dot in the vision of my right eye (a few weeks now). I'm used to floaters, this is different - it's black. Other than that, it's much like a floater: it's out of focus and, while it seems to move around, I think that's just my eye movements (I don't see how it could move around on its own yet still return to the same spot day after day). I only tend to notice it when I read my monitor with my left eye closed (quite common when tired - a bad habit since I was young.) I sit facing a bright window which may contribute to my ability to see it. I guess it's just a floater of some particularly dark material?