Over the last few days I have seen a tiny blue dot when my eyes are open, that quickly vanishes. Sounds just like Janet's (above).
I also see the tiny twirling white dots, millions of them. They're most easily seen when looking at a clear blue sky away from the sun, but can be seen indoors too. I think anyone can see them if they try. You have to focus on open space. I thought they were energy particles unknown to science, but recently I read that they are just your own white blood cells in the blood vessels of the eyes.
I prefer to believe they are mysterious energy.