IS it possible to wake up, but you see little black dots, and then your vision goes back to normal? if yes, why does it

Question: IS it possible to wake up, but you see little black dots, and then your vision goes back to normal? if yes, why does it happen?
- Keywords:
  eye,
  sight
Asked by chance786 to Ben, Dave on 28 Jun 2013.
- David Briggs answered on 28 Jun 2013:
  
  If it is happening to you, then yes, it’s possible. There are a couple of possible explanations:
  
  The little black dots you see could be drops of blood floating around in side your eye – these are called floaters – they could be sign of disease in the back of the eye and should be checked out by a doctor.
  
  However – the fact they go back to normal might mean that you are just getting something on the surface of your eye, rather than actually inside it. Some people sometimes sleep with their eyes partially open, if you are doing this you might be getting dust in your eyes, which you see first thing in the morning, but then it clears as soon as you blink a few times.

Question: IS it possible to wake up, but you see little black dots, and then your vision goes back to normal? if yes, why does it happen?