If you observe dots or spots floating in your vision, they may not be your mere immagination but Floaters

Often people face dots or spots moving in their field of vision. This problem is called floaters. Floaters are basically, dark specks, strands, dots or spots that one sees in his vision specially while seeing a plain background or sky. Although, they seem to be in-front of the eye, but in reality they are opacities floating inside the eye. If you observe such floaters in your vision, it is best to visit an eye specialist.