How long have you had this symptom? Are you having any trouble with your vision? Are you seeing any flashing lights with this?
I sounds like you have a posterior vitreous detachment. There is a gel material in the back of our eyes (called the vitreous). As you age (it can also happen if you are very near sighted or with a blow to the head), the gel breaks up into pieces. Patients will then see floaters. However, the gel is attached to the retina in certain places. During this process of breaking up, the gel can tug on the retina. When it does this, you may see differing types of flickering lights. The floaters that you see are harmless, but can be annoying. They will eventually (over many weeks to months) settle down and you won't see them constantly anymore.
However, the symptoms of a vitreous detachment is the same as the symptoms of a retinal detachment (which is much more rare, but more dangerous). When patients report these symptoms, I always suggest that they have their eyes examined to make sure that the retina is OK. The vitreous detachment is harmless and requires no treatment.
Hope this helps.