Floaters, as you probably now, are light, irregularly shaped lines or specks that appear in the vision. They are caused by small amounts of debris that form in the liquid that fills the inside of the eye. As they float around in the liquid, they cast shadows on the retina, which is what you see when you "see" floaters.
Floaters are a very common condition, and most people have them. They are generally produced as the liquid inside the eye ages and deteriorates, and so they tend to accumulate over time.
Although this deterioration and accumulation is normal therefore in an aging adult, it might not be normal in a small child. This is because the liquid in the eye should not have had time to deteriorate so extensively. Therefore, it is essential that your son have a good eye exam as soon as possible with your ophthalmologist
Rarely, floaters can be a sign of a detaching retina. This is especially true if the number of floaters is large or increases suddenly, if there is accompanying blurry vision, or if there is accompanying flashes of light. An eye exam will be able to rule out this and other serious eye problems.