These are usually black or opaque objects that appear to float accross or down the line of vision. They are sometimes described as what appear to be spiders, or nets floating suspended in the line of vision from inside the eye. They change position with movement of the eye and are often seen more clearly against a white or brightly lit background.
Floaters can be quite annoying to the sufferer who has no way of clearing them from the line of sight. They are generally an age related problem but can be seen by younger people at times. The easiest way to explain Floaters to sufferers is that a floater is a small peice of natural debris, something like a flake of skin, which is floating within the jelly like fluid inside the inner eye.
Whilst there is little or nothing that can be done to effectively cure this problem it is always advisable to have this condition checked by a full sight examination so that the situation can be monitored.