The eye’s shape is supported by an internal jelly called the vitreous humor. When we are born there is a blood vessel system (hyaloid artery) that runs through this jelly and in some cases does not fully degenerate before we are born. This often causes our first floaters as the opaque remnants create shadows on the retina. As we progress through life the vitreous begins to break down and parts of the fibers in the jelly condense causing more floaters. In most instances, floaters are benign, and removal is not warranted and too risky. If the floaters are caused by bleeding within the vitreous a vitrectomy (removal and replacement of the vitreous) may be performed as this blood does not often resolve on its own. Given the risk involved with this surgery it is only performed when necessary.
As we age the vitreous eventually liquifies and collapses. When this occurs it often pulls away for the retina and we call this a posterior vitreal detachment. It is rare to see this condition in those under 40, but incidence increases rapidly, approaching 86% by the 90’s. As this occurs it may cause a large or multiple floaters and flashes of light. The concern with this condition is if the vitreous tears the retina as it pulls away, causing a retinal detachment. The greatest risk of a retinal tear in these cases is in the first 6 weeks after the initial onset of symptoms and remains elevated for the first three months. This condition is considered urgent and does require evaluation.