The vitreous is a clear jelly-like substance which fills 2/3rds of the eye, the space between the lens and the retina. It is 99% water and is attached to the retina. The vitreous shrinks with age and starts to separate from the retina. As it comes away from the retina it can cause the symptoms of posterior vitreous detachment.
Many patients with PVD have no symptoms at all. Others may notice floaters or flashing lights. Floaters can take many forms from little dots, circles, lines, clouds or cobwebs. Sometimes people experience one large floater which can be distracting and make reading difficult.
The flashing lights that occur are also caused by the PVD. As the vitreous detaches from the retina it can pull on this light-sensitive membrane causing the visual disturbance of flashing lights.
Usually nothing has to be done medically for this condition. Fortunately many people find the symptoms fade after about six months. The brain tends to adapt to the floaters and eventually is able to ignore them. In rare cases floaters can become persistent and annoying.
Posterior vitreous detachment does not cause any permanent loss of vision. The only threat is the small chance of a retinal tear leading to a retinal detachment. Fortunately, very few people with PVD go on to develop either of these problems.
However it is not possible to tell whether a patient with symptoms of PVD might have a retinal tear. For this reason it is important that you seek urgent attention if you have new floaters or flashes. Sometimes the vitreous is so firmly attached to the surface of the retina that as the jelly collapses it pulls firmly on the retina. In a few people this may lead to the retina tearing which in turn may lead to a retinal detachment.
Seeking medical advice at the first sign of new flashes or floaters is always recommended. Early intervention may allow treatment of a tear before it becomes a detachment and increase the chances of a good recovery.
Floaters can be particularly annoying. They get in the way of seeing things and can make reading difficult. There is a way of trying to cope with this that some people find useful. If you move your eyes around quickly you can create currents in the jelly within your eyes this can sometimes move the floater out of your direct field of vision. Magnification can also help so that you are able to see around the floaters. Fortunately, most people find that floaters become less of a problem with time.