Posterior Vitreous Detachment (PVD)

What is Posterior Vitreous Detachment?

Posterior Vitreous Detachment (PVD) is a common condition which occurs in about 75 per cent of people over the age of 65. As people get older the vitreous jelly inside the eye can shrink – causing Posterior Vitreous Detachment.

What is the Vitreous?

The vitreous is a clear jelly-like substance which takes up the space behind the lens and in front of the retina. It is 99 per cent water. The vitreous is attached to the retina more strongly in some places than others. When a PVD starts the vitreous separates from the retina.

Why does the vitreous detach?

The vitreous shrinks with age. The central part of the vitreous becomes more liquid and the outer part (cortex) peels away from the retina. As it comes away from the retina it can cause the symptoms of posterior vitreous detachment.

What are the symptoms of PVD?

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. The pull of the vitreous in these areas stimulates the retina. This stimulation causes the sensation of flashing lights since the brain interprets all stimulation signals from the retina as light.

Can anything be done to help with the PVD?

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. Up until recently surgery was discouraged for this condition but new advances in vitrectomy surgery have made it possible to consider this option. Fine instruments are introduced into the eye to gently remove the vitreous gel and replace it with saline solution. Stitches are usually not necessary. Complications are rare but include cataract formation and retinal detachment.

Will I lose any sight?

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. Your GP or optician should arrange for referral to an ophthalmologist to have a detailed retinal examination.

Are retinal tears serious?

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.

Retinal tears are more common in people who are short sighted or have had previous eye surgery eg cataract extraction. There are a few families who have a genetic cause of retinal detachment.

Warning signs of a retinal tear or detachment include an increase in size and number of floaters, an increase in flashing lights or blurred vision. If you experience any of these symptoms you should seek medical advice within 24 hours. This is particularly important if you notice a dark "curtain" falling across your vision, as this may mean that the retina has already partially detached. Early intervention may allow treatment of a tear before it becomes a detachment and increase the chances of a good recovery.

Is there anything I can do to cope with these annoying symptoms?

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.

This works best if you have one large floater rather than lots of small ones. 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.