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Posterior Vitreous Detachment
The retina lies in the back of the eye and is a multi-layered tissue
which detects visual images and transmits these to the brain. In front
of the retina lies the vitreous humor. The vitreous is the jelly-like
material that fills the large central cavity of the eye. It is
composed primarily of water, but it is also made up of proteins and
other substances which are more fibrous. The water and fibrous
elements together give the vitreous the consistency of gelatin.
The vitreous is normally connected to the retina. During aging, the
watery portion of the vitreous separates from the fibrous portions. As
this occurs, the fibrous elements contract and can pull the vitreous
away from the retina. This is called a Posterior Vitreous Detachment.
This contraction on the retina is responsible for the characteristic
"flashes" that often accompany the Posterior Vitreous Detachment. The
"floaters" are frequently caused by the fibrous elements changing
position during the Posterior Vitreous Detachment. They can also be
caused by pieces of the retina being dislodged as the vitreous
contracts. Besides aging, flashes and floaters are also associated
with nearsightedness and injuries to the eye.
Signs and Symptoms
You may notice black ‘floaters’ in your vision which move with the eye
and then settle as the eye rests. You may also be aware of flashing
lights, like little flickers in the periphery. To look at, the eye
will appear normal.
Treatment and Diagnosis
There is no treatment required for posterior vitreous detachment.
The floaters will gradually disappear but this may take some time.
The flashing lights should gradually settle down over the next few
days or weeks.
However, in about 10% of the patients with a Posterior Vitreous
Detachment, a tear of the retina is found. If left untreated, these
tears may lead to a full retinal detachment. A full retinal detachment
is a very serious sight threatening condition requiring a major
surgical procedure to repair. When symptoms appear, it is important to
examine the eye within a day of their onset. Changes can occur
rapidly, and time can be of the essence if a retinal detachment is
present.
Warning signs of a possible Retinal
Detachment
- A sudden increase in the number of
floaters in your vision.
- New floaters.
- A portion of your visual field
missing
- A curtain coming across the vision
This may be a warning of a retinal
detachment and you should see a specialist as soon as possible.
Retinal tears are treated by sealing the tear with a laser or freezing
technique (cryotherapy).
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