In PDR, the neovascularization may cause scar tissue to develop.
The neovascularization and the scar tissue grow along the surface
of the retina and attach firmly to the back surface of the
vitreous gel. The vitreous gel pulls on the blood vessels and
scar tissue and lifts them up. Because the neovascularization
and scar tissue are attached to the retina, the retina is also
lifted up. When the retina separates from the back surface of
the eye, it is called a retinal detachment. Because the retina
is pulled off, it is called a traction retinal detachment. The
scar tissue can also tear the retina and cause a retinal
detachment.
When a retinal detachment occurs, the
patient may notice a shadow or very large dark area in the
vision. When the retinal detachment extends to the macula, the
dark shadow will be straight ahead and vision may be poor. The
neovascularization and scar tissue also can cause visual loss
because they can wrinkle the retina.
The only way the patient
can regain any vision is for the retina to be reattached and the
neovascularization and scar tissue to be removed from the surface
of the retina. This is accomplished by vitrectomy surgery. The
surgeon removes the vitreous gel from the eye so that it stops
pulling on the retina; the traction is released. The surgeon may
remove the scar tissue from the surface of the retina so that
there is no wrinkling of the retina. The detached and wrinkled
retina should flatten and smooth out. The surgeon may also
perform panretinal laser photocoagulation to prevent further
development of neovascularization and rubeosis.
The surgeon also
uses laser inside the eye to seal any tears of the retina. If
there are tears in the retina, the surgeon may place a large gas
bubble in the eye to press the retina completely against the back
wall of the eye while the laser surgery takes hold. In order to
accomplish this, you may be asked to position your head facing
down or up for a week following the surgery. In time, the gas
bubble will disappear and be replaced by the eye's own fluid.
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