Vitreous is the clear gel that fills the central cavity of the eye. It occupies
approximately 80% of the volume of the eyeball. The formed vitreous gel liquefies with
age and eventually falls away or separates from the retina, which is the neuro-sensory
tissue that lines the back wall of the eye. The retina is the structure in the eye that
allows for vision.
This event is called a posterior vitreous detachment (PVD) and is a normal event
occurring in most people sometime between 40–70 years of age.
As the gel separates and falls away from the retina one will often see floaters.
These appear as dots, spots, or curly lines that appear suspended in front of you and
move with your eye. People often think these floaters are flying bugs.
Flashes of light are also a common symptom of a vitreous detachment. These are due to pulling on the
retina as the gel separates. This pulling stimulates the retina resulting in a flash of light.
If a retinal blood vessel is broken from the pulling, a vitreous hemorrhage (bleed) can
occur. A small amount of blood may be seen as a shower of spots. Larger hemorrhages
can cause large dark blobs in the visual field or an overall decrease in vision.
If the vitreous is abnormally adherent to the retina or the retina is weak in a
certain area, a retinal tear can occur as the gel separates and pulls on the retina. Once
a retinal tear develops there is a significant risk of the liquid vitreous going through the
break and detaching the retina from the back wall of the eye, a retinal detachment.
A retinal detachment can result in permanent visual loss if not corrected surgically.
This is why a posterior vitreous detachment is a significant event.
A posterior vitreous detachment is the initiating event of most retinal detachments although less 5% of
posterior vitreous detachments will develop a retinal tear.
Awareness of the symptoms of a PVD is the critical first step in preventing a
retinal detachment. If you have new symptoms of a PVD (floaters, flashes, shower of
spots), or a significant increase in your current floaters after an initial evaluation, it is
important to have a prompt and thorough examination of the retina to search for any
retinal breaks.
If a retinal break can be discovered before a retinal detachment develops it can
be treated with the laser to seal the break and prevent a retinal detachment.
Fortunately the great majority of vitreous detachments do not cause a retinal tear
and not all retinal breaks will lead to a detachment.
