Most serious retinal problems that require surgery are caused by
problems with the vitreous. The vitreous is much like the clear
"white" of an egg and it fills the central cavity of the eye.
The vitreous is attached to the retina. It is most strongly
attached to the retina at the sides of the eye. It is also attached
in the back part of the eye to the optic nerve, the macula, and
the large retinal blood vessels.
Posterior Vitreous Detachment (PVD)
As a person ages, the thick vitreous gel becomes less like a gel
and more like a fluid. Small pockets of fluid form within the
gel of the vitreous. As the eyeball moves, the liquified vitreous
moves around inside the vitreous cavity. Because of this
movement of fluid, the vitreous begins to pull on the retina.
With time, the vitreous can pull free and separate from the
retina and optic nerve in the back (or posterior) part of the
eye. This is called a "posterior vitreous detachment" (PVD).
This kind of detachment happens eventually in most people and
only infrequently causes a problem.
Flashes and Floaters
When a person develops a posterior vitreous detachment, flashes
of light or large spots in the vision may occur. The flashes of
light are caused by the tugging of the vitreous where it is
attached to the retina. As the vitreous pulls on the retina, the
brain interprets this pulling as flashes of light. As it
liquifies and pulls away from the retina, the vitreous becomes
somewhat condensed and stringy and forms strands. The patient
can see these strands and strings; they appear as spots, small
circles, or irregular fine threads in the vision. They seem to
float and are therefore called "floaters".
Vitreous changes are most commonly caused by aging, but they can
also be caused by previous inflammation in the eye,
nearsightedness, trauma, or other causes. If a patient has
floaters, they should be examined to be sure there are no
other serious retinal problems (such as a retinal tear or retinal
detachment). If there are no problems, the patient can feel
reassured, and will learn to ignore the floaters. There is no
treatment for floaters.