Retinal Detachment
What is retinal detachment?
Retinal detachment is the separation of
the retina from the underlying choroid.
This results in a profound loss of
vision and requires major surgery to
re-attach it.
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What causes retinal detachment?
Most retinal detachments are caused by
the presence of one or more tears or
holes in the retina. Normal aging can
sometimes cause the retina to thin and
develop holes, but more often these are
caused by shrinkage of the vitreous body
(posterior vitreous detachment).
The vitreous is firmly attached to the
retina in several places around the back
wall of the eye. As the vitreous shrinks
with aging, it may pull a piece of
retina with it, leaving a tear or hole
in the retina. Fluid from the vitreous
body then passes through the retinal
tear detaching the retina from its
normal position (retinal detachment).
Posterior vitreous detachment (vitreous
separation from the retina) is a natural
process of aging and usually does not
lead to any damage of the retina. It is
however more common and occurs earlier
in people who: -
· Are abnormally nearsighted (high
myopia);
· Have undergone cataract operations (aphakics);
· Have had YAG laser surgery of the eye;
· Have had inflammation inside the eye.
Note:
It should be noted that there are some
retinal detachments that are caused by
other diseases of the eye such as
tumors, severe inflammations, or
complications of diabetes. These
so-called secondary detachments do not
have tears or holes in the retina and
treatment of the disease that caused the
retinal detachment is the only treatment
that may allow the retina to return to
its normal position.
How is a person to know of the presence
of retinal weakness, holes or tears?
In some patients the formation of a
retinal tear is preceded by flashes of
light, which are indicative of pull
(traction) on the retina. In others, the
tear may break a small blood vessel in
its path causing a small hemorrhage
(bleeding), with blurring of vision and
'floaters'.
However in the majority, retinal
holes are completely asymptomatic,
as they usually occur in the
periphery of the retina and not in
the visually important central part.
They therefore do not cause any
visual problem at all, unless they
have led on to a retinal detachment.
At this stage, profound loss of
vision or field occurs.
It should also be noted that 'floaters'
are very commonly seen by people who
have no eye disease. They are seen as
small specks, circles, lines, clouds or
cobwebs moving in one's field of vision.
They are actually tiny clumps of gel or
cells inside the vitreous and cause no
harm.
What can be done about floaters?
Floaters can get in the way of clear
vision, which may be annoying when you
are trying to read. You can try moving
your eyes; looking up and then looking
down to move the floaters out of the
way. While some floaters may remain in
your vision, many of them will fade over
time and become less bothersome. However
you should visit your ophthalmologist if
you suddenly notice new floaters because
you need to know if your retina is torn.
What causes flashing lights?
When the vitreous gel rubs or pulls on
the retina, you may see flashing lights
or "lightning streaks". If you notice
the sudden appearance of light flashes,
you should visit your ophthalmologist
immediately to see if your retina has
been torn. Who runs a greater risk of
developing such a problem?
People more prone to developing retinal
degeneration, holes and tears, and
subsequently retinal detachment are
myopes (near sighted persons), aphakics
(people who have undergone cataract
surgery), those with a family history of
retinal detachment and people with
symptoms like light flashes and onset of
a large number of floaters.
These groups of patients must undergo
regular and thorough retinal examination
by indirect ophthalmoscopy.
How can retinal detachment be prevented?
A careful examination of your retina by
binocular indirect ophthalmoscopy as
mentioned above will be done. For this
procedure, your pupils will be dilated
with eye drops. During this painless
examination, your ophthalmologist will
carefully observe your retina and
vitreous and look for holes and weak
areas. At this stage (i.e. retinal
detachment has not yet occurred), they
can easily be closed or sealed by
producing minute scars in the retina
around them, which "weld" the retina to
the choroid and prevent fluid from
seeping through the hole. These scars
can be produced by the heat of a strong
light source (laser photocoagulation),
or by controlled freezing (cryotherapy).
Which of these two modalities is chosen,
depends on the location of the hole and
the presence or absence of cataract and
vitreous hemorrhage, and the retinal
surgeon decides individually for each
case after a thorough examination. Both
cryotherapy and photocoagulation are
usually carried out as an outpatient
procedure. As the treatment is from the
surface of the eye, no invasive surgery
is involved.
Symptoms of retinal detachment
Some retinal detachments may begin
without noticeable floaters or light
flashes. In those instances, patients
may notice a wavy or watery quality in
their overall vision or the appearance
of a dark shadow in some part of their
side vision. Further development of the
retinal detachment will blur central
vision and create significant loss of
sight in the eye unless the detachment
is repaired.
A few detachments may occur suddenly and
the patient will experience a total loss
of vision in one eye. Similar rapid loss
of vision may also be caused by bleeding
into the vitreous when the retina is
torn.
Detection & diagnosis
A detached retina cannot be viewed from
the outside of the eye. Therefore, if
the above symptoms are noticed, an
ophthalmologist should be visited as
soon as possible. Again, binocular
indirect ophthalmoscopy through dilated
pupils is essential to thoroughly
examine the retina. Other special
instruments including contact lenses,
slit lamp and ultrasound may also be
used.
Next page :
Treatment/ Surgery Of Retinal
Detachment
