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Floaters,
Flashes & Retinal Detachments
Floaters and flashes can be warning signs signaling a more severe
problem in your eye, including retinal tears and detachments. This
section covers the symptoms and available treatments for a number
of conditions relating to retinal detachments. You can click on
a topic below, or scroll through the entire section.
What are floaters?
The central cavity of the eye is filled with a gel-like substance
called the vitreous humor. Floaters are small clumps of cells, pigment,
and or gel matrix, which "float" inside the vitreous .
Floaters may appear as small specks or clouds moving in front of
your vision. They are especially apparent when looking at a plain
white background, or looking at a brightly illuminated sky. Floaters
often appear as if they are floating in front of the eye, and sometimes
imitate a swarm of small insects. In actuality they "float"
entirely inside the eye, and typically move when you attempt to
look at them. Floaters are usually quite small and what you see
are the shadows cast upon the retina and nerve fiber layer. Floaters
that you have noticed or been aware of for some time are typically
benign; however, a "shower" of new floaters may indicate
that you have experienced a new retinal tear, a new vitreous hemorrhage,
or a posterior vitreous detachment, or that there is inflammation
in the eye (uveitis). A shower of new floaters signifies a problem
that requires prompt attention and you should see your eye doctor
immediately.
What is the treatment of floaters?
Typical floaters are not usually treated. If the floaters have
been caused by a posterior vitreous detachment without a retinal
tear, the floaters will typically "settle" out of the
line of vision over several weeks to months. Severe floaters caused
by a vitreous hemorrhage that does not clear after several months
and prevents useful vision can be removed surgically by a pars plana
vitrectomy.
What are flashes?
Flashes are the experience of brief sensations appearing to be
bright lights at the edge of vision. Flashes are usually noticed
all the way to one side and are more prominent in the dark or when
going from a well-lighted area to a darker area. Usually the flashes
have no specific shape, but can sometimes have the appearance of
lightning bolts. The experience of flashing lights, especially in
conjunction with new floaters, can be an indication of a posterior
vitreous detachment, retinal tear, or a retinal detachment. The
flashing lights represent the release of an electrical signal from
the nerve tissue of the retina when there is pulling on the retina
from a vitreous gel that is separating from the retina. If the pulling
is especially strong, or at the site of a weakness in the retinal
tissue, a retinal tear may occur. Any experience of new flashes
should be reported to your ophthalmologist and he or she will usually
perform a prompt dilated exam of the retina.
Some flashing light phenomena involve the experience of a very
distinct, often multicolored or fiery jagged line of light with
or without an adjacent black spot in the vision. Such "fortification
scotomas" may start in the center of vision and then spread
to the side, or start at the side in the first place. Often, if
you carefully close one eye and then the other, you will notice
that the flashes are actually going on in both eyes, but are just
more prominent in one or the other. This type of flashing light
typically lasts from 5 to 30 minutes, and may or may not be followed
by a bad headache. These flashing lights are different from the
flashing lights caused by tugging on the retina described above,
and represent the eye portion of a migraine (with or without a migraine
headache). This type of flashing lights is usually not serious,
but if it is the first time you are experiencing them, or you have
any doubts, you should contact your ophthalmologist.
How are flashes treated?
If you are experiencing new flashes, it is important to undergo
a dilated exam of the eye with a careful exam of the far peripheral
edge of the retina. It is at this very edge of the retina, which
is thinner than the more central part of the retina, where most
retinal tears occur. The ophthalmologist will often use a device
called a scleral depressor to gently indent the side of the eyeball
in order to bring the peripheral edge of the retina into better
view. If no retinal tear or retinal detachment is found, then no
treatment is usually indicated. However, after the initial exam,
it is helpful for you to screen yourself periodically by carefully
observing the world around you with one eye at a time. Look for
new symptoms such as increased floaters, new or increased flashes
or flash intensity, or a shadow. If any of these additional symptoms
occur, you need to return to your ophthalmologist for a repeat dilated
exam, immediately.
What is a posterior vitreous detachment?
The vitreous is the gel-like substance that fills the back of the
eye. When you are young, this gel is quite firm and has a uniform
consistency; however, as you get older, the gel develops pockets
of liquefaction. Within these pockets, the condensations develop
which lead to the experience of floaters. In most people, at some
point in life (usually between the ages of 40 and 60, but earlier
for moderately to severely near-sighted persons or people who experience
a severe trauma to the eye), the pockets of liquefaction become
so numerous that they combine to form larger pockets, and then break
through the boundary membrane at the back of the eye. When this
occurs the "membrane" of the posterior vitreous separates
from the retina at the back of the eye. This is called a posterior
vitreous detachment.
The connection between the posterior vitreous gel and the retina
is not usually firm, but is more like the attachment of a suction
cup to a glass window, or the attachment together of the two sides
of a new plastic trash bag. The seal is firm, but once a separation
begins, all the strength is lost and the separation proceeds quickly
in a peeling process. The place where the posterior vitreous is
attached to the optic nerve at the back of the eye is usually a
point of more firm attachment than to the retina. When this firm
attachment separates, a ring of condensed vitreous gel, which previously
had been the site of attachment to the optic nerve, "floats"
in the middle cavity of the eye. Often this ring appears as a gray,
white or black donut if seen dead on, or as a squiggly line if seen
from the side. It is this separation of the vitreous gel from the
optic nerve with the creation of this ring floater, which is the
hallmark of a completed posterior vitreous detachment. Usually this
peeling of the posterior vitreous from the retina goes smoothly,
and does not present a problem or danger to vision. Occasionally,
however, the vitreous sticks more firmly at the edge of the retina
and "tugs" while it is being peeled off. This tugging
is the cause of flashes, and if the tugging is strong enough a retinal
tear may develop. A retinal tear often tears a retinal blood vessel
as well, and the blood from such a torn vessel leads to the shower
of new floaters that often herald a new retinal tear.
How is a posterior vitreous detachment treated?
An old posterior vitreous detachment or a new posterior vitreous
detachment that is not associated with any retinal tear or retinal
detachment requires no treatment. New floaters associated with a
new posterior vitreous detachment typically resolve over several
weeks to months and are not harmful even if they don’t go completely
away. If, however, a patient with a recent posterior vitreous detachment
also has a retinal tear or retinal detachment, then these require
urgent treatment.
What is a retinal tear?
A retinal tear is exactly what it sounds like, i.e. a tear in the
nerve tissue of the retina. Retinal tears typically occur at the
thin edge of the retina. Tears are seen in two forms – the
triangular horseshoe tear and the circular tear that often has a
small divot of retina floating over the circle.
How are retinal tears treated?
All tears that are new and all tears, new or old, that are associated
with sudden new symptoms of flashes and/or floaters require prompt
treatment. The object of treatment for a retinal tear is to create
a firm adhesion, called a retinopexy, between the retina and the
wall of the eye so that the liquefied vitreous cannot pass through
the tear and then dissect underneath the retina and cause a retinal
detachment. The usual way such an adhesion is formed is by creating
a circle of small scars around the tear with a laser. Sometimes
if the view of the retina is so poor, i.e. from a dense cataract
or from blood in the vitreous cavity, the adhesion is created by
using a metal probe cooled to minus 20 degrees Celsius. This freezing
metal probe, called a cryoprobe, is placed against the wall of the
eye underneath the tear, where the local inflammation caused by
the freezing creates the desired adhesion. A similar process using
a transcleral diode laser can also achieve the same result.
What is a retinal detachment?
A retinal detachment is a separation of the nerve tissue of the
retina from the wall of the eye. When this separation occurs, the
cells of the nerve tissue are isolated from their supplies of nourishment,
will deteriorate, and eventually die. It is therefore imperative
that a retinal detachment be repaired in order to prevent permanent
loss of vision in the affected eye. The most common type of retinal
detachment is called a rhegmatogenous retinal detachment. Rhegmatogenous
retinal detachments occur when fluid from the vitreous cavity flows
through a retinal tear and dissects underneath the retina, thus
raising it up off the wall of the eye. Similar to the posterior
vitreous, the retina is only firmly attached to the wall of the
eye at the optic nerve, and at the far peripheral edge of the retina.
The rest of the retina is attached to the wall of the eye in a fashion
similar to a suction cup. Once a small amount of fluid gets underneath
the retina, the "seal" is broken and the dissecting fluid
can spread rapidly.
The initial symptoms of a retinal detachment are the same as a
retinal tear or a posterior vitreous detachment, i.e. flashes and
floaters; however, as the detachment progresses, a dark, opaque
moon-shaped shadow or curtain will appear from one side of your
vision. This curtain, which can sometimes be seen to billow like
a sail in the wind, is actually the detached retina tissue floating
in the vitreous cavity.
Retinal detachments can be divided into two separate levels of
severity, depending upon whether the very important back portion
of the retina called the macula is affected by the detachment. Macula
"on" retinal detachments tend to be smaller than macula
"off" retinal detachments, and the prognosis for the return
of normal vision after the repair of a macula "on" detachment
is better. In addition, macula "off" detachments which
are less than a week old tend to have a better visual prognosis
than older retinal detachments. Since retinal detachments tend to
start in the periphery as macula "off" retinal detachments,
and only later progress to macula "on" retinal detachments,
it is very important to seek out an ophthalmologist immediately
upon the earliest detection of the suspicious symptoms outlined
above. Fortunately, with modern surgical techniques, over 90% of
all retinal detachments can be successfully repaired. Current methods
of retinal detachment repair can be done on an outpatient basis
and sometimes even in the office.
Besides rhegmatogenous retinal detachments, there are two other
types of retinal detachments. The next most common type is called
a traction retinal detachment. Traction retinal detachments occur
when scar tissue from inside the eye contracts and pulls the retina
off its attachment to the wall of the eye. Traction retinal detachments
are most common in diabetics who suffer from severe diabetic retinopathy,
but also occur in eyes injured traumatically and eyes that have
failed previous retinal detachment repair. The least common type
of retina detachment is called a serous retinal detachment. Serous
or exudative retinal detachments occur when fluid collects in the
normally closed space between the retina and the wall of the eye.
Unlike a rhegmatogenous retinal detachment, the fluid does not come
through a tear in the retinal tissue, but is made within the tissue
itself. The cause of a serous retinal detachment is typically production
of fluid from an inflammatory condition in the choroidal layer of
the eye, uveitis, or from a tumor in the choroid of the eye such
as an ocular melanoma. The small "blisters" of fluid which
develop during the active phase of central serous chorioretinopathy,
are actually small serous retinal detachments.
How are retinal detachments repaired?
Most retinal detachments are an emergency, which require urgent
surgical repair. The object of any retinal detachment repair is
to get rid of the fluid underneath the retina and allow the retina
to lay "flat" upon the concave contour of the wall of
the eye. There are several methods of achieving this goal, each
of which will be discussed in the sections below. The great majority
of retinal detachments are of the rhegmatogenous type, and these
sections will primarily discuss repair of this type of detachment.
At the end of these sections, there will be some more specific comments
about traction and serous retinal detachments.
Scleral buckle to repair retinal detachment
A scleral buckle is made of a piece of silicone (solid or sponge)
which is sewn to the outer wall of the eye, called the sclera. The
scleral buckle was developed in the early 1960’s and was the
first effective treatment for the repair of retinal detachments.
Scleral buckles are still used today either alone or in conjunction
with other methods of retinal detachment repair. The mechanism of
action of the scleral buckle is to indent the wall of the eye toward
the detached retina. This indentation alters the fluid dynamics
within the eye such that the liquefied vitreous no longer passes
through the retinal tear, thus effectively closing the hole. Once
the hole is closed, the fluid is absorbed by the natural mechanisms
of the eye. Sometimes, if there is quite a bit of fluid under the
retina, the retinal surgeon will find it necessary to drain the
fluid under the retina at the time of the surgery by making a small
incision through the wall of the eye. This "external drainage"
is not done routinely by many surgeons because of the risk of bleeding
when the wall of the eye is incised. Once the fluid under the retina
is gone, a permanent seal is made around the responsible retinal
tear by the action of either a cryoprobe or laser used at the time
of the surgery (similar in action to the treatment of simple retinal
tears as described above).
Vitrectomy for the repair of retinal detachments
Vitrectomy is a sophisticated technique of operating upon the retina
from inside the eye. During a vitrectomy, small incisions are made
in the wall of the eye, through which various instruments are passed.
Typically, there are three incisions. One is for the infusion of
fluid into the eye. A second is for insertion of a fiberoptic light
source. A third is for the insertion of a working instrument such
as a microscissor, forceps, knife, or vitrector. The vitrector is
the primary working instrument and it combines a guillotine style
chopping mouth with vacuum-like suction. The vitrector is used to
remove the sticky vitreous gel with causing undue traction upon
the fragile retinal tissue. Vitrectomy techniques have advanced
rapidly over the past 20 years allowing for increasingly more complex
retinal problems to be addressed with increasing safety. Recent
advances in vitrectomy techniques include:
The use of picks and forceps attached to the end of the fiberoptic
light source allowing for a controlled "two-handed" approach
to the dissection of delicate tissues.
The use of sophisticated "wide-angle" optics, which allow
a view of nearly the entire posterior cavity of the eye in one field.
This allows superior orientation for the surgeon.
The use of long acting gases and silicone oil for internal tamponade
of retinal pathology.
The use of heavy liquids intra-operatively to gently manipulate
the retinal tissue and to displace subretinal fluid.
Office-based repair of retinal detachments
In addition to the techniques described above, which are used to
repair retinal detachment on an outpatient basis, techniques are
now available to repair many uncomplicated retinal detachments in
the office, thus saving a trip to the hospital. These techniques,
when performed on carefully selected types of retinal detachments,
have been shown in several studies to have the same or nearly the
same success rate as traditional hospital-based surgery. In addition,
if the office-based repair is unsuccessful, it has been shown that
no ground is lost when a second procedure needs to be performed.
Two such techniques, which can be used alone or in combination,
are discussed below.
Pneumatic retinopexy for the repair of retinal detachments
The word pneumatic refers to the use of a gas. In a pneumatic retinopexy,
a long-acting gas is injected into the eye to create an internal
tamponade of the retinal tear. These gases stay in the eye for 1
to 3 weeks, during which time they slowly dissipate, until they
eventually disappear. With the tear in the retina thus closed by
this "air-lock", the fluid underneath the retina will
be absorbed by natural mechanisms in a few days. The cryoprobe used
at the same time as the gas injection, or the laser used after the
retina is already "flattened," creates the adhesion that
keeps the tear closed once the gas has disappeared. A pneumatic
retinopexy cannot only save a trip to the hospital, but also is
less invasive than hospital-based retinal detachment repairs and
allows for a faster recovery. While the gas is in the eye, it rises
like a helium balloon. In order to keep the air lock over the retinal
tear, it is important for the patient to hold his or her head in
the proper position for 1 to 2 weeks, usually face-down. In addition,
while the gas is in the eye, the patient is unable to travel in
an airplane because a sudden depressurization of the cabin could
lead to dangerous expansion of the gas bubble inside the eye. These
inconveniences aside, a pneumatic retinopexy in the office, when
indicated, is usually preferable to hospital-based surgery.
Temporary Lincoff balloon buckle for repair of retinal detachments
Another technique used in the office to treat retinal detachments
is the temporary Lincoff balloon. The Lincoff balloon works the
same way as a scleral buckle, except there are no sutures, and the
temporary balloon buckle is removed after a week. The tip of the
balloon is inserted under the conjunctiva of the eye via a small
incision in the same longitudinal meridian as the tear requiring
repair. The balloon is then inflated with a small amount of sterile
saline. On one side, the inflated balloon indents the eye in the
same way as a scleral buckle. On the other side, the balloon presses
against the bony orbit, thus holding the balloon in place. The balloon
is attached to a 4-inch long thin tube that is taped to the forehead
during the week the balloon is left in place. The cryoprobe used
at the same time as the balloon is placed, or laser used after the
retina is already "flattened," creates the adhesion that
keeps the tear closed once the balloon is removed. An advantage
that the balloon has over a pneumatic retinopexy is that retinal
tears below the "equator" of the eye can be treated without
resorting to uncomfortable or impossible positioning. For example,
a retinal detachment caused by a retinal tear at "6 o’clock"
in the back of the eye can be treated easily with a balloon. A pneumatic
retinopexy would require the patient to hang his or her head upside
down for a minimum of one week, an impossible task. Without the
availability of the balloon, a patient with such a detachment would
have to be brought to the operating room.
Repair of non-rhegmatogenous retinal detachments
Tractional detachments by definition have a component of fibrous
scar tissue that pulls the retina in off the wall of the eye. Tractional
detachments, such as those that occur in diabetic retinopathy, are
best treated with modern vitrectomy techniques to carefully dissect,
peel, and/or remove the scar tissue forming the traction. Sometimes
a scleral buckle is necessary as well in order to create "slack"
in the tractional bands by indenting the wall of the eye inwards.
Scleral buckles are also used when a tractional band pulls so hard
that the retina is torn, thus creating a combined tractional and
rhegmatogenous retinal detachment.
Serous (exudative) detachments are treated by treating the underlying
cause of the fluid that is being produced to elevate the retina.
In the case of an inflammatory condition, anti-inflammatory medicines
such as steroids can be used to reduce and resolve the fluid. In
the case of a tumor, laser and/or radiation is often used to attack
the tumor, make it shrink, and, in the process, treat the serous
detachment by reducing the fluid produced by the tumor.
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