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LASER TREATMENT OF THE RETINA
Laser treatment
of the retina
A laser is a pure, high-intensity beam of light energy.
The laser light can be precisely focused onto the retina,
selectively treating the desired area while leaving the surrounding
tissues untouched. The absorbed energy creates a microscopic
spot to destroy lesions or weld tissues together.
Laser surgery is usually painless;
at the most it may cause temporary discomfort. It is usually
performed in the operating room while the patient is awake
and comfortable. In rare cases only anesthesia is given to
patients who cannot tolerate the discomfort or to children
to keep them still during treatment. The entire procedure
lasts 10 to 30 minutes.
Who requires laser treatment?
Lasers are commonly used to treat the following eye conditions:
Diabetic Retinopathy
The retinal blood vessels are like pipes, bringing blood into
and taking it out of the back of the eye. In diabetes, however,
the vessels may leak, causing the retina to swell and not
work properly. When the swelling involves the central area
of retina vision may be affected. (This is known as diabetic
macular edema.)
Laser treatment can seal the
leaks, thereby preventing further vision loss. In some patients
new retinal blood vessels may grow, which will replace some
of those that have closed due to diabetes. (This is known
as proliferative diabetic retinopathy). This new retinal blood
vessel, unlike the normal blood vessel, has a tendency to
bleed inside the eye resulting in decreased vision. Laser
treatment can often prevent severe vision loss by making these
new vessels regress.
Retinal Vein Occlusion
The small blood vessels that drain the blood from the
retina (retinal veins) can sometimes get blocked (retinal
vein occlusion). This is more common in patients with diabetes
or high blood pressure. A retinal vein occlusion can cause
the retina to swell with fluid and blood, blurring the central
and peripheral vision. At other times, new blood vessels may
grow and cause pain as well as very high pressure inside the
eye (neovascular glaucoma).
Laser treatment can help reduce
this swelling or cause the new blood vessels to disappear.
Age Related Macular Degeneration
(AMD)
With aging some people may develop changes in the macula,
the portion of the retina responsible for our central reading
vision. Most people develop the dry type of AMD, which usually
causes gradual vision loss. The more severe or wet type causes
the macula to swell with fluid and blood. Symptoms of wet
macular degeneration include painless, blurred and distorted
vision. Urgent laser surgery can sometimes prevent or delay
vision loss in patients with wet AMD. While the off central
wet AMD patients benefit from thermal laser treatment, those
with central vision problems need a prior injection of a drug
(Visudyne). This is known as photodynamic therapy
Retinal Breaks and Retinal Detachment
The retina lines the back of the eye like a wallpaper.
Retinal tears or rips can occur as part of an aging phenomenon,
or following an intraocular surgery or eye injury. When a
retinal tear develops patients often see cobweb-like floaters
or light flashes. The liquid that normally fills the central
portion of the eye (the vitreous) can leak beneath the tear,
lifting the retina away from the eye wall. This is called
a retinal detachment, which if left untreated can cause blindness.
Often laser surgery around retinal tears before the fluid
accumulates enables surgeons to weld the retina to the underlying
eye wall. This can prevent or limit retinal detachment.
Central Serous Chorioretinopathy
(CSCR)
Central Serous Chorioretinopathy
consists of one or more 'blisters' of fluid (serous detachment)
beneath the macula. It can cause reduction and distortion
of vision, abnormal color vision, central scotoma, and temporary
hyperopia or farsightedness. Although the vast majority of
cases will resolve spontaneously, laser photocoagulation is
sometimes necessary for persistent lesions and in those patients
who require early visual rehabilitation.
Ocular Tumors
Some
patients may have non-cancerous leaking vascular tumors that
can cause the retina to swell and not function properly. Laser
surgery can destroy some of these tumors and make the swelling
go away.
How do I know that I require
laser treatment?
With retinal diseases your eye will almost always look and
feel normal, even when there is bleeding and leakage in the
back of the eye. Your vision may also be normal for a while
despite the presence of potentially blinding eye problems.
The only way to find out whether
you need laser surgery is to have a careful, dilated retinal
examination regularly, often followed by a special test that
evaluates the eye's circulation, called fluorescein angiography
(as advised by the retinal specialist).
After laser surgery
There are virtually no restrictions following retinal laser
surgery, but you would need to relax on the day of the treatment.
Most patients find they can go back to their routine a day
later. Invariably the doctor will advise you not to lift heavy
weights for a few weeks. In some cases the doctor may advise
patients to stay at home for several days. You will be required
to come again for a follow-up examination in a couple of weeks
up to a couple of months.
Most patients notice no changes
in vision following their laser surgery, although there may
be some temporary blurring for several weeks or even months.
In addition, depending on the condition being treated, some
patients may notice a permanent blind spot or decrease in
peripheral and night vision.
Is one session of laser
treatment enough?
The number of sessions required by a patient depends on the
disease for which the laser treatment is done. It takes usually
several weeks to months for surgeons to decide whether the
treatment has been successful. Many patients require more
than one session of treatment to control their problem and
prevent further loss of vision.
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