|
LASIK is the
abbreviation of the term "Laser Assisted Stromal In-situ
Keratomileusis".
LASIK gives a new shape to the cornea in order to give the
eye its natural focusing capacity.
During the LASIK
operation, a special instrument called microkeratome creates
a partial thickness corneal flap and then excimer laser
ablation is performed over the imposed corneal bed. The
ablation profile is related to the refractive error.
For myopic
corrections corneal curvature is flattened and for hyperopic
corrections a half-torus (the shape you obtain if you press
a ring halfway on a Dow) shaped corneal tissue is removed in
order to have a steeper cornea. For astigmatism crescent or
football shaped ablation is performed.
In order to figure
out the effect of LASIK, you can roughly imagine that with
the excimer laser the cornea is shaped or carved like the
shape of the contact lens you need to see clearly. After the
laser reshaping process, the corneal dust will be washed
away and the corneal flap is gently put back. Thanks to
continuous vacuuming function of the corneal endothelium (cells
located at inner face of the cornea), the corneal flap
adheres easily like a sticky note. The flap naturally keeps
its position without sutures or other surgical intervention.
In some practices,
eyes are covered after the LASIK operation but we don't
cover our patients' eyes after the procedure. We recommend
sleeping after the procedure.
The next you can go
on with your day as usual. Visual recovery is extremely fast;
in low to medium prescriptions more than 80% of the aimed
vision is achieved even in the first day.
Here at EyeSTAR LASIK
Institute Istanbul, we improved our medical regimen so that
most of our patients don't even have the slightest
discomfort after the LASIK procedure.
PRK
What are the
advantages of PRK?
One of the advantages
of the PRK method is that it is an easy surgical procedure.
Even a novice eye surgeon can accomplish a PRK operation
after watching a few videotapes. But precise programming of
the Excimer Laser for the desired vision requires years of
experience, since every doctor's surgical method and the
environmental factors require construction of special
nomograms for specific prescriptions and age. Another
advantage of PRK is its being a quick, painless and
bloodless laser procedure. PRK consumes lesser corneal
tissue than LASIK. PRK or LASEK become the obvious choice
when corneal thickness is critical (=thin cornea).
What are the
disadvantages of PRK?
One disadvantage of
PRK is its slow and painful recovery period. Even though
many special techniques, such as bandage contact lenses have
been developed for relieving the after-operation pain, still
some discomfort should be expected for 2 to 5 days. Also the
vision is blurry during this period. This may delay PRK
patients' resuming "the normal life" which is the
very next day for LASIK patients. Since PRK is a technique
that harms the epithelium of the cornea, a clear vision
should be expected after the total regeneration of the
epithelium (2 to 15 days). Also achieving the final visual
result may take up to six months and the recovery modulating
drops (such as steroids) should be instilled during this
time under the surveillance of regular doctor visits. Two
more unwanted effects of PRK should be mentioned. These are
especially valid for the treatment of high diopters and in
case of neglecting some preventive measures:
1. Persistent foggy vision: haze.
2. Regression: After having a normal vision for a while, a
portion of the old refractive error may come back.
When do we prefer PRK?
If there is opacity (scarring)
or a specific disease at the cornea besides a refractive
error, a dual-purpose laser therapy (PRK) may be performed.
If the anatomy of the
eye does not allow placing a microkeratome safely on the eye,
then we may choose PRK instead of LASIK.
If the cornea is too
thin for LASIK then PRK or LASEK may be the procedure of
choice.
If the patient wants
to have an unnoticeable laser surgery even with the
microscope during an eye exam, then we consider performing
PRK or LASEK.
LASEK
LASEK (LASer
Epithelial Keratomileusis) is a relatively new procedure
that is technically a variation of PRK. The difference is
that while in PRK the epithelium is removed, it is preserved
and put back in LASEK. As a result, in LASEK there is less
pain and the healing is faster than PRK.
LASEK is used mostly
for people with corneas that are too thin or too flat for
LASIK operation. It has been developed to reduce the
incidence of complications that occur when it is anticipated
that the flap created during LASIK will not have ideal
thickness or diameter.
1- In LASEK, the epithelium, or outer layer of the
cornea, is dented like the letter C with a fine blade called
a trephine.
2- The surgeon then covers the eye with an alcohol
solution for approximately 30 seconds. The solution loosens
the edges of the epithelium. It separates the epithelium
from the underlying stroma layer.
3- After sponging the alcohol solution from the eye,
the surgeon uses a tiny hoe to lift the edge of the
epithelial flap,
4- and gently fold it back out of the way.
5- The surgeon then uses an excimer laser, as
in LASIK or PRK, to sculpt the corneal tissue underneath.
6- Afterward, the epithelial flap is placed back on
the eye with a kind of spatula.
7- Just like other forms of laser treatments, the
cornea gains a new shape for ideal focusing.
After LASEK
In many ways, what
you can expect from LASEK is similar to what you can expect
from PRK. Patients usually wear a bandage contact lens for
around four days. You may feel eye irritation during the
first day or two afterward. Also, the time it takes to
recover good vision is often longer - up to four to seven
days although this varies from one person to the other.
...Special Techniques
MONOVISION
During childhood, our eyes have the ability to focus
on objects as close as our nose and to objects very far away.
A young person without any refractive error can see the
objects at 25 cm distance to infinity clearly. The lens in
our eyes acts as a focusing lens in a camera. When the
objects are near, the lens thickens and focuses the light
rays on the retina to obtain a clear image.
As each year passes, that ability to "focus"
decreases. But typically, by the time we reach our forties,
we need an aid, such as reading glasses or bifocals, to
focus on objects near to us. This condition is called
presbyopia.
When a nearsighted (Myopic) people reach the age of forty,
they too experience presbyopia. Because the nearsighted eye
has a natural focal point "at near", many
nearsighted presbyopes can remove their glasses or contact
lenses and read or do close work comfortably. Many myopes
choose to wear bifocals to eliminate the need for removing
and replacing their glasses. If you plan to have refractive
surgery to eliminate or reduce your myopia, like everyone
else, you will still experience presbyopia sometime in your
forties.
Monovision addresses the problem of presbyopia that
most people start to encounter at the age of 40-45 when they
begin to need reading glasses or bifocals for close vision.
With monovision, the dominant eye (the eye you would use to
focus a camera) is focused for distance vision, and the non-dominant
eye is focused for near to intermediate vision. This can be
done with contact lenses, refractive surgery (Lasik) or
intraocular lenses.
With both eyes open, near, intermediate and far objects can
be seen well without the aid of glasses.
Monovision certainly isn't appropriate for everyone. However,
when paired with the right person, it can be a great fit.
Monovision is a blend of near and distance vision, and is
ideal for people with an active lifestyle. However, there is
a caveat to consider: since it is a compromise, most
people's vision isn't perfectly crisp up close or far away.
Instead, it offers the best of both worlds.
Most people who opt for monovision go through a brief period
of adaptation as the brain "learns" to see with
the eye best suited for the task. If you're considering
refractive surgery as a permanent form of monovision, it
might be best to consider a "test drive" with
contact lenses before making a decision.
About 75% of people like monovision. We test our patients
with contact lenses before laser treatment to see whether
they will be able to adapt to monovision.
PHAKIC
IOL (INTRAOCULAR LENS)
Phakic IOL procedures are being used on severely
nearsighted and farsighted patients who may not be
candidates for the more common laser procedures such as PRK
, LASEK, and LASIK. Phakic IOL is the procedure of choice
for high myopia and high hyperopia.
The word "Phakic" refers to those who have not
undergone cataract surgery and still have their eye's
natural internal lens. IOL stands for "intra-ocular
lens." In the Phakic IOL procedure, an intra-ocular
lens is placed inside the eye. The patient's natural lens is
not removed, as it would be in cataract surgery. Unlike in
clear lens extraction, the crystalline lens of the eye is
not removed so patients undergoing this procedure can retain
any pre-existing focusing ability. There are three lens
designs. The NuVita lens is placed in front of the iris. The
Artisan, or iris claw lens is attached on the front of the
iris. The Implantable Contact Lens, or ICL, is placed
between the iris and crystalline lens.
Advantages include no effect on corneal
thickness, removability and very clear vision.
Eligible
Candidates
-
Individuals who have extreme myopia (over
-15.00 diopters)
-
Individuals who have extreme hyperopia (over
+6.00 diopters)
-
Individuals who are under the age of 40
years of age.
-
Individuals without any health issues
affecting their eyes
What
to expect on the day of surgery
You will arrive at the surgery center about an hour
prior to your procedure. Once you have been checked in, you
may be offered a sedative to help you relax. You will then
be prepared for surgery. The area around your eyes will be
cleaned and a sterile drape will be applied around your eye.
Powerful eye drops or a local anesthetic will be used to
numb your eyes. When your eye is completely numb, an eyelid
holder will be placed between your eyelids to keep you from
blinking during the procedure.
Next, a small incision will be made and the intra-ocular
lens will be inserted. The Phakic IOL procedure is very
quick, typically taking less than 20 minutes. There also is
a short recovery time. The results of the surgery are almost
immediate, however your vision will probably be a little
blurry from the anesthesia, so someone will need to drive
you home. You should relax for the rest of the day. You may
experience some discomfort, but this is usually alleviated
with an over-the-counter pain reliever. Most patients resume
normal activities within a day or two.
|
