LASEK Eye Surgery:
How It Works?
LASEK (laser epithelial
keratomileusis) is a
relatively new variation of
PRK, a procedure in which
laser energy is applied
directly to the eye's outer
surface for reshaping and
vision correction.
To understand how LASEK
works, you first must know
the fundamental differences
between LASIK, PRK and
LASEK:
-
With LASIK, a thin flap
is cut into the eye's
surface and then lifted.
Laser energy is applied
to the eye for
reshaping, and the flap
is replaced to serve as
a type of natural
bandage for quicker
healing.
-
An eye surgeon using PRK
does not cut a thin flap
into the eye's surface,
as occurs with LASIK.
Instead, laser energy is
applied directly to the
eye's surface. The ultra
thin, outer layer of the
eye (epithelium) is
removed completely by
laser energy during a
PRK procedure, and
eventually grows back.
-
A LASEK procedure
involves preserving the
extremely thin
epithelial layer by
lifting it from the
eye's surface before
laser energy is applied
for reshaping. After the
LASEK procedure, the
epithelium is replaced
on the eye's surface.
In LASIK, the thicker flap
is created with a the
microkeratome cutting tool
or a special laser. With
LASEK, the ultra thin flap
is created with a special
cutting tool known as a
trephine.
It is a new surgical
procedure to treat myopia
and able to reduce
intraoperative and
postoperative LASIK
complications. The procedure
was first described by M.C.
(Mussimo Camellin, March
1999), In this technique,
the ablated corneal surface
is covered by full-thickness
epithelium .This epithelial
coverage modifies the
wound-healing response of
cornea, effectively protects
the bare surface of the
stroma and prevents the
influx of inflammatory cells
from tears, reducing the
initial inflammatory change
to the corneal stroma. The
expression of TGF.β1 in the
keratocytes is reported to
be lower after LASEK than
after PRK. This may result
in less Postoperative haze
and questionably less
perioperative pain than PRK
and more favorable visual
outcomes . In addition,
since no lamellar flap is
created, LASEK may retain
the biomechanical stability
seen with PRK. Potential
benefits over LASIK include
elimination of flap
complications and the
ability to treat eyes with
thinner corneas, larger
pupils, and other anatomical
features not amenable to
LASIK treatment.
Advantages:
-
Causes less tendency
toward dry eye with
patients with borderline
tear film.
-
Treats thin corneas with
higher myopia
successfully using newer
scanning lasers.
-
Quicker recovery from
neurotrophic cornea,
post ablation.
-
Less risk of ectasia.
-
Simpler.
-
Better in patients with
tight lids, abnormal
anatomy, or very steep
corneas.
-
Reduction of post
operative pain?
-
Reduction of corneal
haze.
-
Avoiding flap-related
complications associated
with LASIK.
-
Retainment of
biomechanical stability
of cornea.
Theoretical advantages
LASEK Disadvantages
1.Slower recovery, lack of
predictability
-
Back to work: 3-5 days
-
Back to driving: 3-5
days
-
Back to recreational
activities: 3-5 days
-
Full visual recovery
takes one week to one
month (author's
experience)
2.More pain
3.More anxiety for patient
in recovery,
4.Epithelial defect for 2-4
days exposes eye to corneal
ulcer risk
5.Re-treatments more
difficult
6.More risk of haze
7.Recurrent erosion may be
more likely.
According my experiences
LASEK is a safe and
effective technique with
high predictability and
stable visual outcomes to
treat High Myopia, Myopic
Astigmatism and Low
Hyperopia.
Wavefront-Guided LASEK or
Customized LASEK seems to be
more effective and with
higher predictability and
patient satisfaction.
LASEK is used mostly for
people with corneas that are
too thin or too steep for
LASIK, when it may be
difficult to create a
thicker LASIK flap. LASEK
was developed to reduce the
chance of complications that
occur when the flap created
during LASIK does not have
the ideal thickness or
diameter.
In LASEK, an
ultra-thin flap
is created on
the eye’s
surface, unlike
the thicker flap
in LASIK.
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According to a survey of
members of the American
Society of Cataract and
Refractive Surgery (ASCRS),
the popularity of LASEK is
growing among refractive eye
surgeons, as it is with
epi-LASIK - another
variation of the procedure.
Epi-LASIK uses a plastic
blade, called an epithelial
separator, to detach part of
the epithelial layer from
the eye.
However, eyes undergoing
LASEK procedures generally
heal more slowly and result
in more complaints of
discomfort than with LASIK.
For this reason, some
surgeons prefer to perform
PRK rather than LASEK or
epi-LASEK because they find
no advantage in the latter
procedures.
In fact, a 2008 study
published in the Journal of
Refractive Surgery indicated
that people undergoing PRK
tended to have less pain and
healed slightly faster than
people who had undergone a
surgical technique called
butterfly LASEK. "Butterfly"
refers to the shape and type
of thin flap lifted in
LASEK, which is thought to
increase comfort and healing
time.
The LASEK Procedure
During LASEK, your surgeon
uses local anesthesia. Then
he or she cuts the
epithelium, or outer layer
of the cornea, with a fine
blade (trephine). Then the
surgeon covers the eye with
a diluted alcohol solution
for approximately 30
seconds, which loosens the
edges of the epithelium.
After sponging the alcohol
solution from the eye, the
surgeon uses a tiny hoe to
lift the edge of the
epithelial flap and gently
fold it back out of the way.
Then he or she uses an
excimer laser, which is used
for LASIK or PRK, to sculpt
the corneal tissue
underneath. Afterward, the
epithelial flap is placed
back on the eye with a type
of spatula.
After LASEK
In many ways, LASEK vision
recovery is slower than
LASIK recovery, but there
are some differences.
According to doctors who
perform LASEK, the flap edge
heals in about a day, though
patients usually wear a
bandage contact lens for
approximately four days to
protect the eye.
Vision
recovery after
LASEK may be
slower than for
other
procedures, but
there is less
risk of
complications
such as dry eye.
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Your eye may feel irritated
during the first day or two
afterward. Also, with LASEK
compared with LASIK, it
often takes longer to
recover good vision - up to
four to seven days - but
this can vary from one
person to the next. You also
may experience more pain
with LASEK compared with
LASIK.
Talking to Your Doctor
If you are considering
LASIK, but your doctor says
you need LASEK, ask why.
It's not for everyone, but
many surgeons who perform
LASEK consider it a better
option for some patients who
will probably not do very
well with LASIK. Also, in
some studies LASEK has been
associated with faster
recovery of sensation or
nerve function in the eye's
surface (cornea) compared
with LASIK. It also may
cause dry eye less
frequently than LASIK.
However, keep in mind that a
2007 study published in the
Journal of Cataract and
Refractive Surgery concluded
that the outcome of LASEK
depends on the surgeon's
experience. Therefore, it's
always a good idea to ask
how many procedures your
surgeon has performed.
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