Howerton
Eye Center - Lasik Vision Correction
- Austin Texas
VISION QUEST ….The Evolution
of LASIK
Vision Correction in the Past
Leads to a Promising LASIK Future
by Shawn Powell
The
latest craze in medical cosmetic surgery
is LASIK – Laser Vision Correction.
People are more educated than ever
about the procedure; however, most
are not aware of its origination.
At
the end of the last century, doctors
became aware that they could correct
abnormal vision by cutting into the
cornea and changing its shape. However,
the technology did not become available
until the mid 1900’s.
In 1978, doctors began performing
the first refractive surgery called,
“Radial Keratotomy” (RK).
RK is an invasive surgical procedure
involving the use of scalpels to make
several incisions in the cornea depending
on the amount of correction needed.
Although RK has been successfully
performed over many decades, numerous
complications have surfaced. Complications
included unpredictable vision, weakening
to the cornea, and poor healing.
Dr.
Jose Barraquer, of Columbia, began
lamellar refractive surgery by removing
a thick disk from the cornea with
a microkeratome, reshaping the disk
on a cryolathe, then suturing it back
into place. In 1986, Dr. Luis Ruiz,
of Bogota, Columbia, developed Keratomileusis-in-Situ.
The procedure was called “Automated
Lamellar Keratoplasty” (ALK).
The surgeon  creates
a flap by dissecting across the front
of the cornea with an instrument called
a microkeratome. After folding the
flap to the side, the surgeon uses
the microkeratome to remove a thin
disc of tissue from the exposed surface
of the cornea. The front flap is then
replaced without the need for sutures.
By removing the inner layer of tissue,
the central optical zone is flattened,
reducing myopia. Surgeons began performing
ALK in the United Stated in the late
80’s; however, unpredictable
results sent surgeons in search of
a more precise procedure.
The
introduction of laser systems for
laser vision correction has provided
ophthalmologists with more precise
and predictable methods to correct
refractive errors. The excimer laser
was first developed in 1975. The excimer
does not cut tissue like a scalpel;
rather it removes tissue by boiling
away molecules one at a time. The
excimer laser is able to carefully
shape or sculpt the corneal surface
with precision.
The
first human technique to use the excimer
laser was “photorefractive keratectomy”
 (PRK).
The first PRK in the United States
was performed in 1987; however it
was not FDA approved until October
of 1995. The procedure itself consisted
of the surgeon scraping away the outer
layer of the cornea and reshaping
its underlying tissue with a cool
ultraviolet beam. This procedure produced
better outcomes than its predecessors;
however, problems still persisted.
The scraping of the cornea caused
a scar formation and hazy vision after
surgery and the procedure could be
very painful. When PRK began using
the excimer laser to reshape the cornea,
it induced pain, but had a wave of
popularity due to its accurate results.
The
current rave in refractive surgery
is called “Laser-In-Situ-Keratomileusis”
(LASIK). The  first
Lasik procedure was performed in Greece
in 1991. It used an excimer laser
in conjunction with a microkeratome
to reshape the cornea. It is extremely
accurate, quick and painless. The
most important aspect of the excimer
laser is that it is remarkably precise.
It is able to remove 0.25 microns
of tissue in a single pulse; that
is, 1/200th of a human hair in 12
billionths of a second. LASIK is a
procedure for the correction of low
to moderately  high
degrees of myopia (nearsightedness).
LASIK will also correct low to moderate
degrees of hyperopia (farsightedness)
and astigmatism associated with myopia
and hyperopia. Patients remain awake
during the procedure, and the eye
is numbed with drops. There is no
discomfort during the procedure. To
correct vision with LASIK, a thin
disc of corneal tissue is lifted from
the eye through the use of a microkeratome.
 Once
the cap is lifted, an excimer laser
is used to reshape the remaining surface
of the cornea. The laser treatment
typically lasts less than one minute.
Each pulse of the laser can remove
39-millionths of an inch of tissue
in 12-billionths of a second. This
enables surgeons to achieve remarkable
accuracy while maintaining excellent
control throughout the procedure.
Once the laser treatment is completed,
the flap of corneal tissue is lowered
back into place where it adheres to
the eye without the need for sutures.
Although
no procedure is perfect, Lasik allows
for an unparalleled degree of precision
and predictability. This makes LASIK
the best procedure available for suitable
candidates. Although LASIK is a more
complex procedure involving more technical
skill, more staff/surgeon training,
and more equipment, it enables the
surgeon to treat the inner layers
of the cornea; thus the risk of scarring
is substantially reduced.
There
are no guarantees with any surgery;
however, LASIK provides the most positive
outcomes in vision correction with
the least amount of pain, shortest
recovery time and the best results.
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