The
Excimer laser's potential was discovered by Dr. Srinivasan, who was working
in a research laboratory on a laser system to cut plastics and other
organic materials. By the early 1980's, he realized the potential for the
excimer laser to interact with biological tissue. Ophthalmologist Steven Trokel,
working with Srinivasan, introduced the idea of using the excimer laser to
reshape the cornea.
The
first patient to undergo laser vision correction was treated in Germany
in 1988. The highly sophisticated excimer laser uses light energy to
correct focusing problems by vaporizing away a small amount of tissue
from the central area of the cornea. Most surgical laser beams affect
tissue by producing heat that burns it, or by producing a shock wave
that separates tissue with micro-explosions.
The
excimer laser works differently. It uses a charged mixture of fluorine
gases to produce a cool beam of ultra violet light. The beam is unique
because it breaks the molecular bonds and vaporizes tissue,
one microscopic layer at a time. The excimer precisely sculpts tissue
with almost no effect on the surrounding tissue. This ability makes
it ideal for changing the shape of the cornea.
At
present, refractive surgery is most effective for myopia, astigmatism
and hyperopia. LASIK is the most recent advance in laser vision correction.
LASIK is an acronym for Laser Assisted In-situ Keratomileusis. Compared to the
original laser PRK, the surface of the cornea remains largely intact
so that LASIK patients are more comfortable and see better more quickly.
LASIK has been performed internationally for approximately 10 years.
It was first performed in U.S. clinical trials in 1991. It is
important to note that the major components of the procedure have a
long history. Ophthalmologists have been reshaping the cornea for over
50 years, creating a protective layer of tissue for over 35 years, and
using the excimer laser since the 1980s.
In
1996, the FDA acted on the data submitted and approved the laser for
treatment of low myopia up to -6.00 diopters. In 1997, the FDA approved
the laser for treatment of astigmatism up to -4.00 diopters. There are
currently three major manufacturers of the excimer laser equipment:
Summit Technology, Visx and Nidek.
Oct. 21, 1999 - Summit Technology, Inc. announced that the U.S. Food and Drug Administration
(FDA) granted approval for the Company's Apex Plus Excimer Laser Workstation
for the LASIK treatment of myopia with or without astigmatism. The approval
is for the correction of myopia in the range of 0D to -14.0D with or
without astigmatism in the range of -0.5D to -5.0D. This approval gives
Summit the widest range of treatments for nearsightedness and astigmatism
in the industry.
Nov.
19, 1999 - VISX, INCORPORATED (Nasdaq:VISX) announced today that the
U.S. Food and Drug Administration (FDA) has approved the use of its
VISX STAR S2 Excimer Laser System(TM) as safe and effective for the
treatment of up to 14 diopters of myopia, or nearsightedness, with up
to 5 diopters of astigmatism.
September 30, 1999 - Nidek, Inc. announced the FDA had granted PMA supplement
approval for the Company's EC-5000 Excimer Laser System for the treatment
of Photorefractive Keratectomy for moderate myopia with astigmatism.
The
new approval will allow treatment for the reduction or elimination of
moderate myopia (nearsightedness) with astigmatism (uneven curvature
of the cornea). The approval will allow correction of myopia ranging
in severity from -1.00 to -8.00 diopters (D), with refractive astigmatism
from -0.50 to -4.00 D cylinder by manifest refraction.
March
2000 - The LADARVision excimer laser, manufactured by Autonomous Technologies,
Inc. and recently approved by the FDA, is a self aiming, small spot
laser system for the correction of nearsightedness, farsightedness,
and astigmatism. We are pleased to offer this next generation laser
technology to our patients.
LADARVISION
combines both eye tracking and small beam corneal shaping. The built-in
eye tracker automatically follows any eye movements during the laser
procedure. This allows the system to more accurately aim the laser beam
and correct for any movement of the eye during the procedure. The expertise
in the area of eye tracking had its origins in many years of research
and development for the Strategic Defense Initiative and the National
Aeronautic and Space Administration (NASA).
Unlike
other laser systems in current use, the LADARVision system also uses
a very small laser beam of less than 1 mm to shape the cornea. This
beam is moved rapidly across the corneal surface in a computer-controlled
pattern of tiny overlapping spots. The amount of corneal tissue removed
with each spot is very small, less than the thickness of a single human
hair. This changes the shape of the surface of the eye to correct nearsightedness
and astigmatism and helps to produce a smooth postoperative corneal
surface which may reduce side effects and improve visual recovery.
In
addition, by measuring and correcting all eye movements during the laser
procedure, the LADARVision system maintains accurate placement of the
laser beam. At the same time, your surgeon will carefully monitor your
eye on a computer screen which provides additional control.
The
actual procedure and its risks and benefits are similar to PRK and LASIK
in general. Your surgeon will discuss with you, in depth, if a procedure using
the LADARVision system fits your particular needs.
For more information about emerging vision correction procedures, visit AllAboutVision.com.
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