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Custom
Lasik
surgery uses 3 dimensional measurements of how your eye processes images to guide the laser in re-shaping the front part of the
eye
cornea
. With this system, usually called
wavefront, some extremely precise, individualized vision correction outcomes may
be achieved that would be impossible with traditional LASIK surgery, contact lenses, or eyeglasses.
You must be qualified under Food and
Drug Administration guidelines before custom LASIK would be considered
for your eye condition. Depending on the custom laser system used and other
factors such as appropriate thickness of your cornea, you might be considered a
candidate if you have mild to moderately high degrees of common vision defects
such as
myopia,
hyperopia
, and
astigmatism.
Once
you are considered a qualified candidate, then your eye surgeon likely
will give you the choice of whether or not to pay extra costs typically involved
with undergoing custom rather than traditional LASIK. Custom LASIK also might be
the best procedure for you if you have difficult-to-correct or unusual vision
defects, or if you need enhancement from less than optimal vision outcomes
associated with past traditional LASIK procedures.
With custom LASIK, your eye's ability to focus light rays
is measured from front to back, and a 3-D map is created that demonstrates
irregularities in the way your eye processes images. Information contained in
the map guides the laser in customizing the treatment to reshape your eye's
corneal surface so that these irregularities can be corrected.
Standard prescriptions for glasses, contacts, or
traditional LASIK procedures can correct ordinary vision defects such as myopia,
hyperopia, and astigmatism. But other irregularities associated with the eye's
optical system could not be addressed until the advent of wavefront and related
technology used in custom LASIK.
Potential Benefits of Custom LASIK
Wavefront technology is groundbreaking because it has the
potential to improve not only how much you can see, visual acuity measured by
the standard 20/20 eye chart, but also how well you can see, in terms of
contrast sensitivity and fine detail. This translates into a reduced risk of
post-LASIK complications, such as glare, halos, and difficulty with night
vision.
How much you see depends on vision defects known as
lower-order aberrations
associated with common refractive errors including
myopia, hyperopia, and astigmatism, which traditional LASIK can treat.
How well you see can depend on presence of the type and
numbers of visual distortions known as
higher-order aberrations
, which can
include irregularities other than common refractive errors. These higher-order
aberrations can create problems such as decreased contrast sensitivity or night
vision, glare, shadows, and halos. However, higher-order aberrations do not
always affect vision. Unlike traditional LASIK, custom LASIK treats both lower-
and higher-order aberrations.
Custom LASIK's advantage lies in the area of quality of vision:
 | Greater chance of achieving 20/20 vision |
|
| Greater chance of achieving better than 20/20 vision |
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Reduced chance of losing
best-corrected vision |
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| Reduced chance of losing visual quality or contrast sensitivity |
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| Reduced chance of night-vision disturbances and glare |
Potential also exists for custom LASIK to treat those people
who have lost best-corrected vision from any past refractive surgery:
Lasik
,
PRK
,
RK
, etc.
Sometimes patients complain about vision quality problems,
such as not being able to see in dim or low light. This is referred to as poor
contrast sensitivity,
Prior to the advent of
wavefront measurements
, there
wasn't anything we could do to measure or treat higher-order aberrations .With
this technology breakthrough, we can now measure these disorders, show the
patient what's going on in their eye, link that information to the laser, and
actually correct higher-order aberrations that diminish contrast sensitivity.
Wavefront technology enables the surgeon to improve overall vision quality
better than in the past.
FDA-Approved Custom LASIK System
| Laser System and Manufacturer |
FDA-Approved Indications |
Features |
|
Star S4 Active Trak with CustomVue
(VISX) |
Up to -6.00 D, with cylinder up to -3.00 D for myopic astigmatism.
Up to +3.00 D with cylinder up to +2.00 D for farsightedness (hyperopia)
with or without astigmatism. |
Eye tracking, integrated wavefront, no pupil dilation required, which speeds
up procedure, unique wavefront analysis system known as Fourier for
increased resolution. |
How Custom LASIK Works
The surgeon will begin by using the wavefront device to
transmit a safe ray of light into your eye. The light is then reflected back off
the
retina
, out through the
pupil
, and into the device, where the reflected wave of light is received
and arranged into a unique pattern that captures your lower- and higher-order
aberrations.
All of these visual irregularities are then displayed as a 3-D
map, referred to as a wavefront map. This information is then electronically
transferred to the laser (in wavefront-guided systems), and computer-matched to
the eye's position, enabling the surgeon to customize the LASIK procedure to
your unique visual requirements.
Getting Custom LASIK
Numbers of LASIK procedures in general grew significantly in
2004, with many leading LASIK surgeons reporting in publications such as EyeWorld (published by the American
Society of Cataract and Refractive Surgery) that most eligible patients were
opting for more expensive custom LASIK. The advent of custom LASIK also appears
to be contributing to increased public interest in undergoing LASIK. Review
of Optometry in its Oct. 15, 2004 edition predicted about 1.35 million total
LASIK procedures would be performed in the U.S. by the end of the year, up from
1.15 million procedures in 2003. Custom LASIK usually costs significantly more
than traditional LASIK, partly because a fee is paid to the device manufacturer
for each procedure.
Research is continuing into expanding the degree of vision
errors (such as high myopia) that can be corrected with custom LASIK.
Investigations also are underway for use of custom LASIK to create multi-focal
corrections, which would enable older eyes that have developed
presbyopia
to see
at near, middle, and distant ranges at the same time.
Like conventional LASIK, custom LASIK won't cure all
vision-related problems, so it's important to discuss its applications with your
eye doctor or surgeon to determine if you are a good candidate.
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