So
what is Custom Lasik?
Custom LASIK surgery, also known as wavefront
LASIK or wavefront-guided LASIK, 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 a wavefront measurement system, some
extremely precise, individualized vision correction
outcomes may be achieved that would be impossible
with traditional LASIK surgery, contact lenses or
eyeglasses.
You should be qualified under Food and Drug
Administration guidelines before custom wavefront
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.
With custom LASIK, your eye's ability to focus
light rays is measured, 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. [See also:
Wavefront Technology in Eye Exams]
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 Wavefront-Guided 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
- Reduced chance of losing best-corrected
vision
- Reduced chance of losing visual quality or
contrast sensitivity
- 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," said Roger Steinert, MD, associate
clinical professor of ophthalmology, Harvard Medical
School.
"Prior to the advent of wavefront measurements,
there wasn't anything we could do to measure or
treat higher-order aberrations," Steinert said.
"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."
Not all refractive surgeons agree that wavefront-guided
LASIK can treat higher order aberrations. In fact,
some surgeons argue that both wavefront LASIK and
conventional LASIK can sometimes cause these
aberrations because of artificial changes made to
the natural shape of the eye's surface. However,
wavefront-guided LASIK may be less likely to induce
higher order aberrations than conventional LASIK,
according to discussion in the April 15, 2005 issue
of Ophthalmology Times.
A 2005 survey revealed that most refractive eye
surgeons now use wavefront-guided LASIK in their
practices.
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Center
Credits to the FDA
and American Association of Optometry
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The cornea is a part of the eye that helps focus
light to create an image on the retina. It works in
much the same way that the lens of a camera focuses
light to create an image on film. The bending and
focusing of light is also known as refraction.
Usually the shape of the cornea and the eye are not
perfect and the image on the retina is out-of-focus
(blurred) or distorted. These imperfections in the
focusing power of the eye are called refractive
errors. There are three primary types of refractive
errors: myopia, hyperopia and astigmatism. Persons
with myopia, or nearsightedness, have more
difficulty seeing distant objects as clearly as near
objects. Persons with hyperopia, or
farsightedness, have more difficulty seeing near
objects as clearly as distant objects. Astigmatism
is a distortion of the image on the retina caused by
irregularities in the cornea or lens of the eye.
Combinations of myopia and astigmatism or hyperopia
and astigmatism are common. Glasses or contact
lenses are designed to compensate for the eye's
imperfections. Surgical procedures aimed at
improving the focusing power of the eye are called
refractive surgery.