| Links
& Resources |
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www.lasikinstitute.org
- probably the best source of well-balanced information
on LASIK for both the public and physicians |
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www.eyenet.org
- the home page of the American Academy of Ophthalmology |
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www.ascrs.org
- a comprehensive link to relevant information
on eye health and refractive surgery |
|
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Wavefront
Diagnostics & Custom Ablation.
Wavefront sensing is a new diagnostic tool for measuring
the refractive error of the eye. Conventional forms
of refraction, such as that performed by your optician,
are limited to measuring the best spherical and cylindrical
refraction (myopia or hyperopia and regular astigmatism).
But wavefront sensing measures other conditions within
the whole eye that affect a patient's refraction (how
they see)..
Visual
scientists refer to these conditions as higher order
aberrations, and these aberrations are considered
a limitation to best vision with refraction. By characterizing
the components of high order aberrations, doctors
have the ability to quantify levels of naturally occurring
or surgically induced aberration and has the ability
to correct these aberrations.
Like a fingerprint, the human eye has such higher
aberrations characteristics that are unique to each
individual. But these distinctions keep us from achieving
optimum vision after conventional refractive surgeries.
Wavefront sensing seeks to change that. |
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Conceptually,
wavefront sensing uses a simple technique. The patient
stares ahead and focuses on an object. While doing
so, a beam of light is projected into the eye and
this beam is reflected off the back of the eye and
back out. This wavefront of light then passes through
a tiny array of lenses, called the lenslet array,
in the wavefront analyzer. The machine maps (up
to 2000 points) where the exiting rays of light
land and is then used to determine the aberrations
the eye.
If the eye has no irregularities these light rays
will come out of the eye in a plane wavefront, or
a straight line. However, if the eye has irregularities,
also called higher order aberrations, the wavefront
emerges not in a straight line, but with a unique
shape specific for that eye. As it creates a map
of the eye, it exhibits any abnormalities (aberrations)
which prevent maximum vision. This diagnostic information
is then link to an excimer laser system for the
laser surgical correction of the refractive aberrations.
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Advanced
Wavefront Guided LASIK could mean Superior Vision
for Patients
In conventional LASIK, the laser program used in
the surgery to correct a given diopter of myopia
is identical, no matter on whose eye the LASIK procedure
is performed. But people don't share identical eye.
Indeed the aberrations can vary tremendously even
if two individuals are of the same degree of myopia.
Although
the resolution limits of the human retina allow
for vision of approximately 6/3, very few, if any
individuals approach this limit. A person with 6/6
vision, has good vision by today's standards. One
of several factors that keep us from obtaining vision
closer to this retinal limit is the eye's higher-order
aberrations. The theory holds that if these irregularities
could also be corrected, then possibly we can attain
a better visual result
In
wavefront guided LASIK (customized ablation), the
laser draws on the wavefront data to create a custom
surgical correction pattern. This more precise data
is more likely to improve vision beyond the so-called
normal limits of today, especially so in conditions
of low contrast. In addition, the Zyoptic Custom
Wavefront guided LASIK Surgery removes less corneal
tissue when compared to conventional LASIK program
on the Bausch & Lomb Technolas laser. This means
that patients who were previously unsuitable for
LASIK because of having a thin cornea can now benefit
from laser refractive surgery. |
How
Wavefront guided LASIK is done at the TLC The LASIK
Centre
The system we use is the Zyoptix Custom Wavefront
LASIK Surgery. The surgery is similar to conventional
LASIK. In addition, we use a wavefront measuring
device (Zywave aberrometer) and Orbscan II corneal
topography system to analyse the wavefront pattern
of your eye. A computer then link the diagnostic
data with the excimer laser which incorporates a
very fast eye tracker with a small-spot, scanning
laser.
Custom
Wavefront LASIK Surgery will not only correct your
prescription but will also correct the very small
optical aberrations that are found throughout the
entire eye. That means every patient can be treated
as a unique case, as the customised wavefront guided
LASIK technology will generate a new treatment algorithm
that is unique for every person. |
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Summary
of Potential Advantages of Wavefront guided LASIK
Wavefront
Guided LASIK allows every patient to be treated as
a unique case. Wavefront
Guided LASIK has the potential to allow more people
to achieve 6/6 (20/20) vision than before.
Wavefront
Guided LASIK has the potential to allow more people
to achieve better vision, such as 6/4 (20/15).
Wavefront
Guided LASIK has the potential for people to achieve
a higher quality of vision, improved contrast, or
night vision after surgery.
Wavefront
Guided LASIK has the potential to decrease the need
for retreatments (enhancements).
Wavefront
Guided LASIK has the potential to decrease the chance
for complications such as night glare and haloes. |
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