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LASIK
Eye Surgery Information to help the
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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.
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
A 2005 survey revealed that most refractive eye surgeons now use wavefront-guided LASIK in their practices. Read more about the study in the sidebar:
WAVEFRONT - GUIDED LASIK & CONTRAST
SENSITIVITY
Refractive eye surgeons appear overwhelmingly to favor customized or wavefront LASIK as evidenced by results of a 2005 American Society of Cataract and Refractive Surgery (ASCRS) survey of 4,645 U.S. members (16% responded). About 74% of refractive surgeons now use wavefront-guided LASIK in their practice, compared with fewer than 10% in 2003.
In certain cases, outcomes such as improved night vision with use of wavefront-guided LASIK appear to surpass results that can be achieved with conventional LASIK.
In August 2004, the U.S. Navy announced that patients at its refractive surgery center were achieving better distance vision and night vision after custom LASIK than after traditional LASIK.
In a small study, 88 percent of contrast sensitivity measurements improved after wavefront-guided LASIK, while only 40 percent improved after regular LASIK. This was one month after surgery.
Uncorrected visual acuity of 20/20 or better was achieved by similar numbers, however: 72 percent of the wavefront group and 70 percent of the regular LASIK group. The study was published in the March 2004 issue of Ophthalmology, the clinical journal of the American Academy of Ophthalmology.
FDA-Approved Custom LASIK Systems
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Laser System and Manufacturer |
FDA-Approved Indications | Features |
|---|---|---|
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LADARVision 4000 with
CustomCornea & LADAR6000 with CustomCornea (Alcon) |
Myopia: up to -8 D with or without myopic astigmatism up
to -4 D Hyperopia and hyperopic astigmatism: up to +5 D (near vision problems) and astigmatism causing distance vision problems up to -3 D |
Eye tracking, integrated wavefront, small spot system for precise laser application, no pupil dilation needed for treating larger optical zones in LADAR6000 system |
| Technolas 217z Zyoptix System (Bausch & Lomb) | Myopia: up to -7 D with or without up to -3 D myopic astigmatism and total refractive error equal to or less than 7.5 D | Integrated wavefront and "flying spot," meaning fast, uniform application of laser beam with each pulse for smooth corneal surface |
| Star S4 Active Trak with CustomVue (Visx) |
Myopia: up to -6
D, with or without up to -3 D myopic astigmatism Hyperopia: up to +3 D with or without up to +2 D for hyperopic astigmatism |
Eye tracking, integrated wavefront, no pupil dilation required, which speeds up procedure, unique wavefront analysis system known as Fourier for increased resolution |
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Star S4 IR with
CustomVue (Visx) |
Myopia: up to -6 D
with or without up to -3 D of myopic astigmatism Hyperopia: up to +3 D with or without up to +2 D of hyperopic astigmatism Mixed astigmatism: up to 5 D |
Same as S4 Active Trak |
| Allegretto Wave with Allegro Analyzer (WaveLight) | Myopia: up to -7 D with or without up to 3 D of astigmatism | Scanning spot system, eye tracking, integrated wavefront, algorithm (mathematical measurement) based on population studies that helps minimize possibility that a vision error known as spherical aberration might be induced during vision correction |
| Note: D refers to diopters. | ||
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