In order to understand the effectiveness of wavefront-guided LASIK, we must first have a quick roundup on the natural imperfections of the eye. The cornea and the crystalline lens are not perfect, and light rays passing through the eye are subject to being distorted due to these imperfections. These distortions are termed as “aberrations”, which are categorized as lower order and higher order aberrations.
Lower order aberrations constitute a major chunk (90% or more) of these aberrations, and lead to the more prevalent refractive errors, such as farsightedness, nearsightedness and astigmatism. These vision anomalies can be compensated for by corrective eyeglasses and contact lenses, or can be treated through conventional surgical procedures like PRK, LASIK or LASEK. However, the remaining 10% optical aberrations, also known as higher order aberrations, give birth to anomalies that cannot be cured via conventional LASIK.
Such a scenario necessitates the use of wavefront-guided LASIK.
Since higher order aberrations are entirely unique to a particular patient, much like fingerprints, a wavefront analysis system (known as an Aberrometer) is used to measure these aberrations. The Aberrometer is digitally interfaced with a sophisticated, computer controlled laser, which is directed in a precise manner over the cornea. In essence, the laser custom sculpts the cornea – a completely customized reshaping of the corneal surface.
The procedure employed by the wavefront analyzer to measure higher order aberrations would appear quite complex to a layman.
At first, a ray of light is passed through the eye and is reflected off the retina as an outgoing wavefront. This wavefront is compared against a planar wavefront, in order to determine both lower and higher order aberrations. These aberrations are displayed on a monitor screen in the form of precise 3D images. This information is then used for a custom ablation of the cornea, with the aid of an excimer laser eye surgery system interfaced with the Aberrometer.
On the whole, the conventional LASIK procedure would suffice for the treatment of common lower order aberrations, such as myopia, hypermetropia and astigmatism.
However, higher order visual defects normally call for a much advanced surgical procedure like wavefront-guided LASIK.
If you find a LASIK doctor that you are confident about you will be able to get more information about wavefront guided LASIK.
Source: http://www.ArticlePros.com/author.php?Nicola Kennedy
|
