In LASIK, Bigger Is Better
By Dr. Brian S. Boxer Wachler
Published on August 30, 2007
As vision care professionals, we strive to make every patient happy. Unfortunately, however, this is not always possible. For example, after LASIK, patients may be less than fully satisfied with their results due to undercorrection, overcorrection, or induced higher order aberrations such as spherical aberration (causing glare or halos at night) or coma (causing monocular double vision). Surgical accuracy and nomograms help to ensure proper treatment of lower order aberrations, while advanced wavefront technology is necessary to treating higher order distortions.
It is actually quite simple to avoid significant induced spherical aberration if the LASIK surgeon uses an advanced wavefront laser platform that places additional laser pulses in the periphery. A portion of ultraviolet laser light normally reflects off (and does not ablate) the cornea in the periphery. This inadvertently creates a functionally smaller optical zone and increased spherical aberration – a problem compounded as the degree of myopia increases. Additional pulses counteract ultraviolet reflection; however, this counteraction can only be accomplished through precise pulse placement with a small, flying-spot laser. Currently, the Alcon® CustomCornea® platform is the only wavefront-guided laser does this. This technology has allowed us to treat patients with high myopia (up to -9 D) and high astigmatism (up to -5 D) with excellent optical results, even in patients with large pupils.
Remember, the larger the optical zone, the less the spherical aberration and, therefore, the lower the risk of halos and glare.
It is essential to capture and treat flaws in the shape of the cornea with a wide-diameter wavefront pattern. The Alcon® CustomCornea® platform is capable of treating out to 9.0mm. Alcon® CustomCornea® is the only wavefront platform that is approved by the FDA to reduce higher order aberrations compared to conventional LASIK and improve quality of vision.
Capturing and treating corneal flaws with wide-diameter wavefront patterns is also important for fixing aberrations from prior LASIK surgery. In these cases, the source of aberration is the peripheral cornea. If it is not measured, it will not be treated. We have observed 100 percent improvement in patient symptoms after wavefront retreatments, results that we have presented at scientific symposia over the past year.
Advanced wavefront technology that accounts for ultraviolet laser light reflection counteracts the normal inducement of spherical aberration and, as a result, reduces the risk of postoperative glare and halos. As a result of combining this technology with meticulous surgical accuracy and personalized nomograms, the satisfaction rate among LASIK patients has never been higher.