Wavefront-Guided Technology Can Provide Sharper Vision

Jul 03, 2007 at 10:27 pm by steve

Dr. Price Kloess performs customized refractive surgery on a patient, offering hope for higher quality vision.

Higher quality vision is now a reality with an enhanced LASIK procedure that uses wavefront-guided technology. This customized approach to refractive surgery often results in improved quality of vision compared to the traditional LASIK procedures. Dr. Price Kloess, a board certified cornea specialist, was one of the first ophthalmologists in Alabama to use the wavefront technology in the CustomVue® laser vision correction procedures at Alabama Vision Center in Birmingham. “This technique came about because after traditional LASIK surgery to correct lower order aberrations such as nearsightedness, farsightedness and astigmatism, patients still had issues with clarity and problems seeing at night or in dim lighting,” said Kloess. Doctors typically measure vision using the Snellen Eye Chart which can determine the quantity of your vision but not the quality, Kloess said. According to the Snellen vision test, a person’s vision is considered normal if he can identify the letters on the 20/20 line from a distance of 20 feet. But Kloess said that just being able to identify the letters doesn’t mean you have excellent vision. “Today, we know there are visual distortions in your eye’s optical system called higher order aberrations that can affect the clarity of your vision and how well you see in low light and at night,” he said. “The goal of CustomVue® is to decrease the risk of undesirable side effects and improve both the quality of your vision and your lifestyle.” Wavefront is an old technology that has recently been applied to human vision. According to the Council for Refractive Surgery Quality Assurance (CRSQA), wavefront has been used for years by astronomers who need to adjust the optics of their telescopes. A reflecting mirror within the telescope that can be deformed is adjusted using wavefront data to eliminate aberrations induced by the Earth’s atmosphere. In custom wavefront LASIK, the excimer laser uses wavefront information to change the shape of the cornea by ablating tissue. The diagnostic capability of wavefront technology enables doctors to diagnose and measure aberrations they otherwise would be unable to see. A wavefront diagnostic can determine if an individual has aberrations that would be exacerbated by refractive surgery to the point of causing vision problems. No other technology can achieve this level of diagnosis, according to the CRSQA. Wavefront diagnostics can determine if a wavefront-guided ablation is an absolute requirement, conventional ablation would be fine, or the patient should not have surgery at all. “It also helps us diagnose conditions we can’t see with routine tools, such as keratoconus,” Kloess pointed out. The wavefront information is obtained by analyzing light that is reflected from the back of the patient’s eye to see how the light is distorted by visual errors in the eye itself. According to the American Academy of Ophthalmology, a targeted beam of light is sent through the eye and focused on the retina. As the light is reflected back from the retina through the eye’s vitreous, lens, pupil and cornea, a sensor measures irregularities in the wavefront pattern of light as it emerges from the eye. Using this measurement, the wavefront computer creates an accurate, three-dimensional map of the eye’s visual system, including specific imperfections in the cornea. This data is used to program the excimer laser, allowing the ophthalmologist to customize the reshaping of the cornea. Kloess and his team were early users of another new technology known as Iris Registration (CustomVueIR) that dramatically enhances the results of the CustomVue® procedure. When a patient comes into the clinic for treatment, eye measurements are taken with the patient sitting up. However, surgery is performed with the patient lying down. “When the patient lies down, cyclotortion occurs which changes the measurements,” Kloess said. “Iris registration allows the laser to compensate for the turning of the eye and adds an additional level of precision. Anything we can do to be more precise is better.” Another advantage of the CustomVue® procedure, Kloess added, is that fewer patients need the “touch up” that is usually required after traditional Lasik surgery; however the customized procedure is more costly. “Most centers pass along the additional cost for the custom procedure, which costs anywhere from $300 to $1,000 more than the traditional,” he said. Kloess pointed out that CustomVue® isn’t necessarily the answer for all vision problems, and undergoing the procedure is not a guarantee that the patient will be able to give up his glasses or contacts. Limitations with the procedure may occur in patients with thin corneas and dilated pupils that are unusually large. Monovision corrections are usually are better managed with traditional LASIK as well. “All eyes have some level of higher and lower order aberrations so every patient has the potential for improved vision with CustomVue® laser vision correction,” he said. “Our goal is to decrease the risk of undesirable side effects and improve both the quality of a patient’s vision and lifestyle.” Kloess is excited about this new procedure and expects continuing advancements in the technology. However, he said that he thinks future improvements will be geared more toward broadening the spectrum of patients who can be treated than toward just improving the treatment options. He used the analogy of a new digital camera. “I tell my patients that waiting for improvements in this technology is like waiting for the 2008 digital cameras to come out. There will be subtle changes in the technology that is used to run the camera, but it won’t make any better pictures than the current model,” Kloess explained. “As we sit here in mid-year 2007, the technology for correcting vision is extraordinary,” he said. “We are at the point where we can give most patients a chance to see better than ever.” July 2007



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