Adapted from technology that allows land-based telescopes to produce images comparable to those generated by the Hubble Space Telescope, wavefront LASIK consists of a sensor and a laser. A wave of light from a laser beam is sent through the eye to the retina. This light is reflected back through the vitreous, the lens and the pupil. The sensor measures the irregularities at the front of the wave of light as it emerges from the eye. This produces a precise three-dimensional map of the eye's visual system, including the cornea's imperfections or aberrations.
The wavefront data is translated into a mathematical formula that the surgeon uses to program corrections into the laser, which vaporizes tissue to reshape the cornea to correct refractive errors. This new technology also corrects the higher-order aberrations that cause glare, haloes and blurry images. Higher-order aberrations are distortions in the visual system that can only be detected with wavefront analysis and corrected with wavefront LASIK. This is the assessment of refractive surgeons who have begun to use wavefront LASIK systems approved by the U.S. Food and Drug Administration (FDA).
"This is a major advance in LASIK technology," said Roy Rubinfeld, MD, a spokesperson for the American Academy of Ophthalmology and an Eye M.D. at Washington Eye Physicians and Surgeons in Chevy Chase, Md. "With wavefront LASIK the visual results are more predictable than with traditional LASIK."
So far, three different wavefront LASIK systems have been approved by the FDA. Alcon's LADARWave Customized Ablation system was approved in October 2002, the VISX Custom Vue system was approved in May of this year and Bausch & Lomb's Zyoptix system recently received preliminary approval by the FDA's Advisory Panel.
Studies comparing results of wavefront LASIK with conventional LASIK found that 90 to 94 percent of patients receiving wavefront LASIK achieved visual acuity of 20/20 or better, whereas up to 80 percent of those receiving conventional LASIK achieved 20/20 or better.
However, wavefront LASIK may not be for everyone. Because wavefront LASIK removes more corneal tissue than conventional LASIK, patients with thin corneas may not be good candidates. Patients with high degrees of aberration, severely dry eyes, or conditions that affect the lens or vitreous fluid inside the eye also may not be good candidates. However, these patients may still be good candidates for conventional LASIK.
Academy spokesperson Daniel Durrie, MD, of Durrie Vision in Overland Park, Kan., said, "It is important that patients get a thorough eye examination by a reputable eye surgeon before undergoing any surgery. They need to understand the potential risks as well as benefits of the procedure."
In addition to refractive surgery, wavefront technology is also being used in the design of contact and intraocular lenses and to diagnose retinal conditions.
The American Academy of Ophthalmology is the world's largest association of eye physicians and surgeons--Eye M.D.s--with more than 27,000 members worldwide. For more information about eye health care, visit the Academy's partner Web site, the Medem Network, at www.medem.com/eyemd. To find an Eye M.D. in your area, visit the Academy's news release at www.aao.org.