All About Vision
New Approach Reduces Need for Repeat LASIK Visits
LONDON, September 2006 — A new and complex computer formula devised for the latest generation of excimer lasers used in LASIK vision correction reduces by nearly two-thirds the likelihood that repeat visits for enhancements will be needed, according to researchers at the University of Rochester Medical Center in New York.
With the new formula, researchers say LASIK eye surgeons are much more likely to receive the exact right vision correction in the first procedure.
Positive LASIK outcomes using the new formula were presented in September 2006 at the European Society of Cataract and Refractive Surgery meeting in London. Rochester researchers noted at the meeting that, while many LASIK patients do achieve 20/20 or better vision, they still might be slightly farsighted or nearsighted.
Researchers say the new computer formula for LASIK corrections accounts for the presence of many obscure vision errors known as higher-order aberrations that can affect vision outcomes. With the new computer formula, more people undergoing LASIK may now be able to achieve better than 20/20 vision.
WaveLight Laser Is Now Also Wavefront-Guided
STERLING, Va., August 2006 — WaveLight's excimer lasers used in LASIK and similar vision correction procedures now will be sold as wavefront-guided or wavefront-optimized depending on eye surgeon preference, based on a new U.S. Food and Drug Administration approval granted in late August 2006.
WaveLight's Allegretto Wave wavefront-optimized excimer laser has for several years used wavefront technology to help provide measurements for individual, customized treatment of the eye. With the newest FDA indication, the excimer laser now can also be wavefront-guided, which means that wavefront measurements automatically are built into the procedure as it takes place in real time.
A WaveLight news release says outcomes for either wavefront-guided or wavefront-optimized systems are similar, except when patients have a higher degree of complex vision problems known as higher-order aberrations. In those cases, results with a wavefront-guided system are slightly better. Company officials say neither type of WaveLight laser system induced symptomatic higher-order aberrations during clinical trials involving 374 eyes.
In clinical trials involving both WaveLight laser systems, all patients were able to see well enough to drive without vision correction such as spectacles at three months following LASIK.
The Allegretto Wave wavefront-guided system has FDA approval for treating up to -7 diopters of myopia with astigmatism of up to 3 diopters.
Pupil Size May Still Matter in LASIK Outcomes
ST. LOUIS, August 2006 — Despite newer excimer lasers that can treat larger zones in the eye for vision correction, LASIK surgeons still are being advised to notify patients that larger pupil size may be associated with adverse LASIK outcomes.
Large pupil size was a major factor in a St. Louis jury's April 2006 decision to award $3 million in damages to a patient who sued a LASIK surgeon because of vision problems following a procedure. Some recent studies indicate that newer excimer lasers can create favorable outcomes in patients with larger pupils. But LASIK surgeons still should warn patients that large pupils can increase risks, according to discussion in the July 2006 issue of Review of Ophthalmology.
The article notes several reasons why large pupil size can adversely affect outcomes, including the increased possibility that aberrations may result when a larger zone is treated on the eye's surface to accommodate a larger pupil.
