Oct 5 2004
Millions of people have reduced their dependence on eyeglasses and contact
lenses over the past several years with the refractive surgery procedure known
as LASIK.
This procedure can correct refractive errors such as nearsightedness,
farsightedness and astigmatism. Now an enhanced version of LASIK, known as
wavefront LASIK, is available. This improved system allows eye surgeons to
customize the procedure for each eye, providing the possibility of even better
vision.
Adapted from technology used in astronomy, wavefront LASIK is a procedure
that uses an array of microsensors and a laser. A wave of light from a laser
beam is sent through the eye to the retina. This light is reflected out of the
eye, and 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 visual system, including the cornea’s imperfections, or aberrations.
Thousands of people have the same eyeglass prescription, but because the map is
so precise, no two people have the same wavefront measurements.
These wavefront data are translated into a mathematical formula the surgeon
uses to program corrections into the ultraviolet cold laser, which vaporizes
tissue to reshape the cornea. This new wavefront technology has a better chance
of reducing higher-order aberrations that cause glare, haloes and blurry images.
All wavefront patients will have some higher-order aberrations after surgery,
and in fact some types of aberration may increase. However, wavefront technology
is the best tool for quantifying aberrations, and wavefront LASIK results in far
fewer aberrations than conventional LASIK.
Concerns about quality of vision and nighttime glare with previous forms of
LASIK prevented many people from having their vision corrected. In Food and Drug
Administration trials, the majority of patients who had custom LASIK found their
night vision to be better after the procedure than it was with their glasses or
contact lenses. One FDA study showed More than 70 percent of custom LASIK
patients saw better than 20/20.
Wavefront LASIK may not be for everyone because it removes more corneal
tissue than conventional LASIK. Patients with thin corneas, high degrees of
aberration, severely dry eyes or conditions that affect the lens or vitreous
fluid inside the eye may not be good candidates. However, many of these patients
may still be good candidates for conventional LASIK. Check with your
ophthalmologist, or Eye M.D., to see if wavefront LASIK is right for you.
By Roy S. Rubinfeld, Eye M.D.