Jul 29 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 consists of 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 back 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 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.
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 the procedure LASIK 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.
Specially formulated eye drops may offer a simple solution for presbyopia patients