The Eye Surgery Education Council of the American Society of Cataract and Refractive Surgery Foundation
today issued a clarification on the use of the terms "wavefront-guided," and
"wavefront-optimized" in connection with laser-based procedures (LASIK, PRK,
etc.) and implantable lenses used for vision correction purposes. This
clarification is issued to help patients make better-informed decisions
regarding their eye care.
Wavefront-guided vision correction procedures customize laser treatments
based on the individual characteristics of the eye that is being corrected. The
term "wavefront-optimized" refers to laser treatment software that has been
designed with certain corrections pre-programmed, although a true and customized
wavefront plan is not employed.
The advent of wavefront technology enables ophthalmologists to measure and
treat the defects of the eye's visual system that extend beyond what can be
corrected by the basic prescription for eyeglasses or contact lenses. In
addition, wavefront concepts are now being used in the design of artificial
lenses that are implanted into the eye as part of treating cataracts and other
Conventional vs. Wavefront
Conventional diagnostic systems and the treatment software that operates the
lasers, rely upon the same kind of data that would be gathered during the
physical examinations and ophthalmic tests used to make prescription eye glasses
and contact lenses.
By contrast, the most commonly used wavefront technology passes light into
the eye, reflects it off the inside of the back of the eye, and then measures
how this light is distorted as it exits. All of the light rays that exit the eye
form the wavefront, which is representative of the eye's focusing
characteristics. This reflected light or wavefront is analyzed by computer
software for distortions caused by the eye's optical imperfections. For
laser-based vision correction procedures, that information is then used to
generate a customized treatment plan that guides the laser as it treats the
individual eye in question.
Wavefront-guided vs. Wavefront-optimized
"Spherical aberration" is a common optical imperfection that is treatable by
wavefront technology. It occurs when the peripheral portion of a lens system
focuses light to a different point than does the central part of the lens
system. A patient with excessive spherical aberrations may have problems with
glare and lack of sharpness of vision, particularly under dim light conditions.
This problem is well known in the optical industry, and fine cameras, movie
projectors, telescopes, etc., have been designed to overcome the problem.
Since spherical aberration is a common problem, some new laser programs have
a built in software correction for it. Similarly, new artificial lenses (used
for cataract and other vision correction procedures) are designed to correct for
spherical aberration. Because the design or treatment concept has been
influenced by wavefront methods, it has been referred to as wavefront-
optimized, although a true and customized wavefront plan is not employed.
Vision correction surgery (LASIK, LASEK, PRK, etc.) to correct
nearsightedness and farsightedness with or without astigmatism has become widely
accepted. Approximately 655,000 people are expected to have laser- based and
lens-based procedures in 2004. Customized, wavefront-guided laser procedures are
more expensive than traditional ones, and differ from wavefront-optimized
procedures. Patients considering laser-based and lens- based vision correction
can benefit from understanding those differences.
The American Society of Cataract and Refractive Surgery is an international
educational and scientific organization whose 9,000 member ophthalmologists
specialize in surgical procedures associated with the front part (anterior
segment) of the eye. They specialize in treating cataracts, glaucoma, diseases
and trauma of the cornea, and pediatric eye disorders, and in vision correction
procedures using laser-based and artificial lens technologies. The Society
publishes the peer-reviewed Journal of Cataract and Refractive Surgery.