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Presby LASIK :
Presby LASIK, also known as
multifocal LASIK, is an
experimental type of laser
vision correction surgery
that changes the shape of
the eye's clear surface
(cornea) to establish
different zones for seeing
at near to far distances.
This surgery corrects
presbyopia, which causes
near vision to blur as the
eye's natural lens begins to
stiffen, usually at around
age 40. If you are
nearsighted and have
presbyopia, you may be able
to see up close without your
usual eyeglasses or contact
lenses but not when you are
wearing them.
How the Presby LASIK
Procedure Is Performed
Presby LASIK also is called
multifocal LASIK because it
works on principles
virtually identical to
artificial multifocal lenses
used to provide vision
correction for presbyopes.
With presby LASIK, laser
energy reshapes your eye's
clear surface into different
zones, such that light is
bent or refracted
differently in each zone. In
this way, both near and
distance vision can be
achieved simultaneously.
Because presby LASIK still
is in investigational
phases, different approaches
are being studied to
determine how the eye should
be shaped to achieve the
best possible vision
correction for presbyopes.
For people who are
nearsighted and presbyopic,
different configurations of
eye shapes are being
studied. In some cases, near
vision correction is
provided in the central zone
of the cornea, and in
others, near vision
correction is established in
the peripheral area.
Another method of presby
LASIK adds what is known as
aspheric corrections to the
eye's surface. Aspheric
shapes are not perfectly
round and are thought to
help reduce vision
distortions or aberrations
that generally can be
associated with vision
correction.
Still other presby LASIK
methods under investigation
aim to provide customized
procedures uniquely suited
to the individual's needs
and lifestyle. If a person
performs considerable
close-up work, for example,
the presby LASIK vision
correction procedure might
be adapted to enhance near
vision in lieu of better
distance vision.
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