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Images copyright and licensed by Stephen F. Gordon
VISION CORRECTION
Did you know that your eyes are your body's most highly
developed sensory organs? In fact, a far larger
part of your brain is dedicated to the functions of
eyesight than to those of hearing, taste, touch or
smell. For many people, quality vision is something
that is taken for granted. For some, just being
able to see the alarm clock in the morning is a difficult
challenge. Over the past 30 years, several different
procedures have been introduced in the United States
to correct vision.
Originally, doctors placed incisions in the cornea to correct the conditions. However, beginning in the early 80's, doctors began using lasers to physically alter the shape of the cornea. It was then that another use for the Excimer laser was discovered. Originally created by IBM, and used for etching computer chips, the laser produced a cool, non-thermal light beam that is ideal for the procedures. By eliminating the possibility of thermal damage to surrounding tissue the laser is able to remove corneal tissue with an incredible accuracy of up to .25 microns (0.00004 of an inch) with each pulse. The laser has added a tremendous amount of precision, control, and safety to treating nearsightedness, farsightedness, and astigmatism.
NEARSIGHTEDNESS
Clear vision in the normal eye is the result of light
rays passing through the cornea, pupil, and lens and
focusing directly on the retina. Nearsightedness
occurs when the cornea is too curved or the eye is
too long. This causes light to focus in front
of the retina, resulting in blurry distance vision. ^TOP
FARSIGHTEDNESS
Farsightedness occurs when the cornea is too flat in
relations to the length of the eye. This causes
light to focus at a point beyond the retina, resulting
in blurry close vision and sometimes blurry distance
vision as well. In order to treat farsightedness,
the cornea must be made steeper. This is accomplished
by directing the laser beam to remove tissue from around
this area.
ASTIGMATISM
Astigmatism often occurs with nearsightedness and farsightedness.
This causes light to focus in more than one point on
Photo-Astigmatic Refractive Keratectomy (PARK) can
be used to treat low to moderate amounts of astigmatism.
Since regular astigmatism is caused by the cornea being
steeper in one direction, like a football, the Excimer
laser beam is shaped to remove more tissue in one direction
than the other. The result is a more spherical cornea
that allows light to focus more directly on the retina.
PARK can usually be done in the same session as PRK
or LASIK.
LASIK
LASIK is an acronym for LASer In-situ Keratomileusis,
which simply means "to shape the cornea within
using a laser." It corrects vision by reshaping
the cornea (outer window of the eye) so that light
rays focus more precisely on the retina, thereby reducing
or eliminating refractive errors. The process
is relatively easy and involves just a few steps. After
your eye has been numbed with "eye drop" anesthesia,
an eyelid speculum will be positioned to hold your
eyelids open. You will remain awake and comfortable
throughout the procedure. A small suction ring
will be placed around the cornea and serves as a platform
for the microkeratome. The microkeratome separates
the surface layers or the cornea, and the corneal flap
is folded back. You will be asked to look at a
target light while the Excimer laser reshapes the corneal
tissue. A clicking sound can be heard as each
microscopic layer of tissue is vaporized. This
process will last from seconds to minutes, depending
on the amount of correction necessary. The corneal
flap is then placed back into its original position
and allowed to dry for a few minutes. You will
be given additional eye drops, and your eye may be
shielded for protection. Your vision will probably
be a little blurry at first so have someone drive you
home and relax for the rest of the day.
CHOOSING LASIK
The decision to have LASIK is an important one that ultimately,
only you can make. It is important that you have
realistic expectations and that your decision is based
on facts, not hopes or misconceptions. The goal
of LASIK is to reduce your dependence on corrective
lenses. LASIK does not always create 20/20 or
even 20/40 vision. It cannot correct a condition
known as presbyopia, or aging of the eye, which normally
occurs around age 40, which may require the use of
reading glasses. In fact, people over 40 who have
their distance vision improved may find they need reading
glasses after the procedure. Your doctor will
provide you with additional information that will allow
you to make an informed decision. Finding out
more about your refractive error is your first step
toward visual independence. This is accomplished
by calling your eye doctor and scheduling a personal
consultation. Should your refractive error fall
within that range of correction for LASIK, more comprehensive
tests will be necessary. For additional information,
please contact Brenda at (863) 294-5457, or send her
an email at Brenda.LASIK@eyecarefss.com.
