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LASIK
Eye Surgery Information to help the
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The eye requires that it be continuously covered by natural tears produced by the eye. Dry Eyes is a condition where some people so not produce enough tears to keep the eye comfortable and healthy. This condition where not enough tears are produced is called Dry Eyes. Tears may be produced by two different methods in the eye. In the first method, tears are produced at a slow and steady rate and provides the eye with its natural lubrication. In the second method, your eyes produce large quantities of tears in response to irritation or strong emotions. If your eyes are healthy they constantly produce enough lubricating tears. If your eyes are irritated by getting something in them such as a foreign body, crying...or if they are too dry, they will produce an excessive amount of tears.
What
Are The Symptoms of Dry Eyes?
If you have Dry Eyes you may experience a number of common symptoms
that can include stinging or burning, scratchiness, excessive mucous
in or around your eyes, reduced tolerance to smoke or wind,
difficulty wearing contact lenses and possibly excessive tearing.
Excessive tearing from Dry Eyes sounds completely illogical.
However, if the normal tears are not produced in a sufficient amount
to keep your eyes lubricated and wet enough, your eyes will become
irritated and will water excessively. This occurs because the
Lacrimal Gland begins to produce a large amount of tears to
compensate for the irritation and this overwhelms the eye's drainage
system.
What
is The Tear Film?
A normal tear film consists of three layers. The outermost layer of
the tear film is called the Oily Layer and is produced by the
Meibomian Glands. This layer produces a smooth tear film and
prevents it from evaporating too quickly. The middle layer is called
the Aqueous layer is the watery layer that washes away debris from
the eye's surface. It is produced by the Lacrimal Gland and is what
we normally think of as tears. The innermost layer is called the
Mucous Layer and is composed of mucous produced by the conjunctiva
or the clear covering of the eye tissues. The Mucous Layer allows
the normal tear film to stick to the surface of the eye. Your
eyelids act to smooth the tear film and smooth it over the eye's
surface each time you blink. This produces a smooth optical surface
and clear vision. People who have Dry Eyes and do not have a smooth
and regular tear film often have blurry vision from the lack of a
smooth tear film.
What
Causes Dry Eye?
As we age the normal production of tears begins to slow down. Even
though Dry Eyes can occur in men and women, Dry Eyes most commonly
occurs in women approaching and after menopause. Dry Eye can be
caused by some systemic diseases such as Sjogen's Syndrome in which
the Dry Eyes may be accompanied by a dry mouth and arthritis all at
once. There are many common over the counter as well as prescription
medications that can reduce the production of tears and cause Dry
Eyes. It is important that you tell your doctor all of the
medications that you are taking so he or she can be certain they are
not the cause of the Dry Eyes. In particular if you are taking
diuretics for blood pressure, beta blockers for heart conditions or
blood pressure, antihistamines for allergies or colds, sleeping
pills, any medications for nerves or pain relievers please tell your
eye care provider. Since these medications are necessary for your
health it may be necessary to use artificial tears to alleviate the
Dry Eyes symptoms. You should consult your eye care provider because
the selection of the right artificial tear is important. Many
artificial tears contain preservatives that can actually make the
Dry Eye symptoms worse for some patients. Your eye care provider may
recommend a special preservative free artificial tear for better
results.
How
is Dry Eye Diagnosed?
There are several diagnostic tests that your eye care provider may
use to help diagnose Dry Eyes. The first test is called a Schirmer
Tear Test and involves placing a small strip of filter paper under
the lower eyelid. This test measure the actual rate tear film
production. A second test is called a Break Up Time and involves
placing a small amount of fluorescent dye in your tears and
observing the patterns of dryness of the tear film on the eye's
surface. The third test is called a Lactoferrin Assay which can
measure the amount of Lactoferrin in your tears indicating whether a
Dry Eye is present.
How
is Dry Eye Treated?
There are many ways to treat Dry Eyes beside simply artificial tears
depending on your particular situation. These include easily placed
Tear Duct Plugs to help you retain a greater amount of tears that
you produce, certain dietary supplements as well as prescription
medications such as Restasis which will actually stimulate your own
natural tear film production. You should have a thorough diagnostic
evaluation with your eye care provider and they will help decide if
you have dry eyes and which treatment options will be best for you.
Why
Does LASIK Cause Dry Eyes?
LASIK may cause some patients to experience Dry Eyes after their
surgery. This is especially true if there was tendency toward dry
Eyes before the LASIK procedure. During the LASIK procedure, a thin
layer of tissue is created, called a flap, under which the actual
laser energy is applied to reshape the cornea to correct
nearsightedness, farsightedness and astigmatism. Anatomically, when
the flap is created, the very fine cornea nerves may be severed as
part of the LASIK procedure. This is a normal part of the procedure.
However, these nerves are required in order "signal" the Lacrimal
Gland to produce tears. So, sometimes, the temporary interruption of
the corneal nerve impulses can actually cause a lesser amount of tears to be produced, resulting in Dry Eyes
after LASIK. Sometimes
if the Dry Eyes after LASIK are moderate or severe, your vision may
actually be blurry due to the tear film instability. Your LASIK
surgeon may elect to treat you for Dry Eyes before your LASIK
procedure in order to fortify your tear film so that you will have a
comfortable and asymptomatic post operative period. ALL LASIK
patients will need to use artificial tears or lubricating drops as a
matter of course as it helps the tear film reestablish itself after
the LASIK procedure. During your consultation it is important to
disclose any symptoms you may have of Dry Eyes and to disclose any
medications you are taking that might predispose you to dry eyes
after your LASIK procedure. In this way, your LASIK surgeon can take
the necessary steps to prescribe whatever is necessary to obtain the
best possible results for you. Fortunately, virtually all Dry Eyes
symptoms after LASIK are temporary and gradually decrease over time
until they end within a few months of having your LASIK procedure.
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