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LASIK is by far the most popular Laser Eye Surgery for patients wishing to
correct nearsightedness, farsightedness and astigmatism. In
your decision to explore LASIK Eye Surgery as a method to correct your vision,
you may be left with the impression that LASIK is a possibility for everyone who
wants to have it. The information we have provided in www.seewithlasik.com is a
broad overview of things to learn and consider before deciding to proceed with
the LASIK consultation. The section regarding LASIK Risks and Complications is important for you
to read carefully. In addition, we would like to provide the details of certain
LASIK contraindications or reasons why you should not have LASIK.
You should know that there are really two types of
contraindications. First there are absolute contraindications. If you have an
absolute contraindication, it means that you have a clinical finding, condition
or health reason to absolutely NOT have LASIK. Then there are relative
contraindications. These are reasons, clinical findings or health conditions
that mean that you would be considered to have a high likelihood of achieving
the typically excellent safety, efficacy and predictability that the vast
majority of LASIK patients enjoy. If you have a relative contraindication, it
means that your LASIK surgeon will have to take special precautions in your
treatment plan and actual surgery and even so, the results you achieve may not
be quite as predictable.
Corneal Thickness
Successful LASIK surgery requires a sufficient amount of
corneal thickness so that after creating the flap and applying the laser, there
is a threshold amount of corneal tissue remaining that has not been altered by
the procedure. This threshold amount that needs to be left intact, is the amount
necessary for the cornea to maintain is rigidity and its shape and is fairly
agreed upon measurement by LASIK surgeons. Measurement of the corneal thickness
of the cornea is performed with an instrument called a pachymeter. If you have a
thin corneal measurement and you also have a significant degree of refractive
error-nearsightedness, farsightedness or astigmatism-to be corrected, it may not
be possible to leave the critical threshold of intact corneal tissue in place.
Sometimes as part of your treatment plan, it is possible for the LASIK surgeon
to create a thinner flap and overcome this anatomical problem that is unique to
your cornea. This would be considered a relative contraindication for LASIK. If,
it is not possible for the LASIK surgeon to create a thinner flap, then he or
she might recommend that your treatment might be better performed with PRK, LASEK or
Epi LASIK since there is no flap to create and
thus no real concern about the remaining intact corneal tissue that must be left
in place.
In some instances there is a true structural limitation of the
cornea in patients who have a condition called Keratoconus. Keratoconus is a
disease characterized by a pathological thinning of the cornea. It is also
progressive in that it continually gets thinner and bulges into a "cone" shape
causing major distortions to your vision. Keratoconus is an absolute
contraindication for having LASIK and really any type of refractive Laser Eye
Surgery.
The calculations for determining the amount of intact corneal
tissue that must be left are quite straightforward. However, the amount of
tissue that the laser will remove to correct your vision is a bit more difficult
to calculate. The amount of tissue to be removed by the laser is called the
ablation depth. Ablation depth depends not only on the prescription to be
corrected, but also on your pupil size and whether or not you need a traditional
or Custom LASIK procedure. In general, Custom LASIK is produces greater ablation
depths and thus requires patients to have greater corneal thickness before their
surgery. Custom LASIK corrects not only the
nearsightedness, farsightedness or astigmatism-the so-called low order
aberrations, but corrects even the most complex types of aberrations that plague
some patients vision. In order to fully correct this, it requires greater
ablation depth and thus greater corneal thickness.
So, large pupils and or Custom LASIK can potentially be a
relative contraindication and may require a modification of your LASIK surgery
plan in order to obtain the best results for your eyes if you do not have
sufficient corneal thickness. Fortunately, all of these situations can be
measured and planned for and compensated for during your consultation. If in
fact you simply do not have sufficient corneal thickness, then the LASIK surgeon
will recommend a different procedure or perhaps against have refractive Laser
eye surgery at all.
General Health Conditions
Patients who suffer from certain systemic diseases may have
relative or absolute contraindications to LASIK. For example, if you suffer from
Lupus Erythematosus, Rhuematoid Arthritis, or Fibromylagia it suggests that you
have a compromised auto immune system. People with compromised autoimmune
systems, sometime do not heal in a predicatable fashion. For that reason,
depending on the type and whether your autoimmune disease is well controlled,
you may have a relative or absolute contraindication to LASIK and other
refractive Laser eye surgery procedures.
Patients who suffer from diabetes also may have relative or
absolute contraindications to LASIK. LASIK requires good stability of your blood
sugar measurement over a prolonged time in order to be certain that there is
accuracy in the measurement of your prescription. Also, in certain instances
diabetes can cause diabetic retinopathy that may compromise vision due to
changes in the retina. This too may be a contraindication to LASIK.
Patients who are pregnant, anticipating becoming pregnant or
who are currently nursing presents another relative contraindication to LASIK as
well as other refractive Laser Eye Surgery procedures. During pregnancy and
nursing, the hormonal changes that are a normal part of the process, may cause
your prescription to become unstable making LASIK a relative contraindication
until several months after you have completed nursing.
Eye Health Conditions
Patients, who have even the very beginnings of the formation
of cataracts, or clouding of the crystalline lens, are considered to have an
absolute contraindication for LASIK as cataracts are generally progressive and
worsen over time necessitating their surgical removal and replacement of the
crystalline lens with and intraocular lens. Fortunately, while these patients
may not be good candidates for LASIK - they typically will be good candidates
for Crystalens or ReSTOR ReSTOR & Crystalens Lens Replacement Surgery during
which their nearsightedness or farsightedness can be corrected as the new lens
is implanted.
Patients who are being treated for glaucoma and currently using eye drops are also
considered to have contraindications to LASIK. In fact, if you have a history of
serious past eye infection from Ocular Herpes this too may preclude you from
having LASIK, but may only be a relative contraindication if the LASIK surgeon
is able to use oral and topical medications before your treatment to prevent a
recurrence of your infection. Patients, who have had a retinal detachment with
surgery to restore their vision, also pose a relative contraindication to LASIK.
For these patients, a confirmation by a Retinal Surgeon that their eye is
healthy enough and the retina will not be harmed during the LASIK procedure is
necessary.
Dry Eyes
LASIK requires that you have sufficient tear quantity
and quality to heal properly. If you have been a long-term contact lens
wearer, take certain medications, or have other health or age related conditions
that cause you to have dry eyes, you may have
a relative contraindication to LASIK. During your consultation, the surgeon and
staff will carefully examine your tears. If you have a relative contraindication
due to dry
eyes, he or she will likely recommend a number of possible approaches to
enable your tears to be adequate for LASIK surgery. These approaches can be as
simple as the use of artificial tears and
lubricating drops,
dietary supplements, insertion of punctual plugs to help
you retain tears, or even a prescription medication called Restasis, to
help you produce more of your own tears naturally. If even after you have
taken these significant therapeutic measures to overcome the relative
contraindication of dry eyes, and not been able to achieve a good tear film
quantity and quality, then you would not be considered a good candidate for
LASIK.
Stability of Prescription
To obtain the best results from LASIK it is important that all
measurements-especially that of your prescription is accurate and consistent. In
general LASIK surgeons prefer to have patients where it can be demonstrated that
they have had little or no change in their prescription for about 12 months
prior to their LASIK surgery date. Refractive stability is a relative
contraindication as for some patients who fully understand the risk of the lack
of stability; the benefit of dramatically improved vision may outweigh the risk
of less than optimum predictability. Usually in order to have good refractive
stability, LASIK surgeons will not treat patients less than 18 years of age as
their eyes may still be changing.
This discussion of LASIK contraindications is meant to provide
you with a working knowledge of the common conditions that may mean that you
either cannot have LASIK, should have another Laser Eye Surgery procedure or can
have LASIK with certain careful considerations. It is not exhaustive and may not
list everything that you might possibly experience. For a complete understanding
of LASIK Eye Surgery contraindications, it is best to fully discuss your
individual situation with a LASIK surgeon or their staff.
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