following information is adapted from the United States Food and Drug
Administration's Consumer Guide to LASIK.
It is provided as a patient educational service by Robert M.
Kershner, MD, FACS and the Eye Laser Center, Tucson, Arizona.
What is LASIK?
eye and vision errors
types of refractive surgery
type of refractive surgery is thermokeratoplasty in which heat is used to
reshape the cornea. The source of the heat can be a laser, but it is a
different kind of laser than is used for LASIK and PRK. Other refractive
devices include corneal ring segments that are inserted into the stroma
and special contact lenses that temporarily reshape the cornea (orthokeratology).
the FDA regulates
first refractive laser systems approved by FDA were excimer lasers for use
in PRK to treat myopia and later to treat astigmatism. However, doctors
began using these lasers for LASIK (not just PRK), and to treat other
refractive errors (not just myopia). Over the last several years, LASIK
has become the main surgery doctors use to treat myopia in the United
States. More recently, some laser manufacturers have gained FDA approval
for laser systems for LASIK to treat myopia, hyperopia and astigmatism and
for PRK to treat hyperopia and astigmatism.
When is LASIK not for me?
are probably NOT a good candidate for refractive surgery if:
are not a risk taker. Certain
complications are unavoidable in a percentage of patients. There may be no
long-term data (over 10 years) available for current procedures.
·It will jeopardize your career. Some jobs prohibit certain refractive procedures. Be sure to check with your employer/professional society/military service before undergoing any procedure.
is an issue. Most medical
insurance will not pay for refractive surgery. Although the cost is coming
down, it is still significant.
required a change in your contact lens or glasses prescription in the past
year. This is called
refractive instability. Patients who are:
their early 20s or younger,
hormones are fluctuating due to disease such as diabetes,
are pregnant or breastfeeding, or
are taking medications such as steroids that cause fluctuations in vision,
more likely to have refractive instability and probably should not have a
have a disease or are on medications that may affect wound healing.
Certain conditions, such as autoimmune diseases (e.g., lupus, rheumatoid
arthritis), immunodeficiency states (e.g., HIV) and diabetes, and some
medications (e.g., retinoic acid and steroids) may prevent proper healing
after a refractive procedure.
actively participate in contact sports. You participate in boxing, wrestling, martial arts or other activities
in which blows to the face and eyes are a normal occurrence.
are not an adult. Currently,
no lasers are approved for LASIK on persons under the age of 18.
simplex or Herpes zoster (shingles) involving the eye area.
glaucoma suspect, or ocular hypertension.
diseases, such as uveitis/iritis (inflammations of the eye) and
blepharitis (inflammation of the eyelids with crusting of the eyelashes).
· Eye injuries or previous
Make sure this evaluation is done in a dark room. In Doctor Kershner's
office this is done with a computerized device known as a topograph.
Younger patients and patients on certain medications may be prone to
having large pupils under dim lighting conditions. This can cause symptoms
such as glare, halos, starbursts, and ghost images (double vision) after
surgery. In some patients these symptoms may be debilitating. For example,
a patient may no longer be able to drive a car at night or in certain
weather conditions, such as fog.
The cornea is the thin clear covering of the eye that is over the iris,
the colored part of the eye. Most refractive procedures change the eyes
focusing power by reshaping the cornea (for example, by removing tissue).
Performing a refractive procedure on a cornea that is too thin or has too
few cells lining the back surface (endothelial cells) may result in
blinding complications. The corneal thickness will be tested prior to your
procedure with a device called an ultrasonic pachymeter at the Eye Laser
surgery (e.g., RK, PRK, LASIK). Additional
refractive surgery may not be recommended. The decision to have
additional refractive surgery must be made in consultation with your
doctor after careful consideration of your unique situation.
· Dry Eyes. LASIK surgery tends to aggravate this condition. Many people may need to use artificial tear drops following their LASIK procedure.
What should I expect before, during, and after surgery?
What to expect before, during, and after surgery will vary
from patient to patient. This section is a compilation of patient
information developed by manufacturers and healthcare professionals, but
cannot replace the dialogue you should have with your doctor. Read
this information carefully and with the checklist, discuss your
expectations with your doctor.
If you wear contact lenses,
it is a good idea to stop wearing them before your baseline evaluation
and switch to wearing your glasses full-time. Contact lenses change the
shape of your cornea for up to several weeks after you have stopped using
them depending on the type of contact lenses you wear. Not leaving your
contact lenses out long enough for your cornea to assume its natural shape
before surgery can have negative consequences. These consequences include
inaccurate measurements and a poor surgical plan, resulting in poor vision
after surgery. These measurements, which determine how much corneal tissue
to remove, may need to be repeated at least a week after your initial
evaluation and before surgery to make sure they have not changed,
especially if you wear RGP or hard lenses. If you wear:
soft contact lenses,
you should stop wearing them for 2 weeks before your initial evaluation.
toric soft lenses or
rigid gas permeable (RGP) lenses,
you should stop wearing them for at least 3 weeks before your initial
you should stop wearing them for at least 4 weeks before your initial
You should tell your doctor:
about your past and
present medical and eye conditions
about all the medications
you are taking, including over-the-counter medications and any medications
you may be allergic to
Your doctor will perform a thorough eye exam and
whether you are a good
what the risks, benefits,
and alternatives of the surgery are
what you should expect
before, during, and after surgery
what your responsibilities
will be before, during, and after surgery
You should have the opportunity to ask Doctor Kershner
questions during this discussion. Give yourself plenty of time to
think about the risk/benefit discussion, to review any informational
literature provided by your doctor, and to have any additional questions
answered before deciding to go through with surgery and before signing
the informed consent form.
You should not feel pressured by your doctor, family,
friends, or anyone else to make a decision about having surgery. Carefully
consider the pros and cons.
The day before surgery, you should stop using:
These products as well as debris along the eyelashes may
increase the risk of infection during and after surgery. Your doctor may
ask you to scrub your eyelashes for a period of time before surgery to get
rid of residues and debris along the lashes.
Also before surgery, arrange for transportation to
and from your surgery and your first follow-up visit. On the day of
surgery, your doctor may give you some medicine to make you relax. Because
this medicine impairs your ability to drive and because your vision may be
blurry, even if you don't drive make sure someone can bring you home after
A numbing drop will be placed in your eye, the area around
your eye will be cleaned, and an instrument called a lid speculum will be
used to hold your eyelids open. A ring will be placed on your eye and very
high pressures will be applied to create suction to the cornea. Your
vision will dim while the suction ring is on and you may feel the pressure
and experience some discomfort during this part of the procedure. The
microkeratome, a cutting instrument, is attached to the suction ring. Your
doctor will use the blade of the microkeratome to cut a flap in your
The microkeratome and the suction ring are then removed.
You will be able to see, but you will experience fluctuating degrees of
blurred vision during the rest of the procedure. The doctor will then lift
the flap and fold it back on its hinge, and dry the exposed tissue.
The laser will be positioned over your eye and you will be
asked to stare at a light. This is not the laser used to remove
tissue from the cornea. This light is to help you keep your eye fixed on
one spot once the laser comes on. NOTE: If you cannot stare at a fixed object for at least 60 seconds, you
may not be a good candidate for this surgery.
When your eye is in the correct position, your doctor will
start the laser. At this point in the surgery, you may become aware of new
sounds and smells. The pulse of the laser makes a ticking sound. As the
laser removes corneal tissue, some people have reported a smell similar to
burning hair. A computer controls the amount of laser delivered to your
eye. Before the start of surgery, your doctor will have programmed the
computer to vaporize a particular amount of tissue based on the
measurements taken at your initial evaluation. After the pulses of laser
energy vaporize the corneal tissue, the flap is put back into position.
A shield should be placed over your eye at the end of the procedure as protection, since no stitches are used to hold the flap in place. It is important for you to wear this shield to prevent you from rubbing your eye and putting pressure on your eye while you sleep, and to protect your eye from accidentally being hit or poked until the flap has healed.
You should see your doctor within the first 24 to 48
hours after surgery and at regular intervals after that for at least
the first six months. At the first postoperative visit, your doctor will
remove the eye shield, test your vision, and examine your eye. Your doctor
may give you one or more types of eye drops to take at home to help
prevent infection and/or inflammation. You may also be advised to use
artificial tears to help lubricate the eye. Do not resume wearing a
contact lens in the operated eye, even if your vision is blurry.
You should wait one to three days following surgery
before beginning any non-contact sports, depending on the amount of
activity required, how you feel, and your doctor's instructions.
To help prevent infection, you may need to wait for up to two
weeks after surgery or until your doctor advises you otherwise before
using lotions, creams, or make-up around the eye. You should also avoid
swimming and using hot tubs or whirlpools for2-3 weeks.
Strenuous contact sports such as boxing, football, karate,
etc. should not be attempted for at least four weeks after surgery.
It is important to protect your eyes from anything that might get in them
and from being hit or bumped.
During the first few months after surgery, your
vision may fluctuate.
It may take up to three to
six months for your vision to stabilize after surgery.
Glare, haloes, difficulty
driving at night, and other visual symptoms may also persist during this
stabilization period. If further correction or enhancement is necessary,
you should wait until your eye measurements are consistent for two
consecutive visits at least 3 months apart before re-operation.
· It is important to realize that although distance vision may improve after re-operation, it is unlikely that other visual symptoms such as glare or haloes will improve.
your eye doctor immediately, if you develop any new, unusual or worsening symptoms at any point
after surgery. Such symptoms could signal a problem that, if not treated
early enough, may lead to a loss of vision.
What are the risks and how can I find the right doctor for me?
Most patients are very pleased with the results of their
refractive surgery. However, like any other medical procedure, there are
risks involved. That's why it is important for you to understand the
limitations and possible complications of refractive surgery.
Before undergoing a refractive procedure, you should
carefully weigh the risks and benefits based on your own personal value
system, and try to avoid being influenced by friends that have had the
procedure or others encouraging you to do so.
You may be undertreated
or overtreated. Only a
certain percent of patients achieve 20/20 vision without glasses or
contacts. You may require additional treatment, but additional treatment
may not be possible. You may still need glasses or contact lenses after
surgery. This may be true even if you only required a very weak
prescription before surgery. If you used reading glasses before surgery,
you will still need reading glasses after surgery.
Results are generally
not as good in patients with very small amounts of astigmatism or very
large refractive errors of any type.
You should discuss your expectations with your doctor and realize that you
may still require glasses or contacts after the surgery.
Results may not be
lasting. Although the
majority of people achieve their desired correction, in certain
individuals, the level of improved vision experienced after surgery may be
temporary, especially if you are farsighted or currently need reading
glasses. It is especially important for farsighted individuals to have a
cycloplegic refraction (a vision exam with lenses after dilating drops) as
part of the screening process. Patients whose manifest refraction (a
vision exam with lenses before dilating drops) is very different from
their cycloplegic refraction are more likely to have temporary results.
Some patients lose
vision. Some patients lose
lines of vision on the vision chart that cannot be corrected with glasses,
contact lenses, or surgery as a result of treatment. There is little known
about how refractive procedures affect other aspects of vision, such as
contrast sensitivity (the ability to see objects clearly against a similar
background or in dim lighting conditions). Some studies suggest that
patients do not see as well in situations of low contrast, such as at
night or in fog, after treatment as compared to before treatment.
Therefore, patients with low contrast sensitivity to begin with probably
should not have a refractive procedure.
Some patients may
develop severe dry eye syndrome. As a result of surgery, your eye may not be able to produce enough
tears to keep the eye moist and comfortable. This condition may be
permanent. Intensive drop therapy and the use of plugs or other
procedures may be required.
Additional Risks if you are Considering the
Monovision is one clinical technique used to deal with the
correction of presbyopia, the gradual loss of the ability of the eye to
change focus for close-up tasks that progresses with age. The intent of
monovision is for the presbyopic patient to use one eye for distance
viewing and one eye for near viewing. This practice was first applied to
fit contact lens wearers and more recently to LASIK and other refractive
surgeries. With contact lenses, a presbyopic patient has one eye fit with
a contact lens to correct distance vision, and the other eye fit with a
contact lens to correct near vision. In the same way, with LASIK, a
presbyopic patient has one eye operated on to correct the distance vision,
and the other operated on to correct the near vision. In other words, the
goal of the surgery is for one eye to have vision worse than 20/20,
the commonly referred to goal for LASIK surgical correction of distance
vision. Since one eye is corrected for distance viewing and the other eye
is corrected for near viewing, the two eyes no longer work together. This
results in poorer quality vision and a decrease in depth perception. These
effects of monovision are most noticeable in low lighting conditions and
when performing tasks requiring very sharp vision. Therefore, you may need
to wear glasses or contact lenses to fully correct both eyes for distance
or near when performing visually demanding tasks, such as driving at
night, operating dangerous equipment, or performing occupational tasks
requiring very sharp close vision (e.g., reading small print for long
periods of time).
Many patients cannot get used to having one eye blurred at
all times. The difference between monovision with contact lenses and
monovision with LASIK is that you can always take contact lenses out or
have them changed (the treatment is reversible and adjustable) as opposed
to LASIK, where the result of the surgery is not reversible or
adjustable. Therefore, if you are considering monovision with LASIK, make
sure you go through a trial period with contact lenses to see if you can
tolerate monovision, before having the irreversible surgery performed on
your eyes. Just before this trial period starts, find out if you pass your
state's driver's license requirements with monovision, or if you need
supplemental glasses to drive.
In addition, you should consider how much your presbyopia
is expected to increase in the future. Ask your doctor when you should
expect the results of your monovision surgery to no longer be enough for
you to see near-by objects clearly without the aid of glasses or contacts,
or when a second surgery might be required to further correct your near
You may choose to have LASIK surgery on both eyes at the
same time or to have surgery on one eye at a time. Although the
convenience of having surgery on both eyes on the same day is attractive,
if a malfunction of the laser or microkeratome occurs causing a
complication with the first eye, the second eye is more likely to also
experience the same complication if the surgery is performed on the same
day rather than on separate days.
Finding the Right Doctor
The levels of risk and benefit vary slightly not only from procedure to
procedure, but from device to device depending on the manufacturer, and
from surgeon to surgeon depending on their level of experience with a
particular procedure. Select a surgeon with experience in these
Don't base your
decision simply on cost and
don't settle for the first eye center, doctor, or procedure you
investigate. Remember that the decisions you make about your eyes and
refractive surgery will affect you for the rest of your life.
Be wary of eye centers
that advertise, "20/20 vision or your money back" or
"package deals." There are never any guarantees in
It is important for you to read the patient informed consent provided to
you by your doctor who will perform the refractive procedure. Doctor
Kershner will discuss his outcomes (successes as well as complications)
with you and your reasonable expectations for success.
Even the best screened patients under the care of most
skilled surgeons can experience serious complications.
Malfunction of a device or other error, such as cutting a flap of cornea
through and through instead of making a hinge during LASIK surgery, may
lead to discontinuation of the procedure or irreversible damage to the
Some complications, such as migration of the flap, inflammation or
infection, may require another procedure and/or intensive treatment with
drops. Even with aggressive therapy, such complications may lead to
temporary loss of vision or even irreversible blindness.
Under the care of an experienced doctor,
such as Dr. Robert M. Kershner, carefully screened candidates with
reasonable expectations and a clear understanding of the risks and
alternatives are likely to be happy with the results of their refractive
procedure, according to the FDA.
If you are interested in understanding the terminology that may be confusing to the uninformed, briefly review the following list:
in surgery, is to remove.
Ablation zone the area of tissue that is removed during laser surgery.
Accommodation the ability of the eye to change its focus from distant objects
to near objects.
or sharpness of vision.
Astigmatism a distortion of the image on the retina caused by
irregularities in the cornea or lens.
clear, front part of the eye. The cornea is the first part of the eye that
bends (or refracts) the light and provides most of the focusing power.
measurement of refractive error. A negative diopter value signifies
an eye with myopia and positive diopter value signifies an eye with
Dry Eye Syndrome a common condition that occurs when the eyes do not produce
enough tears to keep the eye moist and comfortable. Common symptoms of dry
eye include pain, stinging, burning, scratchiness, and intermittent
blurring of vision.
Endothelium the inner layer of cells on the inside surface of the cornea.
outermost layer of cells of the cornea and the eye's first defense against
Excimer laser an ultraviolet laser used in refractive surgery to remove
Farsightedness the common term for hyperopia.
abbreviation for the Food and Drug Administration. It is the United States
governmental agency responsible for the evaluation and approval of medical
Flap & Zap a slang term for LASIK.
Ghost Image a fainter second image of the object you are viewing.
from bright light that decreases vision.
are rings around lights due to optical imperfections in or in front of the
clouding that causes the sensation of looking through smoke or fog.
inability to see near objects as clearly as distant objects, and the need
for accommodation to see distant objects clearly.
Inflammation the body's reaction to trauma, infection, or a foreign
substance, often associated with pain, heat, redness, swelling, and/or
loss of function.
Informed Consent Form a document disclosing the risks, benefits, and
alternatives to a procedure.
a Latin term meaning "in place" or not removed.
colored ring of tissue suspended behind the cornea and immediately in
front of the lens.
Keratectomy the surgical removal of corneal tissue.
surgical incision (cut) of the cornea.
inflammation of the cornea.
prefix indicating relationship to the cornea.
Keratoconus a disorder characterized by an irregular corneal surface
(cone-shaped) resulting in blurred and distorted images.
Keratomileusis carving of the cornea to reshape it.
acronym for light amplification by stimulated emission of radiation.
A laser is an instrument that produces a powerful beam of light that can vaporize tissue.
the acronym for laser assisted in situ keratomileusis which refers
to creating a flap in the cornea with a microkeratome and using a laser to
reshape the underlying cornea.
part of the eye that provides some focusing power. The lens is able
to change shape allowing the eye to focus at different distances.
Microkeratome a surgical device that is affixed to the eye by use of a vacuum
ring. When secured, a very sharp blade cuts a layer of the cornea at a
purposeful adjustment of one eye for near vision and the other eye
the inability to see distant objects as clearly as near objects.
Nearsightedness the common term for myopia.
Ophthalmologist a medical doctor specializing in the diagnosis and medical or
surgical treatment of visual disorders and eye disease.
expert in the art and science of making and fitting glasses and may also
dispense contact lenses.
Optometrist a primary eye care provider who diagnoses, manages, and treats
disorders of the visual system and eye diseases.
Overcorrection a complication of refractive surgery where the achieved amount of
correction is more than desired.
acronym for photorefractive keratectomy which is a procedure involving the
removal of the surface layer of the cornea (epithelium) by gentle scraping
and use of a computer-controlled excimer laser to reshape the stroma.
inability to maintain a clear image (focus) as objects are moved closer.
Presbyopia is due to reduced elasticity of the lens with increasing age.
hole in the center of the iris that changes size in response to changes in
lighting. It gets larger in dim lighting conditions and gets smaller
in brighter lighting conditions.
Radial Keratotomy commonly referred to as RK; a surgical procedure
designed to correct myopia (nearsightedness) by flattening the cornea
using radial cuts.
test to determine the refractive power of the eye; also, the bending of
light as it passes from one medium into another.
Refractive Errors hyperopia, myopia, and astigmatism.
Refractive Power the ability of an object, such as the eye, to bend light
as light passes through it.
layer of fine sensory tissue that lines the inside wall of the eye. The
retina acts like the film in a camera to capture images, transforms the
images into electrical signals, and sends the signals to the brain.
tough, white, outer layer (coat) of the eyeball that, along with the
cornea, protects the eyeball.
Snellen Visual Acuity Chart one of many charts used to measure vision.
middle, thickest layer of tissue in the cornea.
Undercorrection a complication of refractive surgery where the achieved amount
of correction is less than desired.
Visual Acuity the clearness of vision; the ability to distinguish details and
Vitreous Humor the transparent, colorless mass of gel that lies behind the
lens and in front of the retina and fills the center of the eyeball.
Know what makes you a poor candidate
impact - does your job
prohibit refractive surgery?
Know all the risks and procedure limitations
or undertreatment - are you
willing and able to have more than one surgery to get the desired result?
Know how to find the right doctor
- how many eyes has your doctor performed LASIK surgery on with the same
Know preoperative, operative, and postoperative expectations
contact lenses prior to evaluation and surgery
- can you go for an extended period of time without wearing contact
Commitment to Excellence
We are committed to providing you with the latest in state of the laser vision treatment. Schedule a complimentary consultation now with Dr. Robert M. Kershner at the Eye Laser Center.
To begin learning more, call us now at (520) 797-2020, or contact us through this website to see how you can find out more about the latest in advanced LASIK technology with Dr. Robert Kershner and the Eye Laser Center.
Eye Laser Center
M. Kershner, MD, FACS
1925 W. Orange Grove Road
Suite 303, Tucson, AZ 85707
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*Individual results may vary. Persons over the age of forty are more likely to require glasses for reading. Sunglasses may be necessary when out of doors. As with all surgical procedures, there is no assurance or guarantee as to the outcome of the procedure.
This website is intended for educational purposes only. It is not a substitute for medical advice from a physician. To schedule an appointment with one of our medical doctors, contact us on line, by phone (520) 797-2020 or fax (520) 797-2235. Use of this site constitutes an agreement with the user that releases the Eye Laser Center and Robert M. Kershner, MD, PC from any and all liability.
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