It must be understood that the complications which may result
from LASIK surgery are many. Some are a component of the risk undertaken in
having the surgery performed, some result from inadequate screening, some result
from an error by the surgeon and some from a malfunction of a device used in the
surgery. It is, frequently, difficult to identify the causation, in part because
the medical community is not always forthcoming in their assessment of
post-surgical complications and, in part, because some complication can have
multiple causation, some legally actionable and some not. The first step
in assessing any claim of malpractice is to determine the cause of the problem.
This benefits the client even if it is determined that malpractice has not
occurred as once causation has been accurately determined a treatment plan may
LOSS OF VISION
LASIK surgery can possibly cause loss of vision or loss of best corrected
vision. This can be due to infection or irregular scaring or other causes, and
unless successfully controlled by antibiotics, steroids or other necessary
treatment, could even cause loss of the infected eye. Vision loss can be due to
the cornea healing irregularly which could add astigmatism and make wearing
glasses or contract lenses necessary and useful vision could be lost. Glasses
and contact lenses cannot correct many of the post-surgery complications
experienced by post refractive patients. It is also possible that you may not be
able to successfully wear contacts after LASIK.
Corneal Haze – Corneal haze results from
the superficial cornea's healing reaction after contact with a laser. An eye
care professional can assess the haze response of a patient's cornea under a slit
lamp, but patients' experiences of haze vary. Corneal haze may not affect the
patient's vision at all, but if severe, can cause loss of best corrected visual
acuity. Corneal haze should not be confused with "hazy vision" that
some patients may experience at night or in dim light
Decreased Night or Low-Light Vision -
Characterized by symptoms such as glare, halos and starbursts that are seen
around objects at night or in dim-light conditions. Although these symptoms do
not necessarily interfere with visual acuity as it is measured by an eye chart,
for some patients, the experience can significantly interfere with daily
activities and driving at night.
Loss of Contrast Sensitivity - Refractive surgery techniques are
designed to change the eye's focus and reduce or eliminate the need for glasses
or contact lenses. However, there are other factors in the eye, which may affect
vision quality, that are unrelated to eye focus. These factors can cause the
quality of vision to vary greatly, even when a patient has 20/20 or better
acuity. Contrast sensitivity measurement is the best method of quantifying the
actual quality of a patients vision.
Immediately after LASIK refractive surgery, contrast sensitivity may be such
that the patient's quality of vision is well below the normal range. After
several weeks, or in some cases several months, the quality of vision and
contrast sensitivity may recover to normal levels. For PRK refractive surgery,
the amount of time required to recover to normal levels may be longer, up to six
Severe Dry Eye - All patients should be
aware that dry eye is a potential complication of LASIK. Additionally, patients
who seek LASIK who have suffered from dry eye before, are bothered by contact
lenses, are going through menopause or taking birth control pills should be
certain to explore the increased potential for post surgical dry eyes with their
doctor. Use of post-operative steroids after LASIK may exacerbate
pre-existing dry eye. Previous contact lens wear may disrupt normal corneal
physiology and cause ocular dryness. Hormonal changes during menopause or birth
control pills can cause dry eye.
Intraocular Pressure elevation - An increase
in the intraocular pressure due to post-treatment medications. Usually resolved
by drug therapy or discontinuation of post-treatment medications.
- Initially the eye is over-corrected since the cornea has a tendency to regress
to its original state of refractive error. The regression may stabilize after
1-3 months. If you are permanently over-corrected, you may need glasses for
reading and any close up work.
- In some, but not all cases, re-treatment may be considered. It must be
understood that re-treatment is not always possible, is not always advisable as
it can result in an even worse outcome and may not correct the problems being
Loss Of Best Corrected
Vision - In this
situation the patient is unable to see as well with glasses or conventional
contact lenses after the surgery as he or she could see with glasses before the
surgery. Sometimes specially designed contact lenses can be fit to help remedy
- Two images appear when looking through one eye at a time. May also occur when
both eyes do not align properly.
- Headlight glare when driving at night. Glare is caused by light
scatter which can occur with any loss of corneal transparency.
Night (darkness) Myopia
- This is a tendency for eyes to become more nearsighted in darkness,
leading to blurry vision.
Halos and starbursts
- This occurs when the pupil enlarges beyond the treated area at night or from
surgically induced corneal distortion. Direct light sources (street lights, car
headlights, etc.) become distorted in a variety of ways.
- This is when images appear blurrier after the refractive surgery than before.
Peri-operative Complications (occurring
- May also be required which could induce astigmatism.
Reaction to Anesthesia or
Medication - There are
potential complications due to anesthesia and medications which may involve
other parts of your body.
Microkeratome or Laser/computer malfunction - It is also possible that
the microkeratome or the laser could malfunction making irregular cuts, damaging
the stromal bed or forcing the procedure to be stopped before completion. The laser is
controlled by a computer. Its malfunction during the operation will certainly
impact upon your result.
- While refractive surgery has become a highly automated procedure, it takes
place at the hand of and under the supervision of a surgeon. His training and
experience are factors which can impact significantly upon your outcome.
Surgeons do make mistakes.
- The flap begins to disintegrate and may require surgical intervention.
Flap Dislocation - This is a condition in which the corneal flap
becomes dislodged and no longer properly aligns with the corneal bed. This is treated with surgical
Flap Wrinkles - A major or minor flap dislocation produces flap
wrinkles. This is treated with surgical intervention.
Flap Striae - Fine folds noted in the flap are termed flap striae. There
are various types of striae and treatment depends upon the type and the
patient's symptoms. The treatment and cause of striae is currently somewhat
controversial. If vision is threatened, then surgical intervention is indicated.
Central Island - This is a condition in which an island of corneal
tissue remains in the visual axis following Excimer laser treatment. This is
less common with the new generation of lasers that have been modified with
programs to prevent this complication. This can cause undercorrection and visual
blurring or distortion. Most central islands disappear spontaneously
post-operatively without additional treatment.
Free Flap - Occurs when the microkeratome creates a flap without a
hinge because the microkeratome blade fails to stop and cuts through the hinge. This is more likely to
occur with the ACS type microkeratome and is quite uncommon. The flap will need
to be replaced carefully, and reoriented to its original position after the
laser treatment is completed.
Lost Flap - Could create serious healing and vision problems. Physical
loss of the flap following an incident of a free or dislocated flap.
Incomplete Flap - Creation of an incomplete flap is usually due to a microkeratome malfunction. The procedure will usually need to be aborted and
rescheduled at a later date.
Buttonhole Flap - Improperly produced flap where the top of the flap
is removed causing a buttonhole like defect. Can cause subsequent healing and/or
Corneal Abrasion - A disturbance in the top layer of the cornea
(epithelium) caused by the normal action of the microkeratome moving across the
cornea. Some corneas are more susceptible to corneal abrasion.
Decentered Ablation - This complication is uncommon in the newer
generation lasers. Corneal healing difficulties can produce a pseudo-decentered
ablation especially with PRK. Usually caused by either poor patient fixation on
the laser fixation light, poor patient head positioning, or poor centering of
the laser beam by the surgeon.
Infection - This is probably the greatest risk in the first 24-72
hours after surgery. Antibiotic eye drops may be given to try to prevent this
Post-treatment Discomfort - You may have some discomfort during the
procedure, if any.. Patients having LASIK can expect some watering of the eyes
the day of surgery, and some irritation for a day or two following the
procedure. These symptoms are frequently controlled using eyedrops or oral pain
of the Sahara - Diffuse
lamellar keratitis (DLK) is a concentration of white blood cells on
the surfaces of the corneal flap made before ablation by the laser.
The cells accumulate in a tiny pattern, resembling sand dunes, that
the microkeratome creates during the operation. It is essential that
there be fast, aggressive treatment for Sands of Sahara. This
condition may result from microscopic substances on the
microkeratome blade, such as oil from the blade motor or tiny
particles remaining from the blade manufacturing process (or
resulting from improper sterilization), may be inflaming the corneal
tissue. Another cause may be tiny bacterial toxins not always
removed when blades are sterilized. It is also possible that debris
in the tear film is to blame.
OTHER VISION PROBLEMS
Other complications and conditions that can occur with LASIK surgery include:
anisometropia (difference in power between the two eyes); aniseikonia
(difference in image size between the two eyes); double vision; hazy vision,
fluctuating vision during the day and from day to day; increased sensitivity to
light which may be incapacitating for some time and may not completely go away.
Some of these conditions may affect your ability to drive and judge distances
and driving should only be done when you are certain your vision is adequate.
Additional reported complications include: corneal ulcer formation;
endothelial cell loss, epithelial healing defects; ptosis (droopy eye lid);
corneal swelling, retinal detachments and hemorrhage. Complications could also
arise requiring further corrective procedures including either a partial
(lamellar) or full thickness corneal transplant using a donor cornea. Other
complications include: loss of corneal disc, damage to the corneal disc, disc
decentration and progressive corneal thinning (extasia).
Additional Risks if you are Considering the Following:
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. 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
surgery performed on your eyes. Find out if you pass your state's
driver's license requirements with monovision.
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 vision.
Bilateral Simultaneous Treatment
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, this practice is riskier than having two separate
surgeries. The second eye may have a higher risk of developing an
inflammation if surgery is done on the same day than if surgery is
performed on separate days. 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.
If you decide to have one eye done at a time,
you and your doctor will decide how long to wait before having surgery
on the other eye. If both eyes are treated at the same time or before
one eye has a chance to fully heal, you and your doctor do not have
the advantage of being able to see how the first eye responds to
surgery before the second eye is treated.
Another disadvantage to having surgery on
both eyes at the same time is that the vision in both eyes may be
blurred after surgery until the initial healing process is over,
rather than being able to rely on clear vision in at least one eye at
Regression - This is a situation where an improvement in vision was
initially achieved and the cornea begins to return to its original shape. This
may be corrected by an adjustment in the medication or, in a few circumstances,
by an "enhancement" procedure. There is no guarantee that any negative
result can be reversed by any re-treatment.
Diplopia - Distortion of vision not corrected by contact lenses or
complications listed here represent most of the presently known problems resulting from refractive (eye) laser surgery. Your surgeon should
you of these and any other known issues before your surgery. If you are
thinking about surgery be certain your surgeon discusses all of these and any
other known complications before your surgery and discusses those which may be
unique to your circumstances in great detail. Several of these are avoidable by
comprehensive pre-operative screening and proper device selection.