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Am I a Good Candidate for Custom
Wavefront Lasik, PRK or Laser Vision Correction Surgery in Denver
or Boulder Colorado?
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1. SHOULD I CHOOSE LASIK
OR PRK?
Both LASIK and PRK give excellent
results. Both use an Excimer Laser to reshape your cornea. With
PRK the correction is placed on the surface of the cornea; in LASIK
a thin flap of corneal tissue is lifted and the correction placed
on the underlying corneal bed and the overlying corneal flap then
repositioned. 95% of my patients choose to have LASIK, but if the
thought of the flap in LASIK makes you extremely uncomfortable,
I would strongly encourage you to consider PRK! PRK is slightly
safer and minimally more predictable than LASIK because no flap
is being made. The risk associated with the flap is small, but in
1-2% of LASIK patients, flap complications occur and are usually
treatable without resultant vision loss. PRK is more uncomfortable
than LASIK for 48-72 hours post-op; the vision takes longer to clear
up after PRK than LASIK. Both LASIK and PRK give the same results
long term; however, PRK has a lower retreatment rate (1-2% vs 5-10%
for LASIK) and may have somewhat less glare and dryness than LASIK.
Once again, both LASIK and PRK give excellent long term results;
PRK is slightly safer than LASIK but is more uncomfortable and takes
longer to heal.
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2. CAN LASER VISION CORRECTION
HELP ALL VISION PROBLEMS?
There are 4 types of refractive problems:
1. Myopia (nearsightedness) occurs when the cornea
is too steep relative to the length of the eyeball. As light enters
the eye, the visual image focuses in front of the retina, resulting
in a blurred or distorted view. Without correction, nearsighted
people have blurry distance vision but can see well at near. The
FDA approved the use of the Excimer Laser for Myopia in November,
1995. Laser Vision Correction works extremely well for nearsightedness.
2. Astigmatism (asymmetrical cornea) occurs when
your eye is shaped like a football, unlike a normal eye, that has
a round shape similar to a basketball. Uncorrected Astigmatism causes
blurred vision both at near and far. In April 1997, the FDA approved
Excimer Laser correction of Astigmatism. The Excimer Laser works
extremely well for treating Astigmatism. Hyperopia (farsightedness)
occurs when the cornea is too flat relative to the length of the
eyeball.
3. Hyperopia (Farsightedness) requires people to
exert focusing power to see at near and far. The normal eye only
has to exert focusing power to see at near. When farsighted people
are young and have ample focusing power, they usually see well both
at near and far. However, with aging, people lose focusing power;
farsighted people will begin to notice difficulty seeing at near
and as they continue to age, will also note difficulty focusing
at distance, as well. In November, 1998 the FDA approved the Excimer
Laser for the correction of Hyperopia. The Excimer Laser works well
for correcting Farsightedness.
4. Presbyopia is an age-related condition which causes
people from the mid-forties and older to need reading glasses or
bifocal lenses to read. Presbyopia is a result of loss of elasticity
in the lens of the eye. Presbyopia cannot currently be corrected
with the Excimer Laser. The Excimer Laser can, however, help create
a condition called Monovision, where one
eye is corrected for near vision and the other is corrected for
distance vision. This option actually works very well and allows
most patients over the age of 45 to function without glasses correction
for both reading and distance vision.
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3. WHAT ARE THE ODDS OF
ELIMINATING MY NEED FOR GLASSES OR CONTACTS AFTER EXCIMER LASER
TREATMENT?
In the thousands of cases of
Laser Vision Correction I have performed, 80% of patients have 20/25
or better vision without correction, and 97% of patients will see
well enough to pass a driver's test (20/40) without correction.
Less than 3% of my patients are wearing correction for distance
after Laser Vision Correction.
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4. DIDN'T A CLIMBER
WHO HAD PREVIOUS REFRACTIVE EYE SURGERY HAVE A PROBLEM WITH HIS
EYES WHILE CLIMBING MT. EVEREST?
Yes. However, the climber had
Radial Keratotomy (RK) performed many years before he climbed Mt.
Everest. He did not have LASIK or PRK. In RK, deep incisions are
made in the cornea which flatten the cornea by structurally weakening
the cornea. At very high altitudes, such as Mt. Everest, the decreased
atmospheric pressure caused the cornea to pathologically flatten
further. This caused the patient to experience the onset of farsightedness,
making it very difficult for him to see. This would not occur with
LASIK or PRK because the cornea is not structurally weakened by
these procedures.
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5. WHAT DOES
20/20 OR 20/40 VISION MEAN?
The 20/20 nomenclature is an old
system devised by Snellen, a Dutch Ophthalmologist, in the 1840's.
20/20 means the viewer can see at 20 feet what a "normal" person
would see at 20 feet. 20/40 means the viewer sees at 20 feet what
the "normal" person can see at 40 feet, i.e. the viewer can't see
quite as well as "normal". This system is somewhat misleading. 20/40
vision is not twice as bad as 20/20 vision. In fact, most people
with 20/40 or better vision can, and usually do, function without
wearing correction. 20/40 vision or better is required to pass a
drivers test in Colorado. After LASIK, 97% of patients have 20/40
or better vision and over 80% have 20/25 or better vision. In the
"real world" the difference between 20/20 and 20/25 vision is negligible.
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6. WHOM SHOULD I CONTACT
WITH MORE QUESTIONS?
Please feel free to contact my
office to have any questions answered, or to schedule a free, Laser
Vision consultation. The phone number is 303.393.0347 and the toll
free phone number is 877.393.0347.
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7. WHO IS A CANDIDATE
FOR LASER VISION CORRECTION?
Laser Vision Correction is well
suited for active people who find glasses and contacts to be a nuisance
and those who simply don't want to be so dependent on them. If you
wear glasses or contacts and are over 18 years old, you are probably
a good candidate. Your lens prescription should be relatively stable
for at least one year and you should be free of medical problems
related to your eyes, primarily cataracts. You should also make
sure you have realistic expectations about Laser Vision Correction.
Although Laser Vision Correction has the potential to greatly reduce
or eliminate dependence on corrective lenses, there can be no assurance
that you will obtain perfectly corrected vision. If necessary, visual
sharpness after Laser Vision Correction can be enhanced with lenses,
however, for most people, the use of glasses should be merely occasional.
People who are most satisfied with the results of Laser Vision Correction
clearly understand the potential risks and side effects and have
realistic expectations of what their vision will be like after surgery.
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8. WHAT IS
THE DIFFERENCE BETWEEN THE DIFFERENT EXCIMER LASERS? WHICH EXCIMER
LASER DO YOU USE?
All Excimer Lasers are identical in one respect
only; they all use an argon/fluoride gas laser source which delivers
energy to the cornea at 193 mm wavelength. However, each Excimer
uses a different "delivery system", i.e. spot size and
firing frequency to apply the Laser energy to the corneal tissue.
For nearsightedness, Laser delivery systems can be divided into
two groups based upon the "spot size" of the laser beam;
the large spot-size lasers, called "broad beam" lasers
(VISX and Summit Lasers) and small spot-size lasers, called "flying
spot" lasers (Nidek, Technolas and Autonomous-LADAR Lasers).
The VISX Star S4 actually uses a combination of "broad beam"
and "flying spot" delivery. The broad beam lasers deliver
a large, homogeneous, uniform energy pulse to the cornea. This results
in very smooth tissue removal. The flying spot lasers apply energy
in very small "dots" and create a tissue removal pattern
similar to pixels in a digital image. The flying spot tissue removal
is "grainier" than the "broad beam" laser pattern
but has the advantage of being able to apply energy to very small
areas with pinpoint accuracy. This is useful in Custom Wavefront
treatments. The VISX Star S4 is the only Excimer Laser available
that uses both a "broad beam" and "flying spot"
capability. The VISX Excimer Laser has had three significant
upgrades in the last 18 months and is, in my opinion, the "state-of-the-art"
Excimer Laser. The VISX Star S4 Excimer now has an "auto-tracker",
insuring that the Excimer Laser stays centered on your cornea even
if you have difficulty holding your eye still. I have used the Technolas
Excimer Laser, a "flying spot" Laser, but found it to
be slow and it removes too much corneal tissue. The long treatment
time results in increased dehydration of the cornea, and inconsistent
Laser outcomes. Also the Technolas removes up to 50% more corneal
tissue than the VISX for any given power and diameter optical zone.
The extreme amount of tissue removed by the Technolas can structurally
compromise the cornea and is a major reason most Laser Surgeons
have stopped using the Technolas. The Autonomous (LADAR) Excimer
Laser takes almost twice as long as the VISX for treating nearsighted
patients, and this is somewhat of a problem. Also, the Autonomous
is a more expensive laser to operate, costing about $250 more per
eye.
At this time, I only use
the VISX Star S4 with CustomVue (Wavefront) Technology. I consider
this to be the most advanced, state-of-the-art Excimer laser available.
The NIDEK Excimer Laser is the Laser-of-choice
of "cut-rate" Laser Centers. They use the NIDEK because
it is a less expensive Laser than the VISX. I am not aware of any
Laser Centers, other than the "cut-rate" Laser Centers,
that use the NIDEK Excimer Laser in the Denver area.
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9.
WHAT ARE THE LONG TERM RESULTS? WILL MY EYES DETERIORATE
IN THE FUTURE?
Since 1987, millions of Excimer
Laser procedures have been performed around the world. There is
no evidence of any long term risk from the Excimer Laser that would
adversely affect the health of the eye. Laser Vision Correction
appears to be very stable, and recurrence of refractive error after
six months is uncommon. There does not appear to be any increased
risk of macular degeneration, cataracts, retinal detachments or
any other eye problem related to LASIK treatment.
The "K" in LASIK stands for
"keratomeleusis", which is the "flap cutting"
step in LASIK. Keratomeleusis, without Lasering, has been performed
since 1959, primarily in South American, as a treatment for extremely
high nearsightedness. So we, in fact, have over 40 years experience
with the most "invasive" step in the LASIK procedure,
the cutting of the flap. From this 40+ years of experience we have
learned how deep we can safely treat the cornea without causing
long-term damage to the cornea. Arguably, we have more "long
term" information on the "flap cutting" in LASIK
than we do with soft contact lenses, which have "only"
been available for about 30 years.
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10. WHAT
IS WAVEFRONT ANALYSIS AND CUSTOM CORNEA TECHNOLOGY? HOW GOOD IS
IT?
Wavefront analysis is a new way
of analyzing the cornea. Wavefront
technology was initially developed by astrophysicists to improve
the quality of optics in telescopes. Wavefront analysis involves
sending a reference light ray into a telescopic mirror system and
measuring the reflecting light ray as it exits from the mirror system.
Sensors can detect the location of the exit reference light ray.
The difference between the position of the reflected wave and the
location of where the wave should theoretically have been in a "perfect"
system can be determined. Then, by adjusting the reflecting mirror
surface with small servo-mechanical "suction cups" located
on the backside of the mirror, aberration (distortion) can be removed
from the mirror system. Wavefront analysis has significantly improved
the quality of images in telescopes such as the Hubbell Telescope.
Wavefront analyzers are now available for analyzing human visual
systems. I am have used both the VISX CustomVue and the LadarWave
Custom Cornea Wavefront systems. Both work well but I found the
results to be better with the VISX CustomVue Wavefront system. Wavefront
adds another level of accuracy and predictability to LASIK and increases
the quality of vision after LASIK, especially at night or in dim
lighting situations. Wavefront does add $500 per eye to the cost
of LASIK and PRK, but I feel it is worth the extra expense. Not
every patient is a candidate for Wavefront or even needs Wavefront,
especially if you have small pupils (under 6 mm in dim light). Please
contact my office if you have more specific questions regarding
Wavefront-guided Laser Refractive Surgery.
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11. SHOULD
I WAIT FOR THE LASIK TECHNOLOGY TO GET EVEN BETTER?
Anytime we deal with advanced technologies
we have come to expect continuous, ongoing improvements. And you
could argue why buy a new car, a new computer or undergo LASIK today
when the technology will be "better" in the future. However,
at least with Wavefront guided LASIK,
the Laser Vision technology appears to be stabilizing. We can look
3-5 years down the FDA "pipeline" for new technologies,
and there is presently nothing "revolutionary" on the
horizon. I would expect in the future for the FDA to approve the
use of Wavefront technology on a wider group of patients, including
Farsighted patients. However, the Wavefront-guided LASIK we have
today gives excellent results for 98% of patients and it appears
to me that waiting for future technologic improvements will not
give you access to significantly better visual outcomes.
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12
WHAT IS CK?
CK (conductive keratoplasty) is a refractive surgical procedure
somewhat similar to LASIK. CK reshapes your eye by using a small
needle-like probe that applies radio-wave energy to the surface
of the cornea. The radio-wave energy causes the corneal tissue to
slightly "shrink", thus reshaping the cornea. By applying
the energy in a specific pattern and inducing a controlled "shrinking"
of the corneal tissue, refractive changes can be induced. CK is
an outpatient procedure that takes less than a minute to perform.
The cornea is numbed with eye drops. The needle-like probe applies
the energy in a circular pattern approximately three millimeters
from the center of the cornea. Depending on how much correction
is required, anywhere from 6 to 18 "spots" of energy are
applied. There is mild to moderate discomfort after CK. The refractice
change is almost immediate.
CK can only
treat mild amounts of farsightedness; it cannot treat nearsightedness
or astigmatism. This limits its usefulness. If you have good
uncorrected distance vision, (and are over the age of 45), CK
can also be used to create Monovision,
allowing you to read without glasses. In monovision your non-dominant
distance eye can be treated with CK, making it a reading eye. (This
will blur your distance vision in the treated eye, but with both
eyes open, you can see both distance and near.) CK does not give
you back the focusing power you lost with age.
CK has
three major drawbacks. The first drawback is that CK's effect
regresses within 1-2 years, and CK is not as effective if reapplied
a second time. The second drawback is that CK not only cannot treat
astigmatism, but it can actually induce astigmatism, which then
is difficult to correct. The third drawback is the very limited
number of patients that are actually candidates for CK.
I see
no advantage to CK over LASIK. In fact, I would recommend LASIK
over CK. LASIK is much more precise than CK and can treat a
much wider range of farsightedness, astigmatism and nearsightedness.
LASIK uses an Excimer laser with 1/4 micron (1/200 of a hair) precision
to reshape your eye. CK uses radio-waves to shrink the corneal tissue
and does not have the precision of LASIK. LASIK can be repeated,
if necessary, to enhance the visual outcome. CK cannot be enhanced.
LASIK has a very stable long term effect; CK's effect regresses
over 1-2 years. LASIK can treat astigmatism (just about everybody
has astigmatism), CK cannot treat astigmatism. CK and LASIK cost
approximately the same, take about the same amount of time to perform,
regain vision at about the same rate, and are both performed with
only eye drops to numb the eye. LASIK has very minimal discomfort;
CK is more uncomfotable than LASIK, especially for 2-3 days after
the procedure. I don't really understand why anyone would chose
CK when LASIK is available.
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