 |
|
| RK incisions create a special challenge for Lasik, but correction is possible. |
|
| |
|
It is often possible to have
custom wavefront Lasik, Bladeless Lasik,
or other refractive surgery procedures if
you have had Radial Kertotomy (RK) in the past, but success will be limited by many
factors.
Fluctuation
RK patients often have corneas that are weakened and fluctuate throughout the
day, causing difficulty with glasses fitting. Corneas that
are unstable should probably not have additional refractive
surgery. Cornea stability needs to to be addressed before
considering any additional cornea surgery. For details, read RK Fluctuation and Hyperopic Shift
Shift Toward Farsighted Vision
Many RK patients who were previously myopic (nearsighted, shortsighted) and corrected to plano at the time of their surgery are becoming hyperopic (farsighted, longsighted) due to a shift of the cornea. This hyperopic
shift is apparently cause by progressive weakening of the cornea.
Over Age 40: Presbyopic and Farsighted
As adults pass the age of about 40 they become presbyopic and are unable to achieve clear near vision.
If the patient is both hyperopic and presbyopic, they are
likely to have poor vision at most distances. These patients
often seek additional surgery to correct their poor vision
due to presbyopia, however there are no safe, reliable, and
predictable ways to "cure" presbyopia with surgery. It may
be possible to correct underlying hyperopia, which
exacerbates presbyopia, if the cornea is relatively stable
or if the cornea can be stabilized with treatment. Monovision correction is a workaround for some
presbyopic patients.
Corneal Irregularities
Patients with previous RK may have irregular astigmatism that is difficult to impossible to
correct with current laser technology and techniques. If the
irregularities are too great, wavefront-guided ablation may
be impossible or unwise. Conventional ablation or even C-CAP may be necessary. Although possibly difficult,
irregular astigmatism may be improved with Lasik,
Bladeless Lasik, etc.
Contacts First
Probably the first method of correction for RK patients
with previous RK should be Rigid Gas Permeable (RGP) contact lenses. RGPs are a
stabilizing force for the cornea and correct refractive
error. RGPs improve an irregular cornea by applying a smooth
and rigid surface while "squishing" down the irregularities
and smoothing outer surface of the cornea. Often RGPs
provide the stability needed for good correction.
Surface Ablation or Intacs
Although conventional or custom wavefront Lasik is often performed for previous RK patients, the condition of the cornea must be very carefully examined. RK makes deep radial incisions into the cornea. When the Lasik flap is created, it can fall apart like so many pieces of a pizza. For this reason, it is often more safe for previous RK patients to consider
a surface ablation techniques PRK or LASEK. The use of Intacs may be best suited as Intacs tend to stabilize a
fluctuating cornea. In some instances a combination of
Intacs and surface ablation may be appropriate. Epi-Lasik is also a surface ablation technique, but cannot be safely performed on patients with
previous RK.
Lens Based Surgery
If the cornea is too weakened by previous surgery, it may be appropriate to consider lens-based surgery such
as RLE or P-IOL. These techniques will not resolve fluctuations or
corneal irregularities, however they can be appropriate
techniques to resolve some refractive errors. Intraocular
lenses used for RLE may be multifocal or self
accommodating to lower the effects of presbyopia. Learn more
about presbyopia surgery.
CxL CrossLinking Stiffening
A
developing technique of stabilizing the cornea is Corneal Collagen Crosslinking with Riboflavin (CxL).
This process uses high frequency light with the eyes
protected with a riboflavin solution to cause a stiffening
of the cornea. CrossLinking can be used in combination with other
techniques, such as Intacs.
Not every refractive surgeon will perform new refractive
procedures on RK recipients. Be sure you select a doctor
who has this experience.
Looking For Best Lasik Surgeon?
If you are ready to choose a doctor to be evaluated for conventional
or custom wavefront Lasik, Bladeless Lasik, PRK, or any refractive surgery procedure, we recommend you consider a doctor who has been evaluated and certified by the USAEyes nonprofit organization.
Locate a USAEyes Evaluated & Certified Lasik Doctor.
Personalized Answers
If this article did not fully answer your questions, use our
free Ask Lasik Expert patient forum.
