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| The Verisyse-Artisan phakic intraocular lens (P-IOL) is
implanted inside the eye immediately below the cornea and
is attached directly to the top of the iris. |
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| The Visian ICL is implanted behind the iris and immediately
in front of the natural lens of the eye. |
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A phakic intraocular lens (P-IOL) is an artificial lens placed within the eye either immediately in front or behind the iris. P-IOLs are designed to correct refractive error without reshaping the cornea or interfering with accommodation.
Correct High Myopia
P-IOLs are approved by the FDA to fully correct up to 15.00 diopters (D) of myopia. People with more than 15.00 D of myopia
may use a P-IOL to reduce their refractive error, but will not achieve
full correction. P-IOLs can be used for low amounts of myopia correction, but
are commonly not as appropriate for less than 10.00 diopters of correction. Lower myopia may be better corrected with techniques like conventional
or wavefront Lasik, Bladeless Lasik, PRK, LASEK, and Epi-Lasik.
P-IOLs tend to be better for people with high myopia than Lasik
and similar laser eye surgery techniques because the laser assisted techniques
require greater amounts of corneal tissue to be removed to correct
high refractive error may make the cornea too thin and unstable.
P-IOLs do not thin the cornea.
P-IOLs are not currently approved for hyperopic correction and the nature of a P-IOL
tends to make them less ideal for hyperopic correction.
Astigmatism
P-IOLs approved in the United States do not directly correct astigmatism, however the process of surgery may reduce astigmatism.
If the patient has moderate to high astigmatism, a second procedure,
such as conventional or wavefront-guided Lasik, PRK, LASEK, or Epi-Lasik
may be recommended for the correction of only the astigmatism.
Younger Patients Are Generally Best
P-IOLs are generally not ideal for persons over age 45 or anyone
who is presbyopic.
Presbyopia is when the natural crystalline lens of the eye is no
longer fully able to change focus from items distant to items near
(accommodation). This is when reading glasses or bifocals become
necessary. If the patient is young, not presbyopic, and has a high
refractive error, then a major advantage of P-IOL lens-based refractive
surgery is that the natural crystalline lens remains untouched.
This means that the high myopia can be corrected without limiting
the ability to accommodate.
When fully presbyopic, the natural lens is fixed in its shape
and replacement of the natural lens with an artificial lens
(RLE)
should be considered, however RLE has its own set of limitations
and risks. Some intraocular lenses used for RLE have the ability
to provide near and distance vision as well as the ability to correct
refractive error. It may be possible to reduce or resolve both presbyopia
and myopia/hyperopia with RLE. A person at or over age 45 should also consider presbyopia surgery as an option.
Two Types
There are two primary types of P-IOLs. Both are placed behind
the cornea and in front of the crystalline lens, but one type is
placed in front of the iris and the other is placed behind the iris. The Verisyse-Artisan P-IOL
is placed in front of the iris. The Visian ICL is placed behind
the iris. Each have distinct advantages and disadvantages.
Temporary and Removable
At some point P-IOLs must be removed. As we mature, the natural
lens of the eye becomes cloudy. This is called a cataract. The process
of cataract correction requires the removal of any P-IOL. Everyone
will eventually develop cataracts if they live long enough. This
issue directly affects both types of P-IOLs.
The Verisyse-Artisan lens that is placed in front of the iris
can and usually does disrupt the endothelial cells on the back of the cornea. This disruption should be regularly
monitored to determine if or when the issue becomes critical. At
that point the Verisyse-Artisan must be removed to ensure the health
and integrity of the cornea. This condition does not affect the
Visian ICL.
If for any reason the P-IOL becomes problematic or undesired,
it can be surgically removed in a process essentially the reverse
of implantation.
Short But Steep Surgeon Learning Curve
The implantation of P-IOLs is significantly different surgery
than Lasik, Bladeless Lasik, PRK, LASEK, or Epi-Lasik. P-IOL implantation
is much more like cataract surgery than laser assisted refractive
surgery. For this reason a doctor who has greater practical knowledge
with cataract surgery may be a better choice than a Lasik doctor.
Ideally, the P-IOL doctor would be well versed in both cataract
and laser eye surgery.
The learning curve for P-IOL surgery is relatively short, but
very steep. Trauma induced cataracts and significant loss of the
endothelial cells are two complications often related to inexperience.
It would probably best to select a doctor who has implanted at least
25 P-IOLs of the type being considered, and more is always better.
Extensive cataract surgery experience may make this restriction
less important.
Visian ICL
The Visian Implantable Collamer Lens (ICL - it is not an implantable contact lens) and the Verisyse-Artisan are both phakic intraocular lenses (P-IOL). A P-IOL is a "helper" artificial
lens implanted inside the eye to reduce refractive error. P-IOLs are an alternative to conventional
or wavefront Lasik, Bladeless Lasik, PRK, LASEK, and Epi-Lasik for patients with very high myopic (nearsighted-shortsighted) vision.
The procedure involves placing the Visian Phakic IOL behind your
cornea between your iris and the natural lens of your eye. Before
surgery the doctor must measure the depth of the anterior
chamber of the eye to verify that there is enough room to add the
Vision. An estimated one-third of candidates are disqualified because
the anterior chamber is too shallow.
Implanting the Visian Phakic IOL is an outpatient procedure that
takes approximately 15 to 30 minutes. Usually, one eye is treated
at a time.
Drops will be placed in your eyes in order to enlarge the pupil
size. For better access to your eye, your doctor will use an instrument
to hold your eyelids open during the procedure. A local anesthetic
is given to numb the eye, so the procedure is virtually painless.
A small incision is made in the cornea for the Visian ICL to be
placed in the space between the iris and the natural crystalline
lens. The Visian ICL is centered behind the pupil, and supported
by the inside walls of the eye. The small incision is closed with
stitches that dissolve over time. A temporary shield will be placed
over your eye to protect it for a few days after surgery.
Outside the United States the Visian is called the "Implantable
Contact Lens". The FDA rightfully determined this name to be misinformative
of the true nature of the surgery involved to implant the Visian.
A P-IOL is not, by any stretch of the imagination, a contact lens.
For the US market, the manufacturer adopted the name "Implantable
Collamer Lens" to reflect the material used to make the P-IOL. It
is inappropriate to call the Visian ICL an implantable contact lens.
Verisyse
Implanting the Verisyse Phakic IOL is an outpatient procedure
that takes approximately 15 to 30 minutes. Usually, one eye is treated
at a time.
Before surgery the doctor will create peripheral iridotomies.
A laser makes one or two small holes through the iris. This is to
allow fluid to flow freely between the front and back of the iris.
The procedure takes about 5 minutes. The patient will have blurry
vision for the first few hours.
Drops will be placed in your eyes in order to reduce the pupil
size. For better access to your eye, your doctor will use an instrument
to hold your eyelids open during the procedure. A local anesthetic
is given to numb the eye, so the procedure is virtually painless.
A small incision is made in the cornea for the Verisyse Phakic IOL
to be placed in the space between the iris and the cornea. The Verisyse
Phakic IOL is centered in front of the pupil,
and is attached to the iris to hold the lens in place. The small
incision is closed with stitches that dissolve over time. A temporary
shield will be placed over your eye to protect it for a few days
after surgery.
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.
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