Technology
Our Implants
Intraocular Lens Implants
Lens implants (intraocular lens implant or IOL) have been the
mainstay of cataract surgery since their creation in the 1940’s by
Dr. Harold Ridley. These lenses, when placed inside the eye after
the natural lens has been removed, provide either good distance or
near vision, depending on what has been selected by the patient.
Recently, however, specialized implants have been developed that
can provide both good distance and near vision following their
insertion. Lens implants have now entered the realm of refractive
surgery and can be divided into two main categories, pseudophakic
and phakic. Pseudophakic implants are those that are inserted
inside the eye after the natural lens has been removed. These
lenses have traditionally been used after the removal of a
cataractous (cloudy) natural lens. These pseudophakic implants
can also be used after removing the natural lens before it becomes
a cataract, a process known as “clear lens extraction.” While
cataract surgery is typically covered by insurance, “clear lens
extraction” procedures are not, as they are not correcting the
reduced vision caused by a cataract. In this regard they would be
similar to Lasik and other refractive procedures, being classified
as elective. Phakic implants are lens that are inserted inside
the eye while the natural lens is left in place. These implants
can be used to correct nearsightedness, farsightedness, and
eventually astigmatism.
Pseudo phakic IOLs can be further divided into two distinct groups:
monofocal and multi–focal. Monofocal lenses have a single focus.
This can be selected to corrected either distance or near vision but
not both. Multi-focal lenses have, as their name indicates, more
than one focus point and can be used to correct near and distance
vision at the same time. Multifocal lenses can be further subdivided
into “pseudoaccommodative” and “accommodative”. Accommodation is the
process by which the natural eye shifts focus from distance to near,
allowing our eye to read our favorite book and suddenly look up to
the see the noisy bird in the backyard. This “accommodation” is
caused by a change in the shape of the flexible young natural lens
initiated by a muscular function inside the eye. This function
weakens with age as the lens becomes much less flexible and the
muscles somewhat weaken.
All implants can be modified to improve on their optical quality
with the addition of filtration tints, special edging, wavefront
adjustments, etc. This is an exciting field that will blossom over
the next few years at a technologic rate not seen before. This is
driven by the desire of our patients to retain high quality vision
throughout their lives and not to settle for anything less than being
the most functional and productive people they can be. These are our
patients and we hope you are among them.
Intraocular Lenses
- Pseudophakic Lenses (removing the natural lens whether cataractous or not)
- Monofocal
- Conventional
- Wavefront Adjusted
- Pseudoaccommodative
- Diffractive Optics
- Alcon ReStor
- Alcon ReStor — Natural color filter (NA yet)
- Alcon ReStor/Wavefront adjusted (NA yet)
- Multi-zonal
- AMO Array
- AMO ReZoom (Array II)
- Wavefront adjusted
- AMO Technis-multi (NA yet)
- Accommodative
- Single lens format
- Multi-lens format (NA yet)
- Photo-adjustable (NA yet)
- Phakic Lenses (leaving the natural lens in place)
- AC lenses (vaulting)
- Ciba Vivarte (NA yet in US)
- B&L NuVita (NA yet in US)
- OII Phakic 6 (NA yet in US)
- Vision Membrane (NA yet)
- Iris supported
- Sulcus supported
Pseudo-Accommodative / Accommodative IOL
The FDA approved the first “accommodative” IOL, the
Crystalens, in November 2003. This new type of IOL attempts to restore
the eye’s ability to focus on near objects without the need for
reading glasses, while still allowing the patient to see well in the
distance. A second lens, the ReStor, a diffractive, pseudo accommodative
implant, was approved by the FDA in March of 2005. At Hale Vision Laser
& Implant Center, we believe that over the next decade we will see
tremendous advancements in this area and this type of surgery will
become the surgery of choice for our patients over fifty-five.
While Dr. Hale is trained to perform both the Crystalens and the ReStor,
he is currently favoring the ReStor, as it seems to offer the best chance
of spectacle independence of our interested patients. We feel that it is
important to pick the best procedure and not necessarily the first procedure
when it comes to intra-ocular procedures, as they carry certain significant
potential complications. We will keep our patients updated on this
technology as it becomes available.
Phakic IOL
Some patients, for a variety of reasons, are not good candidates for
laser surgery but still desire vision correction surgery. For a
number of years now, the FDA has been testing a new class of
implantable lenses that can be used to reduce nearsightedness,
farsightedness and eventually astigmatism. There are several models
of these implants and one was approved in late 2004 for the treatment
of nearsightedness without significant accompanying astigmatism.
Another model will hopefully be approved early to mid 2005. These two
approaches to the same problem are somewhat different. The first
phakic IOL approved for refractive use is called the Verisyse by
AMO. This
implant is inserted through an incision in the cornea and clips onto
the colored iris for stabilization and positioning. The probable
second to receive approval will be the Visian lens by
Staar Surgical. This implant is inserted
through a very small incision in the cornea and is placed behind the
colored iris.
All intraocular lenses will have accompanying complications that
are different than those of laser treatments, as the lens are placed
within the eye and laser treatments are performed on the surface or
under a thin surface flap corneal tissue. Dr. Hale has already taken
the certification course for the Visian lens and is awaiting approval
of this lens. He is also considering working with the Verisyse but,
due to the more aggressive fixation of this lens he intends to
observe the early results in its use in the general public before
adopting its use for his patients.
Sharing the Vision
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