The latest technological advance in lens-based surgery
is the introduction of the apodized diffractive intraocular
lens implant called the ReSTOR®.
This multifocal implant, when used with refractive lensectomy
(also known as clear lens extraction), can greatly reduce
or even eliminate the need for glasses, for both distance
and reading! The topic of intraocular lenses (IOL) is
a complex one, so let’s spend a little time going
over the concepts.
Routine refractive lensectomy (without the ReSTOR®
implant) will not completely eliminate the need
for glasses. While distance vision can be made
clear, reading vision is compromised (again, when a
traditional intraocular lens implant is used).
In patients under approximately 40 years of age, the
natural crystalline lens retains the ability to flex
in a process called accommodation. This allows an individual
to generate the extra focusing power needed to read
up close. After 40, the ability to accommodate diminishes
more quickly, which results in a person needing bifocals
or reading glasses. This need for reading glasses
is “accelerated” by removal of the natural
crystalline lens; for all purposes, the traditional
intraocular lens implant cannot accommodate.
TRADITIONAL MONOFOCAL IMPLANT
The traditional monofocal intraocular lens implant
only focuses at one point, either distance or near,
or somewhere in between (intermediate), but almost never
at two or all three points simultaneously. Hence,
the term monofocal or “one focus”.
With monofocal implants, one of three strategies can
chosen, if both eyes are having surgery:
a) Implant selection so that both eyes focused
at distance. While glasses may still be necessary
for distance, they will almost certainly be necessary
for reading and intermediate vision.
b) Implant selection so that both eyes focused
at near. While glasses may still be required for
reading or intermediate vision, glasses almost certainly
required for distance.
c) Implant selection so that one eye focused at
distance, and the other eye for reading.
Glasses may still be required for both distance and
near, but choosing this option can reduce overall dependence
on glasses. This is called monovision. Monovision
can work well but it is a compromise. Decreased
depth perception and difficulty with vision under dim
lighting conditions (such as night driving) may occur.
Golfers and pilots may not like this. People who
drive at night extensively may not like monovision.
MULTIFOCAL IMPLANT: THE ReSTOR® IMPLANT
The multifocal implant is quite different from the
traditional monofocal implant. One such multifocal implant
is the ReSTOR® intraocular lens implant.
(There are other brands of multifocal implants.) It
is a highly sophisticated implant that produces
two simultaneous focal points, for distance and
near, almost like the lens of bifocal glasses. A patient
unconsciously learns to switch between the two focal
points, depending on what is being viewed. The benefit
of using this implant is that each eye can see
both distance and near. This is quite different
than the monovision option (see previous paragraph)
using the more traditional monofocal lens implant, where
only one eye is focused at distance, and the other eye
is focused at near. Vision with the ReSTOR® is arguably
a more natural way of seeing. In a study of the ReSTOR®
implant for cataract patients (this study
may not apply to patients undergoing refractive lensectomy),
92 out of 100 ReSTOR® patients reported
never needing glasses for distance, and 81/100 not needing
glasses for reading. The ReSTOR® implant is
designed for clear reading vision at 14 inches. Reading
material may need to be held closer than usual for some
patients. Intermediate or computer vision, without glasses,
is acceptable for a large number of ReSTOR® patients
(82/100 in above cited study). ReSTOR® patients
may have to move closer to the computer screen or intermediate
range targets, to see very clearly without glasses.
Intermediate vision appears to improve over time.
The best visual results are obtained when both eyes
receive the ReSTOR® implant. It is
not recommended that only one eye receive the ReSTOR®
implant. This is an implant
designed to be used in both eyes.
The optimal result with the ReSTOR® implant requires
getting as close to a “zero” distance prescription
as possible. A few patients who have refractive
lensectomy using the ReSTOR® implant, will
require a "touch-up" procedure to realize
the full potential of this lens implant. In other
words, to fine-tune the visual results, sometimes an
additional procedure may need to be done afterward.
The additional procedure may involve correction of astigmatism
with either a limbal relaxing incisions (LRI) or astigmatic
keratotomy (AK), both of which can be done in the office. Another
procedure which is sometimes used to refine the ReSTOR®
results is laser vision correction, like LASIK, which
is done at another facility.
Are you a candidate for the ReSTOR® implant?
Only your ophthalmologist
can tell you. After a complete eye exam and additional
testing, your doctor will be able to determine if you
are a suitable candidate for ReSTOR®. Your doctor
will talk to you about the risks of surgery, and those
specific to multifocal implants. For patients who
meet the criteria, the ReSTOR® implant can be a life-changing