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December 2000
VENICE — Patient selection
is important with the Array multifocal IOL (Allergan, Irvine, U.S.A.),
and the surgeon must take into account ocular health, refractive error
and the patient’s personality and lifestyle, according to David F. Chang,
MD, who spoke about multifocals at the Venice 2000 meeting, sponsored
by Ocular Surgery News, the Italian Association of Cataract
and Refractive Surgery and the International Society of Refractive Surgery.
“Exploring all of
this might be time consuming, but our patients depend on us to help them
determine if they are good candidates for this technology,” Dr. Chang
said.
Dr. Chang has been
implanting the Array SA40 Multifocal IOL since 1997. He implants the IOL
in approximately 15% of his cataract population, he said, reflecting his
caution in patient selection.
As a result of this
careful approach, however, the majority of his patients are extremely
satisfied, with an average patient satisfaction rating of 3.8 on the Javitt
0 to 4 subjective scale (4 = extremely satisfied; 0 = not at all satisfied).
“As cataract surgeons,
we are used to thinking in terms of objective measures of our success,”
Dr. Chang said. “With the multifocal IOL, important objective criteria
would be spherical refractive error, postoperative astigmatism and uncorrected
near and far acuity. However, patient satisfaction is really a subjective
distinction. For example, two bilateral Array patients may have identical
uncorrected Jaeger acuities, and yet have significantly different subjective
opinions about their need for reading glasses. This is why patient selection
is so important with the Array.”
Prerequisites for satisfaction
Dr. Chang listed four
important criteria for achieving a happy multifocal patient. “First, we
must perform flawless surgery, which is both astigmatically neutral and
which provides optimal in-the-bag centration of the IOL. Second, the eye
must be healthy, with excellent best-corrected visual acuity. Third, we
must select the optimal IOL power. Finally, we need to generate realistic
patient expectations through a combination of education and selection.
This certainly increases the demands on the cataract surgeon, compared
with when patients expect to wear bifocals after surgery,” Dr. Chang said.
“With the latter patient,
if we inadvertently induce 1 D to 2 D of anisometropia, 1 D to 2 D of
against-the-rule astigmatism, or if we miss the spherical target by +
1 D, the correction ends up in the glasses. The patient will likely be
unaware of 0.5 mm or 1 mm of optic decentration. And barring late complications,
the patient will be just as happy with an anterior chamber IOL in the
event of posterior capsule rupture. Unfortunately, all of these scenarios
compromise the uncorrected visual function of the Array patient,” he continued.
“The aim of seeing well without glasses is compromised.”
Dr. Chang added, “The
ideal patient is one who is strongly motivated to see without glasses,
will be able to adapt to the nighttime images and has reasonable expectations
that can be met. These expectations will be shaped by the patient’s personality,
their level of uncorrected acuity preoperatively and preoperative education.
We tend to disqualify individuals whom we feel will be difficult to satisfy
for any of these reasons.”
Preoperative factors to consider
In attempting to identify
Array candidates, Dr. Chang considers five factors that help him to predict
patients most likely to be satisfied.
First, he assesses
lifestyle issues, such as the patient’s occupation and reading needs.
“If the patient drives infrequently at night, adaptation to haloes becomes
much less of an issue,” he said. Second, he looks at the patient’s preoperative
refractive error, because this is what patients will use as a basis for
comparison postoperatively. “For example, uncorrected J4 vision will seem
miraculous to someone who was +3 preoperatively, but will seem disappointing
to someone who was formerly –3 and never wore glasses to read in the past.”
Third, the frequency
of spectacle use preoperatively may provide important clues about the
patient’s motivation to avoid glasses. “We’ve all been impressed by people
who, despite having significant refractive errors, don’t wear their glasses
very often, if at all,” he pointed out. “These people are apparently willing
to tolerate the blur rather than bother with spectacles. On the other
hand, a nearly emmetropic patient who wears bifocals daylong to hide facial
wrinkles, or because he or she is too blurred without that –0.50 sphere,
would seemingly have little to gain from the Array in exchange for the
potential drawbacks.”
Dr. Chang added, “We
know from refractive surgery that individuals differ greatly in the value
they place on their ability to see without glasses. For some patients,
the motivation was so strong that even the tremendous glare and fluctuating
vision that accompanied a 16-incision radial keratotomy was an acceptable
trade-off. Such motivated patients would more quickly accept and adapt
to nighttime halos as well.”
Ability to tolerate nighttime images
Fourth, Dr. Chang
considers the cataract density. “Whether it be a floater, halos, monovision
or progressive bifocals, individuals vary greatly in their ability to
adapt to imperfections in their vision. The degree of cataract and visual
complaint may be telling in this regard,” he said. “A patient with advanced
brunescent lenses, 20/200 acuity, and yet relatively understated complaints
is telling you he’s not a very ‘picky’ person. This is in contrast with
the 20/40 patient with minor lens opacities who, despite being reassured
3 months ago, is back again feeling utterly disabled by his or her deteriorating
vision. Obviously, this person may have more trouble adapting to halos.”
Finally, assessing
pupil size can help to predict the potential for dissatisfaction. Dr.
Chang explained that patients with smaller pupils (that is, less than
2.5 mm in room light) are more likely to require reading glasses, but
will have little problems with halos. “For these people I spend more time
downsizing the expectation of reading without glasses,” he said. Patients
with larger pupils (that is, greater than 4 mm in room light) will enjoy
the best uncorrected near acuity, but will experience the most obvious
halos. “These patients need much more reassurance pre- and postoperatively
about the adaptation that is expected to occur over time.”
Getting started
“Surgeons just getting
started with the Array should select the most ideal candidates who will
be the easiest to satisfy,” Dr. Chang said. “A hyperopic patient with
a 3-mm pupil who dislikes spectacles, rarely drives at night and has a
dense cataract would be such a person. In contrast, a myope with a 4.5-mm
pupil, who wears bifocals full time and who is overwhelmed by painful
glare with nighttime driving attributable to a fairly minimal cataract
would be a riskier candidate.”
Dr. Chang said the
decision to implant the Array is like other non-medical decisions that
surgeons help patients to make every week — decisions about refractive
surgery, cosmetic surgery, monovision contacts or progressive add spectacles.
“In each case the
potential drawbacks should be weighed against the anticipated benefits
that are largely subjective and individual. It would be inappropriate
to push these options on every patient,” he said, “but it would be just
as wrong to deny these options to all patients because of the potential
for dissatisfaction. I believe we owe it to our cataract patients to acquire
the skills and experience needed to offer the Array, and to spend the
necessary time educating them and evaluating their suitability,” Dr. Chang
said.
For
Your Information:
- David F. Chang,
MD, is a clinical professor of ophthalmology at the University of
California at San Francisco, and is in private practice in Los Altos,
CA, U.S.A. He can be reached at fax: +(1) 650-948-0563; e-mail: dceye@earthlink.net. Dr. Chang
is a paid consultant for Allergan.
- Allergan Inc.
can be reached at 2525 Dupont Drive, Irvine, CA 92612 U.S.A.; +(1)
714-246-2201; fax: +(1) 714-246-4297.
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