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Accommodative and
Multifocal IOLs
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How the eye works
• Light rays enter the eye through
the clear cornea, pupil and lens.
• These light rays are focused
directly onto the retina, the lightsensitive tissue lining the back of
the eye.
• The retina converts light rays into
impulses, sent through the optic
nerve to your brain, where they
are recognized as images.
• 70% of the eye's focusing power
comes from the cornea and 30%
from the lens.
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Refractive errors
• Inability to see clearly is often caused by refractive error.
• Four types of refractive error:
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Myopia (nearsightedness)
Hyperopia (farsightedness)
Astigmatism
Presbyopia
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Refractive errors: myopia
• In myopia (nearsightedness),
there is too much optical
power in the eye
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The distance between the
cornea and the retina may be
too long or the power of the
cornea and the lens may be too
strong.
• Light rays focus in front of
the retina instead of on it.
• Close objects will look clear,
but distant objects will
appear blurred.
Myopia, or nearsightedness
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Refractive errors: hyperopia
• In hyperopia (farsightedness),
there is too little optical power.
• The distance between the
cornea and the retina may be
too short.
• Light rays are focused behind
the retina instead of on it.
Hyperopia, or farsightedness
• In adults (but not children),
distant objects will look clear,
but close objects will appear
blurred.
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Refractive errors: astigmatism
• In astigmatism, the cornea is
curved unevenly—shaped more
like a football than a basketball.
• Light passing through the
uneven cornea is focused in
two or more locations.
• Distant and close objects may
appear blurry.
Astigmatism occurs when light
passes through football-shaped
cornea and/or lens
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Refractive errors: presbyopia
• Presbyopia is an age-related condition
in which your eyes gradually lose the
ability to see things up close, because
the lens of the aging eye can no longer
change shape.
• When we are young, the lens in our
eyes is flexible and is able to change
focus easily between near and far
objects, like an autofocus on a camera.
• At around age 40, this flexibility begins
to gradually decrease, making it more
difficult to see objects up close, unless
the eye has nearsightedness.
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What is accommodation?
• The eye’s lens, which provides your focusing power, has four
primary functions:
• Transparency: To provide a clear medium through which light rays
from an object can reach your retina.
• Optical: To focus a sharp image of an object on the retina.
• Anatomic: To create a functional barrier between the anterior and
posterior segments of the eye.
• Accommodation: To vary the eye’s refractive power, thus providing
clear images of objects over a wide range of distances.
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What is refractive surgery?
• A group of outpatient surgical procedures used to alter how your
eye focuses light rays on the retina, thereby improving vision and
reducing dependence on glasses and contact lenses.
• In most cases, refractive surgery affects the shape of your cornea
to redirect how light is focused onto the retina. Popular
procedures include LASIK, LASEK, PRK and CK.
Refractive
surgery
procedure on
the cornea
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What is refractive surgery?
• Most refractive surgery is performed on the cornea and affects
only the front of your eye, while the rest of your eye will change
naturally as you age.
• In some cases, refractive surgery procedures don’t reshape the
cornea; instead, the eye’s natural lens is either replaced or
enhanced by an implantable lens that helps correct vision.
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What are accommodative intraocular lenses (IOLs) and
multifocal intraocular lenses (IOLs)?
• An artificial lens that is surgically implanted in the eye, replacing
the eye’s natural lens.
• Enables your eye to regain its focusing and refractive ability.
• The cornea is not reshaped.
• Used to treat nearsightedness (myopia), farsightedness
(hyperopia) and the inability to focus at near with age (presbyopia).
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What is an accommodative intraocular lens (IOL)?
• The accommodative IOL is
hinged to work in coordination
with the eye muscles.
• The design allows the
accommodative lens to move
forward as the eye focuses on
near objects, and move backward
as it focuses on distant objects.
A type of accommodative
intraocular lens (IOL)
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What is a multifocal IOL?
• A multifocal lens has several
rings of different powers built
into the lens.
• The part of the lens (ring) you
look through will determine if
you see clearly at a far, near or
intermediate distance (this is
sometimes called pseudoaccommodation).
A type of multifocal
intraocular lens (IOL)
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How is the IOL procedure performed?
• The IOL is implanted in a surgical procedure, performed on an
outpatient basis under local anesthesia and taking approximately
20-30 minutes.
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How is the IOL procedure performed?
• In addition to a pre-operative eye exam, measurements of the eye
are taken to give the surgeon the necessary information to perform
the procedure. These measurements include:
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Refractive error measurement.
Pupil evaluation and size measurement.
Keratometry: measurement of the form and curvature of the cornea.
A-scan: Measurement of the axial length of the eye from the cornea to the
retina.
Calculations to determine the correct power of lens (IOL) to use.
A phoropter is used
to measure
refractive errors
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How is the IOL procedure performed?
• After the eye is numbed with
topical or local anesthesia, one
to three small incisions are
made close to the edge of the
cornea.
• After the procedure, these
incisions are usually “selfsealing,” requiring no stitches.
Small incisions are made close
to the edge of the cornea for
inserting the IOL
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How is the IOL procedure performed?
• A tiny, high-frequency
ultrasound instrument is
inserted into the eye to break
up the center of the eye’s
natural, crystalline lens.
• The natural lens is then gently
vacuumed out through one of
the incisions.
The eye’s natural lens is suctioned
out through an incision
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How is the IOL procedure performed?
• An IOL is folded and inserted
through the same incision that
was used to extract the natural
lens.
• The IOL is then unfolded and
placed into the "capsular bag"
that originally surrounded the
natural lens.
IOL in the eye
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How is the IOL procedure performed?
• Once the accommodative or
multifocal IOL is implanted,
your eye can focus on near,
intermediate and far distances.
The IOL firmly in place
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Considerations for the accommodative/multifocal IOL
procedure
• May be an option for people with cataracts or people without
cataracts who are presbyopic and want to reduce or eliminate their
need for glasses.
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Considerations against the accommodative/multifocal
IOL procedure
• The focusing ability of the lens may not be fully realized for six to
eight weeks after the procedure.
• Your eye must re-learn how to focus on objects at various
distances in order to see clearly.
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Risks and possible side effects of
accommodative/multifocal IOL surgery
• Over-correction or under-correction (with a possible need for a retreatment).
• Infection.
• Increased floaters or retinal detachment.
• Dislocation of implant.
• Loss of vision.
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Is refractive surgery right for you?
• Advanced surgical procedures, including accommodative and
multifocal IOLs, are creating more opportunities for people who
want to be less dependent on glasses or contacts.
• Surgery may not entirely eliminate your need for corrective lenses.
Glasses/contacts may still be needed for activities such as fine or
detailed work, reading and perhaps night driving.
• If an accommodating or multifocal IOL is used, then reading as
well as distance vision may be improved.
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Is refractive surgery right for you?
• A large part of the success of any refractive surgery depends on
your understanding of the procedure and your expectations.
• Since refractive surgery is an elective procedure, you have the
opportunity and responsibility to become fully informed about its
risks and benefits.
• Your ophthalmologist will explain the specific technique, its
benefits, as well as possible risks and side effects associated with
your case.
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Discuss options and questions with
your ophthalmologist
• With the help of your ophthalmologist, it’s ultimately your
responsibility to weigh the risks and side effects of a procedure
with the benefits it has to offer.
• If you decide refractive surgery is right for you, you may join
millions of people who have reduced their dependence on glasses
or contacts.
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