Transcript Phakic Intraocular Lenses - This Web site coming soon

Multifocal Intraocular
Lenses & Contrast
Sensitivity
Dr Kerrie Meades
MBBS(Hons) FRANZCO FRACS
Cataract and Refractive Surgeon
Multifocal IOL’s
Come in three basic types;
Refractive
Diffractive
Accommodative
Multifocal IOL’s can also be Aspheric &
contain a UV or blue filter
Aspheric IOL’s
The idea of the aspheric IOL is to return
the eye to that of youthful optics, The
young eye has zero Spherical Aberration
With age, Spherical Aberration increases
reducing functional vision
Filters – Blue light & UV
The human lens has the ability to
filter UV and blue light naturally
Blue light filtration (yellow) & UV
blocking is believed to slow down the
progression of AMD caused by
exposure
virtually 100% of IOL's now contain
UV-absorbers
Multifocal IOL’s
Multifocal IOL’s provide greater
spectacle independence to patients
Careful patient counseling is needed
to match a lens solution to the
patients expectations.
Sometimes you may need to Mix
IOL’s to suit a patients visual
requirements.
Refractive
Refractive multifocal IOL’s
are designed with several
optical zones on the IOL.
These zones provide
various focal points, allowing
for an improvement in
distance, intermediate, &
near vision
Rezoom offers a good DVA.
Mid-distance haloing is a
side effect
Diffractive
Restor
Diffractive multifocal IOL’s
have gradual diffractive
steps on the IOL implant
that create a smooth
transition between focal
points.
The IOL also bends
incoming light to the
Tecnis
multiple focal points to
increase vision in various
lighting situations.
Haloing is a side effect
Tetraflex
Accommodative
An accommodative IOL only has
one focal point, but the focal point
moves
The IOL has a hinge similar to the
mechanics of the eye’s natural
lens.
Using the eye’s muscles, the
single focal point of an
accommodative IOL can shift to
bring objects at varying distances
into focus
Patients get good DVA but NVA
may be variable
No Haloing
crystalens 5-0
Patient Experiences with Restor +3
JW 68years
Pre-op RVA 6/12
LVA 6/6
R +1.25/+1.00x36
L +1.25/+0.75X36
Both IOL’s implanted Sept 2008
Patients vision 6/6, N5 each eye
Patient very happy with vision and overall
performance of IOL especially at
intermediate distances
Contrast Sensitivity
Contrast sensitivity is the visual
ability to see objects that may not be
outlined clearly or that do not stand
out from their background.
The ability to see a shade of gray on
a white background or to see white on
a light gray background declines with
age.
People with Low Contrast
Sensitivity can suffer from the
following:
Trouble seeing traffic lights or cars at night
Not being able to see spots on clothes,
counters, or dishes
Not seeing whether a flame is burning on a
stove
Needing a great deal of light to read
Experiencing tired eyes while watching
television.
Tecnis Multifocal IOL
The diffractive Tecnis ® ZM900 multifocal
intraocular lens (AMO) provides good near
visual acuity & good contrast sensitivity at
all distances
Patients receiving the Tecnis multifocal IOL
had better near visual acuity and better
contrast sensitivity at all distances
compared to implantation with the refractive
ReZoom™ multifocal IOL (AMO),
AcrySof® ReSTOR® IOL
There is no clinical or functional
significant difference between the contrast
sensitivity of AcrySof® ReSTOR® and
monofocal control subjects at lower spatial
frequencies
Lower spatial frequencies are important
for vision related to everyday life skills,
such as walking, driving and reading.
AcrySof® ReSTOR® IOL
Binocular Mesopic Contrast Sensitivity
Clinical Significance  0.3 log units at 2 or more
Spatial Frequencies
Mean Contrast Sensitivity
(log units +/- SD)
2.1
1.8
1.5
1.2
0.9
0.6
US ReSTOR - No Glare
US Control - No Glare
US ReSTOR - With Glare
US Control - With Glare
0.3
0
3 cpd
6 cpd
12 cpd
18 cpd
AcrySof® ReSTOR® IOL
Binocular Photopic Contrast Sensitivity
Clinical Significance  0.3 log units at 2 or more
Spatial Frequencies
Mean Contrast Sensitivity
(log units +/- SD)
2.1
1.8
1.5
1.2
0.9
US ReSTOR - No Glare
US Control - No Glare
US ReSTOR - With Glare
US Control - With Glare
0.6
0.3
Largest difference =0.20 log units
0
3 cpd
6 cpd
12 cpd
18 cpd
Contrast Sensitivity
The following 2 slides clearly show very
little difference between Contrast Sensivity
in a Multifocal IOL vs a Monofocal IOL
It is also clear that Contrast Sensitivity in
photopic conditions varies only slightly to
the Contrast Sensitivity obtained in
mesopic conditions for either style of lens
AcrySof® ReSTOR® IOL
Monocular Contrast Sensitivity
Mesopic Conditions - With Glare
Contrast Sensitivity (log units)
Clinical Significance  0.3 log units at 2 or more Spatial Frequencies
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
Monofocal
ReSTOR
0
3 cpd
6 cpd
12 cpd
18 cpd
AcrySof® ReSTOR® IOL
Monocular Contrast Sensitivity
Contrast Sensitivity (log units)
Photopic Conditions - No Glare
Clinical Significance  0.3 log units at 2 or more Spatial Frequencies
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
Monofocal
ReSTOR
0
3 cpd
6 cpd
12 cpd
18 cpd
Acri.LISA Multifocal
Due to asymmetrical light distribution
Acri.LISA IOLs achieve a high light yield.
The optical performance under mesopic
conditions differs only slightly from
photopic conditions.
The contrast sensitivity is improved to a
level which is within the normal range for
healthy phakic patients.
Thank you