Patient selection to optimize near vision performance with a low-addition trifocal lens

Abstract

Purpose:
To assess the impact of ocular biometric variables on the visual performance achieved with a low addition trifocal intraocular lens (MIOL).

Methods:
Retrospective observational study including 34 eyes. Preoperative measured variables included mean corneal power (Km), corneal regular astigmatism (RA), anterior chamber depth (ACD), axial length (AXL), total irregular astigmatism (IA), spherical aberration (SA) and distance from pupil center to vertex normal (µ). Same variables were retrieved from the three month visit follow-up in addition to the actual lens position (ALP), the calculated effective addition (EA), the IOL centration from vertex normal (d), and the visual acuity defocus curve. The area under the defocus curve was computed along the total curve (TAUC) and ranges for far (FAUC), intermediate (IAUC) and near vision (NAUC). The sample was split in two groups of 17 eyes with TAUCs above and below the mean, and the differences among groups for different ocular parameters were assessed.

Results:
The group of eyes above TAUC of 2.03 logMAR*m-1 showed significantly lower Km and greater AXL and SA. Km was negatively correlated with TAUC and NAUC. NAUC was negatively correlated with IA and positively with d. A multiple lineal regression model including Km, d, and IA predicted NAUC (r-square = 34%). No significant differences between IA and SA were found between preoperative and postoperative values but µ significantly decreased after surgery.

Conclusions:
The mean corneal power, irregular astigmatism, and centration from vertex normal should be considered for optimizing the near visual performance with this MIOL.

Full text

Please
cite
this
article
in
press
as:
Fernández
J,
et
al.
Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
Optom.
(2019),
https://doi.org/10.1016/j.optom.2019.06.003
ARTICLE IN PRESS
+Model
OPTOM-304;
No.
of
Pages
9
Journal
of
Optometry
(2019)
xxx,
xxx---xxx
www.journalofoptometry.org
ORIGINAL
ARTICLE
Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens
Joaquín
Fernándeza,
Manuel
Rodríguez-Vallejoa,∗,
Javier
Martíneza,
Ana
Tauste a,
David
P.
Pi˜
nerob,c
aDepartment
of
Ophthalmology
(Qvision),
Vithas
Virgen
del
Mar
Hospital,
04120,
Almería,
Spain
bDepartment
of
Optics,
Pharmacology
and
Anatomy,
University
of
Alicante,
Alicante,
Spain
cDepartment
of
Ophthalmology
(IMQO-Oftalmar),
Vithas
Medimar
International
Hospital,
Alicante,
Spain
Received
10
December
2018;
accepted
26
June
2019
KEYWORDS
Trifocal
intraocular
lens;
Visual
acuity;
Defocus
curves;
Irregular
astigmatism;
Keratometry;
Centration;
Addition
Abstract
Purpose:
To
assess
the
impact
of
ocular
biometric
variables
on
the
visual
performance
achieved
with
a
low
addition
trifocal
intraocular
lens
(MIOL).
Methods:
Retrospective
observational
study
including
34
eyes.
Preoperative
measured
variables
included
mean
corneal
power
(Km),
corneal
regular
astigmatism
(RA),
anterior
chamber
depth
(ACD),
axial
length
(AXL),
total
irregular
astigmatism
(IA),
spherical
aberration
(SA)
and
distance
from
pupil
center
to
vertex
normal
(␮).
Same
variables
were
retrieved
from
the
three
month
visit
follow-up
in
addition
to
the
actual
lens
position
(ALP),
the
calculated
effective
addition
(EA),
the
IOL
centration
from
vertex
normal
(d),
and
the
visual
acuity
defocus
curve.
The
area
under
the
defocus
curve
was
computed
along
the
total
curve
(TAUC)
and
ranges
for
far
(FAUC),
intermediate
(IAUC)
and
near
vision
(NAUC).
The
sample
was
split
in
two
groups
of
17
eyes
with
TAUCs
above
and
below
the
mean,
and
the
differences
among
groups
for
different
ocular
parameters
were
assessed.
Results:
The
group
of
eyes
above
TAUC
of
2.03
logMAR*m-1
showed
significantly
lower
Km
and
greater
AXL
and
SA.
Km
was
negatively
correlated
with
TAUC
and
NAUC.
NAUC
was
negatively
correlated
with
IA
and
positively
with
d.
A
multiple
lineal
regression
model
including
Km,
d,
and
IA
predicted
NAUC
(r-square
=
34%).
No
significant
differences
between
IA
and
SA
were
found
between
preoperative
and
postoperative
values
but
␮
significantly
decreased
after
surgery.
Conclusions:
The
mean
corneal
power,
irregular
astigmatism,
and
centration
from
vertex
nor-
mal
should
be
considered
for
optimizing
the
near
visual
performance
with
this
MIOL.
©
2019
Spanish
General
Council
of
Optometry.
Published
by
Elsevier
Espa˜
na,
S.L.U.
This
is
an
open
access
article
under
the
CC
BY-NC-ND
license
(http://creativecommons.org/licenses/by-
nc-nd/4.0/).
∗Corresponding
author.
E-mail
address:
manuelrodriguezid@qvision.es
(M.
Rodríguez-Vallejo).
https://doi.org/10.1016/j.optom.2019.06.003
1888-4296/©
2019
Spanish
General
Council
of
Optometry.
Published
by
Elsevier
Espa˜
na,
S.L.U.
This
is
an
open
access
article
under
the
CC
BY-NC-ND
license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Please
cite
this
article
in
press
as:
Fernández
J,
et
al.
Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
Optom.
(2019),
https://doi.org/10.1016/j.optom.2019.06.003
ARTICLE IN PRESS
+Model
OPTOM-304;
No.
of
Pages
9
2
J.
Fernández
et
al.
]PALABRAS
CLAVE
Lentes
intraoculares
trifocales;
Agudeza
visual;
Curvas
de
desenfoque;
Astigmatismo
irregular;
Queratometría;
Centrado;
Adición
Selección
del
paciente
para
optimizar
el
rendimiento
visual
en
visión
próxima
con
una
lente
trifocal
de
baja
adición
Resumen
Objetivo:
Valorar
el
impacto
de
las
variables
biométricas
oculares
sobre
el
rendimiento
visual
con
una
lente
intraocular
trifocal
de
baja
adición
(MIOL).
Métodos:
Estudio
observacional
retrospectivo
que
incluyó
34
ojos.
Las
variables
preoperatorias
medidas
incluyeron
potencia
corneal
media
(Km),
astigmatismo
regular
corneal
(AR),
profun-
didad
de
la
cámara
anterior
(ACD),
longitud
axial
(AXL),
astigmatismo
irregular
total
(AI),
aberración
esférica
(AE)
y
distancia
entre
el
centro
de
la
pupila
y
el
vértice
normal
(␮).
Algunas
variables
se
obtuvieron
de
la
visita
de
seguimiento
a
los
tres
meses,
a
las
que
se
a˜
nadieron
la
posición
real
de
la
lente
(ALP),
la
adición
efectiva
(AE),
el
centrado
de
las
LIO
desde
el
vértice
normal
(d),
y
la
curva
de
desenfoque
de
agudeza
visual.
El
área
bajo
la
curva
de
desenfoque
se
calculó
a
lo
largo
de
la
curva
total
(TAUC)
así
como
los
rangos
para
visión
de
lejos
(FAUC),
intermedia
(IAUC)
y
de
cerca
(NAUC).
La
muestra
se
dividió
en
dos
grupos
de
17
ojos
con
TAUCs
por
encima
y
por
debajo
de
la
media,
valorándose
las
diferencias
entre
los
grupos
para
los
diferentes
parámetros
oculares.
Resultados:
El
grupo
de
ojos
con
un
valor
por
encima
de
TAUC
igual
a
2,03
logMAR*m-1
reflejó
un
menor
Km
y
valores
mayores
de
AXL
y
AE.
Km
se
correlacionó
negativamente
con
TAUC
y
NAUC.
NAUC
se
correlacionó
negativamente
con
AI,
y
positivamente
con
d.
Un
modelo
de
regresión
lineal
múltiple
incluyendo
Km,
d,
y
AI
realizó
la
predicción
de
NAUC
(R2=
34%).
No
se
encon-
traron
diferencias
significativas
entre
AI
y
AE
entre
los
valores
preoperatorios
y
postoperatorios,
aunque
␮
disminuyó
significativamente
tras
la
cirugía.
Conclusiones:
La
potencia
corneal
media,
el
astigmatismo
irregular
y
el
centrado
desde
el
vértice
normal
deberían
considerarse
para
optimizar
el
desempe˜
no
visual
de
cerca
con
MIOL.
©
2019
Spanish
General
Council
of
Optometry.
Publicado
por
Elsevier
Espa˜
na,
S.L.U.
Este
es
un
art´
ıculo
Open
Access
bajo
la
licencia
CC
BY-NC-ND
(http://creativecommons.org/licenses/by-
nc-nd/4.0/).
Introduction
Motivation
to
achieve
spectacle
independence
is
likely
the
most
critical
deciding
factor
for
the
interest
in
multifo-
cal
intraocular
lenses
(MIOLs)
implantation.1MIOLs
have
become
an
alternative
for
treating
presbyopia
by
Refractive
Lens
Exchange
(RLE)
due
to
the
fact
that
many
middle-aged
and
older
patients
are
involved
in
sports
and
other
activities
for
which
patients
demand
spectacle
independence.2How-
ever,
it
is
well
known
that
surgery
with
intraocular
lenses
(IOLs)
may
result
in
adverse
events
and
the
MIOL
implanta-
tion
may
present
additional
adverse
events
to
those
already
established
for
monofocal
IOLs,
such
as
dysphotopsia.3This
makes
the
concepts
of
safety,
efficacy
and
predictability
in
RLE
even
more
important
than
in
cataract
surgery
because
far
distance
visual
performance
is
superior
in
RLE
patients.2
Standards
have
been
proposed
for
reporting
the
refrac-
tive
outcomes
of
intraocular
lens---based
refractive
surgery.4
These
standards
are
very
useful
for
comparing
the
general
results
among
procedures
with
different
MIOLs,
but
are
not
enough
for
understanding
the
performance
of
a
MIOL
as
a
function
of
biometric
eye
parameters.
Since
visual
per-
formance
with
MIOLs
has
been
hypothesized
to
be
related
with
angle
kappa
and
MIOL
centration
in
the
presence
of
dysphotopsia,5,6 corneal
spherical
aberration,7,8 regular
corneal
astigmatism,9,10 corneal
irregular
astigmatism,11,12
and
effective
lens
addition,13---15 it
seems
reasonable
to
report
the
impact
of
these
variables
in
the
visual
perfor-
mance
of
each
MIOL
in
such
a
way
the
vision
of
the
most
exigent
patients,
as
in
those
demanding
RLE,
could
be
bet-
ter
predicted.
The
main
aim
of
this
study
is
to
evaluate
the
performance
of
a
low
addition
trifocal
lens
by
means
of
computing
the
area
under
the
visual
acuity
defocus
curves
(VADC)16 as
a
function
of
biometric
parameters.
A
secondary
aim
is
to
propose
a
model
for
the
prediction
of
the
visual
per-
formance
with
the
MIOL
as
a
function
of
these
biometric
eye
parameters.
Subjects
and
methods
Subjects
This
study
was
approved
by
the
local
ethics
committee
of
research
and
was
performed
in
adherence
to
the
tenets
of
the
Declaration
of
Helsinki.
Data
of
34
eyes
from
34
subjects
consecutively
implanted
with
a
trifocal
low
addition
intraoc-
ular
lens
at
Qvision
(Ophthalmology
Department
at
Vithas
Virgen
del
Mar
Hospital)
were
retrospectively
retrieved
from
our
historical
database.
Only
one
eye
randomly
selected
per
subject
was
included
in
the
analysis.
Exclusion
criteria
included
any
adverse
event
presented
during
surgery
that
might
affect
to
the
performance
with
the
lens,
history
of
corneal
refractive
surgery
and
any
other
condition
for
which
the
implant
of
a
MIOL
was
not
recommended.17

Please
cite
this
article
in
press
as:
Fernández
J,
et
al.
Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
Optom.
(2019),
https://doi.org/10.1016/j.optom.2019.06.003
ARTICLE IN PRESS
+Model
OPTOM-304;
No.
of
Pages
9
Optimizing
near
vision
with
low
addition
MIOLs
3
Surgery
procedure
and
intraocular
lens
description
All
the
eyes
retrospectively
retrieved
were
operated
on
by
the
same
surgeon
(JF)
by
means
of
femtosecond
laser-
assisted
cataract
surgery
through
a
temporal
clear
corneal
incision
(CCI)
of
2.5
mm
performed
with
the
laser.
The
IOL
included
in
the
analysis
was
the
difractive
Alsafit
Trifocal
violet
light
filter
(VF)
lens
(Alsanza
GmbH,
Germany),
which
has
a
6
mm
biconvex
optic
aspheric
with
a
-0.165
␮m
cor-
rection
of
SA
and
total
light
transmission
of
87.9%,
this
distributed
50%
for
far,
20%
for
intermediate
and
30%
for
near
(information
obtained
from
manufacturer
brochure).
The
addition
powers
at
the
IOL
plane
were
+1.50
D
for
inter-
mediate
vision
and
+3.00
D
for
the
near
vision.
The
platform
consisted
of
a
modified
plate
haptic
of
11
mm
(0◦angled)
with
4
flexible
adjustable
haptic
fins
(30◦angled)
at
the
cor-
ner
location
of
the
platform.
The
haptic
locations
during
the
implantation
were
approximately
horizontal
in
the
temporal
nasal
direction
(0◦---180◦).
Measured
variables
Biometrical
parameters
obtained
during
the
preoperative
visit
included
mean
corneal
power
(Km),
corneal
regular
astigmatism
(RA),
anterior
chamber
depth
(ACD)
and
axial
length
(AXL)
measured
with
IOL
Master
500
(Carl
Zeiss
Meditec
Inc.,
Dublin,
CA,
USA).
Total
irregular
astigmatism
at
4
mm
(IA),
total
corneal
spherical
aberration
at
6
mm
(SA)
and
distance
from
pupil
center
to
vertex
normal
(chord
mu,
␮)18 measured
with
the
Pentacam
system
(Oculus
GmbH,
Wetzlar,
Germany).
The
same
variables
were
retrieved
from
the
three
month
postoperative
visit
in
addition
to
the
actual
lens
position
(ALP)
measured
with
Pentacam
system
from
the
anterior
corneal
surface
to
the
anterior
MIOL
surface.
The
addition
at
the
IOL
plane
was
computed
considering
the
dioptric
power
of
the
implanted
MIOL,
approximating
ALP
to
ELP,19 and
the
Km
according
to
the
Holladay’s
refrac-
tive
vergence
formula.15 Then,
the
effective
addition
(EA)
at
the
spectacle
plane
was
computed
considering
a
vertex
distance
of
12
mm.
The
monocular
VADC,
measured
with
the
Multifocal
Lens
Analyzer
for
iPad
(version
1.0.8,
85%
screen
brightness,
background
luminance
of
∼250
cd/m2),20 was
also
obtained
at
the
three
month
postoperative
visit
(from
+1.00
D
to
−4.00
D
in
0.50
D
steps).
The
automated
proce-
dure
for
measuring
the
VADC
with
Multifocal
Lens
Analyzer
has
been
previously
described.20---22
For
calculating
the
centration
of
the
MIOL
versus
the
ver-
tex
normal
(d),
a
slit
lamp
picture
was
taken
and
an
ordinal
scale
was
used
to
evaluate
subjectively
the
degree
of
MIOL
centration
(Fig.
1).
The
geometric
center
of
the
IOL
diffrac-
tive
rings
was
estimated
in
reference
to
the
pupil
center,
considering
a
negative
displacement
for
temporal
or
inferior
directions
and
a
positive
displacement
for
superior
or
nasal
directions.
The
centration
was
established
horizontally
and
vertically
(H,
V)
with
the
following
ordinal
scale:
0,
the
first
ring
was
centered
to
the
pupil;
1,
the
first
ring
was
25%
decentered;
2,
the
first
ring
was
50%
decentered
and
the
pupil
center
matched
to
the
edge
of
the
first
ring;
3,
the
pupil
center
matched
the
second
ring;
4,
the
pupil
center
goes
beyond
the
second
ring
(Fig.
1,
top).
Considering
that
the
diameter
of
the
first
ring
is
approximately
1.2
mm
(esti-
mated
by
the
Pentacam
measurement),
the
level
1
would
correspond
to
an
approximated
decentration
of
0.3
mm
and
the
level
2
to
a
decentration
of
0.6
mm.
Thus,
the
MIOL
centration
with
respect
to
the
vertex
normal
was
computed
considering
dx=
H*0.3
-
␮xand
dy=
V
*
0.3
−
␮y, where
d
is
the
distance
from
the
vertex
normal
to
the
center
of
the
ring,
H
and
V
were
the
subjectively
ordinal
scale
result,
␮
is
the
distance
from
pupil
center
to
the
vertex
normal
mea-
sured
with
Pentacam,23 and
0.3
mm
is
a
25%
of
displacement
considering
a
diameter
of
the
first
ring
of
1.2
mm
(Fig.
1,
bottom).
The
displacement
measured
with
this
method
has
demonstrated
to
be
related
with
visual
performance
in
inter-
mediate
vision
with
a
high
addition
MIOL.21
Statistical
analysis
A
conversion
of
the
␮
center
of
coordinates
was
conducted
for
unifying
sign
notation
between
left
and
right
eyes
with
the
Refractive
Analysis
(1.0.0)
toolbox
for
MATLAB
(The
Mathworks
Inc.,
Natick,
MA,
USA).23,24 Areas
under
the
curve
were
calculated
in
the
same
ranges
of
vision
of
a
pre-
vious
work21 for
comparison
purposes:
total
(TAUC),
far
(FAUC),
intermediate
(IAUC),
and
near
(NAUC)
areas
under
the
curve.
The
Shapiro-Wilk
test
was
used
for
testing
nor-
mality
of
variable
distributions.
Mean
differences
among
groups
including
distinct
eyes
were
tested
with
the
Student
t-test
for
independent
samples,
whereas
the
Mann-Whitney
test
was
used
for
variables
non-normally
distributed.
Mean
differences
between
preoperative
and
postoperative
varia-
bles
were
assessed
with
the
paired
t-test.
Furthermore,
correlations
were
also
evaluated
with
the
Pearson
or
the
Spearman’s
correlations
coefficients
depending
if
the
cor-
related
variables
followed
or
not
a
normal
distribution,
respectively.
A
predictive
model
of
the
NAUC
was
con-
structed
by
means
of
a
multiple
linear
regression
analysis
and
the
simple
regression
analysis
was
used
for
prediction
of
linear
related
preoperative
and
postoperative
variables.
Both
statistical
analyses
were
conducted
after
confirming
that
the
required
assumptions
were
accomplished,
including
the
Durbin-Watson
statistic
for
independence
of
observa-
tions,
the
homoscedasticity,
and
the
normally
distribution
of
the
residuals.
The
Limits
of
Agreement
(LoAs)
were
also
computed
as
the
means
of
the
differences
±2
SD
between
preoperative
and
postoperative
variables.25 The
statistical
analyses
were
performed
using
the
IBM
SPSS
20.0
software
for
Windows
(SPSS,
Chicago,
IL).
Results
Eyes
from
11
men
and
23
women
with
mean
age
of
59
±
8
years
were
included
in
the
analysis,
ranging
from
45
to
78
years
old.
Mean
AXL
was
23.17
±
1.33
mm
and
median
was
22.81
mm,
ranging
from
21.58
mm
to
26.54
mm.
The
mean
EA
at
the
spectacle
plane
was
1.90
±
0.05
D.
Fig.
2A
shows
the
mean
VADC
with
a
near
vision
peak
at
-2
D,
close
to
the
computed
EA.
Mean
TAUC
was
2.03
±
0.70,
FAUC
was
0.61
±
0.18,
IAUC
was
0.25
±
0.12
and
NAUC
was
0.48
±
0.28.
Two
mean
VADC
are
shown
in
Fig.
2B,
corre-
sponding
to
a
split
of
the
sample
in
groups
of
17
eyes
above
the
mean
TAUC
of
2.03
and
17
eyes
below
this
mean.
Signifi-
cant
mean
differences
(m.d.)
were
found
between
groups

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J,
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Patient
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with
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low-addition
trifocal
lens.
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J.
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Figure
1
Top
image
shows
an
example
of
the
ordinal
scale
used
for
evaluating
the
intraocular
lens
centration.
The
diagram
describes
the
right
eye
with
the
pupil
divided
by
a
vertical
line.
The
first
ring
of
the
lens
is
divided
in
4
sections
that
serve
as
a
reference
to
measure
the
displacement
to
the
pupil
center.
From
left
to
right,
the
lens
is
centered
(0.0),
25%
temporal
(−1.0)
and
50%
temporal
(−2.0)
the
size
of
the
first
ring.
The
last
top
image
shows
a
real
example
with
pupil
divided
by
a
red
cross
and
rings
of
the
lens
marked
with
white
circles
for
a
clear
visualization.
For
vertical
centration,
the
same
approach
was
performed
dividing
the
pupil
by
a
horizontal
line.
Bottom
image
shows
the
system
of
coordinates
used
in
the
research
(For
interpretation
of
the
references
to
colour
in
this
figure
legend,
the
reader
is
referred
to
the
web
version
of
this
article).
m.d.
=
1.12
(p
<
0.001)
for
TAUC,
m.d.
=
0.23
(p
<
0.0001)
for
FAUC,
m.d.
=
0.14
(p
<
0.0001)
for
IAUC
and
m.d.
=
0.34
(p
<
0.0001).
Group
with
higher
TAUC
has
significantly
lower
Km,
higher
AXL
and
higher
SA
(Table
1).
Correlations
with
biometric
measures
Correlations
between
the
different
variables
measured
post-
operatively
and
AUCs
are
shown
in
Table
2.
TAUC
was
negatively
correlated
with
Km
(r
=
−0.42,
p
=
0.01)
and
pos-
itively
with
the
SA
(r
=
0.38,
p
=
0.03).
SA
was
significantly
correlated
with
FAUC
(r
=
0.39,
p
=
0.02)
and
IAUC
(r
=
0.37,
p
=
0.03)
but
not
with
NAUC
(r
=
0.12,
p
=
0.49).
On
the
other
hand,
the
NAUC
was
negatively
correlated
with
the
Km
(r
=
−0.38,
p
=
0.03),
as
well
as
with
the
FAUC
(r
=
−0.49,
p
=
0.003).
Correlation
of
NAUC
was
also
negative
with
the
IA
(
=
−0.41,
p
=
0.02)
and
positive
with
the
EA
(
=
0.39,
p
=
0.02)
and
the
d
(
=
0.44,
p
=
0.009).
A
positive
correla-
tion
was
found
between
AXL
and
FAUC
(r
=
0.45,
p
=
0.007),
but
AXL
was
also
correlated
with
Km
(
=
−0.85,
p
<
0.0001)
and
Km
showed
a
correlation
close
to
statistical
significance
with
the
SA
(r
=
−0.34,
p
=
0.05).
Prediction
of
the
near
visual
performance
Two
multiple
regression
models
were
run
to
predict
NAUC.
Model
1
with
EA,
IA
and
d
was
found
to
predict
with
statis-
tical
significantce
NAUC,
F(3,
30)
=
6.64,
p
<
.001,
R2=
.399,
adj.
R2=
.339.
The
Model
2,
including
the
Km,
IA
and
d,
pre-
dicted
with
statistical
significance
NAUC,
F(3,
30)
=
6.56,
p
<
.002,
R2=
.396,
adj.
R2=
.336.
IA
inclusion
was
not
signif-
icant
in
Model
1.
Regression
coefficients,
standard
errors,
and
significances
of
each
variable
can
be
found
in
Table
3.
Agreement
between
preoperative
and
postoperative
parameters
The
agreement
with
preoperative
values
was
evaluated
for
variables
correlated
with
AUCs
(Table
4).
No
signifi-
cant
differences
were
found
between
variables
measured
preoperatively
and
postoperatively,
except
for
the
chord
␮
that
was
significantly
reduced
after
surgery
(Fig.
3A).
Preoperative
mean
␮
was
0.25
mm
at
28◦(SDx
=
0.18
mm,
SDy
=
0.19
mm)
and
postoperative
mean
␮
was
0.11
mm
at
11◦(SDx
=
0.14
mm,
SDy
=
0.11
mm).
A
linear
regres-
sion
analysis
established
that
post-␮xcan
be
predicted
(F
=
29.76,
p
<
0.0001,
R2=
.48,
adj.
R2=
.47)
by
means
of
pre-␮x.
The
regression
equation
was
post-␮x=
0.51*
prex
−

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J,
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Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
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Optimizing
near
vision
with
low
addition
MIOLs
5
Table
1
Groups
with
total
area
under
the
curve
of
visual
acuity
higher
and
lower
to
mean.
Variable
TAUC
<
2.03
TAUC
≥
2.03
t/zap
Mean
±
SD
Mean
±
SD
Median
(IQR)
Median
(IQR)
Age
57.82
±
8.13 60.41
±
8.15
−0.93
0.36
58
(13) 61
(13)
Km
(D) 44.74
±
1.13 42.58
±
2.61 3.15
0.005*
44.54
(1.84) 42.46
(4.63)
AXL
(mm)
22.63
±
0.84
23.71
±
1.52
2.34a0.02*
22.47
(0.87)
23.27
(2.14)
ACD
(mm)
2.97
±
0.32
2.97
±
0.42
−0.94
0.36
2.88
(0.40)
3.13
(0.78)
ALP
(mm)
4.27
±
0.28
4.47
±
0.38
−1.76
0.09
4.23
(0.40)
4.44
(0.73)
EA
(D)
1.90
±
0.05
1.90
±
0.05
0.01
0.99
1.90
(0.06)
1.89
(0.08)
RA
(D)
−0.66
±
0.24
−0.74
±
0.35
0.68
0.50
−0.7
(0.40)
−0.7
(0.6)
IA
(␮m)
0.16
±
0.06
0.15
±
0.06
−0.57a0.59
0.13
(0.13)
0.15
(0.07)
SA
(␮m)
0.31
±
0.07
0.39
±
0.15
−2.11
0.047*
0.31
(0.09)
0.36
(0.17)
␮
(mm)
0.18
±
0.10
0.19
±
0.08
−0.03
0.97
0.19
(0.15)
0.17
(0.10)
␮x(mm)
0.11
±
0.13
0.12
±
0.14
−0.14
0.89
0.10
(0.18)
0.10
(0.21)
␮y(mm)
0.01
±
0.12
0.03
±
0.09
−0.48
0.64
−0.03
(0.16)
0.04
(0.11)
d
(mm)
0.25
±
0.17
0.34
±
0.19
−1.39
0.18
0.21
(0.26)
0.32
(0.24)
dx(mm)
−0.16
±
0.21
−0.22
±
0.20
0.83
0.41
−0.14
(0.35)
−0.19
(0.24)
dy(mm)
0.02
±
0.15
0.02
±
0.25
0.00
1.00
0.03
(0.21) 0.00
(0.29)
TAUC:
total
area
under
the
curve;
Km:
mean
corneal
power;
AXL:
axial
length;
ACD:
anterior
chamber
depth;
ALP:
actual
lens
position;
EA:
effective
addition;
RA:
regular
astigmatism;
IA:
irregular
astigmatism;
SA:
spherical
aberration;
␮:
distance
from
pupil
center
to
vertex
normal;
␮x:
␮
in
horizontal
cartesian
coordinates;
␮y:
␮
in
vertical
cartesian
coordinates;
d:
Intraocular
lens
centration
from
vertex
normal;
dx:
d
in
horizontal
cartesian
coordinates;
dy:
d
in
vertical
cartesian
coordinates.
SD:
standard
deviation;
IQR:
interquartile
range.
t:
student
t-test
for
independent
samples.
za:
Mann-Whitney
test.
*p
<
0.05.
0.002.
On
the
other
hand,
the
linear
regression
analysis
for
post-␮yconsidering
pre-␮ywas
not
significant
(F
=
1.50,
p
=
0.23,
R2=
.0.05,
adj.
R2=
.0.02).
Therefore,
a
mean
dif-
ference
of
0.09
mm
can
be
used
to
predict
postoperative
␮y
(Table
4).
The
mean
IOL
centration
(d)
was
0.19
mm
at
173◦
(SDx
=
0.21
mm,
SDy
=
0.20
mm)
(Fig.
3B).
Discussion
In
this
study,
we
have
evaluated
the
influence
of
biomet-
ric
parameters
in
the
performance
achieved
with
a
trifocal
intraocular
lens
of
low
addition.
The
analysis
of
TAUC
after
splitting
the
sample
in
two
groups
with
the
posterior
evalu-
ation
of
differences
for
the
included
biometric
parameters
showed
that
Km
was
the
most
important
parameter
for
pre-
dicting
the
TAUC.
Subjects
with
lower
Km
resulted
in
higher
TAUC;
conversely,
AXL
and
SA
were
higher
in
the
group
with
greater
TAUC,
but
it
is
important
to
note
that
AXL
and
SA
were
also
correlated
with
Km
and
can
be
considered
as
con-
founding
variables.
In
fact,
Llorente
et
al.26 reported
that
SA
is
greater
in
hyperopes
than
in
myopes
and
it
is
well
known
that
Km
decreases
with
myopia
increase
and
conversely
for
the
AXL.27 The
most
remarkable
result
of
our
data
is
that
the
group
with
greater
TAUC
showed
significant
higher
AUC
at
all
distances,
but
only
Km
was
significantly
correlated
at
far
and
near
distance,
whereas
AXL
and
SA
were
not
cor-
related
with
NAUC.
For
this
reason,
we
consider
Km
as
the
most
important
factor
for
predicting
the
TAUC,
whereas
the
SA
should
not
be
considered
as
a
factor
for
predicting
TAUC,
but
should
be
considered
as
a
confounding
variable.
It
is
important
also
to
note
for
SA
interpretation
that
we
used
the
total
corneal
SA
for
correlation
and
not
the
total
ocu-

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Fernández
J,
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Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
Optom.
(2019),
https://doi.org/10.1016/j.optom.2019.06.003
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6
J.
Fernández
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Table
2
Visual
acuity
defocus
curve
versus
biometrical
parameters.
Area
under
the
curve
(logMAR
*
mm−1)
Correlation
coefficient
(p-value)
Variable
Total
Far
Intermediate
Near
Age
0.14
(0.42)
0.13
(0.48)
0.28
(0.11)
−0.04
(0.83)
Km
(D)
−0.42
(0.01)a*
−0.49
(0.003)a*
−0.17
(0.33)a−0.38
(0.03)a*
AXL
(mm)
0.31
(0.08)a0.45
(0.007)a* 0.07(0.69)a0.28
(0.11)a
ALP
(mm) 0.05
(0.78) 0.27
(0.13) 0.03
(0.86)
−0.14
(0.45)
EA
(D) 0.21
(0.23) 0.03
(0.86) 0.03
(0.87) 0.39
(0.02)*
RA
(D) −0.12
(0.50) −0.03
(0.87) −0.20
(0.24) −0.12
(0.52)
IA
(␮m)
−0.09
(0.63)
−0.15
(0.41)
−0.006
(0.97)
−0.41
(0.02)*
SA
(␮m)
0.38
(0.03)a*
0.39
(0.02)a*
0.37
(0.03) a*
0.12
(0.49)a
␮
(mm)
0.16
(0.37)
0.26
(0.14)
0.28
(0.11)
−0.02
(0.92)
␮x(mm)
0.07
(0.71)
0.18
(0.31)
0.13
(0.48)
−0.08
(-0.64)
␮y(mm)
0.19
(0.28)
0.13
(0.45)
0.21
(0.24)
0.12
(0.50)
d
(mm)
0.34
(0.05)*
0.19
(0.29)
0.28
(0.11)
0.44
(0.009)*
dx(mm)
−0.15
(0.40)
−0.17
(0.33)
−0.09
(0.62)
−0.19
(0.29)
dy(mm)
0.10
(0.56)a−0.07
(0.68)a−0.001
(0.99)a−0.02
(0.91)a
Km:
mean
corneal
power;
AXL:
axial
length;
ALP:
actual
lens
position;
EA:
effective
addition;
RA:
regular
astigmatism;
IA:
irregular
astigmatism;
SA:
spherical
aberration;
␮:
distance
from
pupil
center
to
vertex
normal;
␮x:
␮
in
horizontal
cartesian
coordinates;
␮y:
␮
in
vertical
cartesian
coordinates;
d:
Intraocular
lens
centration
from
vertex
normal;
dx:
d
in
horizontal
cartesian
coordinates;
dy:
d
in
vertical
cartesian
coordinates.
aSpearman
rho
instead
of
Pearson
r.
Table
3
Multiple
regression
linear
models
for
prediction
of
the
near
area
under
the
curve.
Variable B
SEB
␤
t
p
Intercept
−3.28
1.61
−2.02
0.05
Computed
addition
(EA)
1.99
0.83
0.34
2.39
0.02
Vertex
to
IOL
center
(total)
(d)
0.57
0.23
0.37
2.49
0.02
Irregular
astigmatism
at
4
mm
(IA)
−1.14
0.70
−0.25
−1.64
0.11
Intercept
2.36
0.79
3.00
0.005
Corneal
power
(Km)
−0.04
0.02
−0.33
−2.35
0.03
Vertex
to
IOL
center
(total)
(d)
0.53
0.23
0.34
2.32
0.03
Irregular
astigmatism
at
4
mm
(IA)
−1.44
0.69
−0.31
−2.10
0.04
B:
unstandardized
regression
coefficient;
SEB:
standard
error
of
the
coefficient;
␤:
standardized
coefficient.
Table
4
Parameters
variations
after
surgery.
Variable
Preoperative
mean
±
SD
Postoperative
mean
±
SD
t
p
m.d.
LoAs
Km
(D)
43.69
±
2.29
43.66
±
2.27
−0.65
0.52
0.04
0.66
IA
(␮m)
0.14
±
0.07
0.15
±
0.06
−1.33
0.19
−0.01
0.12
SA
(␮m)
0.35
±
0.13
0.35
±
0.12
−0.27
0.79
0.00
0.12
␮x(mm)
0.22
±
0.18
0.11
±
0.14
4.82
<0.0001*
0.11
0.26
␮y(mm)
0.12
±
0.11
0.02
±
0.11
4.23
<0.0001*
0.09
0.44
Km:
mean
corneal
power;
IA:
irregular
astigmatism;
SA:
spherical
aberration;
␮x:
␮
in
horizontal
cartesian
coordinates;
␮y:
␮
in
vertical
cartesian
coordinates.
SD:
standard
deviation.
t:
paired
t-test.
m.d.:
mean
differences.
LoAs:
limits
of
agreement.
*p
<
0.05.

Please
cite
this
article
in
press
as:
Fernández
J,
et
al.
Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
Optom.
(2019),
https://doi.org/10.1016/j.optom.2019.06.003
ARTICLE IN PRESS
+Model
OPTOM-304;
No.
of
Pages
9
Optimizing
near
vision
with
low
addition
MIOLs
7
Figure
2
(A)
Mean
visual
acuity
defocus
curve
of
the
34
measured
eyes.
(B)
Defocus
curves
from
eyes
with
near
area
under
the
curve
(NAUC)
higher
and
lower
to
0.48.
Vertical
bars
describe
the
standard
deviation.
lar
SA.
Furthermore,
an
important
limitation
of
the
study
was
to
use
the
value
at
6
mm
for
SA
offered
by
the
Cataract
Preoperative
Modulus
of
Pentaca.
This
value
does
not
repre-
sent
the
effective
SA
during
the
measurement
of
the
visual
performance
that
should
be
recalculated
for
the
exact
pupil
size
that
the
patient
have
during
the
VADC
measurement.28
Furthermore,
the
age
was
not
significantly
different
between
groups
and
was
not
correlated
with
AUCs
as
might
be
expected,29,30 mainly
due
to
the
fact
that
95%
of
subjects
were
within
56
and
61
years
old.
RA
was
not
correlated
with
AUCs
at
any
range
of
dis-
tances.
Considering
that
subjects
had
a
postoperative
RA
lower
than
1.3
D
in
all
cases,
our
results
are
on
agreement
with
Hayashi
et
al.9,10 who
reported
that
eyes
with
a
mul-
tifocal
intraocular
lens
achieved
good
visual
acuity
at
both
distance
and
near
when
astigmatism
is
within
1.0
D.
With
regard
to
IA,
Maeda11 described
that
0.3
␮m
can
be
consid-
ered
as
the
cut-off
value
for
MIOLs.
All
the
eyes
included
in
our
study
had
an
IA
lower
than
0.3
␮m
but
interestingly
we
found
a
negative
correlation
between
IA
and
NAUC
which
means
that
despite
of
having
less
than
0.3
␮m
of
IA,
sub-
jects
with
lower
IA
would
have
higher
NAUC.
The
IA,
unlike
SA,
was
not
correlated
with
the
Km
therefore
both
variables
were
included
in
a
multiple
regression
analysis
model
which
explained
the
34%
of
variability
in
the
NAUC.
The
model
was
also
calculated
considering
the
EA
instead
Km,
but
the
R2
was
not
improved
as
it
would
be
expected
since
EA
was
com-
puted
considering
not
only
Km
but
also
an
approximation
of
ALP
to
ELP.
Some
authors
have
described
the
importance
of
the
ELP
in
the
EA,13---15 however
according
to
our
results
and
considering
that
the
95%
of
the
eyes
had
an
ELP
in
the
range
of
4.25
mm
and
4.49
mm,
the
variations
in
the
EA
were
mainly
explained
by
Km
and
this
was
one
possible
reason
for
not
considering
EA
instead
of
Km
as
it
did
not
improve
the
model.
The
model
also
included
the
IOL
centration;
higher
d,
which
means
less
centration,
was
related
with
greater
NAUC.
The
95%
of
the
eyes
were
between
0.23
mm
and
0.36
mm
from
the
vertex
normal,
which
is
a
value
below
Figure
3
A)
Location
of
the
vertex
normal
from
to
the
pupil
center
for
preoperative
and
postoperative
measures.
Black
triangles
describe
the
mean
and
the
ellipse
around
the
triangles
the
standard
deviation.
B)
Location
of
the
intraocular
lens
(IOL)
center
to
the
vertex
normal.
Black
circle
describes
the
mean
and
the
ellipse
around
the
circle
the
standard
deviation.
Each
ring
on
the
plot
describes
a
0.2
mm
step.
Locations
are
nasal
for
0◦,
superior
for
90◦,
temporal
for
180◦and
inferior
for
270◦.

Please
cite
this
article
in
press
as:
Fernández
J,
et
al.
Patient
selection
to
optimize
near
vision
performance
with
a
low-addition
trifocal
lens.
J
Optom.
(2019),
https://doi.org/10.1016/j.optom.2019.06.003
ARTICLE IN PRESS
+Model
OPTOM-304;
No.
of
Pages
9
8
J.
Fernández
et
al.
than
0.4
mm,
the
cut-off
value
reported
for
which
MIOLs
are
associated
to
a
deterioration
of
the
MTF.31 Furthermore,
diffractive
MIOLs
have
shown
a
decrease
of
the
near
MTF
as
the
decentration
increase.32 However,
as
we
evaluated
the
NAUC
instead
of
a
particular
point
at
near,
the
improve-
ment
of
NAUC
can
be
explained
by
an
increase
of
the
depth
of
focus
due
to
high
order
aberrations
induction
with
decen-
tration.
Another
possible
explanation
might
be
that
the
light
is
focused
closer
to
the
fovea
for
the
near
foci
for
this
loca-
tion
of
the
IOL
which
is
the
natural
position
of
the
crystalline
lens.33 This
fact
should
be
analyzed
in
future
studies
by
means
of
ray-tracing
simulations
in
model
eyes.
The
kappa
angle
or
better
named
␮-chord,18,34 has
been
also
related
to
the
performance
with
the
MIOL.5,6 In
our
study,
␮-chord
did
not
have
relationship
with
the
AUCs
probably
due
to
the
small
value
which
decreased
signifi-
cantly
after
surgery
and
probably
due
the
location
of
the
IOL
that
has
a
higher
role
on
the
potential
deterioration
of
the
visual
performance.
The
IOL
was
generally
centered
temporal
to
the
pupil.
These
results
are
in
agreement
with
those
described
in
the
literature
and
they
are
due
to
the
location
of
the
pupil
center
relative
to
the
capsular
bag.35
Decentration
higher
than
0.3
mm
has
been
hypothesized
to
induce
a
poorer
corrected
distance
visual
acuity
than
might
be
improved
with
Argon
Laser
Iridoplasty.36 However,
we
found
that
higher
decentration
was
correlated
with
higher
NAUC.
Therefore,
visual
function
should
be
evaluated
in
a
wide
range
of
distances
in
order
to
take
decisions
about
realignment
of
the
IOL.
As
the
decentration
was
not
correlated
with
other
ranges
of
the
VADC,
it
can
be
stated
that
visual
acuity
at
far
or
intermediate
vision
was
not
affected
by
the
decentration.
It
might
be
concluded
that
a
slight
decentration
of
the
lenses
can
be
recommendable
in
order
to
achieve
better
visual
acu-
ity
at
near
with
a
low
addition
trifocal
lens.
This
finding
is
in
agreement
with
a
previous
study
with
a
high
addition
trifocal
intraocular
lens,
but
the
increase
of
performance
was
pre-
sented
at
the
intermediate
vision.21 Therefore,
this
slight
decentration
appears
to
favor
the
foci
with
lower
energy,
either
near
in
a
low
addition
trifocal
lens
and
intermediate
in
a
high
addition
trifocal
lens.
However,
these
results
should
be
interpreted
with
caution
as
it
is
well
known
that
visual
acuity
is
not
a
good
descriptor
of
visual
quality.
Indeed,
the
fact
that
the
visual
acuity
is
not
affected
at
far
distance
with
a
slightly
decentered
IOL
does
not
mean
that
the
optical
quality
in
terms
of
other
metrics
such
as
contrast
sensitiv-
ity
is
not
reduced.37 This
should
be
studied
in
the
future
including
metrics
based
on
contrast
sensitivity.
In
conclusion,
we
analyzed
the
impact
of
several
bio-
metric
eye
parameters
over
the
area
under
the
defocus
curves.
The
corneal
power
was
the
most
important
factor
for
predicting
the
visual
acuity
along
the
total
curve,
this
finding
is
in
agreement
with
a
previous
study
with
other
high
addition
trifocal
lens.21 The
spherical
aberration
can
show
a
false
relationship
with
the
variation
of
visual
acuity
because
eyes
with
lower
corneal
power
have
also
greater
spherical
aberration,
which
means
that
spherical
aberration
acts
as
a
confounding
variable.
Likewise,
irregular
astigma-
tism
should
be
considered
for
the
prediction
of
the
near
vision
with
the
trifocal
IOL
evaluated,
even
for
values
lower
than
0.3
␮m,
because
lower
irregular
astigmatism
is
related
to
better
near
vision.
We
also
reported
that
near
vision
improves
with
the
IOL
decentration,
considering
that
lenses
were
commonly
centered
slightly
temporal
to
the
vertex
normal,
and
this
location
may
be
preferable
for
obtaining
better
near
visual
acuity
results.
Finally,
it
is
important
to
note
that
our
results
were
obtained
with
a
particular
trifocal
low
addition
IOL
and
with
a
sample
with
specific
biometric
eye
parameters
and
the
results
might
not
be
extrapolated
to
other
MIOLs
or
to
sample
of
eyes
with
different
biomet-
ric
parameters.
Similar
future
studies
should
be
performed
including
other
lenses,
eyes
with
different
biometric
char-
acteristics
and
metrics
that
better
describe
visual
quality
that
visual
acuity.
Conflicts
of
interest
MR-V
has
designed
and
programmed
the
Multifocal
Lens
Ana-
lyzer
test
used
in
the
current
study
which
is
distributed
by
the
Apple
Store
as
well
as
the
Refractive
Analysis
Toolbox
for
Matlab.
The
other
authors
report
no
conflicts
of
inter-
est
and
have
no
proprietary
interest
in
any
of
the
materials
mentioned
in
this
article.
Acknowledgments
None.
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