Efficacy of vision therapy in children with learning disability and associated binocular vision anomalies

Abstract

Purpose:
To report the frequency of binocular vision (BV) anomalies in children with specific learning disorders (SLD) and to assess the efficacy of vision therapy (VT) in children with a non-strabismic binocular vision anomaly (NSBVA).

Methods:
The study was carried out at a centre for learning disability (LD). Comprehensive eye examination and binocular vision assessment was carried out for 94 children (mean (SD) age: 15 (2.2) years) diagnosed with specific learning disorder. BV assessment was done for children with best corrected visual acuity of ≥6/9 - N6, cooperative for examination and free from any ocular pathology. For children with a diagnosis of NSBVA (n=46), 24 children were randomized to VT and no intervention was provided to the other 22 children who served as experimental controls. At the end of 10 sessions of vision therapy, BV assessment was performed for both the intervention and non-intervention groups.

Results:
Binocular vision anomalies were found in 59 children (62.8%) among which 22% (n=13) had strabismic binocular vision anomalies (SBVA) and 78% (n=46) had a NSBVA. Accommodative infacility (AIF) was the commonest of the NSBVA and found in 67%, followed by convergence insufficiency (CI) in 25%. Post-vision therapy, the intervention group showed significant improvement in all the BV parameters (Wilcoxon signed rank test, p<0.05) except negative fusional vergence.

Conclusion:
Children with specific learning disorders have a high frequency of binocular vision disorders and vision therapy plays a significant role in improving the BV parameters. Children with SLD should be screened for BV anomalies as it could potentially be an added hindrance to the reading difficulty in this special population.

Full text

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
Journal
of
Optometry
(2017)
xxx,
xxx---xxx
www.journalofoptometry.org
ORIGINAL
ARTICLE
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies
Jameel
Rizwana
Hussaindeena,b,∗,
Prerana
Shaha,b,
Krishna
Kumar
Ramania,
Lalitha
Ramanujanc
aSrimathi
Sundari
Subramanian
Department
of
Visual
Psychophysics,
Elite
School
of
Optometry
(In
Collaboration
with
Birla
Institute
of
Technology
and
Science),
Unit
of
Medical
Research
Foundation,
8,
G.S.T.
Road,
St.
Thomas
Mount,
Chennai
600016,
India
bBinocular
Vision
and
Vision
Therapy
Clinic,
Sankara
Nethralaya,
18,
College
Road,
Nungambakkam,
Chennai
600006,
India
cAlpha
to
Omega
Learning
Center,
Chennai,
India
Received
14
June
2016;
accepted
14
February
2017
KEYWORDS
Binocular
vision
anomalies;
Learning
disability;
Non-strabismic
binocular
vision
anomalies;
Convergence
insufficiency;
Accommodative
infacility
Abstract
Purpose:
To
report
the
frequency
of
binocular
vision
(BV)
anomalies
in
children
with
specific
learning
disorders
(SLD)
and
to
assess
the
efficacy
of
vision
therapy
(VT)
in
children
with
a
non-strabismic
binocular
vision
anomaly
(NSBVA).
Methods:
The
study
was
carried
out
at
a
centre
for
learning
disability
(LD).
Comprehensive
eye
examination
and
binocular
vision
assessment
was
carried
out
for
94
children
(mean
(SD)
age:
15
(2.2)
years)
diagnosed
with
specific
learning
disorder.
BV
assessment
was
done
for
children
with
best
corrected
visual
acuity
of
≥6/9
---
N6,
cooperative
for
examination
and
free
from
any
ocular
pathology.
For
children
with
a
diagnosis
of
NSBVA
(n
=
46),
24
children
were
randomized
to
VT
and
no
intervention
was
provided
to
the
other
22
children
who
served
as
experimental
controls.
At
the
end
of
10
sessions
of
vision
therapy,
BV
assessment
was
performed
for
both
the
intervention
and
non-intervention
groups.
Results:
Binocular
vision
anomalies
were
found
in
59
children
(62.8%)
among
which
22%
(n
=
13)
had
strabismic
binocular
vision
anomalies
(SBVA)
and
78%
(n
=
46)
had
a
NSBVA.
Accommodative
infacility
(AIF)
was
the
commonest
of
the
NSBVA
and
found
in
67%,
followed
by
convergence
insufficiency
(CI)
in
25%.
Post-vision
therapy,
the
intervention
group
showed
significant
improve-
ment
in
all
the
BV
parameters
(Wilcoxon
signed
rank
test,
p
<
0.05)
except
negative
fusional
vergence.
∗Corresponding
author
at:
Elite
School
of
Optometry,
Unit
of
Medical
Research
Foundation,
8,
G.S.T.
Road,
St.
Thomas
Mount,
Chennai
600016,
India.
E-mail
address:
rizwana@snmail.org
(J.R.
Hussaindeen).
http://dx.doi.org/10.1016/j.optom.2017.02.002
1888-4296/©
2017
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:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
2
J.R.
Hussaindeen
et
al.
Conclusion:
Children
with
specific
learning
disorders
have
a
high
frequency
of
binocular
vision
disorders
and
vision
therapy
plays
a
significant
role
in
improving
the
BV
parameters.
Children
with
SLD
should
be
screened
for
BV
anomalies
as
it
could
potentially
be
an
added
hindrance
to
the
reading
difficulty
in
this
special
population.
©
2017
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/).
PALABRAS
CLAVE
Anomalías
en
la
visión
binocular;
Trastorno
de
aprendizaje;
Alteraciones
en
la
visión
binocular
no
estrábica;
Insuficiencia
de
convergencia;
Inflexibilidad
acomodativa
Eficacia
de
la
terapia
visual
en
ni˜
nos
con
trastorno
de
aprendizaje
y
anomalías
en
la
visión
binocular
asociadas
Resumen
Objetivo:
Reportar
la
frecuencia
de
las
anomalías
en
la
visión
binocular
(VB)
en
ni˜
nos
con
trastornos
específicos
de
aprendizaje
(SLD),
y
evaluar
la
eficacia
de
la
terapia
visual
(TV)
en
ni˜
nos
con
alteraciones
en
la
visión
binocular
no
estrábicas
(NSBVA).
Métodos:
El
estudio
se
llevó
a
cabo
en
un
centro
para
discapacidades
de
aprendizaje
(LD).
Se
realizó
un
amplio
examen
ocular
y
una
valoración
de
la
visión
binocular
en
94
ni˜
nos
(Media
(DE)
edad:
15
(2,2)
a˜
nos)
con
diagnóstico
de
trastorno
específico
de
aprendizaje.
Se
llevó
a
cabo
una
valoración
de
la
VB
en
los
ni˜
nos,
con
agudeza
visual
mejor
corregida
de
≥6/9
---
N6,
que
cooperaron
durante
el
examen,
y
que
carecían
de
patología
ocular.
En
los
ni˜
nos
con
diagnóstico
de
NSBVA
(n
=
46),
se
aleatorizaron
24
de
ellos
para
terapia
visual,
sin
realizar
intervención
alguna
en
los
22
ni˜
nos
restantes,
que
sirvieron
de
controles.
Al
finalizar
las
10
sesiones
de
terapia
visual,
se
realizó
una
valoración
de
VB
tanto
en
el
grupo
de
intervención
como
en
el
de
no
intervención.
Resultados:
Se
encontraron
anomalías
en
la
visión
binocular
en
59
ni˜
nos
(62,8%),
de
entre
los
cuales
el
22%
(n
=
13)
tenían
alteraciones
en
la
visión
binocular
estrábica
(SBVA),
y
el
78%
(n
=
46)
reflejaron
NSBVA.
La
inflexibilidad
acomodativa
(AIF)
fue
la
NSBVA
más
común,
estando
presente
en
el
67%
de
los
casos,
seguida
de
la
insuficiencia
de
convergencia
(CI)
en
25%
de
ellos.
Tras
la
terapia
visual,
el
grupo
de
intervención
reflejó
una
mejora
significativa
en
todos
los
parámetros
de
VB
(prueba
de
los
rangos
con
signo
de
Wilcoxon:
p
<
0,05)
exceptuando
la
vergencia
fusional
negativa.
Conclusión:
Los
ni˜
nos
con
trastorno
específico
de
aprendizaje
tienen
una
elevada
frecuencia
de
anomalías
en
la
visión
binocular,
y
en
ellos
la
terapia
visual
juega
un
papel
significativo
para
la
mejora
de
los
parámetros
de
VB.
Deberá
supervisarse
a
los
ni˜
nos
con
SLD,
en
relación
a
las
anomalías
de
VB,
que
podrían
suponer
un
obstáculo
a˜
nadido
a
la
dificultad
lectora
en
esta
población
especial.
©
2017
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
Learning
disability
(LD)
has
been
defined
as
‘‘A
generic
term
that
refers
to
a
heterogeneous
group
of
disorders
manifested
by
significant
difficulties
in
the
acquisition
and
use
of
listen-
ing,
speaking,
reading,
writing,
reasoning,
or
mathematical
skills’’.1Specific
LDs
have
been
reported
to
be
affecting
specific
domains
of
reading,
written
expression
and
math-
ematics,
with
reading
as
the
majorly
affected
domain.2In
India,
the
reported
prevalence
of
specific
learning
disabili-
ties
is
15.17%
among
8---11
year
old
children.3As
reading
is
a
primary
concern
under
the
SLD,
it
also
raises
concern
about
the
efficiency
of
the
visual
system
that
could
contribute
to
the
reading
impairment.4About
80%
of
children
with
learning
disability
are
shown
to
be
affected
with
accom-
modation
and
vergence
anomalies
that
include
convergence
insufficiency
(CI),
reduced
amplitude
of
accommodation
(AOA),
reduced
accommodative
and
vergence
facility,
low
accommodative
convergence/accommodation
(AC/A)
ratio
and
reduced
fusional
ranges.5,6
Also
children
with
reading
and
writing
difficulties
are
shown
to
have
deficits
in
accommodation
and
vergence
parameters
compared
to
age
matched
controls
without
reading
and
writing
difficulties.7---11 It
has
been
shown
that
these
dysfunctions
can
interfere
with
the
reading
speed,
accuracy,
and
reading
efficiency.11 Thus
assessing
the
effi-
ciency
of
the
binocular
vision
in
children
with
learning
disorders
is
highly
recommended.
The
efficacy
of
vision
therapy
in
the
treatment
of
binocular
vision
anomalies
is
well
established
among
children
attending
regular
stream
education.12 Yet
there
is
paucity
of
randomized
controlled
trials
testing
the
efficacy
of
vision
therapy
in
this
special

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
Vision
therapy
for
binocular
vision
anomalies
in
learning
disability
children
3
population.
Among
children
with
reading
difficulties
and
convergence
insufficiency,
8
prism
dioptres
base
in
prism
glasses
have
been
shown
to
improve
reading
speed
and
accu-
racy.
Similarly,
computer
based
home
vision
therapy
has
also
shown
to
be
effective
in
improving
the
vergence
and
accom-
modation
parameters.7Certain
treatment
options
such
as
the
use
of
coloured
filters13 and
behavioural
vision
therapy
remains
controversial.14
This
current
work
aimed
to
find
the
frequency
of
BV
prob-
lems
among
children
with
SLD
and
to
assess
the
efficacy
of
VT
in
improving
BV
parameters
in
children
with
SLD
and
associated
non-strabismic
BV
anomalies.
Methods
Study
approval
and
setup
The
ethical
clearance
for
the
study
was
obtained
from
the
Institutional
review
board
and
ethics
committee
of
Vision
Research
Foundation,
Chennai
and
the
study
adhered
to
the
Tenets
of
the
declaration
of
Helsinki.
The
study
was
carried
out
at
a
school
for
children
with
learning
disability.
All
the
parents
or
guardian
of
each
stu-
dent
was
given
a
detailed
oral
description
about
the
study
in
a
meeting
organized
for
the
study
purpose
and
a
writ-
ten
consent
from
the
parents
were
obtained
to
ensure
the
child’s
participation
in
the
study.
Medical
history
of
children
Medical
history
details
of
the
children
were
obtained
from
the
school
medical
records,
which
included:
(a)
General
medical
and
birth
history,
(b)
developmental
milestones
and
(c)
hearing
and
speech
assessment.
There
were
96
children
in
the
school
(73
male
and
23
female),
aged
10---21
years.
All
the
children
underwent
a
comprehensive
eye
examination
and
binocular
vision
test-
ing.
Out
of
the
96
children,
1
child
had
Down’s
syndrome,
1
had
pervasive
disorder
and
94
children
had
a
documented
diagnosis
of
specific
learning
disability
and
were
enrolled
for
the
study.
Eleven
of
these
children
had
a
comorbid
diagnosis
attention
deficit
disorder
(4
without
hyperactiv-
ity
and
7
with
hyperactivity).
89
children
had
normal
general
health
(92.7%),
14
children
were
born
premature
(14.6%),
17
(17.7%)
children
had
delayed
milestones,
8
(8.3%)
children
had
delayed
speech
and
none
of
the
children
had
hearing
difficulties.
All
children
had
normal
IQ
levels
for
age
with-
out
other
associated
neurological
issues.
Among
the
specific
learning
disorders,
all
children
had
issues
with
reading,
writ-
ing
and
spelling
as
the
primary
concern,
and
no
specific
diagnosis
was
available
from
the
school
records.
Study
design
and
protocol
This
is
a
pre---post-experimental
study
with
a
no-intervention
control
group.
The
study
protocol
and
flow
of
recruitment
is
presented
in
Fig.
1.
The
comprehensive
eye
examination
included:
Recruitment of subjects (n=96)
Comprehensive eye examination
and binocular vision assessment
(n=94)
Normal BV
(n=20)
NSBVA
(n=46)
VR-QOL and reading assessment
No
intervention
(n=22)
Intervention
(n=24)
10 sessions of VT
Binocular vision assessment, VR-QOL, and
reading assessment
Figure
1
Study
protocol
and
flow
of
recruitment
of
subjects.
1.
Assessment
of
presenting
visual
acuity
for
distance
(using
3
m
English
log
MAR
chart)
and
near
(using
reduced
Snellen
at
40
cm).
2.
Refractive
error
with
retinoscopy
followed
by
subjective
acceptance.
Anterior
segment
examination
using
torch
light
and
posterior
segment
using
direct
ophthalmoscope
with
high
magnification.
Appropriate
referrals
were
made
for
the
children
who
needed
further
ophthalmic
evaluation.
A
copy
of
referral
letter
was
sent
to
the
parents
and
school
administration
if
the
child
needed
to
be
referred
for
ophthalmic
evaluation.
The
binocular
vision
testing
was
carried
out
with
the
best
corrected
refraction
in
place.
If
the
subject
was
found
to
have
refractive
error
for
the
first
time
or
if
a
change
in
refractive
error
of
more
than
0.50
D
was
detected
during
the
refraction,
glasses
were
prescribed
and
the
subject
was
enrolled
after
2
weeks
of
refractive
adaptation.
Binocular
vision
testing
included:
1.
Sensory
evaluation
for
near:
Using
Randot
stereo
plate.
2.
Motor
evaluation:
Motor
evaluation
comprised
of
(a)
phoria
and
ocular
motility
testing,
(b)
accommodation
testing,
(c)
vergence
testing
and
(d)
oculomotor
testing.
(a)
Phoria
and
ocular
motility
testing:
Assessment
of
phoria
or
tropia
was
done
using
cover/uncover
test
and
angle
of
deviation
was
neutralized
using
prism
base
cover
test.
Extraocular
eye
movements
were
assessed
using
broad
H
test
and
versions
were
assessed
in
nine
cardinal
gaze
positions.
(b)
Accommodative
testing:
The
amplitude
of
accom-
modation
was
measured
monocularly
and
binocularly
using
the
push-up
test.
Monocular
values
less
than
2
dioptres
from
Hofstetter’s
minimum
expected
criteria
(15---0.25
(age))
were
considered
to
be
abnormal.15

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
4
J.R.
Hussaindeen
et
al.
Table
1
Diagnostic
criteria
used
for
NSBVA
diagnosis.
1.
Convergence
insufficiency
1.
Exophoria
>
4
BI
greater
for
near
than
distance
2.
NPC
>
6
cm
break
with
accommodative
target
3.
PFV
<
15
BO
(break
or
blur
value)
2.
Divergence
insufficiency
1.
Esophoria
>
2
BO
for
distance
2.
NFV
<
7
BI
(break
---
step
vergence
for
distance)
3.
Convergence
excess
1.
Significant
esophoria
at
near,
>2
prisms
2.
Reduced
negative
fusional
vergence
<
13/10
for
break
and
recovery
3.
High
MEM,
>+0.75
DS
4.
Divergence
excess
1.
Intermittent
to
constant
exodeviation
for
distance
5
PD
greater
than
near
2.
Low
PFV
break
value
of
<11
BO
for
distance
5.
Accommodative
insufficiency
1.
Reduced
monocular
amplitude
of
accommodation
at
least
2
D
below
Hofstetter’s
calculation
for
minimum
amplitude:
15---0.25
(age)
2.
Difficulty
with
monocular
accommodative
facility
with
−2.00
DS
3.
High
MEM
finding,
>+0.75
DS
6.
Accommodative
infacility
1.
Difficulty
with
both
plus
and
minus
lenses
in
monocular
accommodative
facility
testing
with
<7
cpm
for
8---12
year
old
and
<13
cpm
for
13
years
and
above
with
±2.00
DS
2.
Difficulty
with
both
plus
and
minus
lenses
in
binocular
accommodative
facility
testing
with
<5
cpm
using
±2.00
DS
8.
Fusional
vergence
dysfunction
1.
Near
NFV
break
<12
BI
2.
Near
PFV
break
<23
BO
3.
Distance
NFV
break
<7
BI
4.
Distance
PFV
break
<11
BO
For
diagnosis:
a
minimum
of
2
signs
are
mandatory
Adopted
and
modified
from
Scheiman
and
Wick
(2014).16
Accommodative
facility
(AF)
was
assessed
in
cycles
per
minute
(cpm)
both
monocularly
and
binocularly
using
+2.00/−2.00
D
accommodative
flipper
lenses
at
40
cm.
Simple
three
letter
words
of
N8
font
size
were
used
as
test
targets.
Monocular
AF
of
7
cpm
for
10---13
years
and
11
cpm
for
greater
than
13
years
were
considered
normal.16
Monocular
estimate
method
(MEM)
retinoscopy
was
used
to
assess
the
accommodative
response
and
a
normal
lag
was
considered
to
be
between
+0.25
to
+0.75
D.16
Vergence
testing:
Near
point
of
convergence
(NPC)
was
assessed
using
an
accommodative
tar-
get
and
diplopic
response
as
the
target
is
brought
closer
was
taken
as
the
subjective
response.
Objec-
tive
measurement
of
eye
deviation
was
also
noticed
and
the
test
was
repeated
twice
to
assess
the
consis-
tency
of
responses.
NPC
break
≥6
cm
was
considered
to
be
abnormal.16
Fusional
vergence
amplitude
was
measured
with
prism
bar
(step
vergence)
for
both
distance
and
near.
The
negative
fusional
vergence
(NFV)
was
assessed
first
followed
by
positive
fusional
vergence
(PFV).
Normative
values
for
diagnosis
and
diagnostic
criteria
for
NSBVA
were
adopted
and
modified
from
Scheiman
and
Wick
(2014)
(Table
1).16
(c)
Oculomotor
testing:
The
developmental
eye
move-
ment
(DEM)
test17 was
used
to
evaluate
visual---verbal
oculomotor
dysfunction.
The
DEM
test
consists
of
three
subtests:
a
pre-test,
vertical
subtest
and
hor-
izontal
test.
The
vertical
subtest
depends
on
the
individual’s
visual
verbal
automatic
skills.
The
hor-
izontal
subtest
consists
of
numbers
arranged
in
non-symmetrical
horizontal
array
that
assessed
the
horizontal
saccadic
function.
The
corrected
time
taken
to
complete
the
horizontal
and
vertical
subtests
was
matched
with
the
provided
age
norms
values
and
DEM
typologies
were
classified
between
Type
1
and
Type
4.
Type
1
specifies
normal
oculomotor
function,
Type
2
specifies
horizontal
scanning
or
tracking
problem,
Type
3
indicates
automaticity
problems,
and
Type
4
indicates
a
combination
of
Type
2
and
Type
3
typologies.
Vision
related-quality
of
life
assessment
The
VR-QOL
was
assessed
using
the
modified
COVD
---
VR
QOL
questionnaire
consisting
of
14
items
with
3
response

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
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Vision
therapy
for
binocular
vision
anomalies
in
learning
disability
children
5
options
(0
---
Never;
1
---
Occasional
and
2
---
Always).
This
has
been
validated
as
a
suitable
screening
tool
among
children
with
learning
disability.18 The
questionnaire
was
given
to
the
respective
class
teachers
and
scores
were
obtained
for
each
child.
Symptomatology
was
assessed
by
asking
each
child
if
they
have
eyestrain,
headache,
eye
pain
or
any
other
visual
discomfort
associated
with
near
visual
activities.
Reading
assessment
Assessment
of
reading
rate
was
performed
for
children
diagnosed
with
non-strabismic
binocular
vision
anomalies
(NSBVA).
Child
was
asked
to
read
a
given
paragraph
for
3
min.
Subtracting
the
number
of
errors
made,
the
reading
rate
was
calculated
for
1
min.19 The
paragraph
was
chosen
from
the
child’s
own
grade
books
that
were
not
famil-
iar
to
the
children.
The
formula
for
reading
rate
is
given
below:
Number
of
words/letter
read
−
Number
of
errors
made
3
Randomization
After
the
diagnosis
of
NSBVA
was
made,
one
half
of
the
chil-
dren
chosen
according
to
the
random
number
tables
were
allocated
to
the
treatment
group
and
the
other
half
served
as
control
(non-intervention
group).
Teachers
were
masked
for
the
name
of
the
children
who
were
allocated
for
inter-
vention.
For
ethical
reasons,
the
non-intervention
group
was
also
provided
with
vision
therapy
after
the
study
was
com-
plete.
Intervention
Vision
therapy
(VT)
set-up
was
planned
at
the
school
premises
itself.
The
children
who
were
randomized
for
inter-
vention
were
given
VT
during
their
class
hours
for
45
min
on
alternative
day.
The
VT
protocol
for
the
NSBVA
was
referred
from
Scheiman
and
Wick
(2014).16 The
performance
of
each
child
and
improvement
on
each
day
was
noted
in
a
separate
proforma.
The
VT
was
supplemented
under
the
supervision
of
a
trained
optometrist
and
VT
technique
was
modified
wherever
necessary
according
to
the
responses
and
difficulty
faced
by
individual
child.
Objectives
of
vision
therapy
Computer
orthoptics,
tranaglyphs
and
vectograms
were
the
equipment
utilized
for
accommodation
and
vergence
training.
For
convergence
insufficiency,
the
objectives
of
the
training
included
improving
the
convergence
fusional
ranges,
monocular
and
binocular
accommodative
facility
and
to
integrate
oculomotor
training
towards
the
end.
For
accommodative
infacility,
the
goals
of
the
training
included
improving
the
monocular
accommodative
facility
integrated
with
fusional
vergence
training.16
Post-vision
therapy
assessment
At
the
end
of
10
sessions,
BV
parameters,
and
reading
rate
was
reassessed
in
the
intervention
group.
The
same
assess-
ment
was
performed
in
the
non-intervention
group
to
assess
the
true
effect
of
vision
therapy
negating
the
placebo,
learn-
ing
and
test---retest
effects.
Outcome
measures
The
outcome
measures
of
the
study
included:
(1)
frequency
of
strabismic
and
non-strabismic
binocular
vision
anoma-
lies
(NSBVA)
in
children
with
SLD,
(2)
comparison
of
visual
efficiency
and
oculomotor
parameters
between
children
with
normal
binocular
vision
and
non-strabismic
binocular
vision
anomalies,
(3)
Correlation
between
reading
rate
and
oculomotor
dysfunction
in
NSBVA
and
(4)
changes
in
BV
parameters
and
reading
rate,
between
non-intervention
and
intervention
group
post-vision
therapy.
Statistical
analysis
The
data
was
analyzed
using
Microsoft
Excel,
2007
and
SPSS
software
version
17.0.
The
normality
of
the
data
was
checked
by
Kolmogorov---Smirnov
test.
Since
the
data
was
found
to
be
non-normally
distributed,
appropriate
non-
parametric
statistics
were
used
to
represent
the
data.
Mann---Whitney
U
test
was
used
to
compare
the
parame-
ters
between
normal
BV
and
NSBVA.
Effect
size
(Cohen’s
D,
1988)20 was
calculated
to
represent
the
magnitude
of
dif-
ference
between
the
groups.
The
guidelines
proposed
by
Cohen
(1988)
for
independent
samples
were
used
to
inter-
pret
the
results
(0.1---0.29
small,
0.3---0.49
medium
and
≥0.5
large).
Spearman’s
correlation
was
used
for
comparison
of
DEM
ratio
and
the
reading
rate.
Wilcoxon
signed
rank
test
was
used
to
compare
the
changes
in
parameters
pre-
and
post-intervention
in
the
non-intervention
and
intervention
group.
p
<
0.05
was
set
as
the
cut-off
for
statistical
signifi-
cance.
Results
The
mean
(SD)
age
of
the
subjects
was
15
(±2.1)
years.
Distribution
of
refractive
error
Out
of
the
96
subjects,
23
(24%)
children
had
refrac-
tive
error;
astigmatism
was
found
in
10
(43.5%)
(range
−0.50
DS
to
−3.50
DS),
myopia
in
8
(34.7%)
(range
−0.75
DS
to
−15.75
DS)
and
hyperopia
in
5
(21.7%)
children
(range
+0.50
DS
to
+5.00
DS).
Frequency
of
binocular
vision
anomalies
Among
the
94
children,
binocular
vision
(BV)
anomalies
were
found
in
59
children
(62.8%)
out
of
which,
46
had
non-strabismic
BV
anomalies
(NSBVA)
(78%)
and
13
had
stra-
bismus
(22%).
Six
children
had
other
ocular
pathologies
(6.4%)
and
9
(9.6%)
children
were
found
to
be
uncoopera-
tive
for
the
BV
assessment
and
were
not
included
for
the

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
6
J.R.
Hussaindeen
et
al.
Table
2
Binocular
vision
parameters
among
normal
and
NSBVA
group.
Parameter
Normal
BV
(n
=
20)
Median
values
with
inter-quartile
range
in
brackets
NSBVA
(n
=
46)
Median
values
with
inter-quartile
range
in
brackets
p-Value
(Mann---Whitney
U
test)
Distance
NFV
break
(in
PD)
8
(6---10)
8
(6---10)
>0.05
Distance
NFV
recovery
(in
PD)
6
(4---8)
6
(4---8)
Near
NFV
break
(in
PD)
17
(16---20)
16
(14---20)
Near
NFV
recovery
(in
PD)
14
(14---16)
14
(11.50---16.0)
Distance
PFV
break
(in
PD)
16
(12---19.50)
14
(10.0---18.50)
Distance
PFV
recovery
(in
PD)
10
(8---17)
10
(8.0---15.25)
Near
point
of
accommodation
---
OD
(in
D) 14.30
(12.5---16.7)
12.5
(11.1---14.3)
Near
point
of
accommodation
---
OS
(in
D) 14.30
(12.5---16.7) 14.30
(11.1---15.72)
NPC
break
(cm)
7
(5---8)
9
(7.0---10.25)
0.005
NPC
recovery
(cm)
8
(6---9)
10
(8.0---11.25)
0.006
Near
PFV
break
(in
PD)
30
(25---35)
25
(14---30)
0.024
Near
PFV
recovery
(in
PD)
20
(16---35)
19
(11.5---21.25)
0.048
AF
OD
(cpm)
11
(10---12)
4
(2---6)
<0.0001
AF
OS
(cpm)
11
(10---12)
4
(1---6)
AF
OU
(cpm)
11
(10.63---12)
6
(3.50---9.25)
Unit:
cm,
centimetre;
PD,
prism
dioptre;
D,
dioptre;
cpm,
cycle
per
minute.
NPC,
near
point
of
convergence;
NFV,
negative
fusional
vergence;
PFV,
positive
fusional
vergence;
NPA,
near
point
of
accommodation;
OD/OS/OU,
oculus
dexter/oculus
sinister/oculus
uterque;
AF,
accommodative
facility.
study.
Twenty
children
(21.3%)
had
normal
binocular
vision
(NBV).
Among
strabismic
BV
anomalies,
exotropia
was
found
in
10
children,
esotropia
in
2
children
and
there
was
a
single
case
of
Duane’s
syndrome.
Among
all
NSBVA
(n
=
46),
accommodative
infacility
(AIF)
was
found
in
31
children
(68%),
followed
by
convergence
insufficiency
(CI)
in
11
children
(25%),
divergence
excess
(DE)
and
fusional
vergence
dysfunction
(FVD)
in
1
child
each
(2%)
and
combination
of
convergence
insufficiency
and
accommodative
infacility
were
found
in
2
children
(5%).
BV
parameters
among
normal
BV
and
NSBVA
group
are
presented
in
Table
2.
The
parameters
of
comparison
include
near
point
of
convergence
(NPC)
break
and
recovery,
neg-
ative
fusional
vergence
(NFV)
break
and
recovery
values
for
distance
and
near,
positive
fusional
vergence
(PFV)
break
and
recovery
values
for
distance
and
near,
near
point
of
accommodation
(NPA)
and
accommodative
facility
(AF)
---
monocular
and
binocular
values.
Mann---Whitney
U
test
revealed
significant
difference
in
NPC
break
and
recovery
values,
and
near
PFV
break
and
recovery
and
monocular
and
binocular
AF
between
children
with
normal
BV
and
NSBVA
(p
<
0.001).
The
median
(IQR)
VR-QOL
scores
of
the
NSBVA
group
was
8
(1---11.75)
and
that
of
the
children
with
normal
BV
was
3
(4---11)
(Mann---Whitney
U
test,
p
>
0.05).
DEM
scores
in
normal
and
NSBVA
In
the
normal
BV
group,
5
children
(25%)
had
normal
oculo-
motor
function
(Type
1),
3
children
each
(15%)
had
horizontal
scanning
problem
(Type
2)
and
automaticity
difficulty
(Type
4)
and
9
children
(45%)
had
normal
horizontal
and
vertical
time
but
high
ratio
when
compared
to
the
normative
test
data
provided
for
the
age.
None
of
the
normal
children
had
a
Type
3
DEM
typology.
In
the
NSBVA
group,
8
children
(18%)
had
normal
ocu-
lomotor
function
(Type
1),
5
children
(11%)
had
horizontal
scanning
(Type
2),
8
children
(18%)
had
automaticity
prob-
lem
(Type
3),
9
children
(20%)
had
both
scanning
and
automaticity
difficulty
(Type
4)
and
15
children
(33%)
had
normal
horizontal
and
vertical
time
with
high
ratio.
The
horizontal
(H)
and
vertical
(V)
time
in
seconds
for
DEM
test
were
compared
between
Normal
and
NSBVA
group.
There
was
no
significant
difference
in
horizontal
scores
between
normal
BV
and
NSBVA
whereas
vertical
time
revealed
significant
difference
between
the
two
groups
as
shown
in
Table
3
(Mann---Whitney
U
test;
p
<
0.05).
Reading
parameters
among
normal
and
NSBVA
The
median
(IQR)
of
reading
rate
among
normal
and
NSBVA
group
are
presented
in
Table
4.
The
median
reading
rate
of
NSBVA
group
was
lesser
compared
to
children
with
nor-
mal
binocular
vision,
and
these
results
were
not
statistically
significant
(Mann---Whitney
U
test,
p
>
0.05).
The
correlation
between
reading
rate
and
DEM
horizontal
scores
were
analyzed
using
Spearman
correlation.
Reading
rate
in
words/min
(wpm)
was
found
to
be
higher
in
children
(n
=
43)
who
took
less
time
in
Developmental
Eye
Movement
(DEM)
test
for
horizontal
task
(r
=
−0.517,
p
≤
0.0001)
as
shown
in
Fig.
2.
Changes
in
BV
parameters
before
and
after
VT
There
was
no
statistically
significance
difference
in
the
mean
age
of
the
non-intervention
and
intervention
group
(Mann---Whitney
U
test,
p
>
0.05).
In
the
intervention
group
(n
=
24),
15
subjects
had
AIF,
7
subjects
had
CI,
and
1
each
had
FVD
and
DE.
The
changes
in
BV
parameters
in
the

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
Vision
therapy
for
binocular
vision
anomalies
in
learning
disability
children
7
Table
3
Developmental
eye
movement
(DEM)
test
time
(in
seconds)
among
Normal
BV
and
NSBVA
group.
DEM
test
Median
(IQR)
p-Value
(Mann---Whitney
U
test)
Horizontal
DEM
time
normal
BV
43.5
(34.50---47.91) >0.05
Horizontal
DEM
time
NSBVA
48.6
(37---64.86)
Vertical
DEM
time
normal
BV
34
(30.75---37) 0.039
Vertical
DEM
time
NSBVA
40
(32---53)
Table
4
Reading
rate
comparison
among
normal
and
NSBVA
group.
Group
Median
(IQR)
In
words/min
p-ValueMann---Whitney
U
test
Normal
(n
=
20)
62
(47---84) >0.05
NSBVA
(n
=
46)
49.5
(26.25---90.5)
120
110
100
90
80
70
60
50
40
30
20
10
020 40 60 80
Reading rate (wpm)
∗p=0.000, r=–0.517
DEM_H (second) time
100
120
140
160
180
Figure
2
Correlation
between
reading
rate
and
DEM
(horizon-
tal
scores).
*Spearman
correlation;
r:
coefficient
of
correlation;
wpm:
words
per
minute;
DEM
H:
Developmental
Eye
Movement
Horizontal
scores.
overall
NSBVA
are
depicted
in
Table
5.
Except
NFV,
all
the
BV
parameters
showed
statistical
and
clinically
significant
difference
post-VT
compared
to
baseline,
whereas
in
the
non-intervention
group,
the
changes
were
not
statistically
significant.
Large
effect
size
for
the
treatment
was
observed
for
parameters
of
AF
and
PFV,
and
medium
effect
size
was
observed
for
NPC
and
NPA.
In
the
intervention
and
non-
intervention
group,
the
DEM
horizontal
and
vertical
time
did
not
differ
pre-
and
post-assessment
(p
>
0.05).
Similar
trend
was
observed
for
reading
rate
and
VR-QOL
scores.
Following
VT,
statistically
significant
changes
in
NPC
break
and
recovery
and
near
PFV
break
and
recovery
values
were
observed
in
CI
(n
=
7)
and
the
monocular
and
binoc-
ular
AF
showed
statistically
significant
difference
pre-
vs.
post-VT
in
AIF
(n
=
15)
(Wilcoxon
signed
rank
test
p
<
0.05).
Discussion
This
study
reports
a
high
frequency
of
NSBVA
(63%)
in
children
with
LD.
Accommodative
infacility
(AIF)
was
highly
prevalent
(67%),
followed
by
convergence
insuf-
ficiency
(CI)
(25%).
Similar
trend
has
been
reported
in
other
populations5,6 wherein,
the
prevalence
of
AIF
ranged
between
26
and
31.7%
and
CI
between
14
and
38%.
In
contrary
to
the
previous
literature,
we
did
not
see
subjects
with
accommodative
insufficiceny
in
our
sample.5,6,9---11,15
We
also
observed
a
higher
frequency
of
refractive
errors
(24%)
in
this
special
population,
with
a
high
frequency
of
astigmatism
in
44%
of
the
study
subjects.
Similar
results
have
been
reported
by
Vora
et
al.21 who
showed
a
high
fre-
quency
of
astigmatism
(27%)
followed
by
myopia
(24.3%)
and
hyperopia
(18.6%).
Statistical
and
clinically
significant
dif-
ferences
were
seen
in
near
PFV
break
and
recovery,
NPC
break
and
recovery
and
monocular
and
binocular
accom-
modative
facility
pre-
and
post-VT
in
the
intervention
group.
As
this
difference
was
not
seen
in
the
non-intervention
group,
the
achieved
improvement
could
be
attributed
to
the
true
effect
of
VT
beyond
learning
and
test---retest
effects.
As
convergence
insufficiency
and
accommodative
infacility
contribute
to
88%
of
the
NSBVA
in
the
intervention
group,
these
results
are
limited
to
these
specific
types
of
NSBVA.
In
children
with
LD,
the
DEM
horizontal
time
was
pro-
longed
compared
to
vertical
time
in
both
normal
BV
and
NSBVA
group,
indicating
that
children
with
SLD
have
deficits
in
saccadic
eye
movements,
a
finding
in
agreement
with
previous
studies.9The
reading
rate
and
DEM
horizontal
time
was
negatively
correlated
suggesting
the
association
between
increased
horizontal
times
with
reduced
reading
rate
observed
in
this
sample.
We
also
found
high
vertical
time
in
NSBVA
group
when
compared
to
subjects
with
nor-
mal
BV
that
signifies
that
the
automaticity
difficulty
was
also
common
among
children
with
NSBVA.
In
our
study,
though
the
reading
rate
of
children
with
NSBVA
was
higher
than
children
with
NBV,
these
results
did
not
reach
statistical
significance.
This
could
potentially
be
attributed
to
the
unequal
sample
size
and
low
power
to
detect
an
adequate
difference.
Similarly
we
did
not
observe
statistically
signifi-
cant
improvements
in
VR-QOL
scores.
One
of
the
limitations
with
the
interpretation
of
VR-QOL
score
is
that,
it
was
filled
by
the
class
teacher
based
on
inputs
from
the
child.
Though
teacher
or
parent
administration
is
the
recommended
mode
in
special
population
and
younger
children,18 it
also
poses
risk
due
to
the
rater
administered
variables
such
as
transla-
tion,
and
interpretation.
This
needs
further
exploration
and
thus
may
not
reflect
the
true
symptomology
of
the
children.
Our
study
confirms
that
children
with
specific
LD
have
higher
frequency
of
NSBVA.
It
has
been
reported
that
five

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
8
J.R.
Hussaindeen
et
al.
Table
5
Pre-
and
post-BV
parameters
in
the
control
and
intervention
group.
Parameter
Non-intervention
group
(n
=
22)
Intervention
group
(n
=
24)
Pre-VT
Median
(IQR)
Post-VT
Median
(IQR)
*p-Value
Pre-VT
Median
(IQR)
Post-VT
Median
(IQR)
p-Value
Wilcoxon
signed
rank
test
NPC
break
(cm)
9.50
(7---12)
10
(5---12)
>0.05
8
(7---9)
7
(6---8)
0.008
NPC
recovery
(cm)
10.50
(8.00---12.50)
11
(6---14)
9
(8---11)
8
(7---9)
0.002
Distance
NFV
break
(in
PD)
8
(6---10)
8
(6---10)
8
(6---12)
8
(6---12)
>0.05
Distance
NFV
recovery
(in
PD)
6
(4---8)
6
(4---6)
6
(4---10)
6
(4---10)
Near
NFV
break
(in
PD)
14
(12---18)
16
(12---18)
18
(16---20)
20
(14---25)
Near
NFV
recovery
(in
PD)
12
(10---14)
12
(8---14)
14
(12---18)
16
(10---20)
Distance
PFV
break
(in
PD)
14
(10---20)
18
(12---20)
14
(10---18)
30
(25---30)
<0.0001
Distance
PFV
recovery
(in
PD)
10
(8---16)
12
(8---16)
10
(8---14)
20
(14---20)
0.001
Distance
NFV
break
(in
PD)
25
(14---30)
20
(12---40)
25
(14---30)
40
(30---45)
<0.0001
Distance
NFV
recovery
(in
PD)
18
(12---25)
16
(10---25)
20
(10---20)
30
(20---45)
<0.0001
AF
OD
(cpm)
4
(2---5)
2.50
(1---5)
2
(2---4)
12
(11---15)
<0.0001
AF
OS
(cpm)
3.50
(1---5)
4
(1.50---5.00)
2.50
(1---4)
12.5
(11.50---15.00)
<0.0001
AF
OU
(cpm)
4
(2---5)
4
(2---5)
3.50
(1---5)
11.50
(10---14)
<0.0001
NPA
OD
(D)
14.3
(11.10---15.40)
12.50
(10.00---14.30)
0.018
11.8
(11.10---14.30)
14.3
(11.10---16.70)
0.008
NPA
OS
(D)
14.3
(11.80---15.40)
11.1
(10.00---16.70)
0.009
12.5
(11.10---14.30)
14.3
(11.10---16.70)
0.014
Unit:
cm,
centimetre;
PD,
prism
dioptre;
D,
dioptre;
cpm,
cycle
per
minute.
NPC,
near
point
of
convergence;
NFV,
negative
fusional
vergence;
PFV,
positive
fusional
vergence;
NPA,
near
point
of
accommodation;
AF,
accommodative
facility;
IQR,
inter
quartile
range.

Please
cite
this
article
in
press
as:
Hussaindeen
JR,
et
al.
Efficacy
of
vision
therapy
in
children
with
learning
disability
and
associated
binocular
vision
anomalies.
J
Optom.
(2017),
http://dx.doi.org/10.1016/j.optom.2017.02.002
ARTICLE IN PRESS
+Model
OPTOM-229;
No.
of
Pages
9
Vision
therapy
for
binocular
vision
anomalies
in
learning
disability
children
9
out
of
the
nine
criteria
for
ADHD
in
DSM-IV
(Diagnostic
and
Statistical
Manual
of
Mental
Disorders)
overlap
with
the
symptoms
of
CI
such
as
loss
of
concentration
when
reading
or
reading
slowly,
failure
to
complete
assignments
and
trou-
ble
of
concentration
in
class.22 This
study
in
children
with
specific
learning
disorders
emphasize
the
need
for
screening
for
binocular
vision
anomalies.
Vision
therapy
plays
a
significant
role
in
improving
the
binocular
vision
parameters
in
this
special
population.
Therefore
we
recommend
a
comprehensive
BV
assessment
to
be
part
of
the
vision
care
protocol
for
children
with
SLD,
and
vision
therapy
should
be
recommended
for
children
with
NSBVA.
The
strength
of
our
study
includes
a
structured
VT
proto-
col
with
a
non-intervention
control
group.
Though
this
is
not
the
best
research
approach,
and
a
placebo
treatment
group
is
recommended
as
control
in
randomized
controlled
trials,
this
experimental
study
proves
that
vision
therapy
improves
binocular
vision
parameters
which
are
beyond
test---retest
and
learning
effect.
We
also
provided
vision
therapy
at
the
school
premises
to
ensure
compliance
with
therapy
and
loss
to
referral
follow-up.
The
limitation
of
our
study
include
an
absence
of
masked
examiner
as
the
same
optometrist
was
involved
in
the
administration
of
VT
and
assessment
of
BV
parameters
pre
and
post-VT.
But
it
was
made
sure
that
baseline
BV
parameters
were
not
looked
into
until
post-VT
assessment
was
carried
out.
Also
the
pre-post-vision
therapy
comparison
in
each
subgroup
of
NSBVA
is
ideal
to
comment
about
the
efficacy
of
vision
therapy
for
each
spe-
cific
anomaly
but
as
the
sample
size
of
the
subjects
were
lesser
in
the
sub
groups,
we
have
represented
this
as
over-
all
NSBVA.
To
conclude,
NSBVA
are
the
commonest
among
the
spectrum
of
ocular
disorders
in
children
with
specific
learning
disorders.
These
anomalies
could
potentially
be
an
added
hindrance
to
the
reading
difficulty
in
this
special
pop-
ulation.
Vision
therapy
plays
an
important
role
in
improving
the
binocular
vision
parameters.
Financial
disclosures
None.
Conflicts
of
interest
The
authors
have
no
conflicts
of
interest
to
declare.
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