Association
of Asthenopia and Convergence Insufficiency in Children with Refractive
Error- A hospital based study
Gupta R1,
Sharma B2, Anand R3,Bawaria
S4,Dewada R5
1Dr. Rachna Gupta, Associate Professor, Regional Institute of
Ophthalmology, Gandhi Medical College Bhopal, 2Dr. Bhavna
Sharma, Assistant Professor, RIO, GMC, Bhopal, 3Dr. Reena
Anand, Director, RIO, GMC, Bhopal ,4Dr. Shefali Bawaria, Senior
Resident, CIMS, Bilaspur, 5Dr. Rajesh Dewada, Resident,
surgical officer, RIO, GMC, Bhopal, India
Address for
correspondence: Dr. Rachna Gupta, E mail:
drrachnagupta2k@gmail.com
Abstract
Introduction:
It is estimated that about 14% of people in India with visual
impairment are suffering from refractive errors. The prevalence of
childhood blindness in India is 0.17% and refractive errors alone are
the major treatable cause (33.3%) of the blindness. Assessment of
Visual acuity should not be the only criteria for detection of
ametropia, as children have strong accomodation. Thus it is emphasizing
the importance of refraction testing under cycloplegic drugs.
Convergence insufficiency is prevalent in about 7.5% of population. Purpose: To study
the association of asthenopia and convergence insufficiency with
refractive error in children. Methods: 2130 ametropic children up to 16
yrs were screened for asthenopia and convergence insufficiency. Result: Ametropia
was found in 40.24% of children .Myopia was prevalent in 47.41%
children. Hypermetropia was detected in 15.49% children. Convergence
insufficiency was observed in 34.14% of children and asthenopia was
found in 82.19% ametropic children. Conclusion:
The study reveals that, asthenopia and convergence insufficiency are
found to be the most common ocular conditions
associated with ametropia.
Key words:
Convergence insufficiency, asthenopia, hypermetropia, Myopia,
Refractive Error.
Manuscript received:
13th July 2013, Reviewed:
26th Aug 2013
Author
Corrected: 19th Sep 2013, Accepted for Publication:
30th Oct 2013
Introduction
Convergence insufficiency (CI) is a common binocular
disorder and is associated with symptoms which become more prominent on
doing near work [1- 3]. Asthenopia is a very common
presenting feature in children with refractive error and convergence
insufficiency [4,5]. WHO reported that about 48 million people are
blind in the world and 135 million are with low vision (3/60) and if
any appropriate action in rehabilitating them has not taken, it is
expected to be double by year 2020 [6]. Vision 2020: The
“Right to Sight” (a global initiation launched by
WHO and task force of International Non-Government Organizations) was
launched in Geneva on Feb. 18, 1999 by the director general of the WHO,
Dr. G.H. Brundtland with the aim to combat the gigantic problem of
blindness and low vision in the world [7]. The incidence of CI in the
general population is estimated to be 0.1 to 0.2% [8]. While exo
deviations are present only in 1% of the general population, Asthenopia
and CI are present in 11-19% of children with an exodeviation [9].
There is great variability in the reported prevalence of CI ranging
from 1.75 to 33%, with the average prevalence reported to be
approximately 5%. Asthenopia is a group of symptoms experienced during
near work, like headache, unable to see blackboard, eye ache, goes
close to television, watering, blurring of vision during reading,
picked up in school, frequent blinking/rubbing of eyes, redness of
eyes, change in palpebral aperture, recurrent swelling of lids, double
vision during reading/writing, burning sensation, deviation of eyes and
frequent fall. Asthenopic symptoms are more commonly experienced in
children with uncorrected refractive error, general weakness, anemia,
nutritional deficiency, extra ocular muscle weakness and latent
strabismus [10].
The prevalence of childhood blindness in India is 0.17% and it is
estimated that about 14 percent of population would benefit from
correction of refractive errors11. Treatable refractive error is the
major cause (33.3%) of the blindness in children, [6, 11] (Global
Initiative for the Elimination of Avoidable Blindness. Geneva: WHO.
1997). This study attempted to find the association of convergence
insufficiency and asthenopia with refractive errors.
Material
and Methods
Present study was undertaken at tertiary eye care centre of central
India. Children up to 16 years were screened to find association of
convergence insufficiency and asthenopia with refractive errors. It was
a cross sectional hospital based study.
Inclusion criteria: children up to 16 years attending OPD.
Exclusion criteria: children > 16 years, post
traumatic and post surgical cases.
The demographic profile in terms of name, age, sex, address &
socioeconomic status were noted. Detailed history of patients was taken
and symptoms were recorded in three categories
1) Ocular - pain in eyes, recurrent redness,
deviation of eyes or heaviness.
2) Visual - Blurring of vision while reading or defective
vision for distance or near.
3) Referred - headache, nausea or vomiting.
Family history of refractive error in siblings and parents,
cerebral palsy or Down’s syndrome or other relevant
neurobehavioral abnormality was recorded. Personal history and any
significant antenatal, perinatal and postnatal history were noted.
Visual acuity was noted and detailed ocular examination was conducted
to look for any ocular morbidity. Objective assessment of refractive
error was done by Retinoscopy to evaluate the type and amount of
ametropia and fundus examination was done under
mydriasis to evaluate any posterior segment involvement
[12].The cycloplegic used were atropine 1% eye ointment /
homatropine 0.5% eye drop / cyclopentolate 1% / tropicamide
1% eye drops. When the refraction had been measured
objectively, fogging method of subjective estimation of refraction was
done to induce a relaxation of accommodation in absence of cycloplegia
[12]. Post mydriatic test was done and suitable spectacles were
prescribed [12].
Observation
and Result
Out of total 2130 ametropic children examined, myopia was found to be
most commonly present (47.41%) in children attending eye OPD, followed
by myopic astigmatism (27.88%). Hypermetropia was present in 15.49% of
children, followed by hypermetropic astigmatism (9.2%). Comparing males
and females, (p =0.9) is statistically insignificant.
Table No.1 Clinical
profile of Convergence Insufficiency
|
S.NO.
|
Complaints
|
No.
of cases
|
%
|
|
1.
|
Headache
|
1011
|
82.19
|
|
2.
|
Unable to see
blackboard
|
923
|
75.04
|
|
3.
|
Eye ache
|
856
|
69.59
|
|
4.
|
Goes close to
television
|
756
|
61.46
|
|
5.
|
Watering
|
603
|
49.02
|
|
6.
|
Picked up in school
|
213
|
17.31
|
|
7.
|
Frequent
blinking/frequent rubbing of eyes
|
98
|
7.96
|
|
8.
|
Redness of eyes
|
98
|
7.96
|
|
9.
|
Change in palpebral
aperture
|
84
|
6.8
|
|
10
|
Recurrent swelling of
lids
|
56
|
4.55
|
|
11.
|
Deviation of eyes
|
23
|
1.86
|
|
12.
|
Frequent fall
|
2
|
0.16
|
It is observed that ametropic children present with varied
clinical profiles. Headache being the most common presentation,
accounts for 82.19%, followed by unable to see blackboard in 75.04% and
eye ache in 69.59%. A significant no. of cases presented with goes
close to TV 61.46%, watering being next 49.02%. Blurring of vision
during reading was found in 31.03%, and 17.31% cases were picked up
during school screening
programme.
Table
No 2: Association of Hypermetropia and Myopia with Convergence
Insufficiency and Asthenopia
|
Children with refractive error
|
Hypermetropic
children
|
Convergence insufficiency and asthenopia
|
% CI & Asthenopia
|
Myopic children
|
Convergence insufficiency and asthenopia
|
%
CI & Asthenopia
|
|
Girls
|
163
|
40
|
24.53
|
550
|
243
|
44.18
|
|
Boys
|
167
|
50
|
29.94
|
460
|
171
|
37.1
|
|
Total
|
330
|
90
|
27.27
|
1010
|
414
|
40.99
|
Out of 330 hypermetropic children, convergence insufficiency
was found in 27.27% of children and asthenopic symptoms were
noted in 71.20%. Males were relatively more affected (29.94%) than
females (24.53%). Out of 1010 myopic children, convergence
insufficiency was found in 40.99% and asthenopia was present in 81.02%.
Females (44.18%) were relatively more affected than males (37.10%).
Table No.3: Association of
Convergence Insufficiency with degree of Hypermetropia and Myopia
|
Degree
of hypermetropia
|
No.
of
hypermetropic children
|
CI & Asthenopia
|
%
CI & Asthenopia
|
Degree
of myopia
|
No.
of myopic children
|
CI
& Asthenopia
|
%
CI & Asthenopia
|
|
<+2
D
|
96
|
70
|
72.91
|
<-2D
|
468
|
357
|
76.28
|
|
+2
D - +4D
|
202
|
10
|
4.95
|
-2 to -6D
|
522
|
47
|
9.0
|
|
>+4D
|
32
|
9
|
28.12
|
>-6D
|
20
|
13
|
65
|
Out of 96 children with hypermetropia of <+2 D,
72.91% had convergence insufficiency and asthenopia. Out of
468 children with myopia of <-2 D, 76.28% had convergence
insufficiency and asthenopia followed by 65 % children with myopia of
> -6 D.
Table No 4: Association of
Hypermetropic and Myopic Astigmatism with Convergence Insufficiency and
Asthenopia
|
|
Children
with Hypermetropic astigmatism
|
CI
and asthenopia
|
%
|
Children
with Myopic astigmatism
|
CI
and asthenopia
|
%
|
|
Girls
|
104
|
10
|
9.61
|
346
|
77
|
22.25
|
|
Boys
|
92
|
12
|
13.04
|
248
|
74
|
29.83
|
|
Total
|
196
|
22
|
11.22
|
594
|
151
|
25.42
|
25.42 % of children with myopic astigmatism had
convergence insufficiency and asthenopia, where as 11.22 % of children
with hypermetropic astigmatism had convergence insufficiency and
asthenopic symptoms.
Myopic astigmatism of -2D to -6 D with the rule was observed
in 2.35% males and 2.52% females, against the rule
astigmatism in 1.95% males and 1.54% females, oblique
astigmatism in 0.56% males and 0.65% females. Myopic
astigmatism of >-6 D with the rule was observed in 0.08% males
and 0.08% females, against the rule astigmatism in 0.16% males and
0.24% females, oblique astigmatism in 0.08%
females. On comparing astigmatism in males and females, p value comes
out to be 0.97 which is statistically insignificant. Of 2130
children with refractive error,69 were found to be anemic.
Table No 5: Association of
Convergence Insufficiency and Asthenopia with Refractive Errors
|
% of
Hypermetropic children with CI and
asthenopia
|
% of Myopic children with CI and asthenopia
|
% of children
with Hypermetropic astigmatism with
CI and asthenopia
|
% children with Myopic astigmatism with CI and asthenopia
|
|
27.27%
|
40.99%
|
11.22%
|
25.42%
|
Highest association of convergence insufficiency and
asthenopia was found with myopia (40.99%), followed by hypermetropia
(27.27%). Least association was found with hypermetropic astigmatism
(11.22%). Overall asthenopic symptoms were present in 81.02% myopic
children with or without convergence insufficiency, as compared to
72.91% in hypermetropic children. Asthenopia and convergence
insufficiency were found to be the most common ocular conditions with
ametropia, 82.19% & 34.14% respectively, observed in cases
presented in eye opd.
Discussion
The present study was carried out to study the association of
asthenopia and convergence insufficiency with refractive error in
children. Out of total 2130 ametropic children, Myopia was found to be
the most prevalent refractive error found in approximately 47.41% of
children [12]. No significant difference in the incidence of refractive
errors in boys and girls was noted [13]. Headache was the most common
presentation (82.19%) with convergence insufficiency and asthenopia,
followed by unable to see blackboard and eye ache [14].
Convergence insufficiency and asthenopic symptoms were most
common associated ocular conditions in children with ametropia [15].
Highest association of convergence insufficiency was found with myopia
(40.99%) followed by hypermetropia (27.27%). Similar observations were
made in the study done by D.J. Risovic et al. 2008 [16], which also
showed that myopia as well as hypermetropia are significantly more
frequent in the student group than in the nonstudent group. The
prevalence of refractive conditions in this study was found to be
myopia 73.9%, hypermetropia 1.5%, and astigmatism 58.7%. In
today’s scenario of reading and writing habits, specially
keeping books close to eyes, are possible risk factors for myopia and
development of asthenopic symptoms [17]. Convergence insufficiency and
symptoms of eye strain may prevent children from progressing with their
peer group and may cause unnecessary social exclusion. The study done
by Chung and Chong’s [18] supported
the hypothesis that near
esophoria is associated
with high myopia. The study suggests that
near phoria might be an important factor in myopia development. We did
not consider myopia progression in our study.
Conclusion:
Our study reveals that due to high prevalence of refractive
errors among children, school vision screening is very important.
Convergence insufficiency and asthenopia is significantly associated
with refractive errors [3]. For detection of ametropia, VA should not
be the only criteria , as children have strong accommodation , also
convergence insufficiency and latent hypermetropia both present with
asthenopic symptoms, emphasizing the importance of refraction under
cycloplegia. Attention of parents and teachers regarding symptoms can
be useful for early detection and treatment of asthenopia and
convergence insufficiency. The importance of diagnosing CI in children
cannot be underestimated, because if left untreated can lead to
difficulties in study which will increase each year with the increase
of educational demands. With early identification of asthenopic
symptoms and detection of convergence insufficiency and health
education, quality of vision can be maintained & complications
can be prevented.
Funding:
Nil, Conflict of
interest: Nil
Permission
from IRB: Yes
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How to cite this article?
Gupta R, Sharma B, Anand R, Bawaria S, Dewada R. Association
of Asthenopia and Convergence Insufficiency in Children with Refractive
Error- A hospital based study. Int J Med Res Rev
2013;1(5):222-227.doi:10.17511/ijmrr.2013.i05.002.