J. Biomedical Science and Engineering, 2011, 4, 516-521
doi:10.4236/jbise.2011.47066 Published Online July 2011 (http://www.SciRP.org/journal/jbise/ JBiSE ).
Published Online July 2011 in SciRes. http://www.scirp.org/journal/JBiSE
The effect of amblyopia on educational activities of students
aged 9 - 15
M. Khalaj1, I . Mohammadi Zeidi1, M. R. Gasemi1, Ahmad Keshtkar2
1School of Public Health, Qazvin University of Medical Sciences, Bahonar Blvd, Qazvin, Iran;
2Medical Faculty, Medical Physics Department, Tabriz University of Medical Sciences, Tabriz, Iran.
Received 12 April 2011; revised 24 May 2011; accepted 10 June 2011.
ABSTRACT
Amblyopia is an illness with reduced vision and a
number of students are affected with this disease. To
determine any association of amblyopia with educa-
tional activities, sport and social activities of students
involved by amblyopia, this study was carried on.
This study was conducted at Boali Hospital in Gazvin,
Iran: A total of 110 patients 9 to 15 years (54.5% fe-
male and 45.5% male; mean age: 13.7 ± 3.2) with
amblyopia (20/25 - 20/400) due to strabismus and/or
refractive errors, and that persisted after treatment
with spectacles. All children wore eyeglasses contain-
ing their refractive correction (based on cycloplegic
autorefractor measurements, refined or confirmed by
cycloplegic retinoscopy or subjective refinement) for
acuity testing. The results indicated that, 25 (22.73%)
patients with strabismus amblyopia, 40 (36.36%)
patients anisometropic amblyopia, 22 (20%) patients
ametropic amblyopia, 18 (16.36%) patients with
strabismic mixed with anisometropia and 5 (4.55)
with deprived amblyopia. Parent’s knowledge about
meaning of amblyopia and amblyopia-related phe-
nomena in 50 (45.5%) of patiens was very low. The
educational level in 45 (41%) of parents were r eported
to be primary school, 40 (36.3%) higher school and
universit y deg r ee s 25 (22. 7% ). T he spor t act ivit y in 35
(31.8%) of patients with amblyopia was very low and
in 14 (12.7%) higher than others. In a comparison
with other students, the educational qualification in
18 (16.4%) was very low, 35 (32%) the as equal as
others and 27 (24.5%) higher than their classmate.
Visual acuity with the best correction, in 75 (67%) of
patients was 20/25, in 30 (27.27%) patients 20/40 or
worse and in 5 (4.5%) of them 20/200 or worse. Poor
eyesight and amblyopia can influence on learning,
sport and social activity, and performance in school,
as well as restrict choice in profession and hobbies.
The parent’s knowledge of amblyopia is high effi-
ciency of treatment of the amblyopia pati ent’ s morale.
Keywords: Amblyopia-Visual; Acuity-Anisometropia –
Strabismus
1. INTRODUCTION
Amblyopia, or lazy eye, defined as a reduction in cor-
rected visual acuity (VA) in the absence of visibl e orga nic
abnormalities. This is the most common cause of visual
impairment in both children and middle-aged adults,
affects a ppr oxi ma tely 1.5% t o 3% of t he po pula tion. Thi s
carries a projected lifetime risk of visual loss of at least
1.2% [1-5]. Am blyopia is clinically defined as a two lines
or greater difference in visual acuity (VA) between the
eyes in the presence of a predisposing amblyogenic con-
dition, and in the absence of visible ocular or visual
pathway disease [6]. It is occurs because child's visual
system does not develop properly, resulting in abnormal
sight in one or both eyes [7]. Amblyopia can be treated
effectively in young children, if left uncorrected, this
vision problem can lead to abnormal neurodevelopment
of the visual system and then visual loss may be perma-
nent [8-10]. Many eye care professionals believe that
treatment beyond early of life age of 6 or 7 years, is in-
effective and a treatment response is unlikely, while oth-
ers consider age 9 or 10 years to be the upper age limit for
successful treatment [11-14]. The American Academy of
Ophthalmology Preferred Practice Pattern for amblyopia
recommends treatment up to age 10 years [15]. Amblyo-
pia, when diagnosed in children, is usually treated with
occlusion (patching) of the sound eye or therapy with a
cycloplegic drug (atropine) that dilates the pupils and
blurs the image seen by eye, has been known for almost a
century. Occlusion therapy is subject to problems of
compliance, due to the child’s dislik e of wearing a patch
for visual, skin irritation, and social/psychological rea-
sons [16]. Therefore the penalization methods are effec-
tive methods for the treatment of amblyopia, with a low
risk of occ lusion amblyopia.

M. Khalaj et al. / J. Biomedical Science and Engineering 4 (2011) 516-521 517
Patient acceptance of these methods was good [17].
The most com m on cause s of am bly opia i s a conge nita l o r
early acquired cataract, but corneal opacities, vitreous
hemorrhage, and ptosis also may be implicated. Depri-
vation of the form of vision is the least common form of
amblyopia but most damaging and difficult to treat. Am-
blyopic visual loss resulting from a unilateral occlusion of
the visual axis tends to be worse than that produced by
bilateral deprivation of similar degree because interocular
effects add to the direct developmental impact of severe
image degradation. Even in bilateral cases, however,
visual acuity can be 20/200 or worse. Unilateral cataracts
have a better prognosis when the cataract is removed and
optical correction is in place by 3 months of age to
minimize deprivation and maximize visual prognosis
[18,19]. Most of the available data on th e natural history
of ambl yopia and s uccess rate s of its treat ment with e ither
patching or drug therapy are retrospective and uncon-
trolled. Despite the common occurrence of amblyopia,
there is little quality data on treatment of this condition.
Thus, there is much to be learned about the course of
treated amblyopia, to provide more precise estimates of
success rates and to identify factors that may be associ-
ated with successful and unsuccess ful treatment. A recent
population-based study of educational, health, and social
outcomes, which failed to identify any “real-life” func-
tional impact of the visual deficits associated with am-
blyopia, hi ghlight ed t he need for furthe r re search on what
it means to have amblyopia [20]. We report an investiga-
tion of the association of amblyopia with diverse health
and social outcomes. In the present investigation, we
provides an opportunity to determine the affects the
educational, sport and social activities of amblyopia pa-
tients aged 9 to 15 years old in Qazvin city in Iran.
2. METHODS
The study was performed at Buali eye clinical in Qaz-
vin-Iran. A total of one hundred ten children participated
in the study, including 60 female (54/5%) and 40 male
(45/5%) aged 9 to 15 years, mean age: 13.7 ± 3.2 [SD].
Subjects were enrolled between January 2007 and April
2008 in a randomized trial had best-corrected visual
acuity (VA) of 20/25 to 20/400 with amblyopia resulting
from strabismus, anisometropia or both, and refractive
errors. Children (9, 10, 11, 12, 13, 14 and 15 years) were
invited to attend in a research clinic. Patients h ad to have
refractive error in each eye between ±0.5 and ±9.00 di-
opters (D ). For doin g some eye exam ination parents of al l
subjects and their teachers were contacted by letter and
telephone to invite them to participate and 95% of them
agreed to participate [21]. Parents completed a compre-
hensive 30-item questionnaire that addressed basic so-
ciodemographic factors such as ethnicity, parental edu-
cation, occupation and social activities of studen t. Cyclo-
plegic autorefraction was performed with an autorefractor
(model RK-F1; Canon, Tokyo, Japan). This instrument
generated three reliable readings of refraction in each eye;
the median reading was used for analysis. Cycloplegia
was induced using cyclopentolate 1 % (1 drop) , 2 minutes
after corneal anesthesia with amethocaine 0.5%. Tropi-
camide 1% (1 drop) and phenylephrine 2.5% (1 drop)
were also used in some children to obtain adequate my-
driasis (a minimum pupil diameter of 6 mm). Autore-
fraction was repeated 30 minutes after the last drop [22].
Measurement of ocular biometric parameters was
performed with an optical biometer. By using Snellen
charts, at distance of 6 meter (20 feet), visual acuity in
each eye and an examination for strabismus by trained
medical examiners was m easured [23]. The child read the
first letter of each row from the top of the logMAR chart
until an error was made (screening). The child was then
redirected to two rows above the screening error row and
asked to attempt each letter until four incorrect responses
were given [24]. All children wore eyeglasses containing
their refractive correction (based on cycloplegic autore-
fractor measurements, refined or confirmed by cyclople-
gic retinoscopy or subjective refinement) for acuity test-
ing. We invited all children to a vision assessment at all
years, including measurement of visual acuity both with
and without a pinhole (with pinhole as a proxy for cor-
rection by spectacles). We sent out a questionnaire on
family history and previous treatment with patching be-
forehand [25]. For this analy s is, we e xc luded p eople with
bilateral visual loss, unilateral loss inconsistent with am-
blyopia, or known eye diseases (suc h as cataract), as well
as those whose vision was tested with and without their
prescribed optical correction. Results were analyzed
using SPSS program, to assess for factors that directly or
indirectly influenced the amblyopia and evaluati on social
activities and other factors of amblyopic students com-
pared to normal students.
3. RESULTS
Reading testin g was com plet ed by 110 students at 9 to 15
years, who were eligible, of whom 60 (54/5%) female and
50 (45/5%) were male; mean age, 13.7 ± 3.2. Of all, 75
(67%) patients with the best correction had mild ambly-
opia (VA worse than 20/25), 30 (27.27%) patients had
moderate (VA worse than 20/40) and 5 (4.5%) severe
amblyopia (legal blindness, 20/200 or worse), Figure 1.
Ambly opi a w a s de fi ne d as be st -co rr ect ed vis ua l a cui ty o f
20/25 or worse in the absence of any pathological cause.
Ninety-five (86.4%) wore spectacles alone, 15 (13.6%)
were wore a combination of spectacles and contact lens.
The prevalence of unilateral amblyopia was (50.5%) and
monolateral was (49.5%). As shown in Table 1, Aniso-
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M. Khalaj et al. / J. Biomedical Science and Engineering 4 (2011) 516-521 518
metropia was statistically more common in amblyopic
cases (36.36%) compared with (22.73%) of strabismics,
Anisometropia & strabismic amblyopia (16.36%), ame-
tropic amblyopia (20%), and patients with deprived am-
blyopia (4.55%) (p<0.001). Parents knowledge about
meaning of amblyopia and amblyopiarelated phenomena
in 50 (4 5.5%) of patiens was very low, 27 (2 4.5%) mi ddle
and 33 (30%) high. The literacy level in 45 (41%) of
parents, was about primary school in 40 (36.3%), in high
school and 25 (22/7%) of them in university degree
qualifications (Figure 2). The sport activity in 35 (31.8%)
of patients with amblyopia was very low, in 38 (34.5%)
low, in 23 (20. 9%) t he sam e l evel as oth er st uden ts a nd i n
14 (12.7%) of students was higher than others. In a
comparison with other students,the educational quail-
fication attained by 18 (16.4%) was ve ry low, in 30 (28%)
of students low, in 35 (32%) was found to be the same
level as othe r students and 27 (24.5%) of t hem, had higher
educational qualification than their classmate. As Shown
in Table 2, the participation in social activities (going
park, or to t he cinem a, meeting frie nds and fam ilies) in 60
(54.5%) of ambl yopi c pat ie nts was ve ry lo w, in 27 (28%)
low, 12 (10.9%) was the same level as other students and
11 (10%) of them, higher than their classmate. Am-
blyopia was found to be statistically different by gender
(p = 0.01), in all age groups, the females were more
activities than male.
JBiSE
4. DISCUSSION
It is generally agreed that amblyopia must be diagnosed
and treated at an early age to prevent the loss of vision and
that treatment is more extended and less ef fective in older
ages. This study showed that children with higher mag-
nitudes of anisometropia had higher prevalence and
greater depth of am bl yopia [26]. Conducti on of preventive
programs direct ed t o chi ldren requires the parti cipat i on of
prevalence of amblyopia
0%
10%
20%
30%
40%
50%
60%
70%
80%
MildModarate Sever
Figure 1. The means prevalence of mild, moderate and
severe amblyopia in children aged 9 to 15.
Par ent s e duca t i o nal level
20%
25%
30%
35%
40%
45%
prim ary schoolhigh scholuniversity level
per cen t
Figure 2. Parents literacy level of students with amblyopia
in one or two eyes. About 41% of parents had a low level of
education
Table 1. Prevalence of Amblyopia in Qazvin-Iran Children by Age (years).
Age
Anisometropic
Amblyopia
[Prevalence (n)]
(N) (%)
Strabismic amblyopia
prevalence(N)
(N) (%)
Strabism&aniso
amblyopia preva-
lence(N)
(N) (%)
Ametropia
amblyopia
prevalence (N)
(N) (%)
Deprived am-
blyopia preva-
lence(N)
(N) (%)
Total
(N) (%)
9-10 9 (42.86) 6 (28.57) 2 (9.52) 3 (14.29) 1 (4.76) 21 (19)
10-11 8 (44.44) 2 (11.11) 2 (11.11) 5 (27.8) 1 (5.5) 18 (16.36)
11-12 6 (35.29) 5 (29.41) 2 (11.8) 4 (23.53) 17 (15.45)
12-13 8 (20) 6 (30) 2 (10) 2 (10) 2 (10) 20 (18.18)
13-14 4 (22.20) 3 (16.66) 6 (33.33) 5 (27.8) 18 (16.36)
14-15 5 (31.25) 3 (18.75) 4 (25) 3 (18.75) 1 (6.25) 16 (14.55)
Total 40 (36.36) 25 (22.73) 18 (16.36) 22 (20) 5 (4.55) 110 (100)
Table 2. Below table shows the participation of students with amblyopia in social activities. About 54.5% of students had very
low social activities in comparison with normal student.
The participate of amblyopic students in social activities
Very low
(N) (%) low (N) (%) Equal (N) (%) higher (N) (%)
(60) (54.5) (27) (28) (12) (10.9) (11) (10)

M. Khalaj et al. / J. Biomedical Science and Engineering 4 (2011) 516-521 519
several sectors of the community involving physicians,
educators, parents and volunteer personnel. This study
indicate that, on average, students with amblyopia can not
expect to do as well as their peers with normal vision in
both eyes in terms of educational attainment, sport, and
social activities. We found that several factors can effect
the improvement and or preve nt i on of amblyopia (e.g. t he
role of parents, childhood socioeconomic environment
etc.).
To our knowledge, no previous reports have addressed
the importance of parents’ educational level prospects for
children with amblyo pia. The parents’ knowledge of am-
blyopia had an important role in educational attainment,
employment, social achievement and etc and can en-
courage children attendance seriously in sports and edu-
cational environments and social activity. Amblyopic
children who t heir parents famili ar with amblyopia, do not
seem to be disadvantaged in relation to social activities,
nor are they at increased risk of behavioral difficulties or
social maladjustment as children [20]. This study showed
the knowledge of amblyopia in 45.5% of parent was very
low and literacy level in 36.3% was about primary school.
These factors can be involved in future activities in chil-
dren with amblyopia in one or two eyes. Our results are
different with Rahi and colleagues, which showed that,
distinguishing, at a population level, between the lives of
people with amblyopia and those without in terms of im-
portant educational, health, and social outcomes may be
difficult. They cited that children with amblyopia did as
well as those with normal vision on educational tests and
was not associated with highest educational qualification
achieved [20]. They reported that people with amblyopia
were no more likely than those with normal vision to
report poor general health, depression, or psychological
distress in adulthood. O ur study i ndicated that only 24.5%
of students was associated with highest educational qua-
lification related to others, in contrast 18 (16.4%) of stu-
dent with amblyopic eyes was very low, in 30 (28%) of
them low, in 35 (32%) was found to b e the same level as
other students, these may be as a result of parents
knowledge of amblyopia and low educational level. Re-
cent study in the UK showed th at the lifetime risk to peo-
ple with amblyopia of visual impairment or blindness
through disease or injury to their normal eye is between
1% and 3% [27]. It is reported that amblyopia has been
found to significantly reduce speed and dexterity of pre-
hension (particularly in children with a history of stra-
bismus), without diminishing accuracy and control
[28-30]. Evidence also has come to light that amblyopic
subjects’ binocular reading speed is significantly slower
than that of normal subjects, despite the amblyopic sub-
jects having the sam e level s of binocular vis ual acuity and
reading acuity as the normal subjects [31]. Woodruff and
colloquies reported, pure anisometropic amblyopia had
the best initial visual acuity, with 25% of anisometropes
having an initial visu al acuity of less than 6/18 compared
with 39% of strabismics and 50% of mixed amblyopes
[32]. Whereas our study showed that the prevalence of
anisometropia was statistically more common in ambly-
opic cases (36.36%) compared with (22.73%) of strabis-
mics, (16.36%) of mixed amblyopes, (20%) ametropic
amblyopia. Our findings suggest a significant effect of
amblyopia on the sports activities. Fewer children in the
amblyopic Group in Qazvin had participated in higher
sport activities (12.7%).
This may be because the student with amblyopia had
almost several times the risk of visual impairment in their
better seeing eye with the best correction to less than
20/25 compared to students without amblyopia. This
underlines the importance of continued childhood scre en-
ing in the early of life and treatment of children with
amblyopia in order to prevent or reduce the risk of visual
impairment and have no significant behavioral problems,
the well reported burden of disease associated with vision
loss later in life. Chua and Mitchel found a borderline
significant effect of amblyopia on higher university de-
grees but no effect on lifetime occupational class [33]
Snowdon and Stewart-Brown interviewed health care
professionals, adults with amblyopia, and children in
amblyopia treatment to gain an understanding of how
amblyopia and treatment for amblyopia affect people’s
lives [34]. Further longitudinal data are warranted to
provide a more com plete account of the nat ural history of
amblyopia and the plasticity of the visual system [33].
Associations between performance at school and am-
blyopia are complicated by the independent associations
of strabismus and refractive error with a variety of neu-
rodevelopmental disorders, including those caused by
premature birth. Nevertheless, bilateral visual deficits
(which were excluded from Rahi and colleagues’ study)
that cannot be corrected with glasses are clearly associ-
ated with educational difficulty and reduced life chances
[35].
5. CONCLUSIONS
It may be difficult to distinguish, at population level, be-
tween the lives of student with amblyopia and those
without, in terms of several important outcomes. Our
findings indicate that, on average, children with amblyo-
pia can expect to do social activities but not as well as their
peers with normal vision in both eyes in terms of educa-
tional attainment, employment, sport activities and so-
cioeconomic achievement. But in some student with am-
blyopia do not seem to be disadvantaged in relation to
social activities, nor are they at increased risk of behav-
ioral difficulties or social maladjustment as children.
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