The effect of amblyopia on educational activities of students aged 9 - 15

doi:10.4236/jbise.2011.47066

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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.

Email: [email protected]

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-

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

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.

M. Khalaj et al. / J. Biomedical Science and Engineering 4 (2011) 516-521

520

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