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International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
Original article
Refractive errors as a cause of childhood blindness in school going
children of a rural set-up
Pradnya L. Samant1, Surekha V. Bangal2, Purushottam A. Giri3, Akshay J. Bhandari4
1Intern, 2Professor, 4Asst.
Professor, Department of Ophthalmology, 3Professor, Department of Community Medicine (PSM),
Rural Medical College of Pravara Institute of Medical Sciences (Deemed University), Loni, Maharashtra, India
Corresponding Author: Dr. Pradnya L. Samant
Abstract:
Objectives: The study was done to determine the prevalence and causes of low vision in school going children and to assess the
pattern of refractive errors and prevalence of common ones.
Materials & Methods: A prospective observational study was carried out in school children of rural area, to find out the
prevalence of refractive errors by vision screening programme. Primary screening was carried out by trained teachers of the
school. During two months of study period, 1220 students of age group 10-12 years were screened to find out the refractive
errors.
Results: A total of 1220 school going children of standard 5th, 6th and 7th were screened for visual acuity using Snellen’s charts.
Out of the total 1220 children screened, 721 were boys and 499 were girls. Total of 266 children had defective vision, out of
which 128 (25.65%) were girls and 138 (19.14%) were boys. The total incidence of refractive error in the screened population of
school going children was 21.80%. Amongst this, the incidence of myopia (17.13%) is high as compared to that of hypermetropia
(4.67%).
Conclusion: There is need for awareness among the community about the ocular health. Vision testing must be added in the
schedule of child health programme implemented by government. Annual school health check-ups must focus their attention
towards vision impairment due to refractive errors and affected children should get visual aids.
Key words: Refractive error, Childhood blindness, Myopia, Hypermetropia, Astigmatism
Introduction:
better eye.1 It can also be defined as visual field of
Majority of the population in India, still lives in rural
less than 10 degree irrespective of visual acuity.1
areas. Health consciousness is much less in the rural
According to WHO, childhood blindness refers to a
population as compared to its urban counterpart.
group of diseases and conditions occurring in
World Health Organization (WHO) in 1999 proposed
childhood or early adolescence, which if left
a programme VISION 2020: RIGHT TO SIGHT. It
untreated, result in blindness or severe visual
plans to decrease the ocular morbidity among the
impairment that are likely to be untreatable later in
people, by eliminating the treatable causes of
life. It is estimated that 1.4 million children are blind
blindness. Blindness can be defined as a vision of
worldwide out of the total 45 million blind people.1
less than 3/60 in the better eye or an inability to count
The prevalence of childhood blindness ranges to
fingers at a distance of 3 meters in daylight in the
about 1.5/1000 in developing countries, whereas it is
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ISSN: 2319-7072
International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
0.3/1000 in well affluent countries.2 The causes of
to treatment and follow-up. The children having other
childhood blindness vary and include corneal
ocular problems such as stye, blepharitis and
2
In
conjunctivitis were excluded. The study was done to
India main causes of blindness in childhood can be
determine the prevalence and causes of low vision in
refractive errors, vitamin A deficiency, congenital
school going children and to assess the pattern of
abnormalities and retinoblastoma. Refractive error
refractive errors and prevalence of common ones. In
contributes about 19% of the total blindness
this study health education about prevention and
scarring, cataract, glaucoma, refractive error.
worldwide.
3
Refractive error is an optical defect
correction of these refractive errors was also done.
intrinsic to the eye which prevents the light from
A pretested questionnaire was used to collect the
being brought to a single point focus on the retina,
information from the students. Primary screening was
thus reducing normal vision. Refractive errors are
carried out in the school setting with the use of
common in children and are easily correctable,
Snellen’s charts after obtaining verbal informed
usually with the use of the spectacles. This is the
consent from the parents or school authorities. The
commonest cause of visual impairment around the
children, who were found to have defective vision or
world.
other associated ocular problems with asthenopic
The majority of the population in rural areas is
symptoms, were referred to Medical College Hospital
unaware about the early symptoms of visual
for detail ophthalmic evaluation and treatment by
impairment and thus results in the high incidence of
specialists. The refractive status of children was
4
uncorrected refractive errors. Visual impairment due
assessed by retinoscopy under cycloplegic refraction
to refractive error can be detected among the
(cyclopentolate eye drops 1%). Children were
population by vision screening programs. Such
prescribed
surveys can best be initiated in schools, since the
evaluation. Statistical analysis of the relevant data
refractive errors identified at a young age can be
was done by using appropriate statistical test.
corrected by providing quality spectacles and thus
Institutional
save the child from becoming visually handicapped.
obtained. A health education activity (IEC) on
Materials and Methods:
common ocular problems was arranged for the
A prospective observational study was carried out in
children in the school and subsequently in the
school children of rural area, to find out the
hospital with the help of charts and posters.
prevalence of refractive errors by vision screening
Arrangements were made for free spectacles.
programme. Primary screening was carried out by
Results:
trained teachers of the school. During two months of
A total of 1220 school going children of standard 5th,
study period, 1220 students of age group 10 to 12
6th and 7th were screened for visual acuity using
years were screened to find out the refractive errors.
Snellen’s charts. Out of the total 1220 children
The inclusion criteria include children in the age
screened, 721 were boys and 499 were girls. Total of
group of 10 to 12 years as they are cooperative for
266 children had defective vision, out of which 128
vision testing and there would be better compliance
(25.65%) were girls and 138 (19.14%) were boys.
spectacles
Ethical
three
days
Committee
after
initial
clearance
was
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ISSN: 2319-7072
International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
Table 1: Age and gender distribution of study population screened
Age
Girls
Boys
Total
10 yrs
151
212
363(29.75%)
11 yrs
180
251
431(35.33%)
12 yrs
168
259
427(35%)
Total
499(40.90%)
721(59.10%)
1220
Figure 1: Distribution of children as per visual performance
266
954
CHILDREN WITH NORMAL VISION
CHILDREN WITH DEFECTIVE VISION
Figure 2: Gender distribution of children with normal and defective vision
700
No of Students
600
Boys, 583
500
400
Girls, 371
300
200
Boys, 138 Girls, 128
100
0
Normal Vision
Defective Vision
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ISSN: 2319-7072
International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
Figure 3: Distribution of students according to their visual acuity
120
107
100
NO OF STUDENTS
100
80
60
40
23
20
19
15
7
0
6 by 9
6 by 12
6 by 18
6 by 24
6 by 36
6 by 60
Figure 4: Comparison between myopia and hypermetropia amongst the screened population
The above bar diagram shows a predominance of myopia over hypermetropia in the screened visually defective
children.
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ISSN: 2319-7072
International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
Figure 5: Other ocular findings associated with refractive error
8
VITAMIN A DEFICIENCY
SQ UINT
11
CO NGENITAL TO XO PLASMO SIS
1
IRIS CO LO BO MA
1
PAPILLARY HYPERTRO PHY
1
KERATO C O NUS
1
AMBYLO PIA
18
NYSTAGMUS
2
MYO PIC MACULO PATHY
2
PO STERIO R STAPHYLO MA
6
0
2
4
6
8
10
12
14
16
18
20
Discussion:
uncorrected visual impairment (≤ 6/12 in the better
Blindness is defined either in terms of best-corrected
eye) in the urban and rural group was found to be
distance visual acuity or presenting distance visual
9.8% and 6.6% respectively, which dropped to 7.1%
acuity. Level of visual acuity of less than 3/60 in the
and 3.3% respectively with presenting vision, and
better eye has been commonly used to define
reduced to 1.1% and 2.5% respectively with best
blindness. A normal eye condition whereby with no
corrected visual acuity. The primary cause of the
accommodation, parallel light is focussed on the
visual impairment was myopia and increased
retina is called emmetropia. Thus any optical
incidence was observed in urban population than
departure from this condition is called refractive error
rural. This was attributed to increased literacy rate
(RE) or ametropia. There are three kinds of refractive
and more visual associated activities like use of
errors
and
computers, watching television for longer hours.7 In a
estimates,
similar type of study, by Kasa T & Allene S D,
globally there are 40 million blind people and an
prevalence rate of visual impairment due to refractive
additional 245 million visually impaired.1 A further
error in a preschool and school children aged 5 to 15
517 million people have significant near vision
years of Debark & Kola Diba towns, was found to be
namely
astigmatism.2,5
myopia,
According
hypermetropia
to
WHO
impairment caused by uncorrected presbyopia.
6
7.6%. Myopia was a major cause of visual
A comparative survey of prevalence of refractive
impairment.8 Further 5.6% of the children were
error in urban and rural school children in and around
observed to have a visual acuity of <6/12 in the better
Hyderabad
eye while 2.6% showed visual acuity <6/18.
was
carried
out.
Prevalence
of
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ISSN: 2319-7072
International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
In the present study as evident from figure 1, the
a previous history and current use of spectacles as a
sample size of girls and boys studying in 5th, 6th and
visual aid. This can be attributed to illiteracy amongst
th
7 standard were apparently not largely different. The
th
the parents of the children. Majority of the parents of
th
total number of children screened in 5 , 6 and 7
the children earn daily wages and belonged to low
standards was 29.75%, 35.33% and 35% respectively.
socio-economic group. Due to low socio-economic
Out of the 1220 children screened, 266 children with
status of the parents they could not afford frequent
<6/6 visual acuity as determined by Snellen’s chart
visits to the eye care centre and the cost of the visual
were identified with defective vision (21.80%).
aids (e.g- spectacles). This depicts ignorance amongst
Children with visual acuity of less than 6/9, 6/12,
the community as a cause of increased risk of ocular
6/18, 6/24, 6/36 and 6/60 were identified and
morbidity in the future. Hence a provision was made
segregated from the total number of students with
for free spectacles for the children with the help of a
defective vision. The number of students (figure 3)
non-governmental organisation.
with the above visual acuity is 100,110,21,19,13 and
The
3 respectively.
hypermetropia in the screened population. Refractive
The prevalence of myopia in the present study (figure
errors were commonly seen in males than females.
6) is 17.13%. There was a similar study which was
Correction was given to these children with
conducted in western china in which the incidence of
appropriate lenses. Arrangements for free spectacles
myopia was found out to be 13.75%. Many studies
were made with help of a non-governmental
which detected refractive error in school children
organisation. Health education was imparted to the
have reported myopia to range from 4% to about 8%.
children
In one primary school study of Qazvin city
importance of regular follow-up and use of spectacles
prevalence of refractive error was 61.9% of those
was emphasised to the parents.
65.03% were myopic. This difference may be
Conclusion:
attributed to various factors such as geographical
There is need for awareness among the community
location,
about the ocular health. It can be done through mass
economic
development,
th
contributing
incidence
and
of
myopia
was
more
than
counselling regarding need and
environmental factors and the overall awareness
media
amongst the masses. Amongst the visually defective
awareness campaigns, rallies, posters, exhibitions,
children 78.57% comprises of myopia while the rest
etc. Vision testing must be added in the schedule of
is
of
child health programme implemented by government.
hypermetropia amongst the total screened masses is
Annual school health check-ups must focus their
4.67% in present study. Hence from the above
attention towards vision impairment due to refractive
findings it is clear that the incidence of myopia
errors and affected children should get visual aids.
amongst school going children is higher than that of
Up gradation of ophthalmic facilities/services at
hypermetropia. The incidence of myopia is 17.13%.
primary health centers should be done so that it
Hence the primary cause of visual impairment
becomes easily accessible for rural population.
of
hypermetropia.
Also
the
incidence
(electronic and
paper
media),
through
amongst these children is myopia. Out of the total
children having defective vision, only 6 children had
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ISSN: 2319-7072
International J. of Healthcare and Biomedical Research, Volume: 03, Issue: 03, April 2015, Pages 45-51
Acknowledgement:
We are grateful to Pravara Rural Hospital, Loni and Indian Council of Medical Research (ICMR) for allowing us to
do this study.
References:
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Resnikoff S, Pascolini D, Mariotti SP, Pokharel GP. Global magnitude of visual impairment caused by
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avoidable blindness. Arch Ophthalmol. 2004; 122: 615-20
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Fotouhi A., Khabaz KM, Hashemi H et al. The prevalence of refractive errors among schoolchildren in
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