Vol.13
No. 1, October 2003
ASSESSMENT
OF REFRACTIVE ERRORS BY SCHOOL TEACHERS
Dr.
C. S. Dhull, Dr. Indira Dhull, Dr. Manju Hooda, Dr. Nidhi
INTRODUCTION
Refractive
errors are a common and important cause of visual impairment
which is usually acquired and nearly always progressive.
According to WHO NPCB survey of 1989, refractive errors are
second most common cause of bilateral blindness at 7.35%.
In visually immature eyes of children they can result in
amblyopia and strabismus. In India children constitute
40% of the population therefore screening for refractive
errors in them is vital to reduce the prevalence of
preventable blindness. 1 Most of the time the
symptoms are mild so visual defects are not noticed by the
parents. As the ophthalmologist to population ratio in
India is 1 in 20000 in cities and 1 in 200000 in rural area.
Similarly the ophthalmic assistant to population ratio is 1 in
200000. 2 So the work load on them is too
much and they cannot perform effective screening . We
did this study to assess if a first level screening by
teachers in schools could be effective or not.
MATERIAL
AND METHODS
The
screening programme was carried out in the year 2001.
Three schools in Rohtak city were selected. Three
teachers of different subjects ( language, sports and Science
) from each school were selected. Female teachers
wearing spectacles were given preference to help the girl
students from over coming their hesitation about wearing
spectacles. These teacher were asked about their
knowledge regarding common symptoms of refractive errors and
treatment methods available using a questionnaire. These
teachers were given one day training in the OPD, Deptt. of
Ophthalmology, Pt. B. D. Sharma, PGIMS. In the training
all the teachers were trained to assess the visual acuity on
Snellen's chart. The training included theoretical part
about refractive errors and how to test visual acuity in
children. It was followed by a practical session where
teachers practised on each other and the patients till they
were fully competent. Vision screening was carried out
in school premises, using a well-illuminated Snellen's vision
box showing English & Hindi alphabets. Visual acuity
≤
6/9 was taken as cut off. A total of 678 students
in the age group of 5-10 years were included in the study and
vision testing was carried out by teachers and the
investigator simultaneously but blind to each other.
Children already using spectacles were not included in the
study.
All
the children detected as having vision <
6/9 were referred to OPD, Deptt of Ophthalmology PGIMS,
static retinoscopy and refraction was carried out to achieve
the best corrected visual acuity.
RESULT
A
total 678 students between the age group of 5-10 years were
examined. A total of 83 students (12.42%) were not able
to see 6/9 with one or both eyes as screened by teacher and
were referred. Of these referred cases 70 cases (10.4%)
were diagnosed as having refractive error and were prescribed
spectacles after refraction.
The
investigator detected 76 students (11.37%) to be having 6/9
vision. Out of these 76 students, 6 students had
been declared as normal by school teachers. There were
13 students with 6/6 vision who were reported by teachers as
having defective vision. The incidence of hyperopia was
5.14%, myopia (3.23%) and astigmatism in 3%. Out
of all cases , 92.2% were correctly identified by teachers.
The false positive rate of school teachers was 2.2% and false
negative rate was 7.8%. Five teachers (55.5%) were found
to possess satisfactory knowledge about refractive errors
which was acquired mainly from newspapers. All the
science teachers had satisfactory knowledge.
DISCUSSION
The
incidence of uncorrected refractive errors as estimated by our
study in urban school children was 11.37% which was quite high
despite the presence of a medical college in the city.
The prevalence of uncorrected refractive error in urban
population as estimated by Murthy et al was 6.4%.3
In our study though the teachers screened for distant vision
only yet the incidence of hyperopia was 5.14%.
The
low false positive and false negative rates by teachers showed
that they can confirm the absence of refractive errors quite
accurately. Using teachers for screening will save an
enormous amount of time and energy of the ophthalmic personnel
and will help in early detection of refractive errors.
Science
teachers had maximum awareness about the refractive errors and
they were found to be most effective in screening the school
children for refractive errors.
REFERENCES
-
Present
status of national programme for control of blindness NPCB
New Delhi. Directorate General of Health Services.
Ministry of Health & Family Welfare 1992.
-
Limburg
H Vaidyanathan R Dalal HP. Cost effective
screening of school children for refractive errors.
World Health Forum 1995; 16 : 173-8.
-
Murthy
GVS, Gupta SK, Ellwein LB, Munoz SR,
Pokharel G, Sanda L et al. Refractive error in
children in an urban population in New Delhi. IOVS 2002;
43:623-31.
Department
of Ophthalmology,
Post Graduate Institute of Medical Sciences, Rohtak
