A multitude of conditions and
diseases can lead to visual impairment and to its extreme manifestations in the
form of blindness. Of these, malnutrition constitutes an important cause of
preventable blindness, especially in young children. Several nutrients, such
as, protein, vitamin ‘A’, and 'B' complex’ vitamins are needed for the normal
functioning of the eye. But it is the I deficiency of vitamin A that affects
the eye most, and the resulting condition is known as xeroph thalmia.
Magnitude
of the problem Though the disease has been known
for many ages and the factors responsible for the widespread prevalence of the
disease are well understood, xerophthalmia unfortunately still constitutes a
major public health problem in many developing countries. It is estimated that
in India alone, over 10,000 children are becoming blind every year as a result
of vitamin ‘A’ deficiency. This may be an under estimate since many children
with severe malnutrition do not survive. His immense social and economic
repercussions of this problem can be well appreciated.
What
are the reasons for this?
The main reason for the widespread
prevalence of this deficiency disease is inadequate dietary Intake of vitamin
‘A’. In addition, other factors like poor nutritional status of the mother
during pregnancy and lactation, delayed supplementary feeding and repeated
infections ate responsible for the development of vitamin ‘A’ deficiency.
A newborn infant has some amount of
vitamin ‘A’ already stored In the body. This depends on how much vitamin ‘A’
the mother lias consumed during pregnancy. The diets of pregnant women of poor
communities are woefully inadequate in their vitamin ‘A’ content. As a result,
the Infants are born with poor stores of the vitamin. And these Infants thus
start life with a handicap.
During the first 5- 6 months of
life, vitamin ‘A’ needs of the child are met exclusively from breast milk. Vitamin
‘A’ content in breast milk again depends on the amount of vitamin ‘A’ consumed
by the mother. The breast milk of many Indian mothers has low concentration of
vitamin ‘A’ and hence the infant does not get enough vitamin from this source.
After the age of six months,
supplementary foods are necessary to meet the vitamin ‘A’ requirements of the
infant. But in most poor communities this is delayed well beyond the age of one
year and foods containing vitamin ‘A’ are seldom given.
The diets of
preschool children are grossly deficient in vitamin ‘A’. They consume less than
100/ug of vitamin ‘A’ while the requirement is about 300/ug per day. Thus the
continued low intake of vitamin 'A' by the child is the main reason for the
development of vitamin ‘A’ deficiency. Repeated infections, which are common
among children, worsen the situation and precipitate xerophlhalmia with tragic
consequences.
What
are the deficiency signs?
Night-blindness
or inability to see in dim light is the first symptom:
This is an
important warning signal and should not be neglected. In addition to night-
blindness, there are some visible changes in the eye. Conjunctiva, the membrane
covering the white portion of the eye, is normally smooth and shining. In
vitamin ‘A’ deficiency it becomes dull, dry and wrinkled. In chronic cases,
greyish foamy patches called Bitot spots appear on the white portion of the eye.
The
conjunctival changes do not interfere with vision but in severe deficiency,
cornea (the black portion of the eye) is affected leading to total blindness.
This condition is called keratomalacia. It is seen mostly in children below five
years of age and is frequently associated with protein-calorie malnutrition.
Measures
for prevention
Early signs of
vitamin ‘A’ deficiency can be treated successfully by giving vitamin ‘A’
supplements. But in more advanced cases of keratomalacia, scar formation is
inevitable. Unfortunately, many children come to the hospital in such late stages that even large doses of vitamin ‘A’ cannot restore vision. Prompt treatment with vitamin ‘A'
can make all the difference between
sight and blindness. The community health
workers should, therefore, be trained in
early detection and treatment of such cases.
Considering the vast number of children known to suffer
from this disorder, a much better approach would be to see that the deficiency
does not develop at all. Pregnant and nursing women should be encouraged to
consume diets adequate in vitamin ‘A’. Children should be given supplementary
foods rich in this vitamin from the sixth month onwards.
Sources of Vitamin ‘A’
Vitamin ‘A’ is present in foods of animal origin such as
butter, eggs and liver. However, these are expensive and beyond the reach of
the poor. Foods of vegetable origin contain a substance called/3-carotene which can be
converted to vitamin ‘A’ in the body. This pro vitamin can be obtained from
inexpensive
foods such as green
leafy vegetable drumstick leaves and carrots. Fruits like papaya and mangoes
are also rich sources of carotene. Inclusion of these foods in ' diets of
children will prevent vitamin a deficiency. People should be encourage to grow
these plants in community and home gardens. This, however, involves an intensive
programme of nutrition education and can be considered only as a long-term approach.
In view of the urgency of the problem, it becomes imperative to devise additional
measures which can be applied immediately and on a mass scale.
Massive
doses of Vitamin ‘A’
Human liver has
enormous capacity to store vitamin ‘A’ and release it as and when the need
arises. It is, therefore, possible to build up vitamin ‘A’ stores in the child
by periodic administration of massive doses of
vitamin ‘A’. Field studies carried out by the National Institute of
Nutrition, Hyderabad, have shown that a dose of 200,000 IU ot vitamin
‘A’ given by mouth every six months can protect the child from blindness
arising from vitamin 'A’ deficiency. Such a programme was initiated by the
Government on a national scale in 1970. It is sponsored by the Department of Family
Welfare and is implemented through the Primary Health Centres. The programme is
now in operation in almost all the States in the country, covering about 24
million preschool children. Integrated approach Administration of massive dose
of vitamin ‘A’ is one of the practical measures suggested to prevent blindness
due lo vitamin ‘A’ deficiency. However, vitamin A’ deficiency is multifaceted
problem and those suffering from it not only need vitamin ‘A’ but also general
improvement in their diet and environ; ment. It is now realized that any
programme for the prevention of nutritional blindness should not be in
isolation but should be integrated with other health and nutrition services.
This is being attempted in the Integrated Child Development Services Scheme
(ICDS).
One of the general objectives of the
International Year of the Child (IYC) is lo provide basic health and nutrition
services to all children below six years of age, especially those belonging to
weaker sections of society. This cannot be achieved in one year but calls for
continued action during the next two decades. In accordance with these
objectives, the Government has already initiated a series of action programmes.
With the proper implementation of these programmes nutritional blindness can be
eradicated before the end of this century.
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