Prevalence and Magnitude of Blindness in Children in India
Available prevalence data suggest a strong association between under 5-year mortality rates and the prevalence of blindness in children. This association has been used where more formal data are not available, to estimate the prevalence of blindness in children in each region of the world as well as the number of children affected.
No population based surveys have been undertaken in India, but data from two CBR programmes, one in West Bengal and the other in Andhra Pradesh, show the prevalence of blindness in children to be 0.65/1,000 children (95% CI 0.51-0.82) and 0.51/1000 children (95% CI 0.37-0.65) respectively. These studies probably slightly underestimate the prevalence, as the field workers were dependent on parents recognising as well as admitting they had blind child. A figure of 0.81/1,000 children has been used for India by World Bank region, using the correlation between under mortality rates and prevalence. Currently there are estimated to be approximately 270, 000 blind children in India.
Causes of Blindness in Children in India
To date almost 2,000 children in schools for the blind in 11 states in India have been examined using the WHO classification system. Data are also available from West Bengal and Andhra Pradesh CBR programmes. The findings are summarised in Tables 1 and 2.
Overall the commonest causes of blindness in children in India are as follows:
Corneal scarring, mainly due to vitamin A deficiency.
Congenital anomalies of the whole eye, usually of unknown cause, but where genetic factors may play a role.
Retinal conditions, mainly hereditary retinal dystrophies.
Cataract, which can be due to congenital rubella or hereditary factors, but usually the cause is not known.
Optic atrophy, due to a variety of causes. Presenting the data in summary form hides the fact that there appears to be considerable regional variation in the major causes of blindness in children in India (Table 3). This probably reflects the differences between the states not noly in levels of socio-economic development and ethnic mix, but also in cultural and social practices.
Congenital abnormalities of globe (anophthalmos/microphthalmos/coloboma), retinal dystrophies and cataract are major causes of blindness in some states. Madhya Pradesh, West Bengal, Uttar Pradesh, Gujarat, Maharashtra have the largest proportion due to nutritional blindness. Control of Blindness in Children
Activities are required in the community and at the primary, secondary and tertiary levels of health care provision.
General measures - Sri Lanka and the state of Kerala have shown the impact of high female literacy on primary health and there appears to be an association with corneal blindness in children. Kerala has a female literacy rate of more than 90% and corneal blindness accounts for only 7% of blindness in children. Uttar Pradesh has a literacy rate of less than 40% and 27% of blindness is due to corneal scarring. Education of women may also reduce the incidence of some genetic disease, by avoiding consanguinity. Economic self sufficiency along with literacy can make the health situation even better; the Grameen (rural) Bank of Bangladesh is one example.
Primary level - Implementation of primary health care : If the eight essential elements of primary health care were to be fully implemented, many causes of blindness in children would be averted. (1) Education concerning main health problems eg, health education concerning breastfeeding practices, food and nutrition and avoiding the possibly harmful effects of traditional eye medicines would reduce corneal scarring; health education about the increased risk of genetic diseases in consanguineous marriages. (2) Promotion of food supply and good nutrition eg, ensuring all children and women of child bearing age have access to vitamin A rich foods would be the single most important measure to prevent blindness in children. (3) Adequate supply of safe water and basic sanitaion eg, diarrhoea control would also reduce one of the major risk factors for vitamin A deficiency. (4) Maternal and child health care and family planning with child spacing eg, good antenatal care, safe delivery and proper care of the newborn. (5) Immunisation against major infectious diseases eg, measles immunisation as measles infection can precipitate a child into acute vitamin A deficiency. Rubella immunisation of school girls would also be a safe strategy for prevention of congenital rubella. (6) Prevention and control of local endemic diseases eg, vitamin A supplementation programmes. (7) Appropriate treatment of common diseases and injuries eg, appropriate and prompt treatment of corneal ulcers in children. (8) Provision of essential drugs- Supplies of vitamin A, as capsules or oil, need to be available for (a) supplementation programmes, (b) treating all malnourished children and those with measles and severe diarrhoea, (c) treating children with established xerophthalmia.
Primary eye care - Primary eye care includes the following :
Preventive measures in the community (see above).
Early identification and treatment of potentially blinding conditions.
Identification and referral of conditions needing more complex care.
Community level workers eg, Anganwadi workers and primary level health workers can play a key role in preventing blindness in children by identifying children who need prompt treatment (ie, those with corneal ulcers) as well as recognising conditions (eg, cataract) requiring urgent referral for assessment and surgery.
Secondary level - At the secondary level, services for the control of blindness in children include expertise in the management of corneal ulcers and trauma, refraction, low vision services for the less complex cases and cataract surgery for the older child.
Tertiary level - At the tertiary level, important activities for the control of childhood blindness include provision of specialised eye care services; human resource development; planning and research. Services need to be integrated with those at the secondary and primary level. There should be close collaboration with other specialists providing services for children eg, paediatricians, neonatologists, geneticists. There is a need to increase the number of ophthalmologists with expertise in the management of children in India, and in order to meet the need there should be at least one paediatrically trained ophthalmologist for every 5 million population. These centres will require a team, consisting of an ophthalmologist working with an anaesthetist, optometrist and low vision therapist.
Incidence on Childhood Blindness
To date there are no published studies on blindness in children or on the incidence of blindness in children. In industrialised countries the incidence of blindness due to acquired diseases is estimated to be only 2/100,000 children/ year. Globally it has been estimated that 500,000 children become blind every year. It has also been suggested that 50-60% of blind children die within a short period of becoming blind, mainly as a consequence of systematic affects of the condition causing blindness (eg, measles infection and pneumonia; vitamin A deficiency and infection; congenital rubella and heart disease).