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| EDITORIAL |
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| Year : 1999 | Volume
: 47
| Issue : 2 | Page : 61-62 |
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Blindness-control policy and population-based surveys in India
Lalit Dandona
L.V. Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad 500 034, India
Correspondence Address:
Lalit Dandona
L.V. Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad 500 034
India
 Source of Support: None, Conflict of Interest: None  | Check |
How to cite this article:
Dandona L. Blindness-control policy and population-based surveys in India. Indian J Ophthalmol 1999;47:61-2 |
The importance of reliable data from well-designed population-based surveys, with samples representative of the target populations, in planning eye-care policy to reduce blindness in India was referred to in a previous editorial in the Journal.[1] The current almost exclusive attention to cataract in the blindness-control policy of India is based on the unflinching belief of policymakers in the report of the 1986-89 national survey of blindness that 80% of the blindness in India is caused by cataract.[2] However, there is no evidence, published or otherwise, that standardised methodology was used in this survey for either selection of the sample or for the examination procedure. Data from the recent Andhra Pradesh Eye Disease Study question the assumption of the current eye-care policy of India that 80% blindness is caused by cataract.[3] These data from Hyderabad suggest that if dilated eye examination and visual fields had not been included in this survey (as was the approach in the national survey), the proportion of blindness attributed to cataract would have been overestimated by 75% because blindness due to posterior segment causes would have been erroneously attributed to cataract. If this is somewhat true in other parts of India as well, the proportion of blindness due to cataract may be closer to 50% in India. This would still make cataract the number one target for reducing blindness in India. However, this should also set us thinking about the other causes of blindness. For example, the data from Hyderabad show that those blind due to causes other than cataract were on average 14 years younger than those blind due to cataract.[3] This has considerable socioeconomic implications as younger people are more likely to be economically productive. The point is that we have to open up our minds to the possibility that causes other than cataract may also be contributing significantly to blindness in India. The natural question that follows then is: if this is so, can anything be done about these other causes? If we examine the data on visual impairment in Hyderabad, refractive errors caused 12.5% of the 1% prevalence of blindness[3] and 59.4% of the 7.2% prevalence of moderate visual impairment.[4] Something can certainly be done about this cause of visual impairment, even in the short term, as refractive errors are potentially easily treatable, even more so than cataract. What about the other causes of blindness found in Hyderabad: retinal diseases, corneal diseases, glaucoma, and optic atrophy?[3] Control of blindness due to these diseases would require long-term strategies for prevention, and early detection and treatment. However, if we do not start thinking about these strategies now, we will be faced with an even more unmanageable problem later. The backbone of such strategies would have to be the effort to establish effective infrastructure and manpower for good-quality comprehensive eye care in India.[5]
In contrast to surveys with detailed eye examination which can reasonably guide eye-care policy, surveys with preliminary eye examination have their value in quickly monitoring blindness in a particular area, as is shown by Limburg et al in this issue of the Journal.[6] Both these types of surveys are necessary as they play complementary roles. However, it would seem unwise to base eye-care policy of the country on surveys with inadequate methodology and preliminary eye examination, as is now the case in India. If we do not pay adequate attention to the basic principles of epidemiology, successful eye-care policy in India would continue to be an illusion.[7]
| References | |  |
| 1. | Dandona L. What role do epidemiology and public health have in dealing with blindness in India? [editorial]. Indian J Ophthalmol 1997;45:201-2.  [ PUBMED] |
| 2. | Survey of blindness, India (1986-89): summary and results. In:Present Status of National Programme for Control of Blindness (NPCB) 1992. New Delhi:Ministry of Health and Family Welfare, Government of India; 1992. p 79-100. |
| 3. | Dandona L, Dandona R, Naduvilath TJ, McCarty CA, Nanda A, Srinivas M, et al. Is current eye-care-policy focus almost exclusively on cataract adequate to deal with blindness in India? Lancet 1998;351:1312-16. [ PUBMED] [ FULLTEXT] |
| 4. | Dandona L, Dandona R, Naduvilath TJ, McCarty CA, Mandal M, Srinivas M, et al. Burden of moderate visual impairment in an urban population in southern India. Ophthalmology 1999;106:497-504. |
| 5. | Dandona L, Dandona R, Shamanna BR, Naduvilath TJ, Rao GN. Developing a model to reduce blindness in India:the International Centre for Advancement of Rural Eye Care. Indian J Ophthalmol 1998;46:263-68. [ PUBMED] |
| 6. | Limburg H, Vasavada A, Muzumdar G, Khan MY, Vaidyanathan K, Trivedi R, et al. Rapid assessment of cataract blindness in an urban district in Gujarat. Indian J Ophthalmol 1999;47:135-141. |
| 7. | Dandona L. Improving health in India. Lancet 1998;352:328. |
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