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Original Study

Prevalence of Cataract Blindness in a Rural Puducherry P. Kanagarajan, Post Graduate, Partha Nandi, Asst. Prof, A. Lokeshmaran, Tutor Cum Statistician — Mahatma Gandhi Medical College & Research Institute, Pillaiyarkuppam, Pondicherry - 607 402.

Abstract

Introduction

Background: Globally there are 45 million people blind, 90% of these live in developing countries and more than 80% blindness is preventable or curable. In south-east asia, cataract is the single most common cause of blindness being responsible for 50-80% of all blindness. In India, 62.6% blindness is due to cataract. Objectives: To estimate the prevalence of cataract blindness among rural population of more than 50 years of age in study area. To know the factors associated with cataract blindness. Materials & Methods: Using multistage cluster random sampling method, out of 5 commune panchayats in Puducherry district, Bahour commune panchayat was selected as primary sampling unit. Thereafter Seliamedu panchayat was selected out of 15 panchayats under the Bahour commune panchayat administrative area. House to house blindness survey was done in Seliamedu (all 5 villages). A person with vision less than 6/60 was considered as blind. Illumination was done to see the degenerative changes in lens, iris shadow. Results: Total 7410 population was covered, in which 11.6% were found eligible for the study. The calculated prevalence of cataract blindness was 10.8%. Increasing age, illiteracy, working status was associated with occurrence of cataract. Conclusion: Further detailed studies are needed to see the actual burden of blindness due to various causes in community for effective planning and to attain the global objective of vision 2020.

Blindness has a great impact not only in terms of morbidity but it also hinders socio-economic development1. Most of developing countries like India face major demographic changes that lead to age related diseases2. WHO survey shows, there is a backlog of 12 million blind eyes in India, of which cataract contributes 80% have vision of 50 years of age was 8.5%15 while it is

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Fig. 1 Multi-Stage Cluster Random Sampling PUDUCHERRY (Dt.)

BAHOUR COMMUNE

SELIAMEDU PANCHAYAT (No. of Households)

Primary Sampling Unit

Secondary Sampling Unit

only 1.1% in the general population, clearly suggest where our vision to focus. The expecting fact that 50+ populations will double at 2016 from 56 million20 at 1991, hence we considered all people with more than 50 years of age in the secondary sampling unit as our sample. The survey was done by visiting every household in the unit to cover entire eligible study population.

In the Indian context presenting vision less than 6/60 has been used to define blindness and hence same definition was used here and similar Indian studies done earlier were used for comparison. Following criteria was used to identify cataract blindness in our study; subjects were assessed with abnormalities in visual acuity; degenerative change in lens; presence or absence of iris shadow when lens colour changed.

With increase in CSR (cataract surgical rate), there is a decrease in magnitude of the problem9 however, the rate was calculated with total population which includes younger population who would not be at risk. Most of the surgeries are done at urban level compared with rural. Moreover, the magnitude is slightly higher in urban than rural10 which shows awareness and literacy level of rural people are poor so diagnosing the problem at early stage is low. Thus the study sampling units were selected only from the rural communities.

A team consisting of 15 to 20 voluntary medical students visited the field twice in a week, preferably in the morning hours, and they were divided into groups of 3 each, houses have been allotted by field health worker and ANM assisting every group for complete coverage of whole village. House to house survey was done and if one or more eligible subject were found in any house was/were also included. If no eligible subject were found in the house, team moved to the next house after collecting family details. If the subject were not available at three subsequent house visits they were coded as a non-responsive. And if any subject found to be uncooperative and not willing for participation was also considered the same. Pre-tested questionnaires were applied to the eligible subjects after getting informed consent. Procedure and purpose of the survey has been explained in their local language.

For maintaining uniformity and to identify the correct clinical picture, one week training was conducted for voluntary medical student who passed the clinical ophthalmology subject. Proper and adequate instruction was also given to ANM, field health officers for guiding the investigating team and to get cooperation from the village side. The questionnaire was pre-tested with 25 people in out-patients of rural health centre after obtaining proper consent from each individual.

Detailed history especially eye complaints, educational and occupational status were enquired to every eligible persons. Details of hypertension, diabetes, were also

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assessed by physician’s advice or treatment history. Abnormalities in visual acuity were assessed by E chart and lens colour by oblique illumination. All suspected cases were shown to coordinator or the chief investigator for final decision. Data’s were entered in excel sheet and analyzed further. Mean age of subjects were calculated. Chi-square test was used to find the association of considered factor and cataract blindness. Results A total of 1749 households were surveyed, covering 7410 total population out of which 863 (11.6%) was found eligible in our study area. The detail of Seliamedu village which was selected by random sampling is given in Table 1.

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Table 2 shows that 788 people were examined during the period of July 2009 and April 2010, out of which 364 were male and 424 were female. Among male 188 and among female 228 had shown any positive findings. The prevalence of person with abnormalities in visual acuity, change in colour of lens, iris shadow were found to increase from 48% to 100%, as age increases as shown in Fig. 2. Female sex show higher magnitude when compared to male but statistically insignificant. Illiteracy and agricultural workers show significant association (p90

3

3

MALE

364

188

FEMALE

424

228

HSC and more

152

64

Some schooling

410

218

Illiterate

226

145

YES

332

223

NO

456

239

B – Opacity of lens;

C – ± Iris shadow

Chi-Square (p-value)

29 (0.000008)

0.35 (0.551) 18.16 (0.0001)

17.25 (0.0003)

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correct interval which is the fundamental exercise in preventable blindness control.

Fig. 2 Age wise distribution of Cataract Blindness

The estimated prevalence of cataract blindness by this study was slightly high (10.8%) from result obtained in a study conducted in a rural district of Karnataka (7.24%) 11 and also national blindness survey data on 2001-0215 and also higher prevalence of blindness among 50 years and above people was observed as compared to study done by Murthy et al in 20058. The reason for high prevalence may due to a substantial increase in the population above 50 years in India over the period from 2002 to 2010. Female sex shows more prevalence like other study11 suggesting that awareness and assessing health facility were low and also negligence among family members, and working groups may actively exposure to sunlight during agriculture based work also add to the above. The response rate was 91.3 %, which is considerably higher when compared to other studies conducted in south India.11 required, at even younger age group to know the association of risk factor and cataract. Discussion Cataract blindness, one of the significant social issues in India with annual incidence 2 millions. India is the first country which started blindness control programme to fight against preventable blindness by most cost effective intervention, like vision-restore surgery. District level surveys should be carried out every 4 to 5 years to know the exact problem in the particular, which may help further planning and allocation of resources. District blindness control society located all over the India, prepare annual action plan for resources and services, implementation from grass root level. But basic level surveys were not done at

Presenting vision is used to assess one’s day to day social and physical function11, so community based programme is required to control the blindness. Blindness due to other causes like glaucoma, demands greater challenge to public health since screening at community level is uncertain13. In such a situation elimination of avoidable blindness like cataract is the only way to reduce the problem. This has to be done at an early stage by correcting defective vision which is one of the most economical methods. So identification of cases should be done earlier and also community based work started at each level. Our study is restricted only to a rural area in Puducherry covering small population which may not represent the whole state or the country14. In the absence of recent national/district level data, this type of studies done in various

Table 3 Association of cataract blindness with hypertension, diabetics A+B+C

Hypertensive

Non-hypert

Diabetic

p=0.7619

Male

Non-diab p=0.101

Yes

41

178

36

183

No

29

116

15

130

p=0.00131

Female

p=0.475

Yes

58

233

49

232

No

12

131

29

114

A – Defective vision;

B – Opacity of lens;

C – ± Iris shadow

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places will present geographical distribution of magnitude considering together, the tool for setting priority and appropriate intervention. The CSR is one of the good indicators of what amount of work actually done in proper. At the same time, it is mandatory to compare pre and post operative vision16. Some of the states reported CSR more than 3000 per million which is beyond the target vision 202017. Recent report from various source in our country states that there is poor post surgery vision (i.e. no change in vision even after correction) 18 but input from our side not only focus to increase the surgery rate, but also aim to look clients’ satisfaction by improving quality of surgery and also strengthening the basic infrastructure, along with follow up after surgery. To fulfill the above needs community participation. In this context we have considered only major factors, but there are still hidden factors which may be associated in developing cataract. Most of the literature reviews only the prevalence of cataract blindness but it is also needed to look for incidence of cataract blindness which is difficult to measure, it is stated conventionally that incidence of cataract is 20% of actual prevalence19. There is no strong temporal relationship proved between cataract and NCD (like diabetes, hypertension) so as increase in age, degenerative disease may show increasing trend. Country like India is experiencing this pattern and it will be more pronounced in near future20 and our result also suggests the same. Though diabetes mellitus and hypertension have minor role, post cataract surgical complication like failure may occur in subject with diabetes mellitus and hypertension. Conclusion Long term prospective study should be conducted at district level for further evaluation rather than cross sectional study. Easy accessibility even at remote areas is one of the key role to reduce the trend. Improving quality of surgery and availing it free of cost even at private sectors also contribute to the right to sight of every citizen. Train auxiliary health workers, ophthalmic assistants to fill the gap of specialists. Yet 10 years is left for attaining the target of vision 2020, coordinated and combined efforts will help to combat the problem and reach the target. Reference 1.

2.

R. B. Vajpayeea, Sujata Joshib, Rohit Saxenaa, S.K. Gupta — Epidemiology of Cataract in India: Combating Plans and Strategies. Sharma S. P., Xenos P. — Ageing in India. New Delhi: Office of

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