CHAPTER EIGHT 342 TABLE 8-21. PREVALENCE, ESTIMATED NUMBER OF CASES, AND DISTRIBUTION BY POPULATION DENSITY, BITOT'S SPOTS (XlB), CHILDREN UNDER AGE 6, DECEMBER-APRIL (NBS 1981) Estimated Number of Children Affected Prevalence per 100 Children Percentage of Nepal's Total Sample N Density 29.1% '10.9 100.0 NA Low High Subtotal Missing data 2,663 3,880 6,543 1,637 3,923 9,558 13,481 0 0.4 0.7 0.6 NA Total 7,580 13,481 0.6 100.0 Source: FRS.002 AN.98 M apart, the village was considered to have scattered houses. Villages in between these two extremes were considered to have separate but not scattered houses. Table 8-22 shows that there is more than a four-fold difference in Bitot's spots prevalence between compact and scattered villages (odds ratio = 5.1, p < .001). However, it is important to note again the confounding role of terrain. In the plains there is a high density of population and compact housing clusters, while in the mountains houses are scattered. Whether the density of population contributes to the geographic distribution of xerophthalmia, or the geographic distribution of xerophthalmia con- founds the relationship with population density, is a subject for additional analysis. Facilities Available in the Neighborhood: The basic political unit in Nepal is the panchayat, containing nine wards. Each ward usually contains at least one village. The panchayat is a convenient unit by which to allocate schools, post offices, etc. The Nepal Blind- ness Survey included a survey of facilities available at the panchayat level. Table 8-23 describes the relationship between resources available in the panchayat and xerophthalmia. Many of these findings are counterintuitive, perhaps due to confounding. For example, only about one-eighth of the population of Nepal lives in villages that have been supplied with electricity, and the prevalence of xerophthalmia is higher in those villages. Because most of the villages with electricity are in the plains, terrain confounds the relationship between electricity and xerophthalmia, if indeed any relationship exists. In the case of medical care facilities (panchayat- level access to doctors, vaidyas, nurses, pharmacies, etc.), there is a
