CATARACT 185 TABLE 6-4. DISTRIBUTION OF CATARACT BY ZONE IN NEPAL (NBS 1981) Estimated Population with Cataract Percent of All Cataract in Nepal Sample N Prevalencea Per 100 Zone 1 Mechi 2 Koshi 3 Sagarmatha 4 Janakpur 5 Bagmati 6 Narayani 7 Gandaki 8 Lumbini 9 Dhaulagiri 10 Rapti 11 Karnali 12 Bheri 13 Seti 14 Mahakali Subtotal Missing data Total 2,481 3,653 3,722 4,037 4,256 4,157 3,294 3,799 486 2,020 483 3,123 1,756 2,398 39,665 222 12,580 38,756 41,335 48,173 28,752 66,693 17,561 48,077 4,627 10,854 6,143 30,793 17,929 24,932 397,205 NA 1.5 (1.4) 2.9 (3.0) 3.3 (3.7) 3.3 (3.1) 1.7 (1.5) 4.4. (4.4) 1.6 (1.3) 3.6 (3.0) 2.8 (2.1) 1.5 (1.9) 3.4 (4.1) 3.0 (3.7) 3.0 (2.9) 2.9 (2.8) 2.8 NA 3.2% 9.8 10.4 12.1 7.2 16.8 4.4 12.1 1.2 2.7 1.5 7.8 4.5 6.3 100.0 NA 39,887 397,205 2.8 100.0 Source: FR6.007 AN.26 aFigures in parentheses are age-sex-standardized prevalence rates. crude and standardized rates. The Central Region has both the highest prevalence rate (3.1 cases per 100 population) and largest share (36.2%) of cataract in Nepal. The prevalence rates in the other regions are fairly uniform, varying between 2.5 and 2.9 per 100. By sampling strata, the Central and Western Terai strata have the highest prevalence rates, between 4.4 and 4.5 per 100, more than twice the rate in the hill strata. The strata with the highest cataract prevalence ratios are located in the south of Nepal near the Indian border. Using sampling strata instead of administrative divisions is appropriate because of a strong relationship between cataract prevalence and topography, as will be discussed later and as is summarized in Figure 6.2. Table 6-4 shows the distribution of cataract prevalence by ad- ministrative zone. Narayani zone has both the highest prevalence rate (4.4 per 100) and largest share (16.8%) of cataract in Nepal. Sagarmatha, Janakpur, Lumbini, and Karnali zones all have preva- lence rates over 3 per 100, while Koshi, Dhaulagiri, Bheri, Seti, and Mahakali zones have prevalence rates between 2 and 3 per 100.
