CAUSES OF BLINDNESS 167 TABLE 6-17. DISTRIBUTION OF BLINDNESS BY AVOIDABILITY OF CAUSE (NBS 1981) Estimated Number of Cases Cause of Blindness Prevent- able Total Avoidable Percentage Avoidable Rank Curable Cataract Cataract sequelae Glaucoma Retinal Other infections Trachoma Trauma Nutritional Smallpoxc Amblyopia Other misc.d Undetermined 78,605 6,195 3,820 3,849 3,305 2,822 2,853 1,094 2,610 1,476 8,841 2,152 0 b 382 0 1,653 2,822 1,427 1,094 2,610 738 4,121 73,103 b 0 0 0 0 0 0 0 0 599 73,103 5,761 382 0 1,653 2,822 1,427 1,094 2,610 738 4,720 83.6%a 1 8 4 0.4 0.0 1.7 3.0 1.5 1.2 2.8 0.8 5.0 2 5 6 3 7 Total 117,623 14,847 73,702 94,310 (80.2%) 100.0 Source: LB+ WH CbyC a If smallpox is removed from consideration this figure increases to 86 percent of the remaining avoidable blindness. b Blindness due to failure of cataract surgery is often irreversible; however, be- cause the surgical failure could have been prevented, the underlying cataract would then have been curable. To avoid semantics, these cases have been con- sidered "avoidable." c Smallpox has been eradicated, but residual corneal scars remain. d lncludes refractive error and miscellaneous combinations of eye diseases, etc. Cataract and its sequelae account for 78,864 cases of avoidable blindness, 83.6 percent of the total number of cases of blindness considered to be preventable or curable. If smallpox is removed from consideration, 86 percent of the remaining avoidable blindness is due to cataract and its sequelae. Cataract accounts for nearly all (99.2%) of the curable blindness in Nepal; it is the pivotal disease for the programme if the programme is to meet its target of 90 per- cent reduction of avoidable blindness. The major cause of preventable blindness in Nepal is trachoma (19.0% of preventable blindness and 3.0 percent of all avoidable blindness), followed by smallpox. The other preventable causes of blindness each consist of relatively few cases: other infections (1,653 cases), trauma (1,427 cases), nutritional blindness (1,094 cases). The miscellaneous case categories consist of an estimated
