Table 1

Summary of data sets and cataract results from National Blindness and Visual Impairment Surveys in Pakistan and Nigeria used in this analysis

Pakistan National Blindness and Visual Impairment Survey*Nigeria National Blindness and Visual Impairment Survey†
Survey details
 Years of survey2001–20042005–2007
 Sample size16 50713 591
 Age (years)≥30≥40
 Participation rate (%)95.389.9
Cataract results
 Crude prevalence of cataract blindness (presenting vision <3/60 better eye) (%; 95% CI)1.75 (1.55–1.95)1.80 (1.57–2.05)
 Proportion of all blindness due to cataract (%)51.543.0
 Number with ‘operable cataract’ (<6/60 in the better eye)904 000 (736 000 –1 107 000)‡399 041§
Age-adjusted and sex-adjusted multivariable logistic regression*†
 Associated with higher cataract blindness and lower CSCCataract blindnessCSCCataract blindnessCSC
 Female sexYesYesYesYes
 Rural dwellingYesYesNoYes
  • *Results reported in Dineen14 and Jadoon.15.

  • †Results reported in Abdull16 and Abubakar.8.

  • ‡Age-standardised and sex-standardised using Pakistan's population in 1998.

  • §Age-standardised and sex-standardised using Nigeria's population in 2008.

  • CSC, cataract surgical coverage.