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 survey | 2001–2004 | 2005–2007 | ||
| Sample size | 16 507 | 13 591 | ||
| Age (years) | ≥30 | ≥40 | ||
| Participation rate (%) | 95.3 | 89.9 | ||
| 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 (%) | 51.5 | 43.0 | ||
| 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 CSC | Cataract blindness | CSC | Cataract blindness | CSC |
| Female sex | Yes | Yes | Yes | Yes |
| Illiteracy | Yes | Yes | Yes | Yes |
| Rural dwelling | Yes | Yes | No | Yes |
*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.