Cataract prevalence, cataract surgical coverage and barriers to uptake of cataract surgical services in Pakistan: the Pakistan National Blindness and Visual Impairment Survey

Aim: To estimate the prevalence of visual impairment and blindness caused by cataract, the prevalence of aphakia/pseudophakia, cataract surgical coverage (CSC) and to identify barriers to the uptake of cataract services among adults aged >= 30 years in Pakistan. Methods: Probability proportional-to-size procedures were used to select a nationally representative sample of adults. Each subject underwent interview, visual acuity measurement, autorefraction, biometry and ophthalmic examination. Those that saw < 6/12 in either eye underwent a more intensive examination procedure including corrected visual acuity, slit lamp and dilated fundus examination. CSC was calculated for different levels of visual loss by person and by eye. Individuals with < 6/60 in the better eye as a result of cataract were interviewed regarding barriers. Results: 16 507 Adults were examined (95.5% response rate). The crude prevalence of blindness ( presenting < 3/60 in the better eye) caused by bilateral cataract was 1.75% (95% CI 1.55%, 1.96%). 1317 Participants ( 633 men; 684 women) had undergone cataract surgery in one or both eyes, giving a crude prevalence of 8.0% ( 95% CI 7.6%, 8.4%). The CSC ( persons) at < 3/60, < 6/60 and < 6/18 were 77.1%, 69.3% and 43.7%, respectively. The CSC ( eyes) at < 3/60, < 6/60 and < 6/18 were 61.4%, 52.2% and 40.7%, respectively. Cost of surgery ( 76.1%) was the main barrier to surgery. Conclusion: Approximately 570 000 adults are estimated to be blind (< 3/60) as a result of cataract in Pakistan, and 3 560 000 eyes have a visual acuity of < 6/60 because of cataract. Overall, the national surgical coverage is good but underserved populations have been identified.