Refractive errors in the adult pakistani population: the national blindness and visual impairment survey.

Shah, SP; Jadoon, MZ; Dineen, B; Bourne, RR; Johnson, GJ; Gilbert, CE; Khan, MD; (2008) Refractive errors in the adult pakistani population: the national blindness and visual impairment survey. Ophthalmic epidemiology, 15 (3). pp. 183-90. ISSN 0928-6586 DOI:

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PURPOSE: To determine the prevalence of refractive error (RE) and spectacle wear and to explore the need for spectacle correction in adults (30 years or older) in Pakistan. METHODS: Multi-stage, cluster random sampling national survey. Each subject had their medical history taken, visual acuity measured, and underwent autorefraction, biometry and fundus examination. Those that presented with visual acuity of less than 6/12 in either eye underwent more detailed examination, including corrected distance visual acuity measurement (autorefraction results placed in a trial lens frame). Myopia was defined as a spherical equivalent of worse than -0.5D, hypermetropia as greater than +0.5D, and astigmatism as greater than 0.75D. Spectacle need (i.e., those that improved from unaided VA with spectacle correction) was determined along with the spectacle coverage, defined as the proportion of need that was met (by the participant's own spectacles). RESULTS: The crude prevalence of myopia, hypermetropia and astigmatism was 36.5%, 27.1%, and 37%, respectively. The prevalence of spectacle wear in phakic participants was 4.0%, significantly lower than for those who were pseudo/aphakic (41.7%). Just over a quarter (25.8%) of spectacle wearers presenting with visual impairment (< 6/12) were able to improve their vision when retested with their autorefraction prescription. The overall spectacle coverage (6/12 cutoff) was 15.1%. CONCLUSIONS: This survey provides the first reliable national estimates. RE services are not covering the majority of the population in need and the provision of spectacle correction, as a highly cost effective treatment for visual impairment, needs addressing within the country's national eye care program.

Item Type: Article
Faculty and Department: Faculty of Infectious and Tropical Diseases > Dept of Clinical Research
Faculty of Public Health and Policy > Dept of Global Health and Development
Research Centre: The International Centre for Evidence in Disability
International Centre for Eye Health
Centre for Global Non-Communicable Diseases (NCDs)
PubMed ID: 18569814
Web of Science ID: 257069300008


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