Refractive errors in the adult pakistani population: the national blindness and visual impairment survey.
OBJECTIVE
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.
Shah
Shaheen P
SP
International Centre for Eye Health, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom. Shaheen.Shah@lshtm.ac.uk
Jadoon
Mohammad Z
MZ
Dineen
Brendan
B
Bourne
Rupert R A
RR
Johnson
Gordon J
GJ
Gilbert
Clare E
CE
Khan
Mohammad D
MD
D017677:Age Distribution; D001251:Astigmatism / Q000453:epidemiology; D003710:Demography; D005139:Eyeglasses / Q000706:statistics & numerical data; D005260:Female; D006301:Health Services Needs and Demand; D006306:Health Surveys; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000453:epidemiology; D010154:Pakistan / Q000453:epidemiology; D012030:Refractive Errors / Q000453:epidemiology* / Q000503:physiopathology / Q000534:rehabilitation; D012720:Severity of Illness Index; D016896:Treatment Outcome