The prevalence, severity and risk factors for pterygium in central Myanmar: the Meiktila Eye Study.
OBJECTIVE
To determine the prevalence, severity and risk factors associated with pterygium in adults in central Myanmar.


METHODS
Population-based, cross-sectional survey of the people 40 years and over residing in rural Myanmar. Pterygium was graded for severity (T1 to T3) by visibility of episcleral vessels, and the apical extent was recorded. An autorefractor was used to measure refractive error.


RESULTS
There were 2481 subjects identified, and 2076 (83.7%) participated. The prevalence of pterygium in either eye was 19.6% (95% confidence interval (CI) 16.9 to 22.2) and of bilateral pterygium 8.0% (95% CI 7.7 to 8.3). Outdoor occupation was an independent predictor of pterygium (p<0.01). The mean apical extent from the limbus was 2.2 mm (95% CI 2.05 to 2.35). Higher-grade pterygia did not have a significantly greater apical extent (p = 0.35). The presence of pterygium was associated with astigmatism, (p = 0.01), and the amount of astigmatism increased as both the severity (p<0.01) and apical extent increased (p<0.01). Two people of the 84 people blinded in both eyes were bilaterally blind from pterygium (1.7%; 95% CI 0.2 to 6.1), and pterygium accounted for 2.2% (95% CI 0.7 to 5.0) of blindness in at least one eye. No participant had low vision in both eyes due to pterygium, but pterygium led to 0.8% (95% CI 0.3 to 1.6) of low vision in at least one eye. Pterygium was therefore associated with 0.4% (95% CI 0.04 to 1.3) of binocular visual impairment and 1.0% (95% CI 0.6 to 1.8) of visual impairment in a least one eye.


CONCLUSIONS
There is a high prevalence of pterygium in central Myanmar, and the risk of developing this condition increases with outdoor occupation. Pterygium in this population is associated with considerable visual morbidity, including blindness.
South Australian Institute of Ophthalmology, Ophthalmology Network, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, Australia 5000. shane_durkin@yahoo.com
S R
SR
Durkin
S
S
Abhary
H S
HS
Newland
D
D
Selva
T
T
Aung
R J
RJ
Casson
D000328:Adult; D017677:Age Distribution; D000368:Aged; D001251:Astigmatism / Q000453:epidemiology / Q000209:etiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D002052:Myanmar / Q000453:epidemiology; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology; D015995:Prevalence; D011625:Pterygium / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology