title: Outdoor work and the risk of pterygia: a case-control study.
abstract: OBJECTIVE
  To investigate the relationship between outdoor work and pterygium formation in a hospital-based case-control study in Singapore.
  
  
  METHODS
  Sixty-one patients with pterygium (49 males, mean age 54.2 years) and 125 controls (41 males, mean age 50.2 years), excluding patients with cataract and age-related macular degeneration presenting at outpatient clinics of the Singapore National Eye Centre were interviewed face-to-face with a standard questionnaire. Demographic data and information on outdoor work and eye protection, were collected.
  
  
  RESULTS
  Thirty-eight subjects (20.4%) were outdoor workers and 148 (79.6%) were indoor workers. Outdoor workers were more likely to be male smokers and alcohol drinkers with lower family income and higher sunlight exposure than indoor workers. The crude odds ratio for pterygium in outdoor workers was 7.0 (95% confidence interval 3.2, 15.3). The adjusted odds ratio was 4.2 (95% confidence interval 1.7, 10.1).
  
  
  CONCLUSIONS
  There is a statistically significant association between outdoor work and pterygium formation, which may be related to the higher exposure to sunlight and dust in outdoor workers. Efforts may be made to educate outdoor workers to wear proper equipment to protect their eyes against excessive sunlight.
authors.affiliation: National University of Singapore, Singapore.
authors.forename: J
authors.initials: J
authors.lastname: Khoo
authors.forename: S M
authors.initials: SM
authors.lastname: Saw
authors.forename: K
authors.initials: K
authors.lastname: Banerjee
authors.forename: S E
authors.initials: SE
authors.lastname: Chia
authors.forename: D
authors.initials: D
authors.lastname: Tan
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology*; D016017:Odds Ratio; D011625:Pterygium / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D017678:Sex Distribution; D013472:Sunlight / Q000009:adverse effects*