title: [Prevalence survey on pterygium in two counties of Hainan Province].
abstract: OBJECTIVE
  To explore the relationship between pterygium and environmental condition, such as area and weather, and human factors, such as sex and race, through the prevalence survey of pterygium in Hainan Province.
  
  
  METHODS
  As a sample, all villagers in 14 villages were chosen by random sampling from all the rural villages of Dongfang and Changjiang Counties, the pterygium was examined and their pterygia were recorded and graded according to the shape and the location of the head of pterygium.
  
  
  RESULTS
  In 7 990 villagers examined, there were 628 cases with pterygium, prevalence being 7.86% and including 439 cases (8.28%) in 5 303 Han people and 189 cases (7.03%) in 2 687 Li people. The difference of the prevalence between Han and Li nationality was significant (chi(2) = 3.897, P = 0.048). There were 266 male cases (6.43%) and 362 female cases (9.40%). The prevalence in male was less than that in female (chi(2) = 19.852, P = 0.001). The distribution of the pterygium in eyes was symmetrical.
  
  
  CONCLUSIONS
  The prevalence of pterygium in Hainan is higher than that in other provinces of China. It may be related to the geographic location and weather condition. In Hainan Province, the prevalence of pterygium in Han nationality is higher than that in Li nationality and in female higher than that in male. The increase of the prevalence of pterygium may be related to the increase of age.
authors.affiliation: Department of Ophthalmology, The People's Hospital of Hainan Province, Haikou 570311, China.
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: L
authors.initials: L
authors.lastname: Zhong
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011625:Pterygium / Q000453:epidemiology*; D011897:Random Allocation; D012423:Rural Health / Q000706:statistics & numerical data; D012737:Sex Factors