title: The distribution of intraocular pressure in urban and in rural populations: the Namil study in South Korea.
abstract: OBJECTIVE
  To evaluate the intraocular pressure (IOP) distribution and its regional association in the South Korean population.
  
  
  METHODS
  Cross-sectional, epidemiologic study.
  
  
  METHODS
  All participants underwent interview and the following ocular examinations: visual acuity measurement, autorefraction, pachymetry, anterior segment evaluation, slit-lamp examination, Goldmann applanation tonometry, binocular optic disc evaluation, fundus photography, and visual field test. Patients with ocular diseases other than mild senile cataract or with history of ocular surgery were excluded.
  
  
  RESULTS
  A total of 3191 subjects residing in urban and rural areas were recruited. Mean IOP of patients from the urban area was significantly higher than that of those from the rural area (14.45 ± 2.67 mm Hg vs 13.53 ± 2.76 mm Hg, P < .05). There was regional difference of mean IOP, even after controlling for different demographic factors in the 2 areas (P < .05). Average IOP in the right eye of the investigated sample of South Korean population was 14.10 ± 2.74 mm Hg. Multiple regression analysis showed positive correlation between mean IOP and central corneal thickness, vertical cup-to-disc ratio, history of hypertension, smoking, and female sex, whereas IOP tended to decrease by approximately 0.2 mm Hg when age increased by 10 years.
  
  
  CONCLUSIONS
  This is the first population-based epidemiologic study measuring IOP in the South Korean population. Mean IOP of the urban area was found to be significantly higher than the corresponding value of the rural area. Therefore, the regional difference, as well as other various factors, has to be considered in epidemiologic study of the distribution of IOP.
authors.affiliation: Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Wool
authors.initials: W
authors.lastname: Suh
authors.forename: Changwon
authors.initials: C
authors.lastname: Kee
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D016021:Epidemiologic Studies; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular / Q000502:physiology; D056910:Republic of Korea / Q000453:epidemiology; D012424:Rural Population / Q000706:statistics & numerical data*; D017678:Sex Distribution; D014065:Tonometry, Ocular; D014505:Urban Population / Q000706:statistics & numerical data*; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests