Fig. 2

Prevalence of pterygium in South Korea. a Prevalence of pterygium stratified by the population of cities. b Prevalence of pterygium stratified by spatial distribution. Metropolitan cities: Seoul (n = 10,195,318), Busan (n = 3,538,484), Daegu (n = 2,505,644), Incheon (n = 2,843,981), Gwangju (n = 1,469,216), Daejeon (n = 1,524,583), and Ulsan (n = 1,147,256). Provinces: Gyeonggi (n = 12,093,299), Gangwon (n = 1,538,630), Chungbuk (n = 1,565,628), Chungnam (n = 2,028,777), Jeonbuk (n = 1,873,341), Jeonnam (n = 1,909,618), Gyeongbuk (n = 2,698,353), Gyeongnam (n = 3,319,314), and Jeju (n = 583,713). The population numbers were obtained from the 2012 census