title: Distribution of central and peripheral corneal thickness in Chinese children and adults: the Guangzhou twin eye study.
abstract: OBJECTIVE
  To describe the distribution of central and peripheral corneal thickness in children and adults by using a Scheimpflug camera.
  
  
  METHODS
  A total of 926 children 8-16 years of age and 662 adults 30-68 years of age were recruited from the Guangzhou Twin Registry. Central and peripheral corneal thicknesses were measured by using the Pentacam system with a standardized method. Regression analyses were used with the generalized estimating equation model, adjusting for the within-cluster correlation.
  
  
  RESULTS
  Corneal thicknesses, measured at the apex, center of pupil, superior, inferior, nasal, temporal peripheral, and the thinnest points, were 537.0 +/- 29.4, 536.3 +/- 29.3, 643.6 +/- 37.2, 613.8 +/- 32.4, 624.5 +/- 35.0, 605.7 +/- 33.4, and 533.2 +/- 30.0 microm, respectively, in adults. In the children, these values were 550.7 +/- 32.8, 550.7 +/- 32.7, 656.0 +/- 38.7, 627.9 +/- 36.6, 642.1 +/- 37.2, 612.5 +/- 36.3, and 548.1 +/- 32.8 microm, respectively. The thinnest point was located in the inferotemporal quadrant in 77.92% of children. All corneal thickness measurements showed no age-related change. Corneal thickness was generally thicker in boys than girls in the children, but this sex difference was not identified in adults. The discrepancy of measurements between the apex and thinnest point was small but statistically significant.
  
  
  CONCLUSIONS
  Central and 3.0-mm peripheral corneal thicknesses were normally distributed. No age-related differences were shown. A sex difference was shown in children but not in adults. Understanding the discrepancy between the apex and thinnest point could be useful in the safe management of refractive surgery.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yingfeng
authors.initials: Y
authors.lastname: Zheng
authors.forename: Guofu
authors.initials: G
authors.lastname: Huang
authors.forename: Wenyong
authors.initials: W
authors.lastname: Huang
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D044466:Asian People / Q000208:ethnology; D001837:Body Weights and Measures; D002648:Child; D003315:Cornea / Q000033:anatomy & histology*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000379:methods; D012042:Registries