title: [Analysis of curvature distribution on corneal surface].
abstract: OBJECTIVE
  To detect the characters of the curvature distribution from a mathematical point of view.
  
  
  METHODS
  Subjects were measured with Orbscan II corneal topography system. Anterior and posterior corneal radius of curvature and thickness of the points located 1.5 mm, 2.5 mm, 3.5 mm and 4.5 mm away from the corneal apex on certain meridians, including 0 degrees, 30 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees, 180 degrees, 210 degrees, 240 degrees, 270 degrees, 300 degrees and 330 degrees meridians, were collected. Distributions of corneal curvature between the two principal meridians were discussed.
  
  
  RESULTS
  The curvature of oblique meridian might be described with the formula F' = Fa+(Fb-Fa) xSin2alpha.
  
  
  CONCLUSIONS
  Anterior and posterior corneal surfaces are similar to toric surface. The distributions of corneal curvature between the two principal meridians have something to do with the law of sine.
authors.affiliation: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Zhang
authors.forename: Mingguang
authors.initials: M
authors.lastname: Shi
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D008875:Middle Aged