title: Statistical eye model for normal eyes.
abstract: OBJECTIVE
  To create a binocular statistical eye model based on previously measured ocular biometric data.
  
  
  METHODS
  Thirty-nine parameters were determined for a group of 127 healthy subjects (37 male, 90 female; 96.8% Caucasian) with an average age of 39.9 ± 12.2 years and spherical equivalent refraction of -0.98 ± 1.77 D. These parameters described the biometry of both eyes and the subjects' age. Missing parameters were complemented by data from a previously published study. After confirmation of the Gaussian shape of their distributions, these parameters were used to calculate their mean and covariance matrices. These matrices were then used to calculate a multivariate Gaussian distribution. From this, an amount of random biometric data could be generated, which were then randomly selected to create a realistic population of random eyes.
  
  
  RESULTS
  All parameters had Gaussian distributions, with the exception of the parameters that describe total refraction (i.e., three parameters per eye). After these non-Gaussian parameters were omitted from the model, the generated data were found to be statistically indistinguishable from the original data for the remaining 33 parameters (TOST [two one-sided t tests]; P < 0.01). Parameters derived from the generated data were also significantly indistinguishable from those calculated with the original data (P > 0.05). The only exception to this was the lens refractive index, for which the generated data had a significantly larger SD.
  
  
  CONCLUSIONS
  A statistical eye model can describe the biometric variations found in a population and is a useful addition to the classic eye models.
authors: Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium. jos.rozema@uza.be
authors: Jos J
authors: JJ
authors: Rozema
authors: David A
authors: DA
authors: Atchison
authors: Marie-José
authors: MJ
authors: Tassignon
mesh_terms: D000328:Adult; D000368:Aged; D005123:Eye / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015233:Models, Statistical; D016011:Normal Distribution; D055095:Optics and Photonics / Q000706:statistics & numerical data*; D012016:Reference Values; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology*; D055815:Young Adult