title: A new schematic eye model incorporating accommodation.
abstract: OBJECTIVE
  To create a schematic eye model with four refracting surfaces and with the new function describing the crystalline lens profile.
  
  
  METHODS
  The new function describing the crystalline lens profile is a combination of hyperbolic cosine functions modulated by hyperbolic tangent functions. It ensures the continuity of the radius of curvature along the whole lens profile. Recent experimental results on cornea and lens shape measurements have been applied to the proposed model. The new function describing the lens profile has been used to model the eye during accommodation.
  
  
  RESULTS
  Spherical aberration and modulation transfer function have been computed to test the eye model. Results of calculations are in agreement with experimental findings.
  
  
  CONCLUSIONS
  The calculations show that spherical aberrations of the cornea and crystalline lens cancel each other. The new description of the crystalline lens offers a reduction of longitudinal spherical aberration. The image quality of the unaccommodated eye model is slightly better than that of the accommodated one.
authors.affiliation: Institute of Physics, Wroclaw University of Technology, Poland. popiolek@rainbow.if.pwr.wroc.pl
authors.forename: A
authors.initials: A
authors.lastname: Popiolek-Masajada
authors.forename: H T
authors.initials: HT
authors.lastname: Kasprzak
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D003315:Cornea / Q000502:physiology; D005123:Eye / Q000033:anatomy & histology*; D006801:Humans; D007908:Lens, Crystalline / Q000502:physiology; D008954:Models, Biological; D009799:Ocular Physiological Phenomena