title: Theoretical calculation of a contact lens thickness designed to correct the eye's monochromatic aberrations.
abstract: OBJECTIVE
  The aim of this work is the theoretical study of high order aberration compensation in the human eye.
  
  
  METHODS
  This compensation should be achieved with uneven thickness contact lenses (rigid gas permeable or soft), capable of inducing a localized delay on the aberrated wavefront, so that light beams originated on a point object would reach the retina at a common point, irrespective of their point of passage through the pupil.
  
  
  RESULTS
  The algorithm for optimal local contact lens thickness determination is explained. For this purpose the aberrated wavefront measured on a patient by the double-pass technique was expressed in terms of Zernike polynomials. The knowledge of the wave aberration as a function of the point of passage through the pupil allows determination of the delay to be introduced in order to produce a wavefront as would result from non-aberrated eye, where all rays would reach the same point on the retina.
  
  
  CONCLUSIONS
  The explanation of how it would be possible to correct wavefront deviations, by varying an RGP or soft contact lens thickness, was made, and a particular eye exemplify.
authors.affiliation: Departamento de Física, Universidade do Minho, Braga, Portugal.
authors.forename: José B
authors.initials: JB
authors.lastname: Almeida
authors.forename: Arlindo M Fontes
authors.initials: AM
authors.lastname: Garcia
mesh_terms: D003261:Contact Lenses; D004867:Equipment Design; D006801:Humans; D008962:Models, Theoretical; D012030:Refractive Errors / Q000628:therapy*