title: Aberration generation by contact lenses with aspheric and asymmetric surfaces.
abstract: OBJECTIVE
  We explored the potential of aberration correction in the human eye by using a new generation of soft contact lenses with aspheric and asymmetric surfaces.
  
  
  METHODS
  Soft contact lens samples were designed with one asymmetrical surface (front) and one spherical (back) to produce predetermined amounts of desired pure defocus, astigmatism, trefoil, coma, and spherical aberration. Contact lens wavefront aberrations were measured ex vivo using a Fizeau-Tolanski interferometer and compared with the in vivo wavefronts obtained by subtracting the aberrations of the eye with and without the contact lenses. These second set of measurements were obtained using a Shack-Hartmann sensor.
  
  
  RESULTS
  We found that an aberration-free contact lens sample induced in the eye a small amount of residual aberration. We obtained a good match between the ex vivo and in vivo wavefront measurements for most of the samples of the contact lenses.
  
  
  CONCLUSIONS
  The aberrations generated by soft contact lenses on the eye were predictable. Rotations and translations of the contact lenses with respect to correct position on the eye were, however, the main limitation for precise correction of the ocular aberrations.
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000209:etiology / Q000628:therapy*; D003263:Contact Lenses, Hydrophilic; D019781:Corneal Topography; D006801:Humans; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000209:etiology / Q000628:therapy*; D014785:Vision, Ocular / Q000502:physiology