title: Pig lenses in a lens stretcher:  implications for presbyopia treatment.
abstract: OBJECTIVE
  To investigate porcine lenses in a lens stretcher with regard to presbyopia corrective procedures.
  
  
  METHODS
  A lens stretching device was designed, which allows to simultaneously determine all relevant geometrical and optical parameters at each stretch position. The setup was used to compare the optical and geometrical lens properties of young slaughter pigs (n = 5) with older sows (n = 7).
  
  
  RESULTS
  The change of optical power with stretching is about five times larger for young porcine lenses than for sows. For young pigs, the gradient index profile of the crystalline lens significantly contributes to the induced accommodation amplitude.
  
  
  CONCLUSIONS
  We have shown that sow lenses are a suitable model for in vitro experiments on possible treatments for presbyopia. The rapid decrease in the induced accommodation amplitude with age may be explained by a reduced change of all geometrical lens parameters, which in turn leads to a smaller contribution of the gradient index profile to accommodation.
authors.affiliation: Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, Jena, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Kammel
authors.forename: Roland
authors.initials: R
authors.lastname: Ackermann
authors.forename: Torsten
authors.initials: T
authors.lastname: Mai
authors.forename: Christoph
authors.initials: C
authors.lastname: Damm
authors.forename: Stefan
authors.initials: S
authors.lastname: Nolte
mesh_terms: D000065:Accommodation, Ocular; D000818:Animals; D004195:Disease Models, Animal; D004548:Elasticity; D007908:Lens, Crystalline / Q000503:physiopathology / Q000601:surgery*; D011305:Presbyopia / Q000503:physiopathology / Q000601:surgery*; D012029:Refraction, Ocular; D013552:Swine