title: fs-Laser induced elasticity changes to improve presbyopic lens accommodation.
abstract: BACKGROUND
  According to the Helmholtz theory of accommodation, one of the major reasons for the development of presbyopia is the progressive sclerosis of the crystalline lens. However, both the ciliary muscle and the lens capsule stay active and elastic. Thus, the concept for regaining the deformation-ability of the crystalline lens is to create microincisions inside lens tissue to achieve gliding planes.
  
  
  METHODS
  For the preparation of the microincisions, near-infrared femtosecond laser pulses are used, generating laser-induced optical breakdowns. Different cutting patterns were performed, and the elasticity regain of the lenses were measured with Fisher's spinning test for thickness determination.
  
  
  RESULTS
  The creation of gliding planes inside lens tissue shows very good results in terms of increasing the deformation-ability. The optimization of laser parameters leads to a minimally invasive surgery with no remarkable side effects like residual gas bubbles. Furthermore, ex vivo elasticity measurements of untreated and treated pig lenses show an improvement in the flexibility of the lens. The deformation-ability increases up to 26% with a very low standard deviation (1.6%) and a high significance (p < 0.05).
  
  
  CONCLUSIONS
  Generating particular cutting patterns inside lens tissue can increase the deformation-ability of the crystalline lens. Thus, it might be one possible way to treat presbyopia.
authors.affiliation: Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany. t.ripken@lzh.de
authors.forename: Tammo
authors.initials: T
authors.lastname: Ripken
authors.forename: Uwe
authors.initials: U
authors.lastname: Oberheide
authors.forename: Michael
authors.initials: M
authors.lastname: Fromm
authors.forename: Silvia
authors.initials: S
authors.lastname: Schumacher
authors.forename: Georg
authors.initials: G
authors.lastname: Gerten
authors.forename: Holger
authors.initials: H
authors.lastname: Lubatschowski
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000818:Animals; D004548:Elasticity; D053685:Laser Therapy; D007908:Lens, Crystalline / Q000473:pathology / Q000601:surgery*; D011305:Presbyopia / Q000503:physiopathology / Q000601:surgery*; D013552:Swine