title: Visualization of femtosecond laser pulse-induced microincisions inside crystalline lens tissue.
abstract: OBJECTIVE
  To evaluate a new method for visualizing femtosecond laser pulse-induced microincisions inside crystalline lens tissue.
  
  
  METHODS
  Laser Zentrum Hannover e.V., Hannover, Germany.
  
  
  METHODS
  Lenses removed from porcine eyes were modified ex vivo by femtosecond laser pulses (wavelength 1040 nm, pulse duration 306 femtoseconds, pulse energy 1.0 to 2.5 microJ, repetition rate 100 kHz) to create defined planes at which lens fibers separate. The femtosecond laser pulses were delivered by a 3-dimension (3-D) scanning unit and transmitted by focusing optics (numerical aperture 0.18) into the lens tissue. Lens fiber orientation and femtosecond laser-induced microincisions were examined using a confocal laser scanning microscope (CLSM) based on a Rostock Cornea Module attached to a Heidelberg Retina Tomograph II. Optical sections were analyzed in 3-D using Amira software (version 4.1.1).
  
  
  RESULTS
  Normal lens fibers showed a parallel pattern with diameters between 3 microm and 9 microm, depending on scanning location. Microincision visualization showed different cutting effects depending on pulse energy of the femtosecond laser. The effects ranged from altered tissue-scattering properties with all fibers intact to definite fiber separation by a wide gap. Pulse energies that were too high or overlapped too tightly produced an incomplete cutting plane due to extensive microbubble generation.
  
  
  CONCLUSIONS
  The 3-D CLSM method permitted visualization and analysis of femtosecond laser pulse-induced microincisions inside crystalline lens tissue. Thus, 3-D CLSM may help optimize femtosecond laser-based procedures in the treatment of presbyopia.
authors.affiliation: Department of Ophthalmology, University of Rostock, Rostock, Germany. oliver.stachs@med.uni-rostock.de
authors.forename: Oliver
authors.initials: O
authors.lastname: Stachs
authors.forename: Silvia
authors.initials: S
authors.lastname: Schumacher
authors.forename: Marine
authors.initials: M
authors.lastname: Hovakimyan
authors.forename: Michael
authors.initials: M
authors.lastname: Fromm
authors.forename: Alexander
authors.initials: A
authors.lastname: Heisterkamp
authors.forename: Holger
authors.initials: H
authors.lastname: Lubatschowski
authors.forename: Rudolf
authors.initials: R
authors.lastname: Guthoff
mesh_terms: D000818:Animals; D021621:Imaging, Three-Dimensional / Q000379:methods; D053685:Laser Therapy / Q000379:methods*; D007908:Lens, Crystalline / Q000473:pathology* / Q000601:surgery*; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods*; D008866:Microsurgery / Q000379:methods*