Intratissue surgery with 80 MHz nanojoule femtosecond laser pulses in the near infrared

The use of 1 nanojoule near infrared 80 MHz femtosecond laser pulses for highly precise intratissue processing, in particular for intraocular refractive surgery, was evaluated. Destructive optical breakdown at TW/cm(2) light intensities in a subfemtoliter intrastromal volume was obtained by diffraction- limited focussing with an 40x objective (N. A. 1.3) and beam scanning 50 to 140 mum below the epithelial surface. Using the same system at GW/cm(2) intensities two- photon excited autofluorescence imaging was used to determine the target of interest and to visualize intraocular laser effects. Histological examination of laser- exposed porcine eyes reveal a minimum cut size below 1 mum without destructive effects to surrounding tissues. (C) 2002 Optical Society of America.