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Proceedings Paper

First in vivo animal studies on intraocular nanosurgery and multiphoton tomography with low-energy 80-MHz near-infrared femtosecond laser pulses
Author(s): Karsten Konig; Bagui Wang; Oliver Krauss; Iris Riemann; Harald Schubert; Sigrun Kirste; Peter Fischer
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Paper Abstract

We report on a method for refractive laser surgery based on low-energy femtosecond laser pulses provided by ultracompact turn-key non-amplified laser systems. An additional excimer laser is not required for ablation of the stroma. The novel method has the potential to be used for (i) optical flap creation as well as stroma ablation and (ii) for non-invasive flap-free intrastromal ablation. In addition, 3D multiphoton imaging of the cornea can be performed. In particular, we used sub-nanojoule near infrared 80 MHz femtosecond laser pulses for multiphoton imaging of corneal structures with ultrahigh resolution (< 1μm) as well as for highly precise intraocular refractive surgery. Imaging based on two-photon excited cellular autofluorescence and SHG formation in collagen structures was performed at GW/cm2 intensities, whereas destructive optical breakdown for nanoprocessing occurred at TW/cm2 light intensities. These high intensities were realized with sub-nJ pulses within a subfemtoliter intrastromal volume by diffraction-limited focussing with high NA objectives and beam scanning 50 to 140 μm below the epithelial surface. Multiphoton tomography of the cornea was used to determine the target of interest and to visualize intraocular post-laser effects. Histological examination with light- and electron microscopes of laser-exposed porcine and rabbit eyes reveal a minimum intratissue cut size below 1 μm without destructive effects to surrounding collagen structures. LASIK flaps and intracorneal cavities could be realized with high precision using 200 fs, 80 MHz, sub-nanojoule pulses at 800 nm. First studies on 80 MHz femtosecond laser surgery on living rabbits have been performed.

Paper Details

Date Published: 13 July 2004
PDF: 8 pages
Proc. SPIE 5314, Ophthalmic Technologies XIV, (13 July 2004); doi: 10.1117/12.528287
Show Author Affiliations
Karsten Konig, Fraunhofer-Institut fur Biomedizinische Technik (Germany)
Univ. of the Saarland (Germany)
Bagui Wang, Friedrich-Schiller-Univ. (Germany)
Oliver Krauss, Friedrich-Schiller-Univ. (Germany)
Iris Riemann, Fraunhofer-Institut fur Biomedizinische Technik (Germany)
Univ. of the Saarland (Germany)
Harald Schubert, Friedrich-Schiller-Univ. (Germany)
Sigrun Kirste, Friedrich-Schiller-Univ. Jena (Germany)
Peter Fischer, JenLab GmbH (Germany)

Published in SPIE Proceedings Vol. 5314:
Ophthalmic Technologies XIV
Fabrice Manns; Per G. Soderberg; Arthur Ho, Editor(s)

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