First in vivo animal studies on intraocular nanosurgery and multiphoton tomography with low-energy 80-MHz near-infrared femtosecond laser pulses

Karsten Konig; Bagui Wang; Oliver Krauss; Iris Riemann; Harald Schubert; Sigrun Kirste; Peter Fischer

doi:10.1117/12.528287

13 July 2004 First in vivo animal studies on intraocular nanosurgery and multiphoton tomography with low-energy 80-MHz near-infrared femtosecond laser pulses

Karsten Konig, Bagui Wang, Oliver Krauss, Iris Riemann, Harald Schubert, Sigrun Kirste, Peter Fischer

Author Affiliations +

Proceedings Volume 5314, Ophthalmic Technologies XIV; (2004) https://doi.org/10.1117/12.528287
Event: Biomedical Optics 2004, 2004, San Jose, CA, United States

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.

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Karsten Konig, Bagui Wang, Oliver Krauss, Iris Riemann, Harald Schubert, Sigrun Kirste, and Peter Fischer "First in vivo animal studies on intraocular nanosurgery and multiphoton tomography with low-energy 80-MHz near-infrared femtosecond laser pulses", Proc. SPIE 5314, Ophthalmic Technologies XIV, (13 July 2004); https://doi.org/10.1117/12.528287

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