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Proceedings Paper

Laser parameters, focusing optics, and side effects in femtosecond laser corneal surgery
Author(s): Karsten Plamann; Valeria Nuzzo; Donald A. Peyrot; Florent Deloison; Michèle Savoldelli; Jean-Marc Legeais
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Paper Abstract

Nowadays, femtosecond lasers are routinely used in refractive eye surgery. Until recently, commercialised clinical systems were exclusively based on ytterbium or neodymium-doped solid state lasers emitting sub-picosecond pulses at a wavelength of about 1 μm and repetition rates of a few 10 kHz. These systems use pulse energies in the μJ range and focussing optics of NA = 0.3 to 0.5. Recent developments have provided a variety of alternative and equally viable approaches: systems are now available using nJ pulses at high numerical apertures and MHz repetition rates - an approach so far only used for femtosecond cell surgery - and fibre laser technology is now being used for femtosecond laser corneal surgery. Recent research has also provided more insight in side effects occurring in present systems: self focusing phenomena and so far unexplained periodical structures have been observed even at high numerical apertures (NA >> 0.5) and moderate pulse energies. The interaction of femtosecond laser pulses with strongly scattering tissue has been studied in view of extending the application of femtosecond lasers to keratoplasty for opaque corneas and to glaucoma surgery. The use of new laser wavelengths and adaptive optics has been proposed. Despite the reputation of femtosecond surgical systems for their precision, repeatability and the absence of secondary effects or complications, a closer examination reveals the presence of subtle phenomena which merit further investigation. We present three of these phenomena: the influence of optical aberration on the quality of the incision, the occurrence of filamentation effects, and the deposit of microscopic glass fragments when performing penetrating incisions.

Paper Details

Date Published: 25 February 2008
PDF: 10 pages
Proc. SPIE 6844, Ophthalmic Technologies XVIII, 68440W (25 February 2008); doi: 10.1117/12.763240
Show Author Affiliations
Karsten Plamann, ENSTA, Ecole Polytechnique (France)
Valeria Nuzzo, ENSTA, Ecole Polytechnique (France)
Donald A. Peyrot, ENSTA, Ecole Polytechnique (France)
Florent Deloison, ENSTA, Ecole Polytechnique (France)
Michèle Savoldelli, Univ. René Descartes, Paris V (France)
Jean-Marc Legeais, Univ. René Descartes, Paris V (France)

Published in SPIE Proceedings Vol. 6844:
Ophthalmic Technologies XVIII
Bruce E. Stuck; Fabrice Manns; Per G. Söderberg; Michael Belkin M.D.; Arthur Ho, Editor(s)

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