Chirurgie du segment antérieur de l'oeil et traitement du glaucome par laser femtoseconde et imagerie de tomographie par cohérence optique

Caroline Crotti 1
1 Groupe OPS
ENSTA ParisTech École polytechnique CNRS LOA - Laboratoire d'optique appliquée
Abstract : My PhD project is closely related to the ANR project named "NOUGAT" which consists of developing a new tool for glaucoma surgery assisted by femtosecond laser and optical coherence tomography (OCT) [ANR-08-TECS-012]. This project is coordinated by the "Optics -Photonics - Health" group of the Laboratory of Applied Optics (LOA) and our partners are the Hôtel-Dieu hospital, the Charles Fabry Laboratory of the Institut d'Optique Graduate School and the company Amplitude Systèmes. Glaucoma is an ocular disease associated with an increase of the intraocular pressure. Surgical treatments consist in creating filtrating canals in deep sclera in order to lower the pressure; however benefits are often only temporary. Corneal grafting is indicated when reduced corneal transparency (visual acuity) is observed. This is the most common transplant but some limits of the laser procedure exist, especially when the incision has to be made in the depth of a pathological tissue. First, my PhD work consists in the characterization of the three main elements of the ocular anterior segment: the cornea, the sclera and the crystalline lens. The light scattering occurring into the cornea is now well understood and it can be quantified. Studies of the scleral tissue have also shown an optical transparency window around 1650 nm, and some preliminary experiments have been performed on the crystalline lens. Thanks to the optimization of laser sources already developed in the group, especially the optical parametric generator, new series of incisions on human corneas from the French eye bank (Paris), have been performed with wavelengths in the 1500 - 1800 nm spectral range. Analysis by histology and by transmission and scanning electronic microscopy of these new incisions confirm that the use of a longer wavelength in the 1600 - 1700 nm range greatly reduces the light scattering in the tissue compared to the one obtained with commercial systems (at 1000 nm). In addition, a new imaging system based on OCT has been developed in close collaboration with our colleagues from the Institut d'Optique Graduate School. Using a wavelength of 1315 nm, the system has a spatial resolution of 5 μm that is compatible with our medical application even if the acquisition rate stills quite low. Corneal structures have been imaged with three different available systems which makes the comparison of the specifications possible. Eventually, my PhD project leads to an optimization of laboratory surgical systems for the anterior segment of the eye and to the consolidation of knowledge on tissue optics, completing anterior studies conducted by my working group and opening new ways for future applications.
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Theses
Optics. Ecole Polytechnique X, 2011. French
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https://tel.archives-ouvertes.fr/tel-00655580
Contributor : Caroline Crotti <>
Submitted on : Saturday, December 31, 2011 - 9:22:46 AM
Last modification on : Wednesday, October 29, 2014 - 1:23:54 PM

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Caroline Crotti. Chirurgie du segment antérieur de l'oeil et traitement du glaucome par laser femtoseconde et imagerie de tomographie par cohérence optique. Optics. Ecole Polytechnique X, 2011. French. <tel-00655580>

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