[Show abstract][Hide abstract] ABSTRACT: We present a first evaluation of the results of the NOUGAT project which has been funded by the French National Research Agency through the 2008 edition of its TecSan program. The objective of the project is to conceive and realise an innovative device for ocular surgery by ultrafast pulse laser for glaucoma surgery assisted by an in situ imaging system. The main advances obtained during the project was the realisation of an ultrashort pulse laser source with a wavelength adapted to sclera transparency and the development of an optimised imaging system based on optical coherence tomography.
[Show abstract][Hide abstract] ABSTRACT: Corneal fibroblast cell (CFC) reticulation is involved in the structural development of corneal stroma and in wound healing. In an earlier paper, it was reported that the expression of VEGFR-1 by CFCs is related to their reticulogenic properties in vitro and decreases with the age of the donors. The present study was focused on the nonreticulogenic corneal fibroblast population and explored whether these cells can be induced to form cell networks in vitro.
The network formation was analyzed using an array of signaling pathway inhibitors: wortmannin for PI3 kinase, U0126 for MEK-1/2 kinase, Rottlerin for PKC, farnesyl transferase inhibitor (FTI-277) for Ras, and picropodophyllin (PPP) for IGFR-1. Among the several growth factors studied, IGF seemed to be crucial to cell network formation. The presence of IGF signaling was demonstrated using gene array analysis and was confirmed by RT-PCR and immunocytochemistry and by cell network formation on reduced synthetic basement membrane arrays. The pleiotropic effect of IGF-1 on the cells was analyzed by protein cytokine array.
The genesis of reticulation was found to occur via MEK-1/2 and IGFR pathways, since inhibitors of these signaling pathways reduced or prevented cell network formation. The addition of exogenous IGF-1 generated a cell network structure in corneal fibroblasts obtained from healthy donors, indicating the involvement of IGF-1.
IGF signaling and the MEK-1/2 pathway are involved in the cell network formation of corneal fibroblast cells from aged donors.
[Show abstract][Hide abstract] ABSTRACT: Femtosecond laser surgery in the volume of corneal tissue is typically performed wavelengths of about 1 mum, which gives excellent results on transparent corneas. However, the outcome is much worse in the case of oedematous or pathological corneas as the laser beam propagation is disturbed by optical scattering. Our studies suggest that this phenomenon can be greatly reduced by using a better suited laser wavelength. Best results are obtained at 1.65 mum. Currently, no compact femtosecond laser at this wavelength is commercially available. We have developed a new simple, compact and stable laser source consisting of a non linear crystal pumped by a compact commercial solid-state laser emitting at 1.03 mum in a configuration of an Optical Parametric Generation (OPG). The output wavelength of this system can be tuned in the spectral range of 1.45 - 1.8 mum. A series of ex vivo penetrating incisions using energies of the order of a few microjoules on corneal tissues have been performed while varying the wavelengths from 1.45 mum to 1.7 mum. The results have been compared to experiments performed at 0.8 mum and 1 mum. The use of longer infrared wavelengths around 1.65 mum for femtosecond laser keratoplasty significantly improves the quality and the penetration depth of incision in case of pathological tissues, without inducing any additional side effects.
Proceedings of SPIE - The International Society for Optical Engineering 06/2011; 8092. DOI:10.1117/12.889658 · 0.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Femtosecond laser surgery in the volume of corneal tissue is typically performed wavelengths of about 1 µm, which gives excellent results on transparent corneas. However, the outcome is much worse in the case of oedematous or pathological corneas as the laser beam propagation is disturbed by optical scattering. Our studies suggest that this phenomenon can be greatly reduced by using a better suited laser wavelength. Best results are obtained at 1.65 µm.
[Show abstract][Hide abstract] ABSTRACT: In the last decade, femtosecond laser applications in the biology and medicine have largely developed. The ultrashort laser has proved to be a strongly accurate and selective cutting tool, by depositing energy in a very confined volume with minimum collateral effects.
Conference on the NATO Advanced Study Institute on Bio-Photonics:; 01/2011
[Show abstract][Hide abstract] ABSTRACT: Introduction
Iterative penetrating keratoplasty procedures (PKPs) increase the risk of graft rejection. Surgeons are reluctant to perform a third procedure following two previous graft failures. We evaluated the outcomes of patients who had three successive PKPs treated with a local combination of cyclosporin 2% A and dexamethasone 0.1% eye drops.
Patients and methods
This is a retrospective study of a series of cases including 15 eyes of 15 patients treated and followed in the ophthalmology unit at the Hôtel-Dieu Hospital in Paris (2006–2009).
After an average follow-up of 20.5 ± 2 months, the risk of transplant rejection was 13.33% and the duration of follow-up corresponded in all patients to the duration of treatment with cyclosporin eye drops. The treatment was not interrupted by any patient because of intolerance.
In this study, we observed a success rate justifying the indication of the third keratoplasty under local cyclosporin 2% classically considered debatable.
Journal Français d Ophtalmologie 12/2010; 33(10):710-714. DOI:10.1016/j.jfo.2010.09.019 · 0.39 Impact Factor