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International audience; Introduction - Optimization of femtosecond laser characteristics in corneal surgery is stilt needed to improve clinical results In this study, we describe an original characterization technique able to measure laser damage of corneal tissues precisely and to provide complementary physical results on the laser matter interaction Method - A femtosecond laser was used to damage corneas not suitable for graft The epithelium and the Bowman layer are exposed to a set of different single shot fixed laser fluences Optical microscopy can determine the probability of laser damage on the corneal surface The high damage threshold (minimum fluence systematically damaging the cornea) roughly fixes the operating laser fluence conditions, while the low damage threshold sets the maximum laser fluence level preserving tissue integrity (safety level) Results - We precisely evaluate the damage fluence threshold of a tissue, using a statistical approach coupled with optical microscopy analysis This technique gives essential information on laser tissue interaction with a high rate of confidence For corneal epithelium and the Bow man layer, we determine the maximum laser fluence level preserving tissue integrity (safety level) and the minimum fluence level systematically damaging the tissue High and low threshold fluences of epithelium and the Bowman layers are (5 6 +/- 0 4 J/cm(2), 2 7 +/- 0 1 J/cm(2)), and (7 1 +/- 1 1 J/cm(2), 3 4 +/- 0 1 J/cm(2)), respectively Conclusion - These data constitute determinant parameters for clinical applications, since they determine a working window providing the minimal effective irradiation dose that is man datory for the development of high quality laser cutting surgery processes with minimized side effects (C) 2010 Elsevier Masson SAS All rights reserved

International audience

International audience; Introduction. We used high-field (3T) functional magnetic resonance imaging (fMRI) to map the retinotopic organization of human cortical areas. Methods. Retinotopic maps were reconstructed using existing mapping techniques. Stimuli were made of a rotating wedge stimulus, which provided angular coordinate maps, and an expanding or contracting ring, which provided eccentricity coordinate maps. Stimuli consisted of a grey background alternating with a flickering checkerboard. A Brucker 3T scanner equipped with a head coil and a custom optical system was used to acquire sets of echoplanar images of 20 occipital coronal slices within a RT of 2.111 ms and an 8 mm(3) voxel resolution. Surface models of each subject's occipital lobes were constructed using the Brainvisa software from a sagittal T1 -weighted image with a 1 mm(3) voxel resolution. The cortical models were then inflated to obtain unfolded surfaces. Statistical analyses of the functional data were made under SPM99, and the response amplitudes were finally assigned to the cortical reconstructed surfaces. Results. We identified boundaries between different early visual areas (V1, V2, V3) using eccentricity and polar angle retinotopic maps and detection of reversals in the representation of the polar angle. Both complete maps and reversals corresponding to the V1/V2 borders were clearly visible with a single recording session. Also, we were able to compare data from subjects across various fMRI acquisitions and found that there was a strong correlation between maps acquired at different sessions for the same subject. Conclusions: We developed a quick (

Clinical measurements by the increment-threshold technique of W.S. Stiles are reported in five cases of age-related macular degeneration. Measurements were made on a modified Tübingen perimeter using 1°, short-wavelength targets presented on a red field.