Aphakia correction by synthetic intracorneal implantation: a new tool for quantitative predetermination of the optical quality.

To improve the a priori estimation of optical quality of synthetic intracorneal implantation, numerical calculations were performed involving the intraocular overpressure, the cleavage depth and the type of the implant. Optical correction ratios, that were determined, are in close agreement with the obtained mechanical effects.

Entropic contrast enhancement.

A technique for the contrast enhancement of a picture is proposed. The method is derived from the entropy concept of information theory. The originality of the algorithm rests on the use of a local contrast to define the digital entropy. The basic idea of the treatment is to enhance the contrast by transforming the global entropy. The same technique can also be used for an adaptive smoothing processing.

[Intra-corneal lens implantation: an experimental study in rabbits]. / L'endo-kératophaquie: étude expérimentale chez le lapin.

After the theoretical analysis, the authors describe the experimental results of hydrogel intracorneal lenses in the rabbit stroma.

Intracorneal correction of aphakia: paraxial approach at null incidence.

The technique of intracorneal implantation, recently proposed by de Laage de Meux and Cinquin [Implants, 2, 26 (1984)] for the correction of aphakia, is analyzed in terms of geometrical optics. The analysis is done by using matrix optics and by assuming a null incidence. The characteristics (diameter, radii of curvature, axial thickness) of the hard or soft lens to be implanted are determined and given. The aniseikonia of such lenses is shown to be nearly the same as that of contact lenses.

Chronorhythms of the circulating erythrocytes and leukocytes--correlation with the E.S.R. cycles.

2750 healthy and fasting subjects, 20-30 years old, were studied over a half-year period in 1980. Considering the mean day value as a basic piece of information for statistics, the Erythrocyte Sedimentation Rate (E.S.R.) and the blood counts (erythrocytes, leukocytes, polymorphonuclears, lymphocytes, monocytes and eosinophils) were compared. The timeless relation between E.S.R. and each cell type number or percentage is rectilinear. The stronger slope and relation apply to the polymorphonuclears (PMN) or to the overall leukocytes. The chronological normalized variations of the E.S.R. and of the PMN or leukocyte number or percentage are highly correlated. E.S.R. is less correlated with monocytes, eosinophils and Lymphocytes. Contrary to what could have been expected, the erythrocyte situation is but an intermediate one. The spectra derived from the time variations show that all the cell types, whatever they are, are to be taken into account to explain the E.S.R. value and variation with time, even if, for a given cell type, the correlation and timeless relation were but faint ones. Each cell type has a specific spectrum. Erythrocytes are subject to low frequency variations (316-158 days). PMNs oscillate with time within the medium frequency range (90 days). Lymphocytes, monocytes and eosinophils fluctuate more quickly (53 days).

Erythrocyte sedimentation rate of healthy subjects--chronological aspects.

Thanks to an elaborated mathematical approach, based on statistics and signal processing, the chronological changes of the Erythrocyte Sedimentation Rate (ESR) of young healthy subjects, considered from a collective point of view, have been discriminated into genuine and well-defined rhythms. These rhythms are tied up either to natural (year, season) or 'social' (month, week, holidays) cycles, or to some other causes, still unknown and possibly intrinsic (such is probably the case of a 26.5-day strongly marked period). The solar induced time variation strictly obeys a frequency modulation law, the relative amplitude of which is 10 per cent. Two axes of symmetry are found, centered on 8 August and 8 February. The rhythm is roughly in accordance with seasons. The modulation frequency is maximum at summer time. Oscillations of the ESR are observed during the week and the month. Fridays and the last fortnight of each month appear to be low ESR time.

[Antinuclear antibodies: analysis of images and classification of immunofluorescence aspects on nuclei isolated from rat hepatocytes]. / Anticorps anti-noyaux: analyse d'images et classification des aspects d'immunofluorescence, sur noyaux isolés d'hépatocytes de rat.

Image analysis and Fourier transformation of the various nuclear immunofluorescence patterns observed while detecting antinuclear antibodies allow an objective and quantitative definition of the fluorescence. They also point out various IF types hidden by the main pattern, without having to dilute the test serum. They make obvious the difference between speckled and reticular patterns, and reveal the existence of intermediate states. The usual nuclear IF patterns (homogeneous, ring, nucleolar, reticulated, speckled and diffuse) may be grouped, according to their photo emission, into nuclear and subnuclear patterns. The first group includes homogeneous, annular and passive nucleolar IF. The second group is composed of speckled, reticulated, mixed, and active nucleolar IF. Alternatively, these aspects may be grouped into three types: homogeneous nuclear IF (homogeneous and ring), heterogeneous nuclear IF (speckled, reticulated and mixed) and nucleolar IF (active or passive). Diffusion can affect or not these aspects and does not apply to a special type or pattern. Image analysis and the study of the image spatial spectrum lead to automated recognition of the IF types, and later on, to the discrimination of antinuclear antibodies.

[Crystallographic and molecular structure of trihexosyl-ceramide deposits characteristic of Fabry's disease (particularly the rheumatic form). Digital imaging processing]. / Structure cristallographique et moléculaire des dépôts de trihexosyl-céramide caractéristiques de la maladie de Fabry (forme rhumatismale notamment). Approche par traitements numériques d'images.

The ceramide trihexoside inclusions, which characterize Fabry-Anderson disease, have been studied using electron microscopy and digital image processing. Results are given showing the various apparent periodicities of the inclusion lamellae and the orientation, perpendicular to the lamellae or oblique, of the ceramide molecular component.

[Crystalline morphology of trihexosylceramide deposits characteristic of Fabry's disease (notably the rheumatic form)]. / Morphologie cristalline des dépôts de trihexosylcéramides caractéristiques de la maladie de Fabry (forme rhumatismale notamment).

This paper deals with the various crystalline aspects of the ceramide trihexoside (CTH) inclusions, in the synovial tissue essentially. A basic classification is proposed and uncommon examples are illustrated. Image processing confirms the membrane-like structure of CTH inclusions and corroborates the proposed classification.

[Fourier transformation study of corneal stroma]. / Etude par transformation de Fourier du stroma cornéen.

The various patterns observed by generating Fourier transforms of the fixed normal corneal stroma are described. The patterns are analysed in terms of the dimensions of the stromal fibers, the dimensional and directional order of the fiber distribution and the order of the fiber-fiber functions by proteoglycans.

[Fourier transform analysis of glycolipid depots in Fabry's disease]. / Etude, par transformation de Fourier optique, des dépôts de glycolipides dans le cas de la maladie de Fabry.

An application of the Fourier Transform Process to the Fabry inclusion study has been made. The study, which rests upon five tissues and eight persons, brings out a new low frequency stratification. Various degrees of freedom exist for the basic molecule association. The periods are given for the three fundamental directions of the inclusion.

[The corneal stroma and its physical properties]. / Le stroma cornéen et ses proprités physiques.

The author has studied the correlation existing between the transparency of the corneal stroma and its microscopic fine structure. The paper is an analysis of the results obtained through diffraction and specular approaches. In addition, the paper gives an objective means to determine the ocular spectral characteristics.

High resolvance interference spectrometry with a high factor of merit in the visible spectrum.

Thanks to the laser, high definition photographic plates, and an achromatic compensation phenomenon applicable to equal inclination fringes, the spectrometric method, based on an analysis of Fabry-Perot rings through an adapted grid, is now simple to use, as shown in this paper. Experimental results are given and compared with those obtained from the conventional Fabry-Perot spectrometer.

Thin film coatings: algorithms for the determination Of reflectance and transmittance, and their derivatives.

The paper deals with the specular optical properties of thin dielectric or metallic multilayer coatings. Recurrent formulas are given for reflectance, transmittance, and their derivatives with respect to thicknesses, indices, incidence, and wavelength. Because of its simplicity and flexibility, the proposed method is particularly well fitted for use in a digital computer and for optimization programs.

Luminous flux amplification in Fabry-Perot spectrometry.

Formulas are derived that enable a comparison, for a given resolution, between the luminosity of a grid Fabry-Perot spectrometer and that of a conventional Fabry-Perot spectrometer.