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Carl Zeiss Meditec Ag

Imedos Gmbh

Carl Ziess Mesitec Ag

Carl Zeiss Jena Gmbh and Institut Fuer Physikalische Hochternologie

Heidelberg Engineering Gmbh

Martin Hammer

Dietrich Schweitzer

Karl-Heinz Donnerhacke

Eike Thamm

Theo Lasser

Walthard Vilser

Wolfgang Triebel

Lutz Leistritz

Achim Kolb

Frank Schweitzer

It is the object of a method for measuring the vessel diameter of optically accessible blood vessels to measure vessel diameters of optically accessible blood vessels in a simple manner based on digital images and with high accuracy even when the vessel diameter is on an order of magnitude at which the determination of the diameter by image point counting is associated with an unacceptably high error. According to the invention, the vessel diameter is determined photometrically from the logarithmized ratio of the intensities of the reflection of the vessel-free environment of the blood vessel and of the reflection of the blood vessel, which intensities are determined in a first monochromatic image.

Method for measuring the vessel diameter of optically accessible blood vessels

The invention is directed to a method for the spectrometric determination of the oxygen saturation of blood in the presence of optical disturbance variables in which transmission measurements and reflection measurements are carried out in at least two wavelengths that are isosbestic for hemoglobin and oxyhemoglobin, and at least one other wavelength at which the extinction of hemoglobin and oxyhemoglobin differ. Corresponding auxiliary functions are defined in the measurement spectrum (M) and in the reference spectra of hemoglobin and oxyhemoglobin, at least two of the measurement values or two of the reference values for the isosbestic wavelengths lying on this auxiliary function. A corrected measurement spectrum (M&#x2033;) is generated by the two auxiliary functions. The oxygen saturation is determined by comparing the changed data of this corrected measurement spectrum (M&#x2033;) with the data of the reference spectra at the other wavelength.

Method for the spectroscopic determination of the oxygen saturation of blood in the presence of optical disturbance variables

An arrangement and method for determining the two-dimensional distribution of fundus pigments, particularly of the xanthophyll macular pigment. The arrangement for carrying out the method comprises an illumination unit which illuminates the retina via an illumination beam path directed to the ocular fundus, observation optics located in the observation beam path proceeding from the ocular fundus, an image processing unit, elements for beam deflection and a central controlling and evaluating unit. In the method, a two-dimensional reflection image of the retina is recorded in a selected narrow-band wavelength region. In evaluating this two-dimensional reflection image, site-specific areas are established for determining the optical density and comparison values. The optical density of the fundus pigment at every fundus location is calculated from the negative logarithmic value of the quotient of the intensity value of the reflection image Iat this fundus site to a comparison intensity value of the reflection image I. The suggested solution for the objective detection of the two-dimensional distribution of the optical density of the macular pigment xanthophyll is also suitable in principle for determining the distribution of other fundus pigments.

Arrangement and method for determining the two-dimensional distribution of fundus pigments, particularly of the macular pigment xanthophyll

A method and apparatus for determining fluorophores on objects, especially on the living ocular fundus, which makes it possible to reliably distinguish at least partially overlapping fluorophores of objects in excitation and/or fluorescence spectra even if fluorescence intensities are very low and to select them for analysis, and optionally create a two-dimensional representation. The object ( ), e.g., the ocular fundus for ophthalmological examinations, is illuminated point to point with a pulsed laser ( ) and excited to autofluorescence with two-dimensional extension. The transient fluorescence light created after excitation by each laser pulse is detected in time-correlated individual photon counting ( ). From the time behavior of the fluorescence light determined by individual photon counting for each site of autofluorescence, the fluorescence decay time constants are calculated, and conclusions are drawn therefrom regarding the excited fluorophores in the object ( ). The time regime for time-correlated individual photon counting ( ) is controlled by the detected pulses of the fluorescence-exciting laser light ( ) and by the fluorescence light created on the object ( ). The spatial fluorescence allocation in multiple scanning excitation is carried out via a routing unit ( ) synchronized with the scanning system.

Method and apparatus for determining fluorophores on objects, especially on the living ocular fundus

An arrangement for spatially resolved acquisition of an object which is illuminated by an illumination arrangement, wherein a relative movement is generated between the illumination arrangement and the object by moving the object and/or the illumination arrangement and, in addition to at least one confocally arranged detection element for confocal acquisition of the light coming from points on the object, there is provided at least one additional detection element for the acquisition of object light at least posterior in time to the confocal acquisition. For at least two-dimensionally spatially resolved measurement of time processes, especially of fluorescence decay times, preferably at the ocular fundus, using a scanning laser ophthalmoscope, the radiation receiver is at least a series of detectors which are arranged in such a way that there is a series of additional detector elements in addition to the confocal detector element at least subsequently in the scanning direction.

Arrangement and method for time-resolved measurement according to the

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Jena, Germany

Martin Hammer