EP1065966A1

EP1065966A1 - Device and method for examining biological vessels

Info

Publication number: EP1065966A1
Application number: EP97951063A
Authority: EP
Inventors: Walthard Vilser
Original assignee: Vilser Walthard
Current assignee: Imedos Intelligente Optische Systeme Der Medezin-
Priority date: 1996-11-26
Filing date: 1997-11-11
Publication date: 2001-01-10
Also published as: WO1998023202A1; JP4140738B2; DE19648935B4; DE19648935A1; JP2000504256A; US6621917B1

Abstract

The present invention pertains to a device for examining biological vessels, especially retinal vessels, including an evaluation unit in the form of an image manipulator (BM) enabling at least partial digitalization or isolation of a measurement window, whereby at least one vessel segment is represented by an electronic picture or picture sequence, which is then transferred to said evaluaton unit.

Description

Device and method for examining biological vessels

The invention relates to a device and a method for examining biological vessels, preferably retinal vessels, wherein at least one vessel section is depicted in an electronic image or in an electronic image sequence that is fed to an evaluation unit. The invention can be used for functional diagnostic analysis for all optically accessible or otherwise mappable blood vessels. It is preferably used to examine the vascular behavior of the large retinal vessels. However, it can also be used for examining vessels of the iris, conjunctiva and vessels that are optically accessible with the microscope or endoscope or in some other way. In particular, vessels exposed during an operation can also be observed and examined using an operating microscope. The invention can be used both on human vessels and for examining animals. The imaging of the vessels can be carried out by optical imaging systems with optoelectronic image conversion or by electronic imaging systems, for example scanning photographic vessel images. The application is not only for the examination of microcirculation vessels limited, it can also be used advantageously on large images of vessel sections generated by means of ultrasound and other imaging principles.

For the examination of vessels, it is known in the prior art to carry out vessel width measurements on the fundus of the eye. These methods are based on the use of optical precision measurement technology in the ophthalmoscopic image, the use of optical precision measurement technology and densitometry on the photographic negative or on photoelectric measurement methods.

According to DE 38 39 272, an arrangement for measuring the fundus of the eye is known which is also suitable for clinical use and enables vascular width measurement, the objective detection of fine pulsatory, auto- or locally regulating vascular width changes being made possible. One and the same image field with vessels of the fundus of the eye is imaged on at least two CCD line sections, means being provided for changing the image position and optical properties of the image. The arrangement can work continuously but also in flash mode. A measuring station according to Suzuki, Y (Surv

Ophthalmol 1995, May; 39 Suppl. 1: 57-65).

The disadvantages of the proposed solutions include in that with individual CCD lines only quasi-continuous measurements with a somewhat improved reproducibility compared to the technical state of the art, but still only with high systematic errors between the

Can conduct meetings and in the course of investigations. Clinically relevant, meaningful statements can only be obtained in the group mean. The complex behavior of the vessels, including the representation of free local Regulatory vascular reactions and pulsatory changes are not certain in individual cases and mostly not detectable. Various devices and methods are described in order to capture the pulse shape of the retinal vessels using pulse-synchronous TV images or photographic images. For such examinations, the image acquisition or digitization is controlled in a pulse-synchronous manner by additional acquisition of pulse signals. For this purpose, a device and a method is described in US 50 31 632, with which the pulse shape is to be ascertainable on-line at only one location of a vessel from a pulse-synchronous TV picture sequence. This is opposed by the fact that the proposed solution has an extremely high measurement uncertainty, which does not allow clinically relevant, individual detection of the pulse shape of retinal vessel diameters. The pulse shapes shown do not correspond to the actual pulse shapes as can be measured using the retinal vessel diameter.

A similar procedure is described by Dumskyi et al (1996 Curr Eye Res. 1996 Jun; 15 (6); 652-632). These methods are not capable on-line, are very time-consuming and too imprecise and are also only of importance for statements in the group mean.

Another photoelectric method is presented by Delori (Applied Optics Vol. 27, No 6, 1988, 1113-1125), in which the vessel diameter is also determined. The measuring principle differs fundamentally from the proposed solution described below. A small, slit-shaped measuring surface scans under differently colored, extremely narrow-band illuminating light at one point of the vessel perpendicular to the course of the vessel over the vessel diameter and the resulting ones Brightness profiles are combined in a location-corrected sum profile, on which the vessel diameter is then calculated from the very faulty half-widths of the edges. High systematic sources of error, in particular due to eye movements, which cannot be completely corrected with the stated principle, in particular eye movements during the scanning process, which cannot be corrected at all, are included in the measurement result. the measuring system can only deliver quasi-continuous measured values with measuring times around 1.6 to 3 s.

Attempts are sometimes described in the literature to determine the diameter of retinal vessels using standard image processing methods or complex mathematical algorithms. For example, Schack and co-workers (Pattern Recognition 1994, Springer-Verlag, 475 - 481) describe special adaptive methods which, however, do not allow the required accuracy or are online-capable, although the mathematical approaches are initially more promising than the known and unsuitable standard methods image processing for edge detection.

With the previously known methods and devices, reproducibility between sessions can only be achieved with low accuracy. This reproducibility is not suitable for the significant detection of regulatory parameters and pathological and therapeutic changes individually on a patient's vessel. Regulatory changes as well as physiological rhythms of stochastic changes in the vessel diameter show deviations of less than 10%, sometimes only 1 to 2%, and cannot be individually individually detected with the known methods. The previous Procedures are usually not online-capable and / or do not have sufficient time resolution and / or are not practical for clinical use.

The invention has for its object to provide a method and a corresponding device for examining vessels, with which the complex vessel behavior can be detected.

According to the invention, the object is achieved by a device and a method with the features specified in the patent claims.

The invention is characterized by a number of advantages.

With the invention technical requirements for the continuous measurement of the vessel diameter in connection with the quasi-simultaneous or exactly simultaneous detection of the temporal and local

Dependencies and their changes created. As a result, the biological variability previously interpreted as a source of error can be detected and clinically evaluated, among other things as vasomotion, blood pressure waves and local lumen changes. Surprisingly, physiological effects such as Bayliss effect, Meyer waves, vasomotion, changes depending on the vascular location, changes in po2 and pco2 are not only individually detectable on individual vascular sections and people, but also their chronological and local course along a vessel can be registered. Out of it This results in a completely new quality for the examination of microcirculation vessels.

The invention not only enables simultaneous online detection of location and time dependency, but also simultaneous online detection of several vessels.

The invention considerably reduces the systematic error of the measurements, noticeably improves the reproducibility and enables the highly significant detection of pathological, therapeutic or provoked

Changes for individual vascular sections individually for individual people and thus creates for the first time the prerequisite for individual therapy optimization from the perspective of vascular behavior.

The invention realizes the possibility of data acquisition and effective

- Evaluation for a variety of useful and new diagnostic methods for evaluating vascular behavior and is not limited to the retinal vessels.

Furthermore, the application of the invention makes it possible to form meaningful parameters for retinal vessels that have not been measurable so far, which can be graphically represented in a clear manner and which enable the diversity of the measured values to be evaluated in the first place.

Particularly advantageous are the special forms of presentation tailored to specific statements, in particular the subsequent correct assignment of the measurement data obtained from the image back into the image. Furthermore, the invention allows parameters to be obtained from a spectral analysis of the vessel diameter.

Furthermore, it is favorable that the arrangement according to the invention enables the methods to be carried out online using inexpensive PC technology.

Another important advantage is that the device according to the invention consists of various special arrangements that can also be used individually. These include in particular: - A fixation device according to the invention with uniform fixation on the

Fixation coordinates related to the object space-eye fundus, which ensures the comparability of the measurement results, - the arrangement of one or more auxiliary windows to reduce the influence of eye movements and - the use of a measurement field, which reduces the light exposure on the eye.

The method and the arrangement according to the invention allow a large number of different designs with different ones

Questions or clinical statements that are equally of clinical relevance. Both digital or analog recording systems for image sequences can be used as photoelectric receiver arrangements, as can imaging systems, such as laser scanner systems and conventional optical imaging systems with optoelectronic imaging or any other system which can supply an electronic image of a section of a vessel, with which the variety of possible embodiments of the invention is expanded. The invention is described in more detail below using an exemplary embodiment. For this purpose, a measuring station for on-line examination of papillary retinal branch vascular sections is explained. Clinical background is, among other things, the question of the degree of local regulatory ability and the causes of limited local regulation with regard to vasomotion or contractility and vascular wall rigidity along vascular sections. These clinical questions could not be investigated using any of the known methods.

In the accompanying drawings:

FIG. 1 shows a block diagram of the overall device,

FIG. 2 shows a block diagram for the device described in the exemplary embodiment,

FIG. 3 shows a block diagram for the device described in the exemplary embodiment in a second view,

FIG. 4 shows an image field with windows,

FIG. 5 shows a block diagram of the process sequence,

FIG. 6 shows a presentation example for a functional diagram, FIG. 7 shows a presentation example for the time display,

FIG. 8 shows a presentation example for the course of the vessel,

FIG. 9 mirrors and pupil positions in the mirror plane S1 / S2 / S3,

FIG. 10 shows the embodiment MSB,

11 shows the embodiment USB,

FIG. 12 shows a representation of the formation of the primary data sequence for the vessel diameter with a scanning measuring surface,

FIG. 13 shows the formation of the primary data sequence for the vessel diameter with parallel detection of the location dependence and

FIG. 14 shows various arrangements of the scan area.

Figure 1 explains the overall arrangement of the device. Object O is preferably the large retinal branch vessels of the living human eye and the object space is given with the fundus. The foveola is defined as the reference point of the object space. An imaging system BS in the form of a retina camera modified on the illumination side described below with a novel combined internal and external fixation device FI and a CCD image sensor, also described below, is used as the video source Image receiver BE used. The imaging system BS is used for illuminating and optically imaging the necessary fundus sections with the vessel sections to be examined. The image receiver BE is used for optoelectronic image conversion into a preferably continuous TV image sequence.

The analog video signals of the image sequence coming from the image receiver BE are fed to an image manipulator BM. The image manipulator BM, for example a frame grabber, is provided with means which implement the image windows according to the invention described below and the associated time windows and which digitize the window contents within the time windows to the signal processing unit BV. The image windows are preferably adaptable to the measurement process in terms of geometry and position and time window with regard to the measurement and recording times and their sequence from image to image. In the image manipulator unit there are furthermore means for displaying the video image on a setting monitor EP, means for displaying the current windows and window positions in the fundus image of the monitor and means for labeling the video images on the monitor preferably with the date, the reference time and an identification number of the current one Investigation IDU. The

Setting monitor Ml is a means of presenting results EP and is used to observe the current result of setting the vessel sections to be examined to the windows for the control or correction before and during the examination process.

The signal processing unit BV consists of memory and computing units, called diameter module DM, which process the digitized window contents according to the methods described below. Automatically detect vessel sections in the individual rows or columns, determine the vessel diameter corrected for the inclined position and output it to the control unit together with its vessel middle positions in the window. Furthermore, the signal processing unit consists of computing and storage means for evaluating the measurement results

Vessel diameter, the optionally additionally measured data from MS and the control data from SS, the storage of the measurement and evaluation results in connection with the patient data - and control data and the formation of parameters. (Evaluation module AM) Additional means are provided for calculating the presentation of results and compiling the measurement protocols (presentation module PM), the data of which are fed to the means of the output unit (EP) via the control unit. Furthermore, the unit BV contains means for storing and managing a database (database module DBM) in which measurement, control, patient and evaluation data are stored in the preferred form described below and put together again for further use and the evaluation or presentation modules . The modules mentioned preferably have their own processors. The diameter module can preferably be constructed as a multiprocessor system to increase the processing speed. Another hardware implementation of the modules mentioned can also be implemented partially or entirely using risk technology.

The control unit SS consists of storage and computing units for realizing the sequence control of the method according to the invention described below and of means for realizing Control and query of the interfaces to the input units for interactive mode (DE) for the optional measuring systems MS, to the optional manipulation units, to the fixation unit (FI) to the CCD camera (BE) and to the imaging system BS. The control unit controls the entire measurement and evaluation process of the method according to the invention described below.

The unit DE provides input means for interactive operation, preferably a mouse and keyboard.

In addition to the setting monitor M1 already described, EP provides means for presenting the results, preferably a PC monitor M2 and a color printer FD. The outputs of the system for dialog operation to the examiner are preferably also realized via the PC monitor M2.

Preferably, an image memory controllable by SS is optionally arranged, which preferably records all or part of the image sequence supplied to the BM from BE parallel to the measuring process and at any time this stored image sequence instead of the image sequence coming from BE

BM, for example for display on the setting monitor or for evaluation. Means are provided in the video memory and in the SS which, in the case of analog tape recording with a controllable video recorder, for example of the type AG7355 with serial interface (Panasonic), identify the tape with a time code and a tape identification or, in the case of digital image memories, at least with the Mark reference time and an examination identification (IDU) (see below) picture-wise. These funds also enable the complete control of all known functions of a TV picture memory, such as recording, search, rewind, fast forward, playback, etc. It is irrelevant to the invention whether the image sequence is stored in analog or digital form. For the optional parallel image recording, the frame grabber must be suitably configured to implement image storage and playback, including image labeling or identification, as well as for transferring or accepting the image sequences. Controlled by SS, these means make it possible to label the image sequence coming from BE image-wise and to make it available to the image memory for storage, as well as to accept and edit image sequences stored in the case of playback instead of BE's image sequences. The picture caption is preferably made picture by picture with the name, the DU and the reference time. It can also be advantageous to write other data into the image, which the SS must then transfer to BM. In the case of the optional use of a video memory, the relationship between the respective examination and patient data to the stored images or image sequences and their time reference is established in the database.

The measuring and manipulation units MP / MS are optionally put together according to the medical question. However, means for quasi-continuous measurement of the blood pressure are preferably provided for all examinations, which are preferably determined at intervals of 1 min, but at least immediately before and after an examination procedure via SS, preferably sequence-controlled systolic and diastolic blood pressure values and via SS for storage, evaluation and presentation provides. The modification of the retinal camera according to the invention is explained in more detail below. The modification relates to the installation of a fixation system according to the invention, consisting of external and internal fixation, the use of special measuring filters and additional means and modifications in the illuminating beam path as well as means for controlling units of the illuminating beam path including the light sources. The modifications described below are not mandatory for the invention except for the use of the special filters, but merely represent advantageous embodiments which bring the advantages of the invention to bear particularly well.

The imaging system BS is shown in more detail in FIGS. 2 and 3.

The figures show two views arranged perpendicular to one another, FIG. 3 showing the top view of the arrangement from FIG. 2 from the direction A. It consists of an imaging main beam path HS with the ophthalmoscope lens OL and the lens system HOS, an ambient lighting beam path US with the ambient lighting system UBS, a measuring field lighting beam path MS with the measuring field lighting system MBS and the fixation beam path FS. The fixation beam path is divided into an outer fixation beam path FAS and an inner fixation beam path FIS via two mirrors S4a and S4b (FIG. 3) shown in FIG. 3b, only the inner fixation beam path being shown in FIG. 2 the illumination pupil plane is reflected into the main beam path via the mirror S3 and with respect to the view from the vertical direction Paper plane comes and then enters the eye together and in parallel with the main beam path HS and the illuminating beam paths US and MS. Via the ophthalmoscope lens OL.

Ambient illuminating beam path US and measuring field illuminating beam path MS are used according to the invention for independently illuminating the fundus of the eye with a measuring field on the illuminating side described below and an illuminated environment. Both beam paths are brought together via the mirror S1 in a pupil-dividing manner in the illumination-side pupil plane p "as shown in FIG. 9 and reflected into the main beam path via the mirror S2. S2 and

Sl are congruent to each other and in this example realize the division or merging of the beam paths by pupil division, i.e. that all illuminating and imaging-side pupil planes including those of the inner fixation beam path in the area of mirrors S2 and S3 in p 'one above the other and congruent to the pupil of the

Eye p are .. All beam paths run together through the ophthalmoscope lens OL and through the optical layers of the object eye and penetrate the object space with the retinal vascular sections to be examined.

The imaging units of the main beam path are the optical layers of the eye, the ophthalmoscope lens OL and the optical system HOS, which map the object plane y into the image plane y "onto the sensor plane of the CCD receiver BE, in this exemplary embodiment forming an intermediate image plane in y ' The main beam path serves, besides the generation of a reflection-free image of vessel sections on the receiver, in addition to the CCD camera BE, to focus the image (Ametropia compensation) by known arrangement of known optical means in the beam path, which are combined to form the lens system HOS. The optical system HOS is provided with an ametropia compensation, not shown, which can be controlled via SS and which is set by the examiner using the control element SG using the control image on the setting monitor Ml, the refraction value for the current ametropia sensor being determined and being supplied to the control unit SS as a signal BSR . The refraction value of the eye to be examined can then be determined in a known manner in relation to the eye of Gullstrand, who is looking for infinite accommodation, from the adjustment of the ametropia compensation detected by bsr, which is in a defined relationship to the refraction value when the fundus image is in focus.

In other exemplary embodiments, the manual actuators for operating the ametropia compensation are provided by automatic actuators and means for controlling these actuators, which in a known manner determine the focus state from the images of the fundus and form control signals for focusing. The actuators are then controlled by SS.

The ambient illuminating beam path US is reflected in the measuring illuminating beam path MS by means of a perforated mirror S1 in a plane preferably congruent to the illuminating pupil by geometric beam splitting in such a way that the surrounding illuminating pupil uses the outer radiation area of the pupil surface. (See Fig. 9). Fig. 9 a shows the

Pupil positions of US and MS on Sl. Fig.) B shows the pulp positions of all beam paths on mirrors S2 and S3 viewed opposite to viewing direction A. Fig. 9c shows the pupil positions of all beam paths in the eye. The illumination optics unit BO on the illumination side serves for the necessary intermediate imaging of the pulp positions of the illumination beam paths in p 'and the surrounding illumination field as well as the measurement illumination field on the fundus of the eye. The radiation space in the pupil region p "is preferably for the imaging of the measurement illumination field and the ambient illumination field at infinity.

The measuring field illumination system MBS produces together with the illumination optics BO, the ophthalmoscope lens OL and the layers of the

Eye a bright illumination-side measuring field sharply depicted in the object plane on the fundus of the eye. The measuring field shown in more detail in FIG. 4 represents an illuminated surface at the back of the eye which can be controlled in terms of geometry and position, in which the measurements are carried out and which implement the lighting required for the measurements in terms of brightness and spectral light composition. The interaction of the measurement field and the observation-side measurement window is described further below with the description of the method according to the invention. The MBS lighting system, which is preferably described for this application example, is shown in more detail in FIG. One by means of controllable

Lamp power supply SVMB-fed halogen lamp LQMB illuminates the measuring field aperture MB F via the aperture diaphragm MBÖ and the lens system MBL1. The lens system MBL2 images the measuring field aperture MBF into infinity and the aperture diaphragm MBÖ into the pulp plane p ", in which the perforated mirror S1 is located. Im There is a bandpass filter FMB with a spectral characteristic defined below in the parallel beam path. The measurement field on the illumination side is preferably designed as a gap. With the adjustment unit SMBF, means for independent adjustment of the gap height and width as well as the position of the gap to the center of the image field are arbitrary in 2 mutually perpendicular coordinates and in the direction of the optical axis. The gap pattern on the fundus can thus be set to cover any desired section of the vessel with any surface. The slit movement in the direction of the optical axis enables the measurement field illumination on the fundus to be focused in accordance with the determined ametropia value from the bsr signals.

Means for controlling the lamp current are provided in the lamp power supply unit SVMB. The aperture diaphragm MBÖ is designed in such a way that it gives the pupil image shown in FIG. The signals necessary for the automatic control of all the described settings of the measuring field lighting system MBS are collectively referred to as the measuring field coordinates bsm on the lighting side.

The UBS ambient lighting system together with the imaging system BS, the ophthalmoscope lens OL and the optical layers of the eye serve to illuminate the fundus. On the one hand, this illumination serves for an overview when adjusting the base of the eye and, on the other hand, it can also be used according to the invention for the light provocation of the retinal vessels. Regardless of the setting of the measuring field lighting, the ambient lighting can be controlled separately in terms of brightness, geometry, position at the back of the eye and spectral light composition. For example, you can put any light stimulus in relation to these coordinates into the retina and analyze the vascular response. The interaction of ambient lighting and that measurement window on the observation side is described further below with the description of the method according to the invention.

The exemplary embodiment selected for this description for the ambient lighting system is described in FIG. 11 and explained below. A SVUB controlled lamp power supply

Halogen lamp LQUB illuminates the light modulator LMUB via the opening diaphragm UBÖ and the lens system UBL1 the surrounding diaphragm ÜB F. The lens system UBL2 images the surrounding diaphragm UBF to infinity and the opening diaphragm UBÖ in the pulp plane p ", in which the perforated mirror S1 is located. In the parallel beam path is a

Bandpass filter FUB for this embodiment preferably with one of the spectral characteristics defined in the claims. The surrounding panel on the lighting side is designed as an adjustable iris panel. The UMBF adjusting unit provides means for setting the diaphragm diameter and the position of the iris diaphragm in the direction of the optical axis. The iris diaphragm movement in the direction of the optical axis enables the ambient lighting on the back of the eye to be focused in accordance with the determined ametropia value from the bsr signals. Means for controlling the lamp current are provided in the lamp power supply unit SVUB. The aperture diaphragm UBÖ is designed in such a way that it gives the pupil image of the surrounding beam path shown in FIG. 9. The light manipulator unit LMUB represents a switch to cover the opening aperture and thus to modulate the ambient lighting, which is controlled by the SLMMB unit.

The signals necessary for the automatic control of all described settings of the ambient lighting system MBS are collectively referred to as lighting-side measuring field coordinates bsu. Optimal fixation of the eye to be examined is an essential prerequisite for optimal examination results. The best fixation is the internal fixation, ie the fixation mark is offered to the eye to be examined. The limits are that those with the

Accessible fundus sections to the periphery are limited and in certain cases the eye to be examined can not see the fixation mark. It is therefore common to use external fixation, in which a non-examined neighboring eye is shown with a glowing fixation mark that can be moved in space at a distance from the neighboring eye.

Various modifications of this internal and external fixation of the state of the art are already attempting to eliminate disadvantages of the conventional fixation devices. For example, means for setting the fixation mark in focus are used and / or blinking fixation marks are used or / and light-emitting diode arrays are proposed with fixation marks that can be set in a defined manner and were in the space for the external fixation. However, the previous methods have a major disadvantage, which is that they do not automatically and sufficiently reproducibly set the fixation coordinates regardless of the type of fixation (external or internal fixation).

The fixation device according to the invention as a modification of the retinal camera has several advantages. It enables simultaneous external and internal fixation to eliminate this disadvantage and, at the same time, to guarantee the automatic setting of the fixation coordinates. The essential aspect according to the invention is the uniform coordinate basis in the object space, ie the angular position of the examined eye and the neighboring eye must be the same regardless of the use of the external or internal fixation with the same fixation coordinates be exactly the same. The solution according to the invention realizes this requirement by parallelism of the main optical axes of the main beam path with those of the outer and inner fiaxation beam path. FIG. 3 shows an exemplary embodiment of this. The imaging system BS is vertical with the integrated fixation device

Shown view of Figure 2. . Both patient eyes can be seen, the eye to be examined being characterized by the main beam path HS penetrating into the eye. The main beam path HS is shown with its main optical axis. The FME fixation mark is imaged to infinity using the FOS1 optical system. The mirror unit S4 splits the common fixation beam path FS into the outer fixation beam path FAS and the inner fixation beam path. This mirror unit either contains a mirror which can be tilted by 90 ° or, as in the exemplary embodiment, preferably contains two mirrors which are tilted by 90 °, each of which realizes the aperture diaphragms for the two beam paths FTS and FAS as shown in FIG. 3b. The mirror S4a is imaged by means of an optical system FOS2 as a pupil image of FTS into the pupil plane of the main beam path and reflects FTS parallel to the main beam path in the direction of the eye to be examined. The fixation mark is imaged in the image plane y '. The mirror

S4b is imaged via the optical system AA into the eye pupil of the neighboring eye, the optical system AA reproducing the fiaxation mark FME coming from the infinite again into the infinite and containing means (not shown) for correcting the ametropia between the two eyes in order to focus the fiaxation mark for the

Neighbor eye. Furthermore, known means (not shown) for adapting FAS to the interpupillary distance are provided, which do not change the parallelism of the optical axis of FTS and FAS to one another. A light-emitting diode is used as the fixation mark. With SFME, means are provided to bring the light-emitting diode sufficiently fine and with a sufficiently large fixation mark movement into the congruent image plane to the foveola. This is done by moving towards the optical

Axis of and in two perpendicular coordinates of the congruent image plane to the fundus are reached, the fixation coordinate axes preferably matching those of the CCD matrix and those of the lighting systems. The fixation mark for the examined eye is brought into focus by setting on the basis of the one already determined

Ametropia values from which the position of the plane congruent to the fundus in the fixation path is calculated and set using fiaxation coordinates and SFME. The brightness of the light emitting diode is modulated by means of the SVFLQ power supply unit. SVFLQ receives the control signal from the control unit

SS. The fixation control coordinates for the light-emitting diode movement and their brightness are summarized under the designation fk and made available by the control unit.

3 shows the right eye as the eye to be examined. If the left eye

If the eye is to be examined, the main beam path is adjusted to the left eye. In this case the fixation system must be mirrored to the main axis. Mechanical means are provided for this mirroring by rotating the entire fixation system by 180 ° about the main axis HS, combined with the tilting of the mirror from a position S3 by 90 ° against the pivot point DP to the position S3 '. The aspect ratios are now exchanged exactly once, with means for detecting the position of the fixation system (right or left) are provided, which transmits this position to the control unit and takes into account the correct calculation of the fixation coordinates. The color of the fixation mark is advantageously chosen red and a red blocking filter is arranged directly in front of the CCD camera to block the fixation light.

The method according to the invention is explained in more detail below using the selected exemplary embodiment. With the device described, the method enables the preferably on-line, but also off-line measurement and a suitable representation of the location-dependence of vessel diameters along vessel sections to be examined and at the same time as a function of time, as well as the analysis of the vessel behavior by including provocation methods. Ren and / or formation and advantageous representation of relevant parameters for describing the local and temporal vascular behavior. The location dependence is preferably over at least one vessel section of sufficient length, preferably 1.5 mm in length, at the same time interval, z. B. determined within an image. However, this exact simultaneity is not essential. The determination of the

Location dependency along a section of a vessel can also take place successively from one section of vessel to another if the accuracy that can be achieved with it is still sufficient for the biological or medical question.

The examination process takes place within the specified window. Fig. 4 shows the relationship between the image field, the measuring and auxiliary windows, the ambient or provocation lighting and the measuring field lighting.

The ambient lighting generated by UBS is used for orientation at the fundus of the eye during adjustment of the vascular area to be examined. The diameter of the ambient lighting and illuminance is just so strong that it is possible to orientate yourself on the fundus. The standard setting is preferably such that the ambient lighting illuminates the entire image field and the papilla and vessels are just recognizable.

The measuring field generated by MBS serves to illuminate the measuring and

Auxiliary window.

The measurement window is an image area cut out by the image manipulator unit BM, digitized and supplied to the DV unit. It is that

Area in which the vessel sections automatically recognizable by the vessel diameter module along the pixel rows or / and pixel columns are analyzed, i.e. all vessel diameters and the associated vessel center positions of the vessel sections intersecting and recognized by the pixel rows and / or pixel columns are determined in the measurement window, output to the control unit and in assigned to the primary data matrix at the relative time RZ in which the current image was recorded. The vessel diameter has already been corrected for the oblique position in the diameter module because the vessel direction is only sufficiently perpendicular to the measuring direction in exceptional cases. If the vessel diameter is determined in the direction of the pixel columns, the location-dependent dependence of the vessel diameter along the vessel is recorded along the perpendicular direction of the pixel line and vice versa. According to the invention, the Direction of measurement and positional dependence perpendicular to each other are recorded in accordance with the pixel rows and pixel columns. The measurement window width in the measurement direction for the vessel diameter is preferably set so large that the vessel intersects the measurement window despite eye movements. Another advantage is that the measuring window can cut several vessels and the

Diameter module DM in this case analyzes all vessel sections intersecting the measuring surface in the manner described or measures them. Perpendicular to the measuring direction, the number of pixels in the measuring window should be at least large enough to determine the inclined position from the displacement of the vessel centers in the measuring window and a value for correcting the inclined position can be formed. The skew correction is preferably carried out in the diameter module. This measuring principle then automatically results in the positionality of the vessel diameter along the vessel perpendicular to the direction of measurement for the vessel diameter pixel column for pixel column or pixel row for pixel row. The time dependence arises in the primary matrix for the vessel diameter, which is described in more detail below, when the measurement process is repeated frame by frame with increasing relative time at the start of the measurement (reference time). When using common European TV cameras, the possible temporal resolution is then 40 ms.

Only a few pixels perpendicular to the measuring direction are required for the inclination correction. For a relevant and medically usable location dependency of the vessel diameter, a few pixels in the direction of the vessel course are not sufficient. In order to satisfactorily record the location dependence, two different methods are preferably possible.

In the first case, a slit-shaped measuring window is used that, depending on the position of the examined vessel in the image field horizontally or as in the example 4 vertically the vessel to be examined is determined by the examiner or automatically cutting. The slit-shaped measuring window width is preferably 10 pixels wide, the measuring window height, for example, 100 pixels high. The image-wise control of the window geometry and position by the control unit according to the invention is used to change the position of the measurement window over time so that it moves stochastically or systematically within a scan area defined by the examiner. The examiner or the control matrix of a reference examination determines the measurement window coordinates for the two outer limit positions (Gl and G2) as shown in Figure 4, within which the measurement window moves in an image or from image to image and scans the location along the vessel. This area is called the scan area. In this case, the diagonally corrected diameter of the slit-shaped measuring surface is output averaged over the slit width. Fig. 12 shows this measurement process and the emergence of the data sequence of the primary matrix schematically. Figure 12 a shows the image field from the back of the eye, as already known from Fig. 4, with the measurement window and the scan area correspond to two measurement window positions entered in FIG. 12a. 12b represents the reference time axis based on the reference time of the start of the examination BZ and the

Data space from relative time RZ, scan location and vessel diameter for the two acquired vessels 1 and 2.

The advantage of this measuring method is the low need for computing capacity for one measuring surface and the possibility to define a large number of parallel measuring surfaces in the image. Another version of the measuring method uses a wide measuring window, the z. B. is again determined by the examiner in such a way on the adjustment monitor that the vessel section or sections to be examined covers sufficiently insensitively to eye movements. The measurement surface remains unchanged in the image field over a longer image sequence and, as shown in FIG. 13, records the location dependency of the vessel diameter along the detected vessel sections within the measurement window parallel to the time perpendicular to the measurement direction. This drawing is to be read analogously to FIG. 12, the coordinate scan location being replaced by the pixel location. The minimum local resolution is determined by the line or

Column width set. Advantageously, with a high computing capacity and favorable inclination of the vessel, the same measurement process can be carried out in parallel for exchanged directions of measurement of vessel diameter and location dependency, image by image, and thus obtains higher accuracy and better control over the inclination correction.

The auxiliary windows are used to control and correct eye movements during the measuring process, the vessel sections can move against the measuring window. With components of the eye movements in the measuring direction of the vessel diameter, this is negligible for the time resolution of 40 ms, it is problematic for the displacements from image to image along the vessels and leads to a high measurement uncertainty. The vessel diameter can change by up to 10% and more, which is reflected in the reproducibility or in the systematic error.

Preferably, two perpendicular auxiliary window-shaped auxiliary windows are defined in the pixel row and column direction. in the described second case of wide measurement areas, at least three pixel rows and three pixel columns each from the center of the first defined measurement window are additionally used as auxiliary windows. In the case of slit-shaped measuring surfaces, the control unit also generates the two auxiliary windows in the middle of the at least 3 pixel rows and 3 pixel columns, preferably of the same height as the measuring window, which do not change their position from image to image. In Fig. 4 only the horizontal auxiliary window can be seen, since the vertical window is covered by the measuring window.

In the auxiliary window, the vessel centers in the auxiliary window are preferably determined and compared with the target values of the first image. Correction values for the movement of the vessel sections from one image to the other are determined from these values and are also stored as correction values for each image in the primary matrix.

Another possibility for the formation of correction values for eliminating the influence of errors in eye movements is the correlation of the auxiliary window information in each case to the first image or the use of a device for additional measurement of the eye movements, the measured values then being converted into correction values for the vessel location, taking into account the known geometric relationships can be saved in the described field in the primary matrix as correction values.

The measuring field on the lighting side serves to reduce the light load.

In the case of a slit-shaped measurement window, the control unit can, after or with the determination of the measurement window, congruently define the coordinates of the measurement field on the illumination side covering the measurement window, ie. H. the size of the measuring field is reduced to the size of the measuring window. The advantage is a significant reduction in light exposure. During the measurement process, the diameter and illuminance of the lighting environment created by UBS can be considerably restricted or even switched off. The position of the ambient lighting can also be set automatically via the control unit or by the examiner. The use of ambient lighting for light provocation according to the invention is described separately below.

In Fig. 4, the measuring field is designed as a circular field. In this case, the field diaphragm in the MBS is designed as an iris diaphragm. 4 illuminates the entire image field, but has a significantly weakened illuminance due to the reduction of the lamp current for the halogen lamp LQUB. In individual cases, it may also be advantageous to dispense with the modified controllable illumination UBS and MBS in the retina camera and instead the field diaphragm of the retina camera on the illumination side is designed as a light-reducing field diaphragm with a fixed free central diameter as a measuring field. The image at the back of the eye could then look as shown in FIG. 4.

The coordinates for geometry, position and lamp current of the ambient lighting bsu and the measuring field lighting bsm are passed on by the control unit SS to UBS and MBS. BM also receives the coordinates of the geometry and position of the measurement windows and auxiliary windows from the

Control unit SS. The control unit receives the above-mentioned coordinates from a reference control matrix defined by the examiner or directly via the dialog mode. In the latter case, the examiner preferably controls with his mouse the definition of the described windows and fields and the brightness. In a known manner, mouse movements and actions can then be converted into control coordinates by the control unit and their effects can be observed online on the setting monitor by changing the respectively controlled fields and windows.

Depending on the performance of the modules and units of the device, several measurement windows can be used by the examiner. The measuring fields on the lighting side are then to be adapted to the measuring windows with regard to their position and geometry. Another embodiment of the measurement process according to the invention is the definition of a plurality of measurement windows, the geometry and position of which is equal to the measurement fields on the illumination side, the measurement windows having only a defined geometry and position in the image field in a defined time interval, but at defined time intervals, controlled by the control unit, their geometry and change the position in the image field in order to examine different vessel sections in succession without interrupting the examination. The same vessel sections can be queried as often as desired with the measurement window and measurement fields once defined. This has the advantage that both the examination of slow time processes and the examination of many vessel sections online are possible within one examination.

The method consists of different method groups: 0. Acquisition of patient data (default setting) Reproducible setting of the fundus, in particular of the vascular sections to be examined in the image field with the modified retinal camera and the fixation device with the help of the control unit and the setting monitor. Determination of the vessel sections to be examined on the setting monitor by defining windows on the lighting and / or imaging side (see further below) with the aid of the control unit and the manipulation unit, as well as means of the DE (mouse and keyboard), forming a control matrix S.

Measuring process for determining vessel diameters along the vessel location and time and forming a primary data matrix P, which establishes relationships between the following primary data for each examination: P (IDU, IDP, A, DFDP, DFMi, DFPi, S, BZ, DZ, BF) as well as graphical on-line representation of selected dependencies, preferably the vessel diameter as a function of time for all examined vessel sections

Examination identification number IDU, a patient key IDP, the examined eye A (right or left), a data sequence DFD with the data for the vessel diameter D, data sequences for i additional measurement variables DFMi data sequences for i additional provocation events DFPi, a control matrix S for the examination process, a measurement start with the reference date BD, and the reference time BZ an examined video image sequence BF

Calculation of a corrected data matrix

Analysis process and formation of characteristic matrices and presentation or output of characteristic values

BZ, BD (reference date and reference time) are understood to mean the date and time at which the images to be evaluated were taken. At the On-line operation, in which image acquisition and measurement take place in the same time interval, the reference time BZ is equal to the current system time SZ. The system time or system date is understood to be the current time or the current date. A time difference is understood as the relative time RZ.

The primary data record of the control matrix S establishes the relationship to the following variables:

1. Sensitivity (magnification setting)

2. Fixation coordinates (x, y, coordinates, lamp current, inside / outside fixation)

3. Ametropia value

4. Measuring field coordinates on the lighting side (height, width, position in the image field, lamp current at the time of starting)

5. Lighting-side environment coordinates (diameter, position in the image field, lamp current, light manipulator state) at the start time

6. Reference value - time and date at the start of the start (BZ, BD)

7. With optional recorder control, tape ID,

8. Timecode of the start picture or file name of the start picture

For the primary data sequence for the vessel diameter, the primary data record contains the vessel diameter D as a function of the following variables: D = F (

1. diameter,

2. current position of the vessel diameter in the measuring window (coordinates), 3. current position of the measuring window in the image field,

4. current correction coordinates from the auxiliary window (s) or additional measuring unit for determining eye movements,

5. Relative time to the start of the measurement process RZ, 6. Location-corrected position of the vessel center belonging to the vessel diameter in the object space).

FIGS. 12 and 13 show the diameter and the relative time RZ and the pixel location or scan location. The scan location is another representation of the current position of the vessel diameter, but this can be calculated from the data of this primary data sequence for the vessel diameter.

Primary data matrix of a manipulation matrix:

Event values

Relative time

Primary data sequence of a measurement data matrix (general)

Measured value relative time

The course of an investigation is described schematically in FIG. 5. Related measurement, control and analysis data within a temporally connected examination time interval with uninterrupted relative time and only one reference time and one reference date at the relative time = 0 are called the examination. Each examination has a unique identification number, which connects the examinations with the examined image sequence, the patient and the measurement, control and analysis data via P. Multiple exams can be performed on one patient's vessel in one session. The examination begins with the assignment of a new IDU and the assignment of the patient (default). The input of the patient data, their editing and storage in the database as well as the data model for the general data on the patient takes place according to known aspects and will not be explained in more detail. It is only essential for the invention that a data relation of the measurement, control and analysis data can be clearly assigned to a patient. According to the presettings, the vessel sections to be examined are set in the image field of the setting monitor and the necessary control parameters of the fundus of the eye with those to be examined

Vessel sections and window positions by the control unit and by the examiner, who can carry out and check the settings on the modified retinal camera and using the keyboard and mouse on the setting screen. The adjustment must be made in such a way that the fundus with the vascular sections to be examined can be seen on the setting monitor with sufficient sharpness and high contrast, the windows described below are arranged correctly to the vascular sections to be examined and the device pupils are exactly centered on the pupil of the eye.

In the case of a repeat examination, all the windows on the lighting side and the windows on the image side (see below) are already specified by the control unit and are visible on the setting monitor. For this purpose, the examiner selects a reference examination whose control matrix is adopted as the reference matrix. The one from the

Setting parameters (control data) to be specified for the control unit for the repeat conditions are taken from the reference matrix and preset. The reference matrix can be used for repeat conditions Set the necessary settings for an examination that has already been carried out and is selected by the examiner. On the dialogue monitor (PC monitor) the examiner is shown an image with the vessel and window position in the setting monitor of the reference measurement. By presetting the fixation coordinates of the reference measurement, the

Examiner only make the adjustment between the device and the eye in such a way that the device pupils are properly fixed to the eye pupil. It is also usually not necessary to focus the image, since the refractive error of the reference examination is known from the reference matrix and the focus is also automatically preset via the control coordinates bsr. Adjustments of the image sharpness and fixation or window positions are nevertheless possible manually and are corrected in the control matrix according to the current values. After setting, the measuring process is e.g. started with the mouse.

In the event that no repeat measurement is to be carried out, the examiner selects one of the predefined reference matrices which carry out the corresponding presettings. In terms of process technology, the examiner provides stipulations for various examination programs and can be stored in a reference matrix, which is then used for

Ensuring the same examination conditions can be called up by the examiner.

In addition to the adjustment between the device and the eye from the point of view of the device pupils, the examiner will adjust the vascular sections to be examined with the help of the fixing unit (movement of the fixing mark using the mouse or keyboard) in the image field of the setting monitor and adjust the image sharpness. Unless the windows are specified, the next one Step the window positions (see further above) according to the examination program on the setting monitor, preferably set with the mouse and the measuring process for recording the primary data is started.

The new current setting parameters of the control unit of this examination are preferably stored in the control matrix of this examination at the time of the start of the measuring process, while preferably also a fundus image with window positions as a control image for the measuring point position of this examination is frozen. This is also the first evaluated image of the image sequence of b = n images (b = l) and the reference value for the time and date of the start of the examination. (BZ, BD) During the measurement process, the examiner can correct the fixation coordinates or the setting of the device and eye pupils and abort the measurement process at any time. The back of the eye, the position of the windows and the vessel sections are on

Setting monitor controllable in parallel. The vessel diameter for each vessel is preferably recorded online on the dialog monitor depending on the time. This setting is carried out either according to standard specifications and its storage takes place according to generally known aspects and the data model characterizing the patient.

FIG. 5 explains the process sequence on a block diagram. The description of the image and signal processing according to the invention in the measurement and auxiliary windows takes place only on the example of a window, since at

The procedure is analogous when using several measurement windows. All windows are processed by the diameter module DM (Fig. 1), the vessels found in the measurement window are output with their obliquely corrected vessel diameter, the vessel center position in the measurement window and the mean oblique position of the vessel against the window and depending on the image number of the sequence and the current location the window in the

Image field stored in a primary data set. The vessel diameter can also be output by the diameter module without correcting the inclined position. In this case, the inclination must be corrected subsequently. The recognized vessels of the current window are assigned to one another based on their characteristics. Each diameter value of the data sequences relating to the vessel diameter in the primary data matrix is then assigned to a vessel from vessel 1 to i, depending on how many vessels are identified as different. Later, software-based means are preferably provided with which, after visual inspection by the examiner, e.g. by checking the stored image sequence if necessary

Classification can be corrected. In the auxiliary window module, according to the invention, as already described, the positional shift of the same vessels in the direction of the auxiliary window is determined as correction values for the small involuntary eye movements from the difference between the vessel center position and the oblique position of the vessels. From these correction values, the

Imaging relationships, the current window coordinates, the fixation coordinates and the vessel centers in the image field, the object position according to the invention of the vessel centers belonging to the vessel diameters, hereinafter referred to as vessel location, based on the reference point (foveola), is calculated in the data sequence relating to the vessel diameter of the primary data matrix (corrected object position of the vessel diameter in the fundus image) saved. The comparability of the vessel diameters is therefore independent of the set object field and the Elimination of the influence of eye movements on the measurement site. A similar effect to switching off small eye movements can also be achieved, for example, if the image shift is calculated by correlating the image information of the first auxiliary window with the current auxiliary window. The vessel inclinations are then determined and taken into account by correlation from neighboring rows of pixels. Another variant is the measurement of eye movements in parallel during the measuring process. The changes in the viewing direction against a reference image, for example the first image, can then be used instead of the correction values calculated from the auxiliary windows in order to correct the influence of the eye movements on the measurement location

According to the invention, the diameter module represents a fast algorithm which recognizes vessel edges in the line signals of the windows, interpolates the photometric focal points in the vessel edges, calculates the oblique position of the vessel edges, assigns the correct vessel edges to one another, determines the vessel diameter between the photometric edge focal points and determines the oblique position the vessel center position in the window is calculated.

Special measuring units are used to measure blood pressure. The measuring unit for periodic pressure measurement MSI has a computer interface via which the measuring process is started and stopped by means of a control signal from the control unit SS. The determined blood pressure data are assigned to the primary data matrix in the correct time or in the image via the control unit. The measuring unit MS2 consists of an EKG device, which supplies the R wave of the EKG to the control unit via a computer interface and is stored by the control unit in the primary data set in the correct image or time and assigned to the data sets.

MSI and MS2 are preferably always included in the measurement process, since the pulsation analysis is simplified by means of the R wave and, on the other hand, blood pressure is a significant factor influencing the vessel diameter, the additional recording of which excludes sources of error. The additional measurands do not have to be recorded in parallel.

Additional additional measuring systems (MS3) can be useful. An example of further additional measurements is the determination of the breathing gases by means of breathing gas analysis or the measurement of the suction cup pressure when combining the measurement of the local and temporal vessel diameter with the increase in intraocular pressure by means of the suction cup method.

It is also possible to use provocation devices MP to cause certain states for corresponding examinations. The respiratory gas provocation device MP1 preferably has one

Airway for free breathing and another airway for rebreathing, which are switchable. In sufficient proximity to the mouthpiece, the oxygen and CO2 content of the breathing air is measured periodically and assigned to the control unit SS in the correct image and time of the primary data matrix. By means of a control signal from the control unit

Respiratory gas routes switched according to sequence control. Studies on the effect of oxygen on the retinal vessels are known by measuring individual values and evaluating them in a group comparison. With the The arrangement according to the invention and the method according to the invention are of particular interest in terms of the temporal and spatial behavior of the vessels on the provocation with oxygen, CO2 or carbogen in various concentrations to the breathing air or, as with oxygen, also in pure form. For example, the combination for provocation is 100%

Oxygen, preferably over 5 minutes, is a preferred embodiment of a functional diagnostic method for examining the contractility of the vascular sections.

The provocation device for physical stress MP2 consists of a set of handy weights and an acoustic signal generator. The weight piece normalized to the body weight of the patient is picked up by the patient in response to a signal and held on the horizontally extended one until a second signal, after which the patient deposits the weight piece again. Both signals are generated acoustically by the PC output unit, the control signal being supplied by the control unit. Depending on the schedule, this provocation takes place during, before or between measurements on the eye.

Another preferably combinable provocation device is one of the known systems for increasing intraocular pressure by means of a suction cup (MP3).

Provocation devices can be provided in parallel, but can also be used individually.

According to the invention, a possibility of provocation by means of the described device is preferred by the modified retinal camera itself realized. The ambient lighting beam path is used for provocation. Using the control unit and the UBS units described (see Fig. 11), the lamp current, the light modulator, the geometry and position of the ambient illuminating light at the back of the eye are changed via the control coordinates bsu during the measurement process in such a way that a constant or only temporary light stimulus changes at a defined level of the examining area of the fundus of the eye, the effect of which on the vessel diameter can be recorded at a different location and time in the fundus. As an embodiment, a light that alternates in brightness, such as was already used as a flicker for measuring other blood flow sizes, could be placed in a central area of the papilla in relation to the foveola in the macula in order to examine the vascular response of the superior temporal vein in comparison to the vena temp . Inferior to investigate .. The advantage is that with the diameter of the vessel the behavior of the microcirculation is recorded directly and not only indirectly via the change in blood speed resulting from the change in diameter, for example. The combination described is a simple method for functional diagnosis of the retinal vessels and also the functionality of the nerve fibers.

The further processing of the measurement results is preferably carried out first by the formation of further vessel signals in which all vessel diameters are squared and the squares are squared once more and in each case in further temporary columns of the primary data matrix for the

Evaluation as the speed-relevant diameter Ag (x, y, t) and as the flow-relevant diameter Qg (x, y, t) are stored correctly in terms of vessel, location, time and image. These steps allow a significant expansion of the Meaningfulness of the invention, since they additionally directly describe the unmanageable effect of vasoactive activities of the vessel diameter on the flow variables blood velocity and blood flow. The inclusion of these parameters is optional.

The further processing of the measurement results is preferably carried out first by the formation of further vessel signals, by squaring all vessel diameters for themselves and squaring the squares one more time, and in each case in a further temporary column of the primary data matrix for evaluation as a velocity-relevant diameter Ag (x, y, t ) and stored as the flow-relevant diameter Qg (x, y, t) in the correct vessel, location, time or image. These steps enable a significant expansion of the meaningfulness of the invention, since they also directly describe the unmanageable effect of vasoactive activities of the vessel diameters on the flow variables blood velocity and blood flow. The inclusion of these parameters is optional.

A distinction is made between on-line evaluation and off-line evaluation. The on-line evaluation is controlled by the control unit SS after factory or user-defined presetting. The off-line evaluation is carried out by menu selection of the vessel sections and signals of interest, as well as the evaluation method and the parameters in a known manner.

The evaluation methods offered to the examiner for selection in this example for the formation of parameters are compiled in blocks in FIG. 5. The basis is permanent in the primary data matrix or temporarily stored vessel, - measurement and provocation signals in their local and temporal dependence. The following description is only for the evaluation of a vessel section and only for the vessel diameter Dg as a vessel signal, since it is carried out analogously for the other vessel sections or vessel signals (Ag, Qg) (g denotes the

Vessel membership of the vessel diameter).

Using a data mask, the data to be analyzed are read out of the primary data mask in the correct time, place and vessel and fed to a filter for spectral and / or local filtering that corresponds to the state of the art and is used in accordance with the evaluation task.

The method of local frequency analysis determines the power spectrum, detects significant local frequencies Fo and determines the associated phase positions Po of the supplied data sequence either as a function of a time interval set in the filter as time-dependent spectral parameters or as a complex spectral parameter. The block temporal frequency analysis determines the power spectrum of the selected signal sequence, detects significant frequencies Ft, determines their power Lt and phase position Pt and stores the spectral values determined

Parameters i in the associated parameter matrices. From the determined spectral powers, the parameters VAPU as a quotient from vasomotion and pulsation, PPU as a quotient from provocation response to pulsation and PVA as a quotient from provocation response to vasomotion, PUB as a quotient of the first-order blood pressure wave for pulsation are formed, which correspond to the data mask or the filter can be assigned to one of the parameter matrices. Phase differences between predetermined measurement sections are calculated and, in the case of connected vessel sections, wave speeds are calculated from the associated path lengths.

The pulsation analysis method determines with Rzack-triggered a temporally average pulsation signal as a function of the pulse phase over a pulsation period, which is stored in the parameter matrix as a pulsation signal. The peak values of the pulse signals are determined and stored as separate parameters.

The location analysis procedure group provides the significant maxima MaO and MiO of the data sequence about the location, its time interval TO and the associated peak values SO, the mean value MWO, its dispersion SMWO and the confidence interval MWOK for a given static safety as well as the number of images nb and measurement locations no .

The calculation of the mean is based on the vascular pathways belonging to a pixel.

The process group static time analysis provides the significant temporal extreme values MAT and MOT of the data sequence, their time interval TT and the associated peak value ST, the mean value MWT, its dispersion SMWT and the confidence interval MWTK for a given static safety as well as the number of those included in the mean values Images nb and the measuring locations no. Depending on the filter selection and parameters, further parameters for vasomotion, pulsation and blood pressure are determined.

The process group dynamic time analysis uses adaptive processes from the temporal trend to estimate the value of a significant increase APROV (also negative increases) and the significant start of the increase BT.

By appropriately setting the parameters of the data mask and the filter parameters, the total mean values and associated scatter are determined and used as location-specific and time-independent complex parameters (KMW,

KSMW) stored in the complex parameter matrix for the corresponding vessel sections.

The evaluation methods that can be carried out iteratively are also constructed iteratively, so that they can optionally be displayed in monitor windows for on-line evaluation and on-line presentation of the measurement or evaluation results.

The cross-correlation method group uses the cross-correlation factor to determine parameters that describe the relationship between the vascular responses and the additional provocation and measurement signals.

Time-dependent parameters are stored in the time-dependent parameter matrix, location-dependent parameters are stored in the location parameter matrix and time- and location-independent parameters are stored in the complex parameter matrix.

The image sequence comparison procedure group forms the percentage differences of the parameters of the same vascular sections and vessel locations (x, y) and time phases (t) from the parameter matrices of a selected image sequence with the current image sequence and preferably also the associated confidence intervals. The reference picture sequence can be defined as desired, the previous picture sequence is preset. Only those parameters are compared that are comparable in terms of their tax data matrix. The time comparison method group forms the percentage time differences of parameters of the same vascular section of an image sequence and preferably also the associated confidence intervals, the time interval of the reference value being able to be set as desired. The first time value of a parameter in the image sequence is preset for the reference value. The peak value of the provocation responses is determined as a further benchmark for the regulatory area RB, the provocation-related maximum is determined as a benchmark for the upper regulatory reserve and the minimum is determined as the URR - lower regulatory reserve.

Figures 6 to 7 explain presentation methods. According to the invention, the results are presented in monitor images either in parallel or in succession using the presentation methods described below.

The functional images presentation group graphically represents the parameters or measured values corresponding to the vessel locations or optionally also in the middle, as shown in FIG. 6. The measured values, parameters or comparative variables are visually sufficiently distinguishable as vertical or horizontal bars compared to the line-shaped vessel location. Different parameters are color-coded. These function images are shown in gray with the fundus images documented at the beginning of each image sequence, which are previously converted into the coordinates of the object planes analogously to the measured values. The presentation procedure can also be based on image field coordinates, in which case the vessel centers are used instead of the vessel locations. FIG. 6 shows the parameter Lt of pulsation versus Lt of vasomation as an example, the values for the pulsation being below and the values for the vasomotion are shown above the vessel location. At first glance, those vascular areas that are stiff, show neither pulsation nor vasomotion, or those vascular sections that still react flexibly to the pulse, but for which vasomotion can no longer be detected. The metabolic or provocation parameters, the regulatory areas, the regulatory reserve or other parameters can be displayed in the same way. Appropriate control also provides for the collection of different vessel sections from different image sequences in a functional image, which were recorded one after the other, for example.

The presentation group time display enables the display of value sequences from the different levels of the evaluation process depending on the time, whereby the display can be determined optionally.

The presentation group location display enables the display of value sequences from the different levels of the evaluation process depending on the vascular path, whereby the display can optionally be determined. The vascular path is the distance corrected for the inclined position

Vascular centers (vessel segment) or the vessel position (vessel path calculated and saved in the primary matrix. The vessel segment is therefore the image of the vessel path in the object plane.

Preferably, all of the evaluation methods mentioned should be available for device systems that are intended for research use. However, it is irrelevant to the invention how many of the methods are available or are used for the application. Even one simple representation of the numerical values for evaluation by the doctor would, even if considerably restricted, enable qualitatively new statements to be made regarding the technical status. However, the graphical representation of data from the primary data matrix, the formation of characteristic values and their graphical presentation go beyond the representation of the primary data in terms of content and effectiveness, since the abundance and meaningfulness of the new visual and temporal relationships recorded according to the invention in numerical values are no longer manageable.

The invention also enables results to be presented on line.

The on-line output operations are controlled by the control unit according to the schedule. The presentation of the results is also preset in the factory or in a user-defined manner using the online evaluation method. The setting monitor Ml continuously displays the image from the back of the eye and the current window positions. At the start of the measuring process, the first image of the fundus is completely digitized and stored in the control data matrix of the image sequence and is available in a Minitor image window. With the start of the

As a control signal in a further monitor window, the vessel diameters of the detected vessels are output as a control signal, depending on the time parallel to the provocation signals - and optionally - to the additionally recorded measurement signals, either unprocessed or after filtering. In other monitor windows you can choose iteratively

Characteristics of the evaluation method with priority of the measurement process and the other monitor windows mentioned are displayed on line. The control unit SS takes over the entire sequence control of the measurement process and evaluation, the interface control for the exchange of control and measurement signals with the units, the control signal formation, the synchronization between the units and in particular the dialog operation with the input and output units. The control unit also manages the database system in which the generated control, parameter and primary data matrices or, if appropriate, the image sequences are stored and managed under an image sequence identifier and examination identifier IDU. The image sequence identifier consists of a primary key for the image sequence identifier BF generated by the database management system of the control unit and a continuous image identifier b. The images belonging to an examination are called an image sequence. In the case of autonomous video sources, the control unit uses the frame rate of the video source as a clock base and assigns a time base to the frame sequence. In the case of controllable video sources, the control unit provides the clock for the

Frame rate or for the transfer of the next image. The image identifier then consists of the image sequence identifier and a consecutive number as an identifier for the current image. In addition, the identifier of the storage medium on which the evaluated image sequence is recorded parallel to the evaluation is recorded in the control matrix.

In addition to the other process steps, the measuring method is characterized in that functional time segments are formed in the form of measuring and pause phases in accordance with the clinical question and the provocation method used. The program sequence consists of measuring phases and pause phases, which are freely programmable with regard to the number of phases z, number of frames per phase or, frame rate fb, image evaluation frequency fa. The default procedure is preferably the default Vo hase, provocation phase 1, reaction phase, provocation phase 2, reaction phase 2 and post-phase, whereby a pause phase can be provided between the phases, but which are preset for the example with 0 pictures. Pause phases mean a continuation of the time base in the measurement sequence without image evaluation, combined with automatic dark control of the lighting and weakening of the fixation lighting for the patient's recovery. These time ranges are preferably adopted by the mask and the filters for the standard evaluation. In the functional phase, several no longer take place in one

A sequence control for successively querying the various measurement windows and the variation of the measurement windows in the scan areas belonging to the various measurement windows can be evaluated in the image sequence clock. The innermost interrogation cycle preferably consists of the sequence of the various measurement windows, the outer cycle being determined by the stochastically defined change in position of the measurement window in the scan area.

According to the invention, an auxiliary program of the control unit SS calculates the definition of the measurement window and the examination program on the basis of the desired temporal and local resolution and the

Measurement times the expected limits for significantly detectable changes. For repeat measurements, the systematic errors and reproducibilities for an estimated representative of a patient group are determined from the database or the parameters of representative patient groups stored in a parameter set are used, the parameter sets of which are updated by each new examination and provide the database for these calculations . The examiner can make the appropriate adjustments Priorities in clinical questions make an optimal compromise between patient stress and the expected statement and adapt the metrological properties of the system to the patient and the question. In the exemplary embodiment, a combination of two is used according to the invention

Provoaktionssy steme used, which on the one hand cause opposite reactions (constriction-expansion) and thus allow a regulatory area to be recognized and on the other hand enable the effect of blood pressure on the metabolic regulation to be recognized and calculated. With that, the pulsations and blood pressure waves are from others

Aspects can also be assessed. New parameters, which relate pulsatory and vasomotor activities in the individual measuring times to the provoked changes in blood pressure changes due to physical exertion, suggest diagnostic significance and can be defined and presented as desired using the described method.

FIG. 5 shows an overview of the method steps summarized in groups for the cycle of an image.

The presetting enables the factory settings to be changed and, if desired, the free programming of the measuring, evaluation and presentation procedure, including the presetting of parameters for the control, the scope of the dialog operation for the setting of the measuring windows, auxiliary windows and the measuring field to adapt the measuring station to the individual requirements of the examiner and

Patient. Various presets can be saved and then updated via the menu. At this point, the measurement and pause phases of the method and the type of the Presentation of results on the monitor and in the measurement protocol as well as the recording of patient data.

The setting procedure enables the parameters left open by the presetting, the initialization of the

Device and program units. The updated default settings are offered and can be modified. A sequence of comparison images can be defined. It is selected from the database and kept available in the working memory. Optionally, parameters or the entire control matrix of the comparison image sequence can be used for presetting. In the case of repeat measurements, the setting of all previous examinations is offered as a default, which automatically implements exact comparison conditions, including the reproducibility of the measuring locations. The lack of comparability of the examination conditions, in particular of the measurement location, is a major deficiency of the known technical status, especially from the point of view of the high biological variability. After setting the examination device to the patient's eye, an object field section appears in the image field in accordance with the presetting of the fixation device and can be observed by means of a control monitor. The presetting of the measuring and

The auxiliary window and the measuring field are superimposed on the fundus image on the control monitor Ml. The fixation device for changing the imaged object field from the back of the eye, the position or geometry of the measuring window, the auxiliary window and the measuring field can be changed by mouse movement, as can the preset ametropia compensation.

At the start, an image sequence identifier is generated and the control matrix is saved with the first image. The sequence control calls first Control programs for controlling the device units via the interfaces, query the measurement data and store them in the control or primary data matrix in the correct image or time, generate and send control signals. With the start, the ambient lighting is reduced to a preset value, switched off by default and the measuring field lighting is increased to the preset value.

The sequential control system records image by image in the image manipulator, stores it with the identifier, displays it with the measurement and auxiliary windows on the control monitor and, in parallel, transfers the image windows digitally, evaluates them in the described process steps and the results in the primary data matrix saved. In each image, the window coordinates are changed in accordance with the sequence planning by controlling the image manipulator and, if necessary, the measuring field coordinates are also changed by controlling the imaging system.

In this exemplary embodiment, the quotient from the number of recognized vessels to the number of lines in the measurement window is preferably used as the quality parameter QUALI. This quality parameter is used to control the brightness of the measuring field to minimize the exposure to light. According to the invention, further parameters can be derived from the intermediate results of the algorithms for window evaluation, which, as quality parameters, detect the image contrast, the SNR, the current photometric resolution and others, which optimize the optical filter layers by tilting in the beam path, optimize the light load and optimize of CCD camera properties can be used. The adaptive control of the CCD camera according to the measurement optimization criteria according to the invention enables adaptation to the high biological variability in image quality. However, the use of quality parameters is not mandatory.

Not necessarily, but a significant extension of the meaningfulness of the invention is the formation of further vascular signals, such as the squares and 4.

Potencies of the vessel diameter, which can be set by default, as described earlier, stored in the primary data matrix and included in the parameter determination. The determination of additional plethysmographic vessel signals, the vessel diameter and its, can also be included in this group of methods

Determine changes plethysmographically and enable comparison to the diameter vessel signals.

With the next process group, the formation of parameters, the selected evaluation methods and associated masks and filter parameters are called up and set one after the other according to the default setting. Via the adjustable masks and filters, data from the primary data matrix, or the parameter matrices of the current image sequence and possibly also from the reference image sequence, are compiled, processed and processed with the current evaluation method for determining the parameter and then stored in the parameter matrices.

The process block on-line presentation accesses the primary data and parameter matrices, possibly also the control matrices via adjustable masks, in order to calculate the output data with the selected presentation methods and to transfer them to the control unit SS for output in the next cycle. After processing the intended number of images in the sequence program, the on-line measurement process is ended, the marices of the current image sequence are saved, documentation programs are called up via the menu if required, and the measured value logs and the result presentations created in the on-line process are output on paper.

After that, access to the off-line evaluation is made possible, the pre-set evaluation programs for parameter formation and corresponding presentation programs are processed automatically, or menu-driven individual formation of parameters and the creation and output of suitable result presentations. The integration of the database manager also allows the inclusion and comparison of the results of any other image sequences stored in the database.

A significant novelty of the invention compared to the technical state of the art is the possibility of continuously determining and analyzing the vessel diameter on-line at the same time as the location dependency along the vessel. In addition to this qualitative step, the invention also enables the measurement error and thus the detection limit for

Changes in vessel diameters to reduce almost a decimal potency and thus penetrate into the area of biologically-related changes in the vessel diameter and the influence of blood pressure.

In Figures 7, 8 and 9 three examples of measurement results are selected which show the performance of the invention. FIG. 6 shows a functional diagram with the comparative representation of vasomotion peak values and pulsation peak values. The representation for the spectral power of the pulsation frequency and vasomotion frequency would look similar. The values of the parameters are plotted in the direction of the y-axis with the course of the vessels as the abscissa, positive for the vasomotion and negative for the pulsation. The graphic is stored with the fundus image so that the parameters and their measuring locations are assigned to the background of the eye again. This picture shows the advantage of this presentation of results, which enables quick problem identification and evaluation.

Immovable vascular areas with very small or missing vasomotions and pulsations indicate skierotic vascular areas. Vascular areas with a lack of vasomotion but with pulsations mean that these areas still react flexibly to blood pressure, but do not show any activity of the vascular muscles. Vasomotion and pulsations can not only be detected, but also quantified locally.

The more vessel sections are included in the measurements, the clearer the fundus situation can be assessed. The possibility of the invention not only to measure simultaneously on several vessels in a measurement window, that is to say in parallel, but also to detect vessels of different quadrants in one session quasi-parallel with a plurality of measurement windows represents a further significant advantage.

FIG. 7 shows the changes in the mean vessel diameter D over the vascular section over time and measurement phases together with the mean upper arm blood pressure PP. The advantage of the continuous recording of the vessel diameter according to the invention under provocation, as well the connection to blood pressure and the combination according to the invention of the types of provocation used in the example is clear here. In the Voφhase the initial value of the vessel diameter, so to speak its working point under the current blood pressure conditions is measured. The physical stress leads to an increase in blood pressure and accordingly to a passive dilation of the vessels, which due to the stretching is answered with a constriction (autoregulation). The quotients that can be calculated as parameters, for example from changes or increases in blood pressure and vessel diameter, are a measure of the flexibility of the vessel wall (provocation phase P1) and of the contraction response in the second maximum (reaction phase 1). While in the provocation phase P2 an increase in blood pressure as in phase P1 is achieved by rebreathing and the beginning of the contracting autoregulation is just barely recognizable, in the second part of P2 the metabolic regulation begins in response to the rebreathing. The maximum makes the reserve for regulatory expansion clear and can also return to the size of the province, for example. to the changes or increases in the CO ₂ or O ₂ content of the rebreathing air, not shown in this diagram. In the diagram are the regulative area, the upper and lower regulative

Reserve, shown, which can also be calculated as parameters. The ability of the vessels to regulate can be assessed directly for the first time. The major advantage is the new possibility of evaluating the current vessel diameter. The anatomical spread of the retinal branch vessel diameters is 15 to 20% interindividually, which allows the detection of a constriction or widening only with gross changes and very uncertain. Through the measuring station according to the invention, a narrow or wide position can be based on the upper and lower regulatory reserves evaluate much more sensitive and safe. The absolute value of the vessel diameter has hardly any meaning. This eliminates the source of error of the individual imaging scale of the eye, provided that changes in the optical properties of the eye can be neglected between the examinations.

This means that the technical prerequisites for a functional diagnosis of the microcirculation and, among other things, for a screening method to assess vasocative drugs and to assess the degree of sclerosis as a risk factor. Since all the vessels detected by the measurement window can be measured and their characteristics can be displayed, the diagram of FIG. 8 is also possible as a comparative illustration of an ast artery and a branch vein, which enables further conclusions to be drawn.

The diagram of FIG. 7 is particularly suitable for on-line presentation as a display in a window of monitor M2. In this case it would also make sense to display the oxygen and CO ₂ content of the breathing air in parallel.

Figure 8 shows another example of the comparative presentation of results on the behavior of a branch vessel at two different times, e.g. before and after therapy. The actual path along the course of the vessel is shown as the abscissa and the spectral vasomation performance and the local change in the vessel section for the current image sequence (full line) and the reference image sequence whose vessel diameter was used as the reference value in the coordinate origin is shown as the ordinate. Compared to the

At the reference point in time, the vessel widened, particularly strongly in the first half of the section. It is precisely in this area that the vasomotion missing at the reference time is not yet normal, while the vasomotion is restored in the originally contracted vascular area.

In the exemplary embodiment explained above, various solutions of the arrangement and method according to the invention were combined with one another, which differ significantly in their effect on the measurement result from the technical state, since they involve a comprehensive analysis with hitherto unknown reproducibility and detection limit of changes which were not considered possible by experts allow the vessel diameter. However, not all of the listed

Procedures for the formation of parameters for every medical question are required. In simple cases, the determination of a parameter is sufficient. The application of the invention allows both only one and all parameters to be formed and only the local and / or the time profile of the vessel diameter to be recorded and evaluated. Already simple

Embodiments of the invention result in a surprising effect and a reproducibility or detection limit for changes in diameter which is sufficient for many clinical questions. For example, the fixation device according to the invention makes it possible to dispense with the automatic reproducibility of the measurement location if inaccuracies in the assignment of the vessel sections to one another are permitted. You can also do without the auxiliary window if you allow local inaccuracies in the measured value assignment, which, due to eye movements, lead to a more or less strong and exact moving averaging over the location dependency combined with a reduction in the local resolution. A simple embodiment consists, for example, of a retinal camera with a known one Illumination and imaging beam path that is not modified at all. The usual red free filter is used as a filter. Additional provocation and measuring systems as well as the parallel recorder recording of the TV picture are also dispensed with. Only a measurement window with a scan area is placed in the image, or a measurement window that covers the entire scan area. In this case, the parameters can be determined and presented as in the first exemplary embodiment, but only the temporal or local course or only the averaged pulsation period can be assessed visually. It is a prerequisite that the vessel diameter is determined with local resolution in the non-scanning measurement window and not as the mean value for the measurement window as in the scanning measurement window. With such an apparatus, surprising effects such as vasomotion and pulsation, therapeutically or functionally provoked changes can also be seen, but far from with the detection limit and resolution as in the exemplary embodiment presented.

It is also possible to record a flash image sequence defined over time instead of the camera and to evaluate it off-line or on-line in the manner described. The disadvantage then is the lack of temporal resolution. The sequence control must then design the image so that the influence of the pulsations or vasomotion z. B. is switched off by randomization. The off-line application according to the invention makes it possible to evaluate all of the vessel sections that can be measured in the image, in that the scanning movement covers the entire image field in sections in succession or, according to the invention, the scanning movement of the measuring window is controlled in such a way that the center of the vessel is always in the center of the measuring window and the scanning movement in both directions of the vessel course as long as the vessel is measurable. In this case a ring-shaped auxiliary window is sufficient, the diameter of which is larger than that of the papilla. This auxiliary window generates small measurement windows at the locations of recognizable vessels, the scanning movements of which adaptively follow the course of the vessel.

Another simple embodiment is the plethysmographic spectral analysis for conjunctival vessels, which is another simple embodiment. An illumination beam path with a red-blocked bandpass filter 540 nm with 100 nm bandwidth and an imaging beam path is used as the imaging system, e.g. can be a slit lamp, with a single-surface photoelectric sensor that is matched to the spectral transmission of the filter being located in the imaging beam path. An amplifier and a frequency analyzer, which outputs the power spectrum, is connected downstream of the sensor. With the imaging system, a larger vessel of microcirculation is transferred to the photoelectric

Measuring area of the sensor shown. This mapping must be done in such a way that the vessel diameter in the vessel section is completely covered by the measuring surface. The frequency spectrum provides the pulsation and vasomotion performance, whose values or their quotient are displayed as a parameter for clinical evaluation.

The exemplary embodiment can be extended to other optically accessible areas, for example by using and modifying endoscopes as an imaging system. The use of a fluorescence angiograph, see imaging systems, also makes sense. It is initially irrelevant to the invention whether conventional optical systems or laser scanners are used as imaging systems. The use of laser scanners has the disadvantage, however, that the reproducibility and locality that can be achieved Resolution or accuracy of the local measured value assignment is significantly reduced.

For the invention, it is also irrelevant whether the measuring surface covers the entire scan area and the evaluation of the measuring surface reflects the local course of the vessel diameter or, advantageously, with a low computing power, as described in the exemplary embodiment, consists of a narrow measuring window that has an average value for the Reproduces the vessel diameter in the measuring window and determines the local course one after the other by a scanning movement of the measuring window.

It is irrelevant to the invention on which computing hardware basis the implementation takes place. The computational hardware basis only determines the compromise between temporal, local resolution, number and area of the measuring window, and the performance of the online result presentation.

A special embodiment of the invention is the design of an annular measuring fei congruent to an annular measuring surface. The ring-shaped measuring surface can also be composed by a plurality of strip-shaped measuring surfaces which are combined to form a polygonal ring, preferably with ends which overlap one another. However, this embodiment of the invention requires a higher computing power for the online capability. Furthermore, it is irrelevant to the invention whether the back calculation on the object level is carried out with the correct imaging scale or is specified in relative units. The decisive factor is the precise local assignment of the measured values and the measuring locations to one another within the image or object level.

REFERENCE SIGN LIST

O object

BS imaging system

FI fixation device

BE image receiver BM image manipulator

EP units for the presentation of results, e.g. TV monitor

ES Controllable VCR

SS control unit

BV evaluation unit DE keyboard

MP manipulation unit

MS measuring unit

HS main beam path

US ambient lighting beam path UBS ambient lighting system

BO lighting optics

BLS lighting beam path

FS fixation beam path

FAS outer fixation beam path FTS inner fixation beam path

SE mirror unit

S1 ... S4 mirror

OL ophthalmoscope lens HOS optical system

MBS measuring field lighting system y fixation mark y ', y ^" images of the fixation mark FME fixation mark unit

FOS fixation optics system

AA optical unit

MSB measuring light beam path MBÖ aperture

MBÖ 'pupil of the aperture

FMB filter

MBL 1 lens system 1

MBL 2 lens system 2 Y "Image of a plane congruent to the fundus

MBF field diaphragm (picture is created at the back of the eye)

SMBF control unit for field diaphragm

SMBÖ control unit for aperture diaphragm (regulation of brightness)

LQMB light source

SVMB controllable power supply for the UBS light source

UBÖ aperture diaphragm UBÖ 'pupil of the aperture diaphragm

FUB filter

UBL 1 lens system 1

UBL 2 lens system 2 UBF field diaphragm (image is created on the back of the eye)

SUBF actuator for field diaphragm

SUBÖ actuator for aperture diaphragm

LQUB controllable power supply for the light source

LM light modulator

SLMUB control unit for light modulator

P, P ^' , P ^" pupil positions

G1, G2 end points of the scanning area or the measuring surface in the direction of the vessel

BZ reference time

BD reference date

IDU identification number of the examiner

RZ relative time

Claims

PATENT CLAIMS

1. Device for examining biological vessels, preferably retinal vessels, in which at least one vessel section is shown in an electronic image or in an electronic image sequence that is fed from a photoelectric receiver arrangement to an evaluation unit, the evaluation unit being an image manipulation unit (BM ) for partial digitization or masking of at least one measurement window in the image generated by the photoelectric receiver arrangement and for identifying the image and the position of the measurement window in the image, a control unit (SS) for generating the image identification drawing and the measurement window coordinates, which determine the position and geometry of the

Describe the measurement window in the image, contains image or signal processing computing and storage units (BV) and output units (EP) for displaying the image and / or displaying measured values and / or measurement results.

2. Device according to claim 1, characterized in that the geometry and / or position of the measuring window in the image and their orientation in the image can be controlled.

3. Device according to claim 1 or 2, characterized in that at least one measuring window is strip-shaped.

4. The device according to claim 3, characterized in that means for switching between the horizontal and vertical position are provided.

5. Device according to one of claims 1 to 4, characterized in that the component of the measuring surface transverse to the course of the vessel is 10 times the expected vessel diameter and that at least 6 pixels of a row or column on the component of the measuring window lying transverse to the course of the vessel the vessel at the same time.

6. The device according to at least one of the preceding claims, characterized in that at least one measuring window is designed as an annular strip or as an annular polygon made of rectangular, preferably overlapping at the corners, strips.

7. The device according to claim 5, characterized in that for use on the fundus of the eye, the inner diameter of the ring or polygon is at least as large as the diameter of the papilla.

8. The device according to at least one of the preceding claims, characterized in that means are provided with which for the component of the measuring window in the direction of the vessel course at least as many pixel layers can be set that the maximum and minimum changes in vessel diameter of the quasi-periodic local vessel diameter changes are detected.

9. The device according to at least one of the preceding claims, characterized in that means for manual or automatic

Definition of a scan area is provided within which the measurement window changes its position stochastically or systematically from picture to picture and that the scan area is preferably at least 1.5 mm in size.

10. The device according to at least one of the preceding claims, characterized in that means are provided which change the radius of the circular or polygonal measuring surface within a manually or automatically defined scanning area from image to image and that the scanning area is preferably at least 1.5 mm in size is.

11. The device according to at least one of the preceding claims, characterized in that the photoelectric receiver arrangement is an imaging system with at least one image receiver and an illuminating beam path is provided and that a partially transparent diaphragm for defining a measuring range is arranged in the plane of the illuminating beam path congruent to the object plane, which consists of a fully transparent measuring field area and a partially transparent surrounding area.

12. The device according to at least one of the preceding claims, characterized in that the intensity of the illuminating light and / or the position of the partially transparent diaphragm in the plane congruent to the object field can be controlled by means of measuring field coordinates.

13. The device according to at least one of the preceding claims, characterized in that the photoelectric receiver device is an imaging system with at least one receiver and has at least one illuminating beam path for ambient lighting and that at least one additional illuminating beam path is introduced into the main beam path on the lighting side, which has an additional measuring field on the lighting side generated in the object plane, which is superimposed on the skin duty or geometrically separates the object field on the lighting side into the measuring field and the environment formed by the main beam path.

14. The apparatus according to claim 13, characterized in that actuators are provided which control position and / or geometry and / or intensity and / or spectral properties by means of measuring field coordinates independently of the main lighting or ambient lighting and that

Measuring field coordinates generated by the control unit and passed on to the actuators.

15. The device according to at least one of the preceding claims, characterized in that means are provided with which the

Measurement window and the measurement surface are confocal and moved.

16. The device according to at least one of the preceding claims, characterized in that means are provided in the image manipulation unit, which in addition to the measurement window at least one auxiliary window in

Image with a fixed position to the image is generated, the movements or / and position of object edges are detected in the auxiliary window and stored as correction coordinates in the primary matrix and / or are used image-wise for the immediate correction of movements of the vessel center positions in the image field during an image sequence.

17. The apparatus according to claim 16, characterized in that the auxiliary window is identical to the measurement window in the first image at the start of the measurement.

18. The apparatus according to claim 16 or 17, characterized in that the auxiliary window is designed as a strip-shaped window and is perpendicular and centered to the measuring window at the start of the measurement.

19. The device according to at least one of the preceding claims, characterized in that means are provided for spectral tuning of the illuminating and / or imaging light, which have bandpass character with steep edges and properties with the smallest possible tolerance for center wavelength and bandwidth in a row to the following examples:

Center wavelength bandwidth

(Full width at half maximum)

540 nm 100 nm

533 nm 70 nm

563 nm 50 nm

574 nm 10 nm.

20. The device according to at least one of the preceding claims, characterized in that an internal and / or external fixation device with fixation actuators is provided for use on the eye, in defined fixation coordinates, which clearly the angle between the optical axis of the eye and the imaging system describe, make the fixation setting and that means are provided for controlling and / or determining these fixation coordinates and for transmitting the fixation coordinates between the control unit and fixation devices.

21. The device according to at least one of the preceding claims, characterized in that the fixation coordinates of the inner and outer fixation device for the overlapping fixation areas are identical and that means for controlling or / and determining them Fixation coordinates and for transferring the fixation coordinates between the control unit and fixation devices are provided.

22. The apparatus of claim 20 or 21, characterized in that refraction actuators are provided with which the fixation marks for the patient can be focused once before the start of the measurement sequence and that the set fixation refraction value for focusing is measured and transferred to the control unit by suitable refraction measuring means.

23. Device according to one of claims 20 to 22, characterized in that an aperture is arranged in the illuminating beam path or behind the outer fixation mark that it covers at least the foveola of the eye to be examined or in the case of external fixation of the neighboring eye.

24. The device according to at least one of the preceding claims, characterized in that means are provided which stochastically change the brightness or shape of the fixation marks.

25. The device according to at least one of the preceding claims, characterized in that means are provided with which an acoustic signal and / or a temporarily deviating modulated brightness control or shape control of the fixation mark takes place in the case of coarse or undeterminable relative positioning shifts.

26. The device according to at least one of the preceding claims, characterized in that means are provided with which the overall image with the measurement window for checking the measuring point is stored at the start of the measurement.

27. The device according to at least one of the preceding claims, characterized in that means are provided which

- Detect vessel edges in the digitized measuring windows, - The photometric for all recognizable vessel edges in the measuring windows

Determine edge focal points in an integrated manner,

- Make a vessel edge assignment by individualizing the determined values

Assign vessel sections clearly, - the inclination of the vessels to the measuring window from the displacement of the

Middle or

Calculate the edge positions of mutually associated vessel sections of the same image,

- determine the vessel diameter from the inclined-corrected distance of associated photometric edge sword points,

- Determine the center position of the vessel in the image for each vessel diameter and

- Save the determined vessel diameter and vessel center positions for each recognized vessel per image in a primary data set.

28. The apparatus according to claim 25, characterized in that means for vessel assignment are provided which clearly assign the currently recognized vessel to the recognized vessels of the previous images or define a new vessel and expand the primary data record by a new vessel.

29. The device according to at least one of the preceding claims, characterized in that means are provided for calculating and storing the average brightness in the existing ones Measuring windows or measuring window areas as vessel signals describing the vessel diameter in the primary data set.

30. The apparatus according to claim 28, characterized in that means are provided which determine the mean brightness in the center as vessel brightness, in the edge area as edge brightness and in the vascular environment as surrounding brightness and store it in the primary data set in the correct vessel.

31. The device according to at least one of the preceding claims, characterized in that additional measuring means (MS) are provided, whose measurement signals are stored in the primary data or control data record in the correct image or image sequence.

32. Apparatus according to claim 30, characterized in that the measuring means determine a quasi-continuous detection of blood pressure signals and / or / ntraocular pressure signals and / or EKG signals and / or pulse signals.

33. Apparatus according to claim 30 or 31, characterized in that the measuring means can be controlled by the control unit.

34. Device according to at least one of the preceding claims, characterized in that manipulation systems (MP) are provided which bring about a defined change in biological influencing variables on the microcirculation and / or the metabolism and in that the associated provocation signals are stored in the primary data record in an appropriately assigned manner.

35. Apparatus according to claim 33, characterized in that the biological influencing variables are the intraocular pressure and / or the breathing gas composition or / and the physical stress and / or the temperature and / or light stimuli.

36. Apparatus according to claim 34 or 35, characterized in that the manipulation systems can be controlled by the control unit.

37. Device according to at least one of the preceding claims, characterized in that

that an on-line storage unit ES is provided for image sequences,

that the image manipulator provides each image with an image identifier and measurement sequence identifier,

- That the image identifier and measurement sequence identifier are generated by the control signal unit and transferred to the image manipulator and that the image identifier of the respectively evaluated image is stored in each primary data record and the measurement sequence identifier is stored in the associated control data record.

38. Device according to at least one of the preceding claims, characterized in that units for spectral analysis of the vessel and measurement signals and for displaying and storing the results of the spectral analysis are provided.

39. Device according to at least one of the preceding claims, characterized in that

Means for optional local and temporal filtering of the vessel signals are provided and that filtered vessel signals are fed to the unit for spectral analysis.

40. A method for examining biological vessels, preferably retinal vessels, in which at least one vessel section is shown in an electronic image or in an electronic image sequence, which is supplied from a photoelectric receiver to an evaluation unit, characterized in that vessel signals are generated which describe the vessel diameter of at least one vessel section and dissolve it temporally and / or locally.

41. The method according to claim 40, characterized in that in the

Acquisition of an image with a photoelectric receiver arrangement by means of the automatic or manual setting of at least one measurement window and a measurement range and the multiple movement of the measurement window within the measurement range, measurement data are generated which represent at least one vessel diameter in a spatially and temporally resolved manner.

42. The method according to claim 40 or 41, characterized in that the time-varying measurement data of the measurement window are recorded, stored and processed.

43. The method according to at least one of the preceding claims, characterized in that

- Images of the image sequence are evaluated or created in a predetermined number and with a predetermined interval in accordance with a task-specific flow chart,

- That this time interval is used as the time base of the vessel signal and

- That the vessel signal values together with the vessel center position and / or measuring window and / or measuring field coordinates are related to one another in terms of location and time assigned for each evaluated image can be stored in a primary data set.

44. The method according to at least one of the preceding claims, characterized in that the primary data records of a measuring process are combined in a primary data matrix.

45. The method according to at least one of the preceding claims, characterized in that fixation and auxiliary window coordinates and / or scan areas and / or refraction value of the device for

Fixation mark focus are determined or formed, which are not changed during a measurement process or an image sequence and are assigned to an image sequence of the primary data matrix together with an identifier of the measurement process in a control data record.

46. The method according to at least one of the preceding claims, characterized in that in the auxiliary window and / or in the main window the spatial shift of at least one characteristic image pattern in each evaluated image to the first image of the measurement process or to the previous image is determined in the correct coordinate manner and as auxiliary window correction values stored in the primary data record in the correct time.

47. The method according to claim 46, characterized in that the characteristic image pattern is the vessel itself to be analyzed and the position of the vessel pattern is the position of the center of the vessel.

48. The method according to at least one of the preceding claims, characterized in that the corrected from the fixation and / or measurement window coordinates and / or the auxiliary window correction values The vessel center positions of the respective vessel diameter value are calculated with respect to a defined reference point in the image plane and stored in the primary data matrix at the correct time.

49. The method according to at least one of the preceding claims, characterized in that the location-dependent vessel signals before or / and after filtering are frequency-analyzed as a function of location and / or time, graphically representing the frequency spectrum and phase position and / or following local and / or temporal Frequency parameters are determined and saved in a complex parameter matrix.

50. The method according to claim 49, characterized in that as parameters one or more of the variables vasomotion frequency, hand width, power and phase position, pulsation frequency, hand width, power and phase position, as well as frequency, phase position, bandwidth and power further detectable Frequencies are used.

51. The method according to at least one of the preceding claims, characterized in that additional measurement signals which describe influencing variables on the vessel diameter are assigned to at least one value in the control data record of the image sequence or are assigned to the vessel signals in the primary data record in a temporally resolved manner.

52. The method according to claim 51, characterized in that blood pressure large or / and the intraocular pressure and / or pulse and / or heart phase are used as influencing variables.

53. The method according to at least one of the preceding claims, characterized in that additional manipulation signals that the Describe artificially generated variables on the vessel diameter, at least temporally resolved and assigned to the vessel signals in the primary data set.

54. The method according to at least one of the preceding claims, characterized in that further vessel signals are formed from the vessel signals in which the squares of the values and / or the 4th powers of the values are formed and stored in the primary data sets.

55. The method according to at least one of the preceding claims 39 to

44, characterized in that parameters are formed from the vessel, measurement and / or manipulation signals.

56. The method according to at least one of the preceding claims, characterized in that vessel, and / or measurement and / or manipulation signals and / or parameters superimposed or assigned to the vessel image or as a temporal and / or local two- or three-dimensional course as function-diagnostic images are presented and / or presented numerically or graphically as complex overall values that are independent of location and time.

57. The method according to at least one of the preceding claims, characterized in that after and / or before temporal and / or local filtering of the vessel signals from the corrected vessel central positions of the vessel signals, local areas and time areas are formed which comprise at least one value and that within the vessel signals the location areas and time areas determine location-dependent time parameters and are stored and displayed in a time parameter matrix for the defined time and location area and / or as a function of corrected vessel layer center superimposed on the original image as a function diagnostic image for the defined time range and location range.

58. The method according to claim 57, characterized in that the location-dependent time parameters maximum and minimum values over the time and / or the temporal mean values from the vessel signals, their temporal scattering and confidence intervals and / or the roots from the temporal mean value from the squares of the vessel diameter , the associated scatter and confidence intervals and / or the V power from the temporal

Average of the 4th power of the vessel diameters and their scatter and confidence intervals.

59. The method according to any one of claims 57 or 58, characterized in that heart rate ranges are specified and that for everyone

Local area can be formed and stored within the heart pulse areas by means of EKG-triggered signal averaging of the vascular signal or diameter, mean value, scatter and confidence interval.

60. The method according to claim 59, characterized in that pulse parameters such as the pulse phase position, the pulse maximum value and the pulse minimum value are determined and stored from the pulse profile.

61. The method according to at least one of claims 57 to 60, characterized in that the signal filter processing the vessel signals

Bandpass filters with subsequent moving averaging are the heart pulsation or / and vasomotion or / and 1st and / or 2nd order blood pressure waves and / or the respiratory rate select or smooth and / or smooth external signals and / or disturbances.

62. The method according to at least one of the preceding claims, characterized in that after and / or before predetermined local and / or temporal filtering of the vascular signals, time ranges and vascular ranges are formed which comprise at least one value and that the local vascular courses within the time ranges and vessel areas, time-dependent location parameters are determined and stored in a location parameter matrix for the defined location and time area and are output graphically as a function of time for the vessel area in question.

63. The method according to claim 62, characterized in that the time-dependent location parameters form the maximum and minimum values and / or the local mean value from the vascular signal, its scattering and confidence interval and in the location parameter matrix as a function of the

Time and / or that the roots from the local mean are from the squares of the vessel diameters, the associated scatter and confidence intervals and / or the Vi power from the local mean over the fourth power of the vessel diameters and their scatter and confidence intervals.

64. The method according to any one of claims 62 or 63, characterized in that heart rate ranges are specified and that for each time range by means of EKG-triggered signal averaging of the vascular signal or diameter, the mean value, scatter and confidence interval within the heart rate ranges are formed, stored and stored as mean values over the location being represented.

65. The method according to claim 64, characterized in that pulse parameters are determined and stored from the pulse profile and that the pulse parameters are the local average pulse phase position, the local average maximum pulse value and the local average minimum pulse value.

66. The method according to at least one of the preceding claims, characterized in that complex parameters are formed from the location parameter and / or time parameter matrix or primary data matrix, which are stored and output in a time-and location-independent complex parameter matrix, in the correct manner in terms of time, location and area.

67. The method according to claim 66, characterized in that maximum and minimum value, temporal and local mean and its dispersion from the location and / or time parameters and / or vessel signals, e.g. the vessel diameter and / or that the root is formed from the temporal and local mean and its scatter from the squares of the respective vessel signals and / or that the V * power from the temporal and local mean and its scatter from the 4th power of the Values of the vascular signals, e.g. the vessel diameter is formed.

68. The method according to at least one of the preceding claims, characterized in that quotients and / or differences and / or percentage differences are formed as derived parameters from the location, time and complex parameters with one another and with one another, each in the local or time - or complex parameter matrices are stored and displayed or output accordingly, such as location, time or complex parameters.

69. The method according to claim 68, characterized in that pulse peak values and vasomotion peak values are related as a derived parameter and / or that the frequency powers and / or the frequencies or phase positions of pulse and vasomotion are related as new parameters and / or the peak values of

Vessel diameter can be related to the local or temporal or complex mean.

70. The method according to at least one of the preceding claims, characterized in that dynamic parameters are determined by signal analysis from the time courses of the provoked or pathologically or therapeutically-induced signal changes and are stored and displayed in the complex parameter matrix or in the time parameter matrix as dynamic parameters in a vessel-correct and / or location-correct manner.

71. The method according to claim 70, characterized in that the

Dead time, the fall and rise time constants of the direct response and the reactive phase of the vessel sections to oxygen respiration and / or to isometric loading and / or to a change in intraocular pressure and / or to light stimulus are spatially resolved or determined in response to a vessel area.

72. The method according to at least one of the preceding claims, characterized in that different vessels and / or vessel regions of a vessel are analyzed simultaneously or in succession or within the same image sequence and the distances of the corrected vessel center positions are converted into comparable vessel length units and for comparison thereof Vascular signals or parameters can be suitably graphically compared in two or three dimensions.

73. The method according to at least one of the preceding claims, characterized in that parameters are formed which relate to local and / or temporal and / or complex changes in a vessel and / or vessel section against a reference vessel or a vessel section.

74. The method according to at least one of the preceding claims, characterized in that simultaneous measurements are carried out on at least two mutually related vessel sections or vessel areas and that the phase difference of mutually associated vessel sections of a vessel area and / or different vessel areas is determined and or additionally the flow paths between the vessel sections be determined and the pulse wave velocity is determined and output from the phase difference and flow paths.

75. The method according to at least one of the preceding claims, characterized in that the temporal and local relationships between the corrected and / or uncorrected vascular signals and the provocation signals and / or additional measurement signals and / or parameters are graphically represented in two and / or three dimensions.

76. The method according to at least one of the preceding claims, characterized in that the parameters for each new evaluated image are redetermined and output in one of the graphical or textual representations.

77. The method according to at least one of the preceding claims, characterized in that a control parameter positioning uncertainty with each image iteratively as the scatter of the auxiliary window correction values in is calculated in both directions and / or continuously displayed and the end value of the measurement sequence is stored in the control parameter set with the measurement value sequence.

78. The method according to claim 76, characterized in that at a predetermined value by the parameter positioning uncertainty by the sequence control an acoustic signal and / or a conspicuous visual signal is introduced into the brightness or shape of the fixation mark by the sequence control.

79. The method according to claim 77, characterized in that the acoustic or visual signal becomes stronger with increasing positioning uncertainty.

80. The method according to at least one of the preceding claims, characterized in that the image quality quantities are stored in the primary data set in a time-assigned manner for each evaluated image.

81. The method according to claim 79, characterized in that the image quality parameters are used for the deletion of vascular signal values if a predetermined value is undershot or exceeded.

82. The method according to any one of claims 79 or 80, characterized in that the image quality parameters are used to provide each measured value with a weighting factor which is very good

Image quality has a certain value and, in the case of very poor quality, has the value zero and has a graded value for intermediate values of the image quality parameter and that these weighting factors are more reliable when determining mean values for greater weighting Measured values and for weakening or eliminating unsafe measured values.

83. The method according to at least one of the preceding claims, characterized in that the first image of a measurement sequence is stored completely assigned to the control set of the measurement sequence and the measurement and auxiliary window and / or the scan areas are identified in the image with the associated name of the measurement sequence and graphically as Measurement site image is displayed or output.

84. The method according to at least one of the preceding claims, characterized in that in the case of repeat measurements, measurement and / or auxiliary window coordinates and shape and / or fixation coordinates and / or measurement field coordinates and / or scan areas are automatically preset by the sequence control or are displayed for manual adjustment and that the measurement site image of the previous measurement process is presented.

85. The method according to at least one of the preceding claims, characterized in that the measurement signals or parameters are represented graphically in their temporal or local course or on-line with your determination.

86. The method according to claim 84, characterized in that the mean value and a confidence interval of the mean value are determined iteratively and are displayed as the current value with each evaluated image or are graphically represented with the measurement signal.

87. The method according to at least one of the preceding claims, characterized in that the measurement window and / or measurement field is moved stochastically or in an image pixel-by-pixel or segment-wise in the direction of the vessel course between different images or within an image within the predetermined scan area.

88. The method according to at least one of the preceding claims, characterized in that different clinical standard questions are assigned to different sequence controls for the measuring process, that the creation of the image sequence or evaluation of an existing one

Image sequence for a measuring process takes place in the number of pictures and / or in the temporal image spacing and / or is automatically controlled with a predetermined control data record, that these data are stored as control parameters in a control data record and that the measurement process takes place when a predetermined value for the confidence interval is undershot is canceled.

89. The method according to claim 87, characterized in that the reproducibility desired by the examiner is queried in interactive mode and the required number of measured values and / or examination time is calculated from predetermined scatter values.

90. The method according to claim 87, characterized in that an image sequence of at least 10 images / s over at least 10 s or at least 1 image / s over at least 120 s or at least 0.2 images / s over at least

600 s is recorded and / or evaluated.

91. The method according to claim 87, characterized in that an image sequence of at least 10 images is recorded stochastically over at least 5 minutes and / or evaluated.

92. The method according to at least one of the preceding claims, characterized in that the sequence control controls the illumination of the measuring field and only switches to full intensities during the measurement and otherwise uses reduced values.

93. The method according to at least one of the preceding claims, characterized in that the illumination intensity in the measuring field is regulated by the sequence control during the measurements and predetermined values for the image quality parameters are used as control variables, only the minimum light intensity being set for predetermined image quality parameters.