DE2409614A1 - METHOD OF EXAMINING FIELD OF VIEW - Google Patents

Description

UEXKÜLL & STOLBERG PATENTANWÄLTE

2 HAMBURG 52 O / flQfsi /

BESELERSTRASSE 4 C. H U Ό QI **

OR. J.-D. FRHR. by UEXKÜLL

DR. ULRICH GRAF STOLBERG i> CXPL.-INQ- JÜRGEN SUCHANTKE

Oculometrics, Inc. (US $ 335 72 prio 02/26/1973

1950 One Main Place ⁵ ° ⁵³ " ^lll6 9)

Dallas, Texas / V.St.A. . Hamburg, February 21, 1974

Procedure for testing the visual field

The invention relates to the examination of the visual field of living beings, in particular human patients, and in particular on methods that can be carried out automatically by means of devices as well as devices for testing the visual field of humans using the principles of campimetry. and perimetry.

The visual field of a living being or human can be called the- ' that group of solid angles are considered in which the living being or the human being a given set of graded Observing stimuli while gazing at a point in space. If, in more general terms, this one Fixing point in space (or the direction of view) "changes, the field of view can be that group of solid angles be viewed in which a living being. a given sentence

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perceives of graded stimuli in the moment in which his gaze is directed to a fixed point. In this way, the field of view remains essentially constant in relation to a fixation point, regardless of the direction in which the living being is looking, if all other conditions remain the same and external obstacles such as the nose or eyebrows are neglected. Each solid angle or conical space section of this group is a function of the stimulus value, which is determined by the point size, the color tone and the brightness of the light point as well as by the condition of the organ of vision of the living being and its psychological condition. In a normal human, a maximum stimulus can be seen using both eyes over a lateral extent of approximately 216 °, or using a single eye over an extent of 170 °. The methods according to the invention relate to the measurement of the field of view of an individual eye.

Visual fields are important in the discovery and diagnosis of ailments that affect the brain and the organs of vision. For this reason, fields of view are important to ophthalmologists. Neurosurgeons and other specialists who treat these diseases. Visual fields are also of interest and useful for the general practitioner in the treatment of diseases such as diabetes. So all seven major causes of organic blindness in the United States (glaucoma, cataract, diabetes, other vascular diseases, uveitis, retinal

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detachment and destruction of visual spots in old age) characteristic disturbance patterns in the visual field. Field of view measurements taken in are objectively very accurately reproducible from time to time are for the indication of the progress of the above These diseases are very valuable and can also be used to determine the location of other health disorders, for example of pituitary tumors, may be beneficial. '

Heretofore, fields of view have been indicated by the use of isopters or lines of constant visual sensitivity, which drawn based on a test carried out by hand. ■ The tests carried out by hand that were previously used were usually kinetic or static. With both procedures it was necessary that the living being constantly on one Fixing point, which was normally in the center of the test field, looked. In the kinetic process, points or stimuli become known size and brightness from beyond the limit of the patient's perception of perception inward, until the The patient indicates to the examiner in any way that he is seeing these points or stimuli. Although this procedure is relatively quick is., it contains a source of inaccuracy, since there is a reaction time between the sight of the stimulus by the patient and its signaling results. .

The static procedures for examining the field of vision by hand

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use at fixed points, based on the fixing point of the Stationary stimuli in the visual field. Ah such a point is initially using an imperceptible Stimulus value increases the size and / or brightness of the stimulus gradually with pauses until the patient perceives it of the last brightest stimulus. This results in a threshold value at the selected test point, and that The method is extended to a number of other selected locations in the field of view, the stimulus being determined again that is just perceptible. This method generally gives more accurate results than the kinetic ones Procedure, however, this procedure takes a relatively long time to perform a full test. ■ In addition, the repeated performance causes a static Stimulates in the same place without sufficient pause or, what is even worse, the gradual lightening a permanent stimulus a local "bleaching" of the retinal pigment and / or neutral adaptation in the retinal Area to which the test spot is directed. This process, the so-called local adaptation, can thereby be avoided tests on the same retinal site are delayed until the eye is different from the previous test has recovered. By successively presenting stimuli at different fixed points in the visual field, this becomes Source of error switched off.

Because of the relatively long duration of the visual field test the patient can lose interest or his

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Look away from the pixel point. In previous test methods, this resulted in a reorientation of the visual field and led to incorrect results because they were based on the assumption that for any given stimulus a single Point was adhered to as the fixing point. The test results are usually discarded when the examiner is aware that the Fixing point is not retained. With the method according to the invention, however, using new test methods and apparatus, the direction of the eye is recorded and provides stimulus values that refer to the same relative position are reoriented in the field of view even when the direction of gaze changes. In the new test system of the invention During the procedure, the test person is shown whether a given stimulus was perceived correctly or incorrectly at the same time, the formation of stimuli dynamically for the patient depending on his reaction to previous stimuli will be changed.

With the method according to the invention, the seemingly arbitrary or non-predictable presentation of the Unintentional test stimuli at various points in the visual field Influences by the examiner avoided. This contributes significantly to the objectivity and reproducibility of the test process at. The non-predictable presentation of the stimuli in proportion random spots in the field of vision reduce the patient's cramping and keep his interest awake. Time consuming rest as a countermeasure to local

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Adaptation of the retina necessary are also avoided.

It is therefore the object of the invention to develop a method for examining the visual field of a patient, which by Use of automatic data processing in combination with devices for generating stimuli and devices that the Record the patient's gaze, is marked.

Another object of the invention is to provide an automatic To develop methods and apparatus for determining the field of vision of a patient that are faster and more objective than before are known methods, and which are not influenced by a change in the direction of the patient's gaze.

Another object of the invention is to provide a method and apparatus for determining the field of view of a patient to develop in which the patient can change the direction of gaze during the experiment and change the field of view in a way is recorded, which is usable for the medical professionals.

These objects are achieved by the method and apparatus according to the invention for determining and recording facial

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field of a patient by recording and balancing the Movement of the eye resolved. The method according to the invention »that preferably using a programmable automatic data processing system, which in connection used with the external testing equipment provides accurate and reproducible results.

The location, size, color and intensity of the test stimuli generated by suitable external devices are formed at predetermined locations in the field of view, are in one embodiment by means of a Computer program controlled. This program determines the threshold value the stimulus, which the patient can detect at a given point in his field of vision, by means of stimuli calculated intensity and more constant in a pseudo-arbitrary and non-predictable manner with respect to a background field Color and intensity. The movement of the eye is recorded and the relative position of the test points in the background field is recorded dynamically changed taking into account the coordinate translation of the fixation point as a result of the eye movement. Movements of the head, excessive movement of the eye or blinking are noted so that the attempt can be interrupted immediately.

The patient reacts to the stimuli formed in the test field Display of the relative position in his field of vision at which a stimulus was perceived. The manually operated response device, which can be referred to as a baton and which has two degrees of freedom, is used to display the angular range of the field of view in which the patient observed the stimulus.

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The system uses the living being's response to a given stimulus to control the size and intensity of subsequent ones Stimuli that are formed at the same geometric point in the field of vision. So becomes the threshold of the living being at a given geometrical point in the field of vision in an effective manner and with a willingness that at previous and manual tests are not possible.

In this way, examinations of the visual field can be carried out at random a suitable number of locations within the field of view of a living being in order to make an accurate determination the shape of the field of view even if the pixel point of the living being changes. Are all like that Test points in the field of view have been examined, the device records the output data in a suitable form or shows them so that they can be evaluated by the doctor. Such output data can, for example, in a card of the field of view with isopters or with lines of constant threshold values.

In another embodiment of the invention, the test stimuli in the test field are generally outside the field of view of the patient and then controlled by a data processing system to the fixation point or another point in the test field too moved. The patient's eye movement is recorded, and the relative position of the stimulus on the background area

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is dynamically changed to reflect the movement of the eyes The patient's translation of the fixation point must be taken into account. Again, the baton is used to measure the angular range of the field of view in which the stimulus is observed, as well as the point in time at which the stimulus was observed moved into the patient's field of vision. From this display, the system determines the point in the test field at which the stimulus was observed first. After a sufficient number of such locations has been determined, these locations can be used to construct the isopters that together determine the patient's field of vision.

The invention is explained in more detail below with reference to the figures.

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Fig. 1 shows a block diagram of a preferred invention Contraption.

Fig. 2 shows in perspective the general arrangement of some elements of the device in relation to the being to be tested.

Fig. 3 shows the flow diagram of an experimental program of a preferred one Execution of the method according to the invention.

4 shows the preferred format of the test station data in a diagram.

Fig. 5 is a flow chart of a program for starting a visual field examination.

Fig. 6 shows a flow diagram of the relationship between functions of the computer and the internal devices during a series of experiments .

Fig. 7 shows a flow chart of a subroutine for change the test point data, based on the reaction of the test entity versus the stimulus.

8 through 8a is a flow chart of a subroutine for determination of blind spots.

9 shows a diagram of a preferred procedure for determining blind spots.

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10 shows a flow chart of a program for output data. Fig. 11 shows a way of displaying the output data.

Fig. 12 shows another way of displaying the output data.

13a shows a simplified coordinate system which is related to a single fixing point, centered in the test field.

Fig.13b shows the shift in the coordinate system when the Fixing point, based on the test field, shifts.

Fig.I ¹ I shows in a diagram the reflection of a light beam that hits the eyeball.

Fig. 15 shows schematically an oculometer.

Fig.lö shows in a diagram the use of electrooculography for recording the viewing direction.

Fig. 17 shows how the corneal-retinal potential is expressed as Function of the angle of movement of the eye changes.

Fig. 18 shows in a diagram the use of four sensors for information about horizontal and vertical angles of movement.

Fig. 19 shows the flow diagram of a subroutine for transmission the screen coordinates of the test centers to be offered in the test field,

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Fig. 20 shows the block diagram of a device ^ in the analog techniques are used to transmit the screen coordinates.

21 shows a block diagram of another exemplary embodiment of a device according to the invention.

Fig. 22 shows schematically a preferred method for kinetic Examination of a visual field.

23A shows an output display of various isopters and an arrangement of test centers for an isopter test.

Fig. 23B shows schematically a preferred method for kinetic Examination of a blind spot.

Fig. 24 shows in a diagram a ray which a chord in perpendicular to a Cartesian coordinate system.

FIGS. 25 A to 25 C show, in this order, the flow chart of a test program according to another exemplary embodiment of FIG Invention.

Fig. 26 shows the flow chart of a subroutine for performing a quadrant check.

Fig. 27 shows the flow chart of a subroutine for execution

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an examination of the blind spot.

28 shows the flow diagram of a subroutine for carrying out an isopter test.

29 shows another exemplary embodiment of a device according to the invention in a block diagram.

Fig. 30 shows in detail the structure of the servo and control units from Fig. 29.

FIG. 31 shows one which can be inserted into the device from FIG Device for changing the speed of the test points.

32 shows a perspective illustration of the display input, direction from Fig. 29.

The field of perception of the human eye is that part the space in which stimuli are visible during a momentary fixation of the gaze in a certain direction. In the Representation according to FIG. 2, the gaze of the patient 21 is directed along a visual axis 22 to a fixing point 23 which is is located in the middle of a two-dimensional test field. According to an embodiment of the invention, the test field can .Screen 24 of a cathode ray tube 25. It "is however clear that the test field does not necessarily have to be level and that the principles described below do not only apply to two-dimensional ones Test fields, but also to other test fields,

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approximately hemispherical are applicable, as later in Relation to another embodiment of the invention will be described.

The line of sight 22 is the line that forms the pupil of the eye

and connects the pixel point 23. A mask 27 with an opening 28 preferably includes a headrest (not shown) for positioning the patient's head at the desired distance from the patient Area of the screen 2 * 1 and with respect to the opening 28. Lies the visual axis as indicated, the surface of the cathode ray tube 25 covers part of the field of vision of the patient 21, whereby, as shown, a horizontal angle of about 60 ° is covered. The mask 27 and the opening 28 cause only one eye of the patient the front surface of the. cathode ray tube 25 can look at. ".

In Fig. 2, a coordinate system with an x- and y-axis is drawn, the zero point at the lower left corner of the Screen and that can be used to determine the positions in the field of vision of the patient 21 by each. Point on the screen surface 24 of the cathode ray tube 25 two Assigns coordinate sizes χ and y. Thus, the places in the patient's field of vision can be automatically Describe data processing equipment in a suitable manner. This automatic data processing system is with the test facility and programmed to perform the examination of the patient's visual field as described later will.

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The method according to the invention for determining the field of view takes into account the possibility that the fixation point of the test object (23 in FIG. 2) can change during the test. This will change the field of view of the test subject, based on the screen surface of the cathode ray tube 2 ¹ I. However, the attempt need not be interrupted because of this. When trying to determine the field of view by means of coordinate transfers of the viewing directions of the test subject, the change in the point of focus can be taken into account by any type of fixation recording. Such a device, which will be discussed in more detail later, is shown schematically in FIG. 1 as an oculometer 34. Of course, other "fixation point recording devices such as an electrooculographic monitor, the skin electrodes (not shown) attached to the mask 27, can be used as will be shown later. Using the oculometer device (34 of FIG. 2) half-silvered mirrors (or beam splitters) 32 (two of which are shown, one for simplicity between the mask 27 and the screen 24 and one between the patient's eye and the opening 28) and 33. In the practical experiment, the mirror 32 is used between the Subject eye and eyepiece mounted to cover the full field of view without being too large and to prevent interference between the optics of the oculometer and corrective lenses in the ocular sur checking the eye movement and delivering values to correct the test results in order to compensate f for the

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Get eye movement. Though the beam splitter If only part of the light stimulus on the screen is transmitted to the eye, its effectiveness is determined in the attempt to determine it of the field of view is not significantly influenced, since the percentage of the reflected light is constant and compensation is possible is.

To the right of the computer-controlled cathode ray tube 25 and oculometer 34 (Fig. 2) there is a control panel 29, which is shown schematically. The control panel 29 has a plurality of toggle switches (30 o.a.) that are controlled by the examiner can be used to display the conditions during testing or enter data into the automatic data processing system. A manually operated response device is located between the mask 27 and the screen surface 24 of the cathode ray tube 25 within comfortable reach of the patient 21. During the course of the visual field test, the patient is connected to this manually operated response device with the automatic data processing system connected. Details of the operation of the response device 31 will be given later described.

It is important to note that communication between experimental

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essence and data processing device to others Way can be done. For example, an electroencephalograph (EEG) can be used to show the evoked cortical potentials in the occipital cortex, which as a result a visual stimulus of sufficient strength arise and indicate to the data processing devices that a stimulus has been received became. An electroretinograph that displays electrical signals generated by the light-excited retina, or a pupilometer, which is a decrease in the size of the pupil determined when the retina is excited by light, can perform the same puncture. It should be noted that a Oculometers can fulfill pupilometric functions, but electroretxnographs or pupilometers do not have all neural connections to the brain, for example, they determine that the eye has been stimulated, but not if the one detected by the eye Stimulus was transmitted to the conscious area of the brain. Identifying a visual response when looking of the test being directed in the direction of the point of light is also possible. It should be noted that in the present description the terms "perception" and "reaction" Represent synonyms and refer to both cortical and subcortical reactions of the experimental subject.

Although not shown in FIG. 2, it will be understood by those skilled in the art be that any corrective refractive lenses to correct refractive defects of the test object 21 between Eye and screen surface of the cathode ray tube 25 'are to be attached as in the eyepiece 28.

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For one type of examination, up to which one is measured Scope. The normal eye can indicate the presence of objects that are out of sight. This method is called perimetry. Large and relatively bright test items are generally in place seen whose coordinates are very eccentric with respect to the fixation point. On the other hand, small objects or such with low contrast to the background usually cannot be seen before the angular spacing or the eccentricity from the line of sight is relatively small. When checking with perimetry. the distance of the test stimuli from Eye kept constant, i.e. the test stimuli are formed on an arc or spherical surface, with the eye in the center of the sphere lies. Campimetry is a method similar to perimetry for measuring the field of vision in which the test stimuli are in a distance from the patient's eye that is proportional to the minimum eye-screen distance given by the secant of the angle of eccentricity. This means that a test device as shown in Fig. 2 is a campimetry device is because the surface on which the test stimuli appear is a flat surface and therefore the objects are close to the Edges of the display screen 24 a little further away Eye of the patient 21 are removed than the stimuli formed in the central area of the screen. This of course makes the The size of the stimuli on the patient being examined is somewhat impaired. Both perimetry and campimetry are acceptable Test methods and can be used equally well for testing the field of view of a living being. However, it is difficult to get the results of the various test methods to compare qualitatively with each other.

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In the embodiment of the invention to be described now, the principles of static perimetry or Karapimetry applied, whereby stationary stimuli are present at different selected points in the visual field of the living being. The stimulus value or the size and the brightness of these stimuli can be changed, and the consequence in which they affect the living being are offered, is - as already described above, preferably changed in an unforeseeable manner.

In addition, when changing the direction of view of the test subject, the campimeter (or flat surface) used in this exemplary embodiment must be corrected with regard to the size effects which the coordinate transfer of the pixel point exerts on the stimuli generated in the field of view of the test subject. A recording device for the pixel point or points can be designed in such a way that, as described later, these relationships are taken into account. If the principles of the invention are applied to non-planar test fields ₉ , the required correction differs from that described below. For example, hemispheres do not require correction.

The threshold value of a point in the visual field of a living being can be defined as the level of stimulation that is just required for a perceptible response in the test area to reach. To use a test stimulus as the threshold value of a To establish static perception, the response to a given stimulus value must be a non-response to a second Be coupled to a stimulus, the value of which is

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rather than the intensity of the perceived stimulus. One An expedient way of recording the field of view consists in recording the numerical threshold values at the selected points in the field of vision.

According to the invention there is an automatic data processing system or a digital computer to form a two-way feedback loop between the living being to be examined, ie the patient and the test system or the test program. In this two-way feedback device, the testing process updated based on the patient's response.

By using an acoustic response indicator, the patient receives an indication of correct or incorrect response to an existing stimulus point. A pleasant sound is produced if the response is correct, while if it is not correctly addressed Responding to a display by means of an unpleasant sound. This increases the motivation of the patient being examined improved and the accuracy of the response increased. Motivation is a major psychological factor in the visual field test to achieve precise results,

In perimetry or campimetry, the patient's degree of fixation or ability to focus on their gaze is fixed Keeping the job directed has been very important in conducting a usable exam. The present invention can be applied to do a visual field test that does not depend on perfect fixation. This will make the psychological demands on the experimental system are reduced, so that improved experimental results are obtained. Eye movements of the experimental system can be recorded and

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Search execution through the use of suitable devices must be taken into account.

In Figs. 13a and 13b, the influence of the displacement of a fixation point of a test object in a simplified 4x4

Coordinate system described, the coordinates in quotation marks Mean test field coordinates and the coordinates of the test screen are not given in quotation marks are. In Fig. 13a it is assumed that the fixation point exactly with the center of the test screen, which is used to test the field of view is used (e.g., like the CAT screen 24 of Figure 2) is collapsed. A checkpoint on a test field that re centered on the direction of view has coordinates that correspond to the coordinates on the test screen. That means, that when looking at the center of the screen, the coordinates of a test point in the test field exactly through the corresponding XY coordinates of the corresponding test screen defined are as previously described and listed in Figure 13a. If the gaze is now looking for another fixation point (like "in 13b), the coordinates of the test screen are no longer correct with those of the test field, which shifts its center point so that it remains in the viewing direction. So get a Point that had coordinates (4,1) in the test field and (4,1) on the screen, for example, now has coordinates (2,3) the screen receives while its coordinates in test field

(4,1) remain 1. It can be seen that the X coordinate has now increased by 2 and the Y-coordinate are increased by 2. In the same way, the coordinates (3,2) in the test field to (1,4) on the screen, the coordinates (4,2) become (2,4) etc. The exact position of the points in the test field on the screen will therefore, if the line of sight is no longer on the

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The center of the screen is directed, mainly determined by the transfer of the coordinates of the test point (into the coordinate system of the screen) by an amount equal to the deviation from the view. Of course, excessive change in the line of sight can lead to some test points in the 7th Test field are outside the shield area. If more than the desired percentage of checkpoints are outside of the screen area, it is possible in some way to tell the experimental subject to look within acceptable limits on the screen and / or to stop the experiment until it is done. If the test point to be examined is moved from the screen at the moment in which the viewing direction changes, the individual test is of course to be regarded as invalid and must be repeated.

There are alternatives to recording the screen coordinates of the viewing direction. One of them, the oculometric system, was briefly discussed in relation to FIG. A system of this type will now be described in more detail with reference to FIGS. Ik and 15. 14 shows the geometry when tracking an eye movement (only taking into account the one-dimensional transfer of the fixation point to the screen of an image decomposition tube, for example in the direction of the Y coordinates). The basic principle of measurement with an oculometer is that the direction of an eye is defined by the cable of the corneal reflection of a light source in relation to the center of the pupil. Assuming that the eye is illuminated along one axis, as is done by a point source of light at infinite distance and by an optical system with a collection device that optically coincides with the light source,

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forms the reflection of some incident more targeted Rays at the interface between cornea and air (23D, a virtual image (230) of the point light source, the lies roughly in the plane of the pupil. For each eye the displacement Y of this virtual image is related to the center of the image of the pupil, 232 as measured by the imaging tube, proportional to the coordinate Y the direction of view on the screen. The displacement of this virtual image of the point source from the center of the pupil image is expressed by

Y = K. sin θ

where K is the distance between the plane of the iris and the center of the bulge of the cornea and θ is the angle between optical axis of the eye and the direction of the targeted rays. The dimension K can be determined by calibration of the oculometer at the beginning of an experiment with an experimental entity in which the experimental entity has at least its gaze fixed one, preferably several point of known coordinates, one of these points being the center of the screen is. After this calibration, the angle θ can be measured. If the angle θ is known, the pixel point

Ii
coordinate Y from the equation

Y ¹¹ = D Tan θ can be determined. For small angles the following applies approximately :

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Sin θ = Tan θ = θ

Accordingly, after the calibration constant K is known, the coordinate can be selected for the transmission of the coordinates.

11
nate Y of the changed fixation point after (for small angles Θ)

Y ¹¹ = 0Θ

be calculated. This approximation is sufficient for angles smaller than 10 °. It is recommended to use the necessary more precise trigometric puncture for larger angles.
Same analysis is applicable if the shift is along the X-axis and if θ is the angle,
which is the angular displacement of the viewing direction along the X-axis and θ y that along the Y-axis:

Y ¹¹ = D θ _γ
Y ¹¹ = De _x

An oculometer for recording eye movement according to the principle just described is available from Honeywell Corp. of
Boston, Mass., Offered. Such an oculometer is shown schematically in FIG. In the coulometer of the figure, the eye is illuminated by a light source via a beam splitter 2 * f2 (as in FIG. 2). This light source can be an infrared source, for example, in order not to distract the test subject of a visual field test. The refractive one

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The medium of the eye (especially the cornea and the lens) guide the light onto the retina. Thrown back from the retina Rays illuminate the pupil. An image of the illuminated pupil is taken through a lens 243 on the photocathode 244 of a vidicon tube or similar (not shown) precisely adjusted. An electronic system including a device for sensing and tracking the light source image in the pupil (not shown, but part of a commercially available oculometer) is used to measure the angle θ and θ.,. which have been described above, and for the delivery of signals, as required in digital or analog form, which correspond to the values. These values can then be used as follows to determine the consequences of the Correct or eliminate changes in the direction of view of the test subject to the visual field test.

The viewing direction can be an alternative to this, albeit a little less precisely but with sufficient precision for the visual field examination, by applying the principles of electrooculography to be determined. This technique relies on the fact that a D.C. Potential difference between Corneal surface (on the surface of the eye) and the the posterior vascular layer of the eyeball. This potential is called the corneo-retinal standing potential and is shown very schematically in FIG. 16, and shows the corneal part of the eyeball 251 with. a positive potential related to the rear

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located or retinal part 252. This standing potential changes slightly from person to person, ranging from around 1 millivolt for some. Persons and · 0.30 Millivolts for others. A value from 0.50 to 0.70 f4illivolt ' can be seen as an indication of the corneo-retinal standing potential.

The electrodes 253 and 25 ¹ I (such as mounted in Fig. 16) are used for recording of eye movement in the horizontal plane, by measuring the changes in the electric field in the vicinity of the eye, caused by the corneo-retinal state potential, . If, for example, as indicated schematically in FIG. 16, the eyeballs move in a horizontal plane in the sense of direction indicated by the arrows and 256, the positive corneal surfaces of the eyes would be closer to the electrodes 25 ^ and the negative rear regions closer to the Bring electrode 253. This would increase the potential difference between the two electrodes from its initial value before the eye movement. The algebraic sign of the movement is therefore indicated by the direction of the change in the potential difference, which is measured at the electrodes. A characteristic recording of the tension generated in this way by eye movement as a function of the angle of movement of the eyeball is shown in FIG. In FIG. 17, the voltage between electrodes 253 and

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plotted as a function of the angle of angular movement Gt. Strictly speaking, in some patients this tension is a puncture of the sinus of the angle o £ and for other patients a linear puncture of the angle. However, approximation is practical for small angles (less than 30 °) useful that the tension created by the corneo-retinal potential due to eye movement is linear Function of the eye rotation angle is generated; this approximation is used to correct the change in viewing direction in the invention Test system acceptable.

The DC amplifier 257 of FIG. 16 is used to amplify this relatively small voltage, and the resulting output data can be calibrated for a particular experimental subject at the beginning of the visual field test to obtain the previously discussed Θ: values which are used to calculate the relative coordinates of the fixation point on the test screen are required. Similarly, a vertically mounted set of electrodes 260 and 2β1 in Fig. 18 can be used in conjunction with horizontally mounted electrodes 262 and 263 to measure vertical eye excitation ₉ and the amplified voltage thus obtained can be used to generate the Q data, as discussed previously. Because of individual changes in the corneo-retinal standing potential, calibration of such an electrooculographic recording device for eye movements would be necessary at the beginning of a visual field test. Of course, this is easily possible - as discussed in connection with the oculometer - by plotting fixation points of known distances or angles on the

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Test screen used. In practice only three electrodes are used and it is known in the prior art that by using the potentials of three electrodes ^ the Output values of θ and θ can be obtained.

χ y

The electrodes for determining the eye position after Methods according to the invention can be applied to a cover screen 27 in FIG. 2, or can also be applied to the Skin of the experimental body attached by plaster and connected to the system by flexible lines. In In any case, it is desirable to make good contact between the electrode and the skin, as the one to be measured Voltage is relatively small. Using this technique, it is possible to adjust the position of the eye to one degree determine. This is sufficient to sufficiently record the fixation point during the visual field test.

In Fig. 1, the overall device according to the invention is shown in a block diagram. The essence of the device is an automatic data processing system or a useful general-purpose digital computer ¹ H. The computer 4l can be selected from the group of usable general-purpose machines so, for example from the end surface 113 o IBM-series; or a hardwired computer can be used for special purposes. If necessary, the device according to the invention can also be used in subscriber operation with a large computer. In this case it can

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a variety of outside bodies, such as those in Pig. I. are indicated, are located remotely, for example in medical treatment rooms, and the processing can be done in parallel using a single large computer. In any case, the computer 41 is with the environment and the patient connected via a variety of external facilities. For example, the input circuit 42 for the computer data to any of a variety of input devices such as a tape reader, card reader, or typewriter contain. Output signals or commands in the form of digital numbers from the digital computer 41 are on a large number of data lines to the external test equipment fed. For example, the x, y coordinates of a test point on the screen at which a stimulus is generated is to be, from the computer 4l to a position control register 43 in to the external devices. The content of the location control register 43 is converted by means of a digital / analog converter 44 is made into an analog form and supplied to a deflection control circuit 45 as a pair of analog signals. the The mode of operation of such an analog point control circuit can be the same as that in a conventional television set, or a circuit such as that used in conventional digitally controlled cathode ray tubes can be used.

The intensity control register 46 receives digital output signals from the computer 41 and its contents are updated by a second Digital / analog converter 47 converted into analog form and the

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Intensity control circuit 45 supplied. The deflection and Intensity control circuit 45 uses three analog input signals, simultaneously with additional θ and θ -analog-

X -j

Signals of the fixation point monitor 56 for the formation of a point or test stimuli in the desired coordinates and with the desired intensity on the screen surface of the cathode ray tube 48. The device thus forms test stimuli for the patient under program control from the computer 41. The fixation point monitor 56 delivers Correction information to the deflection and intensity control circuit 45 in an analogous manner. Digital correction information is also passed to the computer 41 via the digital converter 57. This digital information can be saved in Program, as described below, can be used to determine whether the line of sight is within acceptable Limits are on the screen and whether the test point that is provided occurs at the appropriate place would, and to abort the attempt if the former or the latter is not the case. Digital correction information can also be used to provide correction information to converter 44 to thereby control the deflection control circuit to improve. More precise control is obtained with direct application of the analog information from monitor 56 for controlling the control circuit 45 and is therefore preferable.

The patient closes the test loop by responding by means of the manually operated response circuit 49. This manually

response circuit to be actuated is also referred to below as "pointer ¹¹ ".

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direction there are two things. First, the section or spatial angle in which the pointer contact is made is encoded in digital form by the diode matrix 50 and supplied to a digital response register 51. This register can again, optionally scanned by the computer 4l under program control will. Furthermore, actuation of the pointer 59 causes the tone generator 52 to start up in order to provide an output signal produce. As will be described later, the pitch of this acoustic output signal becomes between different pitches changed to show the patient whether his or her response to the test stimulus was correct or incorrect, i.e. whether it was sufficient was fast and accurate in the direction. · · ■ - ■ · .-

The test conditions can be controlled by the operator using switches 30 on control panel 29 (Figure 2). These switches correspond to block 53, which is labeled "system data input circuits" in FIG. These switches can be used to control the system parameters, for example the duration of the test point and the time between the delivery of test stimuli to the patient. Other system parameters can also be regulated, such as checking the threshold value at the points where it deviates more than specified from a predetermined threshold value, by appropriately attaching the relevant switches. This is desirable in preventing patient errors due to lack of attention or other factors. Switches on the housing can also be used to determine whether corrections should be made to the fixation point if the line of sight

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and the accuracy of the patient's response changes or decreases during the experiment. The switch positions are encoded as digital digits by means of the system data input circuits 53. The system control circuits 54 speak to the output signal of the data input circuits 53 and allow the computer 41 access to the status of the Switch positions.

The system communicates with the operator and the environment through the use of output circuits 55. These Circuits may include any computer output display or recording device such as a cathode ray tube Chart recorder, a line printer, a typewriter or other devices that contain the computer output signals convert it into a form that can be evaluated for the environment. The system control circuits 54 are also in communication with the computer output circuits 55 »so that the status of the system can be checked by the operator.

In operation, the system is operated according to Pig. I by the operator via the data input circuits 42 and the system data input circuits 53. These data input circuits are used together with the program control of the computer 41 to control the digit control register 43, the Intensity control register with the associated digital / analog converters 44 and 47 and the deflection and intensity control circuits 45 on the screen of the cathode ray tube 48 To generate test stimuli. If a stimulus is generated, it reacts

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Patient by displaying the angular range on the test field (denoted by the dashed lines) of the wedge-shaped areas from FIG. 2) in order to indicate via the manually operated response device k $ in which area the stimulus was observed. The response of the patient is fed to the computer in a usable form via the diode matrix 50 and the response register 51. Appropriate response feedback (correct or incorrect) is provided to the patient via tone generator 52. The response of the patient is then used dynamically in the program to change the test procedure. Once the testing according to the program has ended, the output circuits 55 scan the state of the system control circuits 54 and the visual field data generated by the test and convert this data into a form that is usable for the examiner Thus, the system or the device according to the described embodiment forms a careful feedback with the patient and dynamically changes the test procedure while a visual field examination is carried out using the principles of campimetry and real-time control of the digital computer 41.

In Fig. 3, the overall method according to the invention is shown together " connected with a real-time program of the digital computer 41 in a macro flow diagram (it should be noted that that in this program flow chart as well as in the following Program flow diagrams with the inscriptions written in English, as is the case with conventional computer programs). Details of the overall procedure will be described later in conjunction with the other figures. In general, it begins Examination, after the operator receives input test data,

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for example in card form, has fed to a card reader which contains part of the data input circuits k2 according to FIG. This method can be shortened by using input signals from magnetic disks or tapes. The initial test samples can be selected by the examiner on the basis of preliminary tests, clinical observations or the like. The system data input circuits 53 of FIG. 1 have previously been set to the state desired for the test. The computer 41 was put into operation and carries out the visual field examination under program control; the first program step, which is shown in block 61 in FIG. 3, causes the start of a subroutine which reads the input data, determines which eye is being examined, and the result the entrance test center adapts to the particular eye. At this point it is possible to display an error caused by the operator and / or the patient (block 62). In this case, as indicated in block 63, an error message is written out and the program waits for the error to be corrected and then returns to block 61.

It is assumed that the input data are adapted to the eye to be examined. A checkpoint becomes arbitrary from the checkpoint series selected. The selected test point, as will be explained later, is stored in the computer in visual field coordinates. That is, its coordinates are related to the viewing direction of the patient. Based on input from the fixation point recorder 56, previously described Art, the program then determines via block 66 whether

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the operator has decided to switch 30 and the system data input circuitry to regulate the recording of the fixation point via the program. Is the regular order of the program is performed, the input data of the recording device of the fixation point 56 at block used to translate trial field coordinates into screen coordinates. It should be noted that block 67 is a represents a closed loop in which the computer continuously displays the eye position while a test point is offered and the location of the test point on the screen changes to any eye movement during the inspection process compensate. It should also be mentioned that at this point it is possible to exit the program if the viewing direction has changed to such an extent that the value of the visual field test is questionable. That would be for example the case when the gaze wanders so far from the center of the screen that accidental delivery of stimuli is excluded. That's why it is practical to require that the view remains within 10 ° of the center of the screen. This is shown in Fig. shown by the dotted guide line and exit 68. Assuming that there are no other problems with the fixation, the remaining program function is to be described in general.

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Test points are repeatedly offered by the input data area until all test point threshold values have been determined. Are all test point thresholds determined, a data output program (block 65) is called and the test is ended. A program specification, controlled by the switches 30 described above, for example, is a record of the normal blind spot of the patient. Every normal eye generally has an elliptically shaped blind spot. The blind The right eye spot is to the right of the fixation point and that of the left eye is to the left of the fixation point. if it was decided in block 69 ^ that the blind spot was recorded should be, a subroutine is called in block 7 °, which carries out an examination of a single point in the area of the blind spot. Successive points in the area of the blind spots are randomly mixed with points in the preselected test series to prevent tension in the patient and to support a good fixation. Assume that the blind spot recording is finished or that it is Information is not desired, a "NO" decision is made at block 69 .. By calling up a subroutine (block 71.) the patient receives a stimulus from the visual field test series. This subroutine (a more detailed description follows later) feeds the test center data to the patient via the external device described above and saves his Reaction.

Another subroutine which interprets the patient's reaction to the test stimuli is called up in block 72. If that

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If the patient's response was in the affirmative or is interpreted as correct, the data is modified to indicate that the point has been seen (block 73). If the patient's response is incorrect or if he does not respond at all within the permitted time, the program modifies the test point data accordingly in order to indicate that this point has been overlooked (block 7 ² J). In any case, the program continues to block 75 where it is determined whether a threshold value has been reached. If this is the case, this data location is removed from the test series (block 76) and placed in an output buffer for later display. The program then runs back to continue the test sequence by selecting a new test point (at block 6M) . Finally, as described above, the visual field examination is ended when all test points have been used up. A preset logic circuit can also automatically add additional test points or test points and,! check if the field of view deviates from the expected values ^! or has special internal contradictions. At this point, the resulting field of view output signals are fed to the tester in a desired form.

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In FIGS. 4 and 5, the puncture method of the in block 61 from Fig. 3 retrieved initial subroutine in detail described. As already mentioned above, the operator introduces a number of test points into the system, in-the input data to the data input circuits 42 according to FIG. 1 are introduced. These input data contain a large number of unpredictably distributed test points and predictable ones Threshold brightness values for each location., These test locations are in test field coordinates or Coordinates given in relation to the viewing direction. If the direction of view changes, corrections can be made as follows attached to the pilot screen coordinates. You can use as many digits as you need, but 'It has been shown that about two hundred test centers have one Enabling detailed field of view recording with isopters, as soon as this is desired. For other purposes, such as a quick examination for the driver's license, ten or fifteen test centers are enough. In any case, typing represents the test point data represents the first step in the implementation of the visual field test.

The test site data can optionally have the format shown in FIG. In this representation, the data for each test point is summarized in a section of 24 bit length. In the embodiment shown in Fig. 4, the first six bits included in the ^f left side of the computer definition of the testing range, the x-coordinate of the inspection on the screen surface of the

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Cathode ray tube. The second six bits of the word form the y-coordinate. This means that the area of the test screen or The cathode ray tube is divided into a 64x64 grid on which the test points appear. It goes without saying to the person skilled in the art It is clear that, if necessary, a computer with a word length of twenty-four bits can also be used. Is the word length of a computer less than twenty-four bits, for example sixteen bits, the data can be distributed over two or more words will. You can also change the number of binary digits or bits for each input signal. For example if eight bits are used for each of the x-y coordinate data, a 256 χ 256 grid can be provided. This gives you a greater recording precision text is possible for the test point data than for data with six bits. However, practice has shown that a digit 64 χ 64 arrangement is suitable for performing this operation according to the invention.

In the exemplary embodiment according to FIG. 4, the rest are then eight bits of every 24 bit word of two 4-bit numbers, the b-number and the d-number, the use of which will be described later. For the moment it suffices to point out that the b-number denotes the highest stimulus value that can be tested or that has been tested, and that the d-number the lowest stimulus value indicates that can be checked or has been checked. The intensity data, which is also four bits in length, becomes initially set to a predeterminable threshold stimulus value and via the intensity control register 46 and the assigned

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belonging digital / analog converter 47, the intensity control circuits 45 forwarded. It is therefore possible from the first 4 bit number any one of sixteen predetermined intensity settings to obtain.

When the test location arrangement appears in memory (block 101), selects the initial program, which is shown in the flow diagram according to FIG. 5, a test point in approximate coordinates, the is predicted as the area of the normal blind spot of the right eye, as indicated in block 22.

By introducing a test center with a predetermined one maximum brightness in the area in which the blind spot of the right eye is supposed to be located is determined by the response or failure of the patient to respond, machine decision as to which eye to examine is possible. At block 203 an attempt was made to determine whether the operator has chosen to use the fixation point monitor, or whether other external devices as described below automatically take over this function. If this program is selected (at block 204) the subroutine is called and the coordinate of the blind spot in the patient's right eye is transferred to it in the event that the patient is present changes the fixation point.

If the fixation is satisfactory, at block 205 a later described is made Subroutine called to link the computer 41 with the external facilities for the display

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to effect a test center. The initial program runs through an indicator that determines whether the patient responded to the stimulus offered. If there was a reaction to this stimulus, indicated at blocks 206 and 207, it is necessary to provide the input data easily modified, as shown in block 208 of FIG. If there is no response from the patient to the stimulus, it concludes the program that the right eye is checked, since the test point was generated in the position in which the blind one is Right eye spot. Operator error, patient uncertainty, or visual field error, which overlaps with the blind spot in the other eye can be determined by adding an additional test point in the Area of the blind spot. Of the left eye created.

The modification of the input data is desirable because the format of the original input data is in coordinates relative to the Fixation point for the right eye was chosen and a typical one Test setup is usually set up in such a way that a test is not carried out in the area of the blind spot. This is a coordinate transformation required according to a figure around a vertical axis through the fixing point, to change the input data so that it can be used for recording of the visual field of the left eye are suitable. If this has taken place at block 208, the subroutine ends. The next act of the main program (block 64 in Figure 3) is to select a test site for the patient.

In Fig. 19, the flow chart of the subroutine becomes for recording the viewing direction for either changing the screen

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coordinates of a selected test site when looking within acceptable limits. is changed, or the termination of the experiment, if necessary, is shown. The direction of view of the screen can change so that some places in the test field fall out of the screen, such as the places (1,1), (1,2), (2,1) or (2,2) in Figure 13b. Obviously, these spots cannot be formed in the otherwise more random way. This non-randomness According to some authors, it can affect the results of a visual field test; therefore is in the invention Method the option of selection via a selection of switches on the housing 30 of FIG. 2 and system data input circuits 53 of FIG. 1, to end the attempt or to write an error signal and interrupt the attempt until the patient's line of sight is again within acceptable limits.

The test at block 209 in Figure 19 determines whether the improvement a fixation point is necessary. The angle © is selected in a suitable manner for, for example, error measurements. Is not a correction necessary, the program will run out with the continuation of the visual field test without compensation of the fixation point.

However, if the viewing direction has been significantly changed, the test in block 291 is used to query according to the following procedure. If the "end" command is selected, then at block 291 an error signal is written in the device for the output data and the program stops until the fixation is restored is made. If the fixation correction is desired, the test field coordinates are transferred by the required amount

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(Block-293) · If the corrected coordinates are on the screen (as determined at block 29 ¹ I), the compensation is complete and the program runs out. If the compensated point falls outside the screen, block 295 inquires whether other check points remain. If this is not the case, the program runs out at block 296, writing an error message. If a few test points remain, as indicated at block 297, a new test point is selected from the pseudo-random series and the transfer of the coordinate is applied again. In this way, the relative coordinates in the memory can be adapted to the change in the viewing direction within reasonable limits under program control.

In addition, in the device of FIG. 20, the brightness of the computer-controlled brightness signal can be used for compensation the relative change in size in the experiment can be varied by recentering the fixation point. That means simply changing the brightness of the test point when the fixation point is recentered, so that the test point as well appears large, as before the patient's line of sight changes. Before this part of the control loop of FIG. 20 for brightness compensation is described, that of the applied The theory underlying the technology will be discussed.

The stimulus value of a light spot of predetermined size and brightness is, provided it lies on a perimeter, essentially independent of its position on the screen, so that the subsequent corrections are not required with such a device. This is because the eye-to-spot distance is essentially constant. At, _{Λ Λ Λ} ~ <·. / nooo

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However, this eye-to-screen distance D is not on a campimeter constant, and the stimulus value W changes to the extent that the solid angle changes with respect to the test point. That leaves the area around the inspection body regardless of its position, this means that the stimulus on a campimeter is a function of l / D. The stimulus value of a light spot changes according to the equation W = (A: D). Because of a change in the direction of gaze, a given point on the retina is not correct at every point in time Experimental coincides with that on the screen, so that it is desirable to compensate for the inherent non-linearity on the campimeter, to provide more meaningful threshold values, and when eye movements have to be accepted.

If A is the range of the stimulus at distance D and A ₁ and D are equally defined, then if it is required that W ₁ = W and since W = (A: D) ^{2, it} is easy to show that A ₁ = (D ₁ ID ₀ ) ² A ₀ , now with regard to the screen, let d be the distance from the eye to the screen center along a perpendicular axis to the surface of the screen, and let E be the eccentricity of a certain test part, e.g. the distance of the location of the test point on the Screen from the center of the screen so that

2 2 2

is. If A is the range of a certain stimulus value of a test point at distance d and A ₁ is likewise defined as D, it follows from the above equation

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24096Η

= (DZd) ² A ₀ or

i = / T + (ΕΛ1) ² 7Α
ι - —-

= YY ₀ ,

where X and Y are the coordinates of the screen center and X and Y Coordinates of the test parts are, follows

_r E ² = UX) ² + <ΔΥ) ² -η and ^{2 2 2} I

U) <Δ) « d ² + (ΔΧ) ² + (ΔΥ) ²

where the expression in brackets is the coefficient of the desired Compensation is. The control circuit in FIG. 20 for calculating the compensation coefficient is described below.

Signals for the coordinates X 'and Ϊ' the "corrected!" Checkpoint are provided by adders 302 and 303, and subtracters 305 and 306, respectively. At the same time there is a device for generating a reference voltage, 308, signals representing the Represent coordinates X and Y of the screen center (the

CC

are of course constant for a certain test section) and transfer them to the subtractors 305 and 306. The coordinates of the screen center are determined at the beginning of the experiment and the device for the reference voltage 308 is adapted so that the corresponding signals of the coordinates can be applied. * The coordinates of the screen center are subtracted from the (corrected) test point coordinates, so that signals for Δ X undAY is obtained, which is needed for the multiplier 310 and 312 will. The multipliers multiply each signal by itself

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itself, so that one receives signals for (ΛΧ) and CdD ^ sr. These signals are from the multiplier 310 and 312 zn an adder 314 together with a signal of the device for the. Reference voltage (308), corresponding to constant δ ". The adder 31 * 1 adds these signals and forwards the result to the divisors 316. The signal for d is also used to generate a

Signal for the compensation coefficient d ² + f & Q ² + (ΔΥ) ²

forwarded. This signal is sent to a multiplier 318 together with the request for the reference signal A _Q from the computer. These two signals are multiplied by the multiplier 318 to form a compensated signal A ^ which is passed to the CRT direction 304.

The procedure described above for generating a compensated Brightness signals and spesisil oils use of the angles

θ and θ is only sufficiently accurate if the angles of the χ y

Direction of view with a line to the center of the screen 10 ° or less so that the approximation for small angles according to β = tangent θ is applicable. If compensation is required for a larger angle, it is necessary to build a device into the control loop of FIG. 20 for generating the necessary tangent function. This Control loop is inserted between the recording device of the pixel point 301 and adders 302 and 303 and can be one of the already known. Of course, use can be made of the fact that the brightness of the spot (B) in the Ratio to the area of the spot (A) according to the equation

_{B. A} o, 83o5 _ _constanfc
stands.

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Even if the fixation point is not re-centered, it will be through the device of FIG. 20 achieves brightness compensation, so that the campimetric device in FIG appears like a circle, i.e., devices with constant eye-to-screen distances, that is, with the coordinates of the Test site representing signals X and Y from the computer via adders 302 and 303 (which do not add anything to the signal

would ₃ because θ and θ = 0) the subtractors 305 and 306 χ y

be forwarded. The further processing of the signals is then continued, as described above, so that compensated brightness signals B _{1 are} obtained.

FIG. 6 shows the flow diagram of the interface program for the presentation of a test point. You can see that the interface of external device and computer can change with the computer model and the change in the external device. the The special order described results from a special interface between an IBM 1131 B computer and a external device designed for use with it. However, the invention is not limited to this structure. • In the flow chart, some steps are shown by the programmed computer 41 from FIG. 1 and some steps by the external circuit,

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for example the system control circuits 54 of FIG. 1, carried out. The blocks shown in solid lines Steps are performed by ... the outside facility. When the program is introduced, care must be taken (block 77) that the external facilities requires termination of the remaining time delay between the stimuli being offered before attending a the next stimulus is supplied to the patient with new test parts can be.

The coordinate data for the 6 bit x-y coordinates and the Four bit intensity data (i.e. stimulus strength) is provided to the external device (block 78), and that data is sixteen Output lines and four control lines are fed, which are connected to the external device.

Buffer registers in the external devices are used to hold this data when the computer 41 connects the control line 2 clocks, whereby the input buffers for the external devices are cleared (block 79). then the computer 41 clocks the control line 3, which conveys the new data from the output lines into the buffers, which are located in the external facilities. These steps are performed at blocks 80 and 81 in FIG. 6 executed.

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When this data is received, the external devices cause a delay of 15 microseconds and then signal the receipt to the computer by means of an interruption (blocks 82 and 83). When the program receives the interruption signal, the control line 4 receives a pulse from the computer. This clears the pointer or input buffer in the external devices, as indicated by blocks 8 ¹ I and 85. This enables the external devices to form a digital response to the movement of the pointer when the patient signals that he has observed a location or a test stimulus. The pulse on control line 4 (block 84) also causes the external devices to begin with a "duration of a place" time delay and the place to appear at the desired xy coordinate and with the desired intensity on the CRT screen (block 86 ).

The pulse on the control line 4 also actuates the Sound generator, so that when the pointing stick is deflected, a relatively high-pitched sound is produced as a result of the patient's reaction indicating that the patient responded correctly to the stimulus offered.

It is of course clear that at the speed with which the digital computer and the external devices make a decision regarding the acceptance of the reaction, the patient never makes one indicative of a correct observation Sound hears when a few milliseconds later the program determines that this reaction was inaccurate or incorrect and that it modifies the tone of the generator accordingly.

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In any case, the patient will either react to the test stimulus, if he perceives it in any way that may be correct or incorrect, or he will not react, if he does not observe the test stimulus. As indicated in block 87 of FIG., If "the patient is not before the expiry of the "Duration of a position" time delay reacts, the position is automatically switched off by the external devices, and the Stimulus is no longer applied to the patient. This is in the block

88 indicated. A signal to the computer indicates that in the block

89 no response is formed, and the "time delay between Digits "is started in block 90. It should be noted that the" time delay between digits "is changeable and can be controlled by the operator by using the switches 30 in the input device 29 according to FIG can or is changed automatically based on the subject's reaction time.

When the patient responds to the stimulus by pointing the stick or pointing stick in the general direction of that person Moved part of the circuit that corresponds to the section on the screen in which he saw the point, this can Reaction may be correct or incorrect depending on a permissible error limit selected for the test. This margin of error can be determined by changing the position of the switches 30 in the input direction 29 according to FIG chooses accordingly.

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A patient's response is usually not accurate and can deviate from the correct direction by 45 degrees or more.

The circuit includes a variety of switches, such as 28, to provide an equal plurality of sectors of desired angles, such as 12.86 °, which is the number of adjacent ones Sectors around the angular sector are determined by generating the stimulus that is perceived as the correct response accepted.

The diode matrix 50 of Fig. 1 is used to create the switching section to encode information formed by the patient. Gray coding is used for this purpose. Two adjacent switch positions never differ from each other by more than a binary digit or a bit. This will the possibility of fault reactions due to simultaneous touching of two switching contacts by the stick avoided and a response accuracy of - 1/2. angular segments ensured. A digital digit representing the sector in which the patient's reaction was determined is conveyed to the response register 51 in this way.

In the event of an interruption as a result of the closure of a baton switch As indicated in block 91 from FIG. 6, the address register 51 in FIG. 6 is queried by the computer.

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At the same time, the external devices switch off the stimulus point, as indicated in block 92. On the basis of the known point coordinates which were offered to the patient, the program then calculates in block 93 the angular segment in which the patient's reaction should have been. If the reaction or response is not within the permissible number of fault sections in which it should have been (block Sk) ₉ , a control line is clocked (block 95) in order to change the pitch of the tone generator to a relatively dark sound, the indicates an incorrect response from the patient (block 96). This corresponds to the interpretation program from FIG. 3 (block 72). The wrong response is recorded and the program begins the "time slot delay" cycle to prevent premature presentation of the next test point (block 97).

If the reactions were within the permissible number of error segments, so the "interim timing" delay becomes instantaneous is started (block 98) and the program runs to call the modification programs, as in the blocks 70 and 71 of the overall flow diagram of Figure 3 is shown, whereby the reaction of the patient to the test stimulus is interpreted.

The subroutine shown in FIG. 7 for modifying the data locations due to the patient's response to the stimulus (blocks 70, 71 and 32 in Figure 3) is shown in flow diagram form. This The program determines the next intensity of the test point to be offered to the patient in the coordinates in question.

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This program also determines whether in these coordinates the threshold has been reached. If the threshold value is reached, the test of this point or this point is ended. An item that can be used if the manipulated variable is too far from the predicted threshold, is to check the threshold again at the specific point.

It has been shown that if a stimulus value was not seen, the intensity of the subsequent stimulus value is increased by 4 units at the same point
target; however, if a given stimulus was recognized, the
Intensity of the next stimulus decreased by 2 units.
This way the best effect was achieved.

These described steps are carried out by the program, as is indicated in blocks 101, 102 and 103 from FIG. The lightness limit B and the darkness limit D of a data location denote the highest and the lowest value from the at any given time
Set of irritation values checked at this point. The numbers B are initially set to the highest stimulus value level to be used in the experiment and then decreased during the test process according to the patient's reactions.

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The numbers D are initially set to the lowest stimulus level to be used in the experiment and then during the Test procedure increased according to the patient's reactions. the IBB number mentioned in blocks 102 and 103 of Figure 7 " a predicted test value that will be used for the next test bid is used in the coordinates when certain conditions determined by the rest of the program are met.

In either case, the next step (block 104} is to determine whether the B-limit of the test coordinates has already been tested. If this has already happened, the program determines (block 105) whether the darkness limit was already checked beforehand. Were both previously checked, the predicted value of IBB is set to half of the previously checked values (block 106). This type of query can be referred to as the binary clipping technique which can be shown mathematically that it is very effective. If the B limit has not been checked (Block 104), an indicator k is set equal to 1 to indicate it. Has the limit of darkness not been checked beforehand has been, the display k is set to another value (3) to display this. Have both extreme values been checked beforehand the display k is set to 2. These steps are performed in blocks 107, 108 and 109, respectively.

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Provided with the information regarding the border check for
The program logic can determine whether the threshold value has been reached in lightness or darkness. The absolute numerical difference between the brightness and darkness indicators B and d is either greater than, equal to or less than 1. This difference is an indication of whether the threshold value has been reached. Such a test is carried out in block 109 in FIG
and corresponds to the entry in block 32 in FIG. 3. If the difference is greater than 1, it is clear that the threshold value has not yet been reached, since the threshold value, as already explained above, is defined as the brightness value of the stimuli, which is no longer seen when decreasing by one step. On the other hand, if the difference between B and D is exactly 1, the threshold value may or may not have been reached. It remains to be determined whether the above limits have been tested to determine this fact. Such a check is carried out in block 110, and if the brightness limit was not checked beforehand or if both limits were not checked beforehand, as indicated by the value of the display k, then the threshold value has not yet been reached. Another check is therefore required to obtain the threshold value. Using the newly calculated brightness criteria (intensity specification = IBB) (block 111), runs
the program to continue the exam.

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In the case where the difference B - D is less than 1, a test is carried out in block 112 of FIG to determine the value of the display k. If the display k is equal to 2 or 3, then the threshold value has been reached. Is the ad k equals 1, this indicates that the brightness limit has not yet been checked, and the brightness limitB is in the block 118 is set to the maximum +1 to indicate that the maximum available brightness cannot be seen could. Thus, the output scale of the brightness values contains an additional number when compared with the scale of the Test is carried out. The threshold value has been reached in all three cases, and a check is carried out in block 113, to see if the recheck indication was retrieved shall be. If this is not indicated, an immediate exit takes place via block 114, in which the data for the Test point can be removed from the test arrangement and stored in the output data arrangement. Is a re-examination statement present, a check is made in block 115 to determine whether the re-examination is necessary. In this test, the measured threshold value is compared with a predicted, compared with the predetermined threshold value based on the normal vision threshold value. Failure of this test is an indication that an abnormality may have occurred. Such an abnormality may include blinking or momentary defocusing Show. The test center is in block 116 for a new

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test is set by reactivating the data for the brightness and darkness limits. Ain't no Re-examination displayed and was' the threshold determined, so the test point is removed from the test arrangement in block 114 and its threshold value data is stored in the output arrangement. In any case, at this point in time, the program changed the test site, depending on the patient's reaction, in such a way that that an approximation of the threshold value determination has been reached.

In Figures 8 and 8a is the flow chart for the subroutine shown to record the blind spot. A normal blind spot is shown schematically in Figure 8a. The record The blind spot is a program item that can be controlled by the switches located in the system data input circuit 53 from Figure 1 are located. Before describing the details of the logic arrangement of FIG a general representation of the manner in which the blind spot recording is carried out, resulting in the understanding of the subsequent logic arrangement facilitated. Let us first assume that the program determines the retinal or relative Coordinates of the geometric center of the blind spot are known. Then the patient will be tested roughly l ° steps along a ray (ray 1) offered from the assumed center point until the right edge of the blind

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Stain is detected. It can be seen that the order of the tests shown in FIG. 9 is the order of the Are exams that are used to record the boundaries of the blind 'spot.

The blind spot recording test is preferably used between the pseudo-random, otherwise used Test stimuli inserted, with a blind spot test every two other tests, but in a random manner Series.

The left edge of the blind spot is determined in the same way by means of the ray 2. The vertical bisector of the line connecting the two horizontal edges of the blind spot is calculated. Test points are in about 1 steps vertically downwards along a beam 3 and in the direction along this Bisector offered until the bottom of the blind spot is reached. Then contact points become vertical at about 1 ° intervals offered upwards along ray 4 until the upper edge of the blind spot has been determined. Be that way the upper and lower limits of a vertical tendon formed by the blind spot. The vertical bisector this chord runs through the geometric center of the blind spot and can be referred to as the calculated horizontal meridian of the blind spot. Along the

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horizontal meridian are test points at about 1 intervals offered (rays 5 and 6) to determine the true horizontal extent of the blind spot. With the horizontal Extension and the horizontal meridian can then set the center of the blind spot with accuracy will. A multitude of rays are then drawn from the center of the blind spot to its edges at different angles placed, as indicated by the dashed lines (rays 7, 8, 9 and 10). Along these rays you can Check points offered v / ground / to the real form of the blind To determine the stain.

As many rays can be used as for the determination the shape of the blind spot may seem necessary. Generally 8 or 10 beams are sufficient / around one Obtain a record of the blind spot with the desired accuracy.

In Fig. 8, the flow chart is the subroutine for the recording of the blind spot shown in detail. After entering the program, a test is carried out (block 121) to determine if a new ray should be checked or if it is the first entry into the program.

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If a new beam is to be checked or if it is the first entry into the subroutine, in Block 122 performs a second test to determine whether all the desired rays have been checked. If both conditions are met / i, the recording of the blind spot ended. A further study of the extent of the blind spot is made by setting an indicator (Block 123) suppressed and the program runs out.

If the blind spot test is still being performed (as indicated by the test results of blocks 121 and 122), thus a new ray is selected by the logic arrangement (block 125) described above. A test site coordinate is calculated in a step of about 1 ° along the beam (block 126). Of course, every test center will before they are generated, taking into account the displacement of the fixing point in the manner already described corrected. The calculated test point coordinate extends beyond the edge of the field of view or into the fixation point, it is clear that an error has arisen or that there is a large disorder of the visual field.

Such an error can be caused by inattentiveness on the part of the patient or a lack of fixation. To determine a test is carried out (block 127) a and if such an error has occurred, in blocks 128 · and 129 the remedy to be taken is displayed. The program then continues to point B from FIG. 8a.

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If the calculated test point is permissible, it will be given to the patient offered (block 130) by calling the interface subroutine described above. On return A test is carried out by this program (block 131) to see if the site was seen. If this was not the case, then it was the blind spot, and its coordinates are entered into the output array at block 132. In this case the program will expire to take the exam of the blind spot continue until all test beams are finished. If the spot was seen, this happened immediately outside the edge of the blind spot, and his Coordinates are entered into the main arrangement of the test points, to enable an accurate threshold value determination (block 133).

It is also desirable that the coordinates of a point be entered two steps along the beam into the main test site array for accurate thresholding. Then, a display xfird set to indicate that perform on this beam no further tests are (block 13 ¹ O, since the edge of the blind spot has been detected on this beam. The program continues to b Fig. 8a..

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At B (block 135) it is determined whether both the horizontal and vertical meridians of the blind spot are being examined has been. If both have been checked, it is determined (block 136} whether the real center of the blind spot is within is an acceptable margin of error from the predicted center point. When the two midpoints are within acceptable limits coincide, a new horizontal meridian is calculated on the basis of the test data. this happens by means of the program logic described above, and the program will expire to continue blind spot testing.

When both the horizontal and vertical meridians have not been checked and when the real center point of the blind spot coincides within acceptable limits with the predicted center point, the program runs to continue recording the blind spot. That The subroutine for recording the blind spot is finished when all rays have been checked.

It will be understood by those skilled in the art that essentially the same procedure can be used to record disease scotomas leaves, which can have a lower density than the normal blind spot. In this case, those are for recording of the scotomas used brightness values of the test somewhat darker than the threshold value in the scotomas.

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When recording disease feces it is usually desirable along additional rays to be examined from beams of extensive length.

Has the entire entrance arrangement of the test centers been checked and if all threshold values have been determined, an output program is created , the flow sheet of which is shown in Fig. 10, to record the data in a usable form. One Form which has been found to be particularly useful is a graphical plot by means of a curve. One Such curve recording can include a representation of the entire field of view with isopters, as in FIG. 12 shown. The isopters connect those points of the visual field that have the same threshold value. on the other hand a very simplified field of view display has only a few data locations, which is sometimes desirable (FIG. 11). These Type of simplified field of view display is useful, for example, in examinations for driver's licenses or in a Quick scan search for a visual defect or scotoma in a certain area of the field of view.

The program according to FIG. 10 initially determines (block 140) whether a simplified visual field test should be displayed. If such a record is to be provided, so the data is recorded in the format shown in Figure 11 (block 141). The numbers show the threshold

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on each individual test item. At the top of the record There is a title, and at the bottom is the patient's name, the date of the exam, and others the data in question are shown in a designation. For example, in a recording according to FIG a typical designation will contain the indication that the angular range covered by the circle is 5. It goes without saying clear that when using a large number of test centers this type of display because of its confusion becomes impractical.

If a simplified visual field test is not to be carried out, a check is carried out in block 144 to determine whether a complete display of the field of view with isopters should be made. If this is the case, a field of view recording is carried out drawn according to FIG. 12 (block 145). A record of this type can be of great interest to the Be an examiner to locate visual field abnormalities. This type of recording can also be used to interpret a disease affecting the visual system or to follow their course and treatment.

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In Fig. 21, another embodiment of the invention is shown in the form of a block diagram. In this embodiment the kinetic method of visual field testing is used, in which stimuli come from outside the circumferential area of the patient's visual field can be moved inwards until the patient notices these stimuli. As In the static method, the patient should look at a fixation point while the stimuli are being offered. Here lets not only does the stimulus size and brightness change, as was described with reference to the above exemplary embodiment, but also the speed with which the stimulus is moved on the screen can be changed.

The system of Figure 21 includes all of the components of the system of Figure 1, but the location or position control register becomes 1 in FIG. 21 as the start position control register 43. The constituent parts which are common to FIGS. 1 and 21 are given the same reference numerals and designations in FIG. 21 as in Fig. 1. The operation of these components in the system of Fig. 21 is the same as that in that System according to FIG. 1 and will not be explained in detail.

The intensity control register 46 and the control register 43 receive digital information from the computer 4l regarding the

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Intensity of the checkpoint to be offered and the. At first-" position in which the point appears on the screen of the cathode ray tube 48. The system of FIG. 21 also includes a speed control register 350 which receives digital information from computer 41 indicating the speed * and denote the direction in which the test point is moving will. This information can be in the form of two digital digits, the ratio of which is the tangent of the angle, i.e. the The inclination of the path traversed by the stimulus, and its absolute size indicates the speed with which the stimulus is to move. The direction in which the test point should move on the path is also specified.

The contents of registers 43 and 46 are used by digital / analog converters 44 and 47 put into analog form and the deflection and intensity control circuits. 45 supplied. Controlled by These circuits 45 would appear on the screen 48 of the cathode ray tube a checkpoint will appear at the location and with the intensity as determined by the contents of registers 43 and 46 to be determined. The contents of the speed control register are also converted into brought into analog form and the ramp generator circuits 354 fed. These analog signals represent the horizontal and vertical components of the speed. Dependent on

of these analog signals, each of the ramp generators 354 supplies a changing analog signal to a

409836/0898

talking adding circuit 356 or 358. These adding circuits 356 and 358 sum the corresponding analog signals from ramp generator circuits 354 and digital-to-analog converter 44 and carry changing analog signals Signals to the corresponding deflection control circuit 45. The deflection control circuit 45 then causes the Checkpoint on the screen of the cathode ray tube 48 in the Direction and at the rate as determined by the signals received from adders 356 and 358 were received, the signal from the adding circuit being the x component of the movement and the signal from the adding circuit 358 define the y component of the movement. The mode of operation and the circuit for moving a point of light on the screen of a cathode ray tube is of course known.

As in the system according to FIG. 1, the fixation point monitor 56 determines changes in the subject's line of sight and reports this to the distraction control circuit 45, which moves the test field accordingly in order to compensate for this change.

When the test point shown on the CRT screen moves into the subject's field of view, so that this perceives the test point, it reacts by moving the pointer with which it the sector or the

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angular range of the test field corresponding to this sector, in which the test point was perceived. When moving of the pointer 49 is the computer 41 a signal supplied, through which this interrupts further movements of the test point and switches off the test point. Of the Computer 41 then controls the ramp generators 354 so that its output signal is fixed at the current value. This prevents further movement of the test point. The output signals from the adding circuits 356 and 358 are converted to digital by an analog-to-digital converter 360 Form implemented and fed to the computer 41. This digital information identifies the coordinates in the test field where the checkpoint was paused. This information can be combined with corresponding information from the Offering other stimuli can be used to record the isopters in a visual field representation. Every isoptere will determined by the location of the points at which a stimulus of a given intensity was detected.

Pig. 22 shows a method for performing a kinetic field of view test. The test field is by imaginary, dashed Lines 370 and 372 are divided into four quadrants and the test is performed quadrant by quadrant. The quadrants are labeled I, II, III and IV in a counterclockwise direction starting with the upper right quadrant. In the In the initial phase of the test, the test stimuli or points are initially offered on a so-called start circle 374, the is located immediately outside the area from which

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it is assumed that the test subject can perceive stimuli in it. The stimuli are moved towards the fixation point 376 of the test field. The paths traversed by the test points in the initial phase of the test or the experiment are referred to as basic rays, with three basic rays in each quadrant. Two of these basic rays of each quadrant, for example rays 378 and 38O of quadrant II, run from points on starting circle 37 ¹ * very close to two dividing lines which delimit the quadrant. These basic rays are referred to as outer quadrant rays. Thus, the outer quadrant ray 378 runs from a point on the starting circle 37 ^ close to the perpendicular quadrant dividing line 372 to the pixel point 376 and forms a path along which a test point can be moved. The outer quadrant beam 380 forms a similar trajectory. An outer quadrant ray lying on the opposite side of a quadrant dividing line is referred to as an opposing ray. The reason for the small distance between the opposing rays is that one can assume that they lie directly on opposite sides of the natural anatomical dividing lines of the field of view. Since a large percentage of clinically significant visual field damage occurs in this area, an examination of this area may be desirable very early in the course of the examination. If the test is made along the quadrant dividing line, it is possible that small but important displacements along these lines will not be found.

409836/0898

In the embodiments of the "invention in which the to The examining eye is identified very early during the examination, the horizontal counter-rays in the test field can be used Side of the normal blind spot are replaced by a single ray running along the quadrant dividing line, since there are no important anatomical separations within this area.

The fundamental rays that are not outer quadrant rays are referred to as inner quadrant rays, for example the ray 382 in quadrant II. Each of these four inner quadrant rays in the test field from FIG. 22 runs from the Starting circle 37 ^ along a path that corresponds to the corresponding Divides quadrant into equal parts.

When the visual field test is carried out, the test points are moved from their initial positions on the starting circle 37 ¹ J towards the fixing point 376 until they are perceived by the test subject. The locations of the perception of the test points are then recorded, as has already been described above, in order to use them later for the construction of an isopter, for example the isopter 38 ¹ I in FIG. These locations are called threshold points. In quadrant I of the test field from FIG. 22, for example, three threshold value points were determined by moving one test point one after the other along the three basic beams 386, 388 and 390.

409836/0898

After performing the initial phase of a visual field test, in which the test stimuli were moved along the basic rays, additional rays are selected by determining the chords that extend between predetermined, neighboring threshold points of a quadrant, after which the vertical bisecting lines of these chords are then calculated. These vertical bisecting lines form additional rays along which test stimuli are moved. In quadrant I of the test field from FIG. 22, a chord 392 is shown which extends between the threshold value points 388 and 390. The perpendicular bisector (LS) of this tendon is also shown. The starting position of the ray LS can either be on the start circle * 37 ^ or, in order to reduce the test time, it can be close to the chord that determines the ray LS. In doing so, however, it must lie outside the probable position of the threshold value point. In Fig. 22, the beam LS is shown as lying approximately in the middle between the tendon 392 and the reset circuit 37 ¹ I in quadrant I, but also various other criteria can be applied to determine the start point of the beam LS. The number of additional rays to be selected and checked is determined by the perimetric separation of the perimetric threshold value points in a quadrant, ie the separation of adjacent threshold value points. If the greatest distance between threshold points in a quadrant is less than a certain predetermined value, then the selection of additional rays for that quadrant is terminated.

409836/0898

A determination is also made as to whether the distance between Threshold points on two sides of a quadrant dividing line is greater than a certain predetermined value. If this is the case, a so-called quadrant interim test is carried out carried out. The threshold value points are located in the test field according to FIG. 22 on both sides of the quadrant dividing line between quadrants I and II / III and IV as well as I and IV all proportionally closely together so that no inter-quadrant check would be performed for these pairs of points. But when the threshold points on either side of the quadrant dividing line between quadrants II and III have a certain distance from each other, which is due to the shape of the isopters can be caused close to the quadrant dividing line, an intermediate quadrant check would be carried out. This interim quadrant exam, which will be explained in detail later, involves determining the tendon between the ones in question standing threshold points and the calculation of the bisecting line perpendicular to it in order to determine a ray, along which a test point is to be moved.

The speed at which a certain stimulus moves in the test field can either be constant or changeable, and a stimulus can have either different constant speeds or different speeds from one test to another have variable speeds. Since different test subjects have different reaction times,

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it may be desirable to set the speed for the movement of the Stimuli to choose based on the reaction time of the test subject «So can the speed of movement of the stimulus for a test subject can be considerably higher with a short reaction time, and yet the stimulus can be perceived sufficiently quickly stop by the test subject so that there is little error between the point at which the stimulus was perceived and where it was stopped. For test subjects with a long reaction time, a slower speed may be desirable to reduce this error.

To compensate for the error between the position of the stimulus when perceived and the position when stopping, which is a consequence of the Reaction time of the test subject, this reaction time can first be determined in order to determine the situation of the stimulus when perceived. The computer that determines the location of a stimulus when stopping, the reaction time of a Test subject and the speed with which a certain stimulus was moved, entered can be the location of the stimulus determine when perceived by the test subject. ' The response time can be determined, for example, in that the subject is offered a static stimulus and then the time between the offering and the reaction is calculated. Because of subjective Factors such as fatigue, impaired reaction " ze, it o.a. it is desirable to set the response times to different Points in time "to be determined during the test.

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To increase the reliability of the test or the attempt, a variable speed for the movement of each Stimuli are desirable. Clinical experience shows that more reliable responses result at speeds that change depending on the eccentricity from the fixation point, with higher speeds at a distance from and lower speeds occur closer to the fixation point.

Although a specific method of defining the rays for performing the visual field test is described above various methods of choosing these rays can be used. For example, all rays start at points that are evenly spaced on the starting circle and then run to the fixation point. Furthermore it is possible to let the rays run in directions that do not point to the fixation point.

The isoptere 384 of FIG. 22 denotes the location of all threshold points for a test stimulus with a fixed intensity or the same Brightness value. In the course of a facial field test, further isopters become more different through the application of stimuli Brightness values determined. The result is the recording of a number of isopters such as this for example shown in Fig. 23A. The distance between the isopters is generally constant there, but there are two intermediate isopters, where this is not the case, as indicated by arrow 394. When a "bulge" of the type shown in Fig. 23A

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species shown is discovered, this may be an indication of be a blind spot. If a blind spot is suspected, a so-called isopter intermediate test is started to determine whether there is actually a blind spot. One possibility for an interim isopter test is to do one after the other to offer a number of test points within the bulge which are arranged in a grid-like manner, such as this in FIG. 23A is indicated. Each checkpoint has from every other checkpoint and from the two isopters between which the check is carried out is executed, at least a distance of Z / 2, where Z denotes the threshold value distance that is before the start of a Intermediate isopter test between neighboring isopters available is. The intensity of the test points offered could be the same as the intensity of those test points which was used to determine the outer isopters of the pair of isopters in question. The arrangement of the checkpoints in the bulge and the distance between these points can of course be chosen arbitrarily, the only criterion being is that they should be arranged so that there is a likelihood that there will be a blind person Stain is discovered. If the test points are offered and no point is perceived by the test person or the patient, so the presence of a blind spot is fixed. posed.

If the presence of a blind spot is detected, then

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a corresponding test is carried out. The purpose of this test is to determine the boundaries of the blind spot. Such a method is shown in Fig. 23B. In this case, the border of the blind spot is given by a kidney-shaped border. A test of the blind spot according to the present method begins by offering a test stimulus and successively in four directions in the horizontal and vertical from one of the test points of the test point distribution used to determine the presence of the blind spot, ie from one of the test points that is not perceived by the test subject is moved outwards. Such a starting point is designated by 402 in FIG. 23B. The paths traversed by the point of light moving outwards from the starting point are called principal rays. In Fig. 23B, rays kok, * JO6, 408, and ¹ HO are chief rays. The stimulus moves along a main ray until it is perceived by the test person or the patient. The point at which the stimulus is perceived is called the limit point. After determining four boundary points in the intersection of the main rays with the boundaries of the blind spot, a chord is determined between adjacent pairs of boundary points and the bisecting line perpendicular to it is calculated, as described in connection with the normal visual field test. Then along the vertical bisecting line of its intersection with a main ray a stimulus is traced

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moved outside until another limit point is determined. This process is repeated for other neighboring boundary points until a sufficient number of boundary points is determined. As described above, the starting point for the vertical Halving lines can be freely chosen, and other starting points could also be specified. The sufficient The number of limit points could then be reached if, for example the maximum perimetric distance between any pair of boundary points is less than a predetermined one Value.

The calculation of the vertical bisecting lines or the straight line LS both for the normal visual field test and for the quadrant intermediate test and the test of the blind spot is described in connection with FIG. Assume that two threshold or limit points 420 and 422 have been determined and that, in the event of the blind spot inspection, point 424 is some internal point such as point 402 of Figure 23B. This can also correspond to any calculated point, roughly analogous to the. Point (x ¹ , y ') 426 from a previous test. In all cases L ^ and

L «perpendicular, in order now to use the equation that defines the line segment LS

' 1

to determine the equations of the straight line L _Q

2 ·

and L. determined from FIG. 24 in the coordinate system of the test field

1
will. For the line or straight line L _Q applies to every point

(x, y) on this straight line the following equation, where the coordinates "(x, y) coordinates in the coordinate system of the test field are: '

409836/0898

_s ^y o ' ^y i

If mari solves this equation for y, one obtains

< ^χ - ^χ ι> ⁺ Γι

ο ι

y "" V
With M * = ( ), and B * =

one then obtains the equation y = M _Q x + B_

This is the equation for a straight line. Through appropriate

Analysis results in the straight line L ₀ in the coordinate system of the

Test field too

= ^M o ^{x + B} o

Correspondingly, the straight line of the chord 428 is given by y = M ^ x + B ^.

In the case of straight lines that run perpendicular to one another in a Cartesian coordinate system, the inclination of one straight line must be equal to the negative reciprocal of the inclination of the other straight line. The inclination of the straight line LS from FIG. 2 ¹ is thus 1

- ¹ X ₁ -X ₂

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This results in the equation for the straight line LS to

yy ¹ = m_ (xx *).

By inserting

X ₁ + X ₂
x '= - ^ - and

r = ^y i

2 results

χ -

Substituting in M and solving the equation gives

the straight line LS to:

This equation denotes the straight line LS in the coordinate system of the test field.

If one applies these principles to the examination of a blind spot, - after examining the main rays and after determining the chord between a pair of boundary points, the vertical bisection line on the tendon is determined and then the stimulus from the intersection of the main ray and the vertical bisection line to the outside emotional. This intersection point is the point in Fig. 24 which has the coordinates (x, y). A determination

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these coordinates in the coordinate system of the test field can be carried out according to known methods of analytical geometry and is not described in detail. Of course, such a provision is only made when examining a blind spot and not performed on a normal visual field test or an inter-quadrant test. Apart from this determination, the procedure for determining and testing is along the vertical bisecting line a tendon does the same for both the normal visual field test and the inter-quadrant test and the blind spot check.

As already mentioned above, a stimulus along a Beam moves at any predetermined speed, which can be both constant and variable. if the speed V at which a stimulus moves along a ray given by the equation y = Mx + B with M and B given as constants is known, the vector components of the velocity in the x and y directions can be like follows, be determined.

First, the equation of the ray is differentiated to get = M ~, since ~ = 0. One takes into account

CIt Qt

V “- ^ J and V = ~ , then V = MV. the end

Jf QX »λ Qu y X

V ² = V ² + V ² follows V ² = V ² + M ² V ² = (1 + M ² ) V ² .

Λ · Jf Λ. Λ Χ

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This equation can be solved for V- , and one obtains

"7

^X "1 + .M ²

The components of V can be determined through appropriate analyzes

V =

y ti -ι +

It should be noted that the V and V denoting,

χ y

The above equations indicate that the 'direction of the Velocity components is positive. A negative sign for V and V would indicate a reverse direction of the Indicate movement.

Pig. 25A, 25B and 25C show a flow diagram of the kinetic Method according to the embodiment of the invention. The process shown in this flow diagram belongs to that in Figure 21 shows the system; The first step is to choose the intensity or brightness value for the Stimulus from a pool of brightness values to locate the isopter of interest (block 502 in FIG. 25A). Usually a visual field test starts with a

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Test stimulus of almost maximum brightness is used and, after recording the first isopters, the brightness is used Determination of other isopters is gradually decreased.

After the brightness value has been selected, the next step in the process sequence (block 50 * 0 is the selection of any basic beam along which the test stimulus is moved. The test stimulus is then moved from the starting circle to the fixation point along this beam until the patient or the test person The location of the threshold point is recorded (block 506), whereupon it is determined whether the beam being tested is an outer or inner quadrant beam (block 506 ¹ ) a determination (block 508) whether the opposing beam has been checked, if not, then block 510 is passed, while if the opposing beam has been checked, flow proceeds to block 512, where it is determined whether the distance between the threshold points of the one in question This is done simply by reducing the distance between the threshold nwertpunkte is compared with a predetermined distance. If the determined distance is greater than the predetermined distance, then this distance is regarded as "noteworthy". If the distance is appreciable, a marker is given indicating that a quadrant cross-check should be performed and the two threshold points in question become

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added to a pool of intermediate quadrant checkpoints. Of the Operation then proceeds to block 510.

If the test in block 5θ6 · shows that the observed If the ray is an inner quadrant ray, a determination is made as to whether all of the fundamental rays have been tested (Block 510), and if it has not, flow returns to block 504. Are all basic rays checked, the program determines whether the quadrant inter-test flag has been set (block 518). The marking may have been set at any earlier point in the processing sequence, whereupon the Process via connection A (border 516) to block 518 may have returned.

If the flag for the quadrant interim check has been set, the program proceeds to block 520 in FIG Figure 25B, where a quadrant interim check routine is called will. The sequence of this program is briefly explained with reference to FIG. The first step in the quadrant interim program (Block 602) consists in the selection of an intermediate quadrant area, which is to be checked / grounded. If tests are required for several intermediate quadrant areas, then an area selected at random. After selecting this area, the pair of points in the area between the quadrants is selected that has the greatest perimetric distance (block 6o4).

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If this is the first call to the quadrant interim test program acts, this pair of points consists of those threshold value points that are obtained by passing through outer quadrant counter rays were determined. Was that Run through the intermediate quadrant test program beforehand, points can be chosen between these. After selecting the points, the vertical bisecting line LS becomes the die Points connecting chord are calculated in the manner described above and a test point along the straight line LS moved (block 6O6). The point at which the checkpoint is to Movement along the straight line LS appears for the first time can, as already mentioned above, be freely selected. In the embodiment of the quadrant interrogation program however, as shown in Fig. 26, the starting point is on the starting circle on the same side of the intermediate quadrant line like the threshold point closest to the pixel point. It is necessary to find the intersection between the The straight line LS and the starting circle where the test point appears first, since the straight line LS is the starting circle two places. After the test point has been determined by the patient or the test person, the threshold value point becomes recorded (block 6O6). The program then determines whether all of the threshold points are in the intermediate quadrant are allowed close and sufficiently numerous "(typically three points are needed) (block 608). If this is the case, the test of the intermediate quadrant area is completed and the results, namely the determined ones Threshold points, stored (block 610). the

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Questioning whether the threshold points are sufficiently close is made simply by comparing the distance between the two points with the greatest perimetric distance determined with a predetermined value ·. Is that distance less than the predetermined value, then all threshold points are considered to be sufficiently close. If the program has determined that all threshold value points in the area between the quadrants are not sufficiently close, it returns to the main program at block 522 in Figure 25B.

If it was determined in block 518 that the inter-quadrant check mark had not appeared, then flow moves directly to block 522 in Figure 22B and skips the inter-quadrant check. At block 522, the program determines whether there is a blind spot examination marker. If this is the case, a test program for the blind spot is called up (block 52 ¹ I).

A flow diagram for a possible test program for a blind spot is shown in FIG. The first step in this program consists in the selection of a blind spot to be examined (block 620). Should be more than a blind one Are checked, the selection of a blind spot is arbitrary. Then the program selects from the stock Test points for the blind spot select a point that is the starting point for the test. As will be explained later, does the supply of checkpoints for the blind spot contain data,

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which, for each blind spot, identify all static test points that were used in an intermediate isopter test to determine whether a blind spot is present. As already mentioned, these test points formed an arrangement in which one point had a distance of at least Z / 2 from all other points of the arrangement and from the two isopters under consideration. An isopter intermediate test program will be explained later. After selecting a point from the pool of test points for the blind spot, it is determined whether all of the fundamental rays, of which there are four, have been tested for that point (block 624). If this was not the case, a test stimulus is moved outwards from the selected point along an unchecked basic ray (block 622) until a limit point is determined (block 626), ie a point at which the patient or test person can Perceives stimulus. This boundary point is recorded and the program proceeds to block 632. If it is determined in block 62h that all fundamental rays have been checked for the points under consideration, the pair of boundary points which has the greatest perimetric distance is selected (block 628). The vertical bisecting line LS on the chord between the two points is then calculated and tested, and the boundary point found in this test is recorded (block 630). As already mentioned above, one possibility for testing along the straight line LS is to move the stimulus from the point of intersection of the straight line LS with the basic ray closest to the chord between the two points. Of course, other methods can also be used.

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After the test has been carried out along the straight line LS, the program proceeds to block 632, where it is determined whether all boundary points are sufficiently close. Again, the determination is made simply by comparing the distance between the pair of points having the greatest perimetric distance with a predetermined value. If all boundary points are sufficiently close together, a marker is given indicating that no further tests are required for this blind spot, and the test results are stored (block 63 ¹ I). The blind spot check routine then returns to block 526 of the main routine (Fig. 25B). If it is determined that the boundary points are not sufficiently close, the blind spot check routine returns directly to block 526.

After returning from the blind spot test program, it is determined whether all threshold points are on the test Isopters are sufficiently close together (block 526 in 25B). This test is carried out in the same way as for the square intermediate test program and the test program for the blind spot. If the threshold value points are sufficiently close, the process goes through connection B. (Border 528) to block 552 in Figure 25C. Are the threshold points not sufficiently close together, the pair of points with the greatest perimetric distance is selected (block 530). The bisecting line LS lying perpendicular to the chord connecting the points is calculated and along this line

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an examination carried out. Upon the patient's perception of the checkpoint, the threshold point is recorded (block 532). Thereafter, it must be decided whether a sufficient number of beams in the quadrant in which the calculated straight line LS is previously checked (block 53 ¹ O. If this is not the case, the program returns via the Compound A (border 516) for 25A, block 518. If a sufficient number of rays have been tested, the program marks the quadrant under consideration for which this isopter test is complete (block 536) and proceeds to the block in FIG. 25C. If this is not the case, the program again moves back to block 518 in Fig. 25A, otherwise it goes to block 5 ¹ JO In block 5 ^ 0 it is determined whether an earlier isopter is checked If so, a determination is made as to whether the maximum distance between the isoptere currently checked and the isoptere checked earlier is greater than a certain threshold value distance Z (block 5 ^ 2) Z, it is determined whether the minimum distance between the isoptere currently under consideration and the earlier isopter is less than Q (block 5 ^ 3) Presence of a blind spot is great. In other words, if the distance between isopters, such as the bulge shown in FIG. 23A, is suspiciously large compared to the smallest distance, there is a likelihood of a blind spot being present.

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Is the maximum distance between the currently considered . and the earlier isopter less than Z (block 542) or if no previous isopters were checked (block 540), the program returns to block 544.

If the maximum distance between the considered isoptere and an earlier isoptere is greater than Z and the minimum Distance is less than Q, an intermediate static isopter test program retrieved (block 5 ^ 6) · A flow chart a method for carrying out this intermediate isopter program is shown in FIG. The first step (block 64O) is to compute the coordinates of static points to carry out a test between the isopters under consideration, the points at least one Have a distance of Z / 2 from each other and from the two isopters. An arrangement of such points is shown in Fig. 23A shown. After determining the static test points, the brightness value of the stimulus is set to the same value, the one for testing the outer, delimiting the test area Isoptere was used (block 642). Then a point is selected and applied the stimulus to that point (block 644). If the stimulus is sensed (block 648), the point becomes off removed from the test assembly (block 650). Will the stimulus not 'Perceived, the item is placed on a list (block 652) for later use in blind spot testing, and the program flow goes to block 65O. After Ent-, removal of the tested static point from the test arrangement

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a transfer to block 646 is made where it is checked whether the test arrangement is empty. If this is not the case, the program returns to block 644, if it is 'If so, there is a transition to block 548 of the main program (Fig. 25C).

If no blind spots were found during the isopter intermediate test, the program returns via connection A (border 516) to block 518 in Fig. 25A. "If a blind spot has been found, it is checked, for example through an additional isopter interim test. To address the demand for a blind spot examination show, a marking is generated, and, which were not perceived by the patient during the isopter intermediate test Checkpoints become the supply of checkpoints for the blind

Stain added (block 550). The program then goes to the block 544 about.

If the maximum distance between the considered and the earlier isopter is greater than Z and the minimum Distance not smaller than Q, is indicated by the fact that an isoptere is recorded as a result of the large distance between the considered and the earlier isopter is required, for which the program goes to block 5 ^ 5. there a brightness value is selected that is between the values for testing the present and the previous' Isoptere lies and in the store of brightness values

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entered. The program then goes to block 5 ^^ .

The procedural step according to block 5 ^ includes the setting of a marker that indicates the end of the test for the isopter currently under consideration, as well as the beginning of the next isopter test, i.e. resetting the counters, registers, etc., as well as the selection of the test point size, the speed, the direction of movement etc. A decision is then made (block 552) as to whether all normal tests, all intermediate quadrant tests, and all blind spot tests have been completed (the term "normal" test is understood to mean those tests which are used to determine an isopter along the fundamental rays and the bisecting lines be performed). If all the necessary tests have not yet been completed, the program returns to block 518 in FIG. 25A, otherwise there is a transition to block 553. In this block 553 it is determined whether all brightness values in the supply of brightness values have been tested. If this is not the case, the program goes to block 502 via connection C, otherwise the program is terminated.

Fig. 29 shows another embodiment of the invention for kinetic testing methods, one being hemispherical Screen as shown in Fig. 32 is used. Again, many of the components of the system of FIG. 29 are the same as those of FIG.

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elements are designated in the same way as the components according to FIG. 1. Furthermore, in the system according to Fig. 29 Components for the operation of the device from Fig. 32 inserted, which allow the computation of spherical coordinates requires.

In a spherical coordinate system there are three parameters or variables, namely -the variable Θ, the one denotes a horizontal angle coordinate, the variable 0 denotes a perpendicular angle coordinate, and the Variable r that specifies the radial coordinate. In the device according to FIG. 32, the patient or the test person becomes brought into a position in which the eye is substantially equidistant from all areas of the hemispherical screen, so that the coordinate r is constant is. The position of the test point on the hemispherical screen is indicated solely by the coordinates θ and 0. Taking these explanations into account, the system according to FIG. 29 will now be described.

This system includes a number of registers, such as a Θ-speed control register JOH for receiving digital information from the computer * J1 ₅ denotes the Θ-component of the velocity of the moving test point, a 0-speed control register 706 for receiving digital information on the 0 -Component of speed, a point size control-

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register 7O8 for recording digital information about the size of the checkpoint, an intensity control register 709 for receiving information indicating the intensity or brightness of the test point and a color control register 710 for receiving digital information that denote the color of the test point. There is also a Θ position control register 712 for receiving digital information from the computer 4l via the Θ start coordinate which the test point is offered, as well as a 0-position control register 716 present, the digital information receives via the initial 0 component at which the checkpoint is offered. A free running clock 726 provides Output pulses to an AND gate 727, which is used to select clock pulses for two multiplier circuits 714 and 718 is controlled by the computer 4l. The multiplier circuits. 714 and 718 multiply the frequency of the clock signal a value corresponding to the contents of the respective speed control registers 704 and 706. The resulting Signals are applied to the respective position registers 712 and 716.

The position registers 712 and 716 consist of simple up / down counters which increase or decrease their count as a function of each pulse received from a corresponding multiplier circuit. Whether a ^v position register increases or decreases its counter reading is determined by "a sign bit, which is stored in a corresponding

409838/0898

corresponding speed register is stored. For example, if the sign bit is positive, the corresponding one counts Position register forwards or increases its counter reading. with each received from a multiplier circuit Pulse. However, if the sign bit is negative, the position register counts down or decreases it Counter reading with each pulse from a multiplier circuit.

In each of the speed register 7O ¹ J 706 and stored information is an integer from the ratio of Θ- and 0-speed components. If the test point is thus to be moved five steps in Θ * · direction for each step in the 0 direction, a 5 is stored in the Θ speed control register 704 and a 1 in the 0 speed control register 706. If the speed of the test point is twice the value indicated by this ratio, an IO would be stored in the Θ speed control register 70 * 1 and a 2 in the -0 speed control register 706. An increase in the value stored in the speed registers results in a corresponding increase in the number of pulses ^{generated by the multiplier circuits 71 1} I and 718.

The counter information in the Θ-position control register 712 and in the 0-position control register 7l6 are each supplied to an adding circuit. 728, 730, which give the counter information to the registers 732 and 73 ¹ J in the absence of stored information in the registers 7 ^ 6 and JUB. the

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Information in registers 732 and 734 identify the current location of the test point in Θ and 0 coordinates. This information is passed to servo and control units 736 and 738 which control certain parts of the display device 740 for controlling the position of the test point on the hemispherical screen. The servo and control units 736 and 738 are shown in detail in Fig. 30 and will be described later.

While the test is running, the fixation point monitors. monitor 56 the line of sight of the patient and supplies signals to two analog / digital converters 742 and 744 as soon as a change of line of sight is detected. The signal fed to the converter 742 indicates the Θ component of the change in the line of sight, while the signal fed to the converter 744 indicates the 0 component of the change in the line of sight. The digital information generated by the converters 742 and 744 is fed to the register 746 and 746, respectively, whereby this information can reach the adding circuits 728 and 730. The adding circuits 728 and 730 add the content of the register 746 or to the content of the position control register 712 or 716. The resulting sum denotes a "shifted" position of the test point, whereby the change in the patient's line of sight is taken into account. This process is of course very similar to that which has been described in connection with the system from FIG. The output signals of the adding

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Circuits 728 and 730 enter registers 732 and 732 in the manner previously described

The information in Dot Size Control Register 708, Intensity Control Register 709, and Color Control Register are fed directly to servo and control units 720, 722, respectively. The servo and control units react quickly Control certain parts of the display device 740 so as to adjust the size, intensity and color of what appears on the screen To determine the point. The servo and control units 720, 722 and 724 have the same structure and are im each shown in FIG.

If the patient perceives a stimulus, he actuates the pointing stick 49, as a result of which a signal is fed to the computer 4l. As a result, the computer 4l removes the activation signal from the AND gate 727 and lets the Θ-position control register 712 and the 0-position control register 716 interrupt further counting. Then the computer 41 reads out the content of this register, which designates the point at which the stimulus was stopped.

A servo and control unit is shown in the part outlined by dashed lines in FIG. 30 and is connected to a register 810, sound to which digital information is received, as well as to a servomotor 8o8, the ποη of the unit 800.

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is controlled. The information from register 810 goes to a digital comparator 80 * 1 and is compared with digital information from a shaft angle encoder 802. The information from the shaft angle encoder 802 designates the angular position of the drive shaft of the servo motor 808. If the angular position of this shaft agrees with that designated by the information from register 810, the digital comparator 804 does not generate an output signal. If the angle of the position of the drive shaft of the servomotor 8θ8 is greater than specified by the information from the register 810, a signal is sent via the line 812 to the puncture amplifier 8o6, which uses the signal to activate the servomotor 8θ8 to reduce the angular position of the drive shaft by one the line 812 indicated value. If the angular position of the drive shaft is smaller than indicated by the information from register 810, the digital comparator 80 ^ 1 sends a signal to the function amplifier 8θ6 via line 814, whereby the servomotor increases the angular position of the drive shaft. In this way, digital information is used to control the angular position of the drive shaft of a servo motor. The connection 8l6 denotes a mechanical connection with the drive shaft of the servo motor 8θ4, while the connection 8l8 is an electrical connection. The structure and mode of operation of servo and control units according to FIG. 30 are known. ■

Before describing the display device 7 ^ 0 according to Fig. 29, - ,.

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detailed in Pig. 32, the circuit of FIG. 31 will be described.

The circuit according to FIG. 31 is used to change the speed of a test point as a function of its distance from the fixation point. The circuit shown in outline '828 can be combined with the system of FIG. 29 by connection to the clock 726, the Θ position control register 712 and the 0 position control register 716. "In operation, the digital-to-analog converters 834 and 83o receive counter information from the position control registers 712 and 716, and the resulting analog signals indicating the Θ and 0 coordinates · of the location of the test point ₃ are fed to the multiplier circuits 838 and 840.

These multiply the signals to get signals that are 2 2

denote θ and 0 and which are then supplied to an adder circuit 8 * 12. This adding circuit adds the signals and outputs the result to a square root circuit 844, producing a signal denoting J _Q 2 ^ 2.

If the coordinates of the test point change, the size of this signal will of course change. One assumes that the switch 846 is closed, the signal reaches an adder circuit 848. This is also on Signal supplied which is generated by a basic speed circuit 850. Having a manually selectable basic speed designated. The size of this signal determines one

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so-called basic speed _s and this variable can be changed by means of the control button 852. The basic speed circuit 850 can for example consist of a voltage generator. The base speed is the minimum speed at which the test point is moved regardless of its distance from the fixation point.

The signals from the square root circuit 844 and the Base speed circuit 85O are by means of the Adding circuit 848 added and the clock 726 to Control of the frequency of its output signals supplied. The larger the value of the signal from the adder circuit 848, the larger the pulse frequency of the clock pulses becomes. In this context, reference is again made to the description of FIG. 29, from which it follows that the The greater the pulse frequency of the clock pulse, the greater the speed of the test point. Thus, the The circuit shown in FIG. 31 reduces the speed of the test point when it approaches the fixation point which has the coordinates 9 = 0 and 0 = 0, and vice versa. So if the test point directly overflows the fixation point, so that the signal from the square root circuit 844 becomes 0, the adder circuit 848 will still be on Signal supplied by the base speed circuit 85O so that the clock 726 has a certain minimum speed of the checkpoint.

If the test point is to be moved at a constant speed, the switch 846 is opened and the

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Adding circuit 848 only takes the signal from the base speed circuit 850 supplied. Thus, a constant magnitude signal is applied to clock 726.

Fig. 32 shows a display device which is related can be used with the system of FIG. This device includes a hemispherical screen 902 on to which a checkpoint 904 is offered '. A test subject or a patient 906 is brought in front of the screen so that the eye to be examined is substantially the same distance from all areas of the screen. It should be noted that no mask and no eyepiece in the device according to Fig. 32 is shown 'how this is in the device according to FIG was the case, although such elements may be present. In addition, the device for checking the line of sight of the Patients not shown in Figure 32, although such a device can be used.

A number of servo motors 908, 910, 912, 914 and 916 controls the various elements of the display device. Each of these servomotors is equipped with a corresponding servo and control circuit as described in connection with FIG. The servo motor 908 controls the Angular position of a brightness filter wheel 920, the one Contains number of segments offset by angular positions for determining the brightness of the light beam falling through. This light beam 922 comes from a light source 924,

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behind which a reflector 926 is arranged to a larger To provide proportion of the light for the light beam 922 available. A pair of lenses 928 focus and guide the light to the filter wheel 920.

The servo motor 910 controls the angular position of a color filter wheel 930, which determines the color of the test point offered on the test screen. The color filter wheel 930 is rotated by a servo motor 10 to change its position so that a color filter is placed in the path of the light beam 922 which filters out all colors except the desired one from the light beam.

The servo motor 912 controls the angular position of an aperture wheel 932 for determining the size of the test point. This aperture wheel has a number of openings of different sizes, which are distributed around the circumference of the wheel. If a certain test point size is desired, the servo motor 912 rotates it Wheel 932 until the opening of the appropriate size is in the way of the light beam 922 is located. The openings shown in FIG. 32 are significantly larger than those in FIG. Practice to be used. This enlargement was chosen only to clarify the representation.

Two mirrors 936 and 9 ¹ IO guide the light onto the test screen 902, as indicated by the dashed line 9 ^ 1. The mirror 936 is arranged in a fixed position to the

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Direct light beam down onto the mirror 9 ² JO. This mirror 9 ^ 0 can be rotated about two vertical axes lying in the plane of the mirror. Two servomotors 914 and 916 control the rotation of the mirror 9 ^ 0 'about each of the two axes, one of which represents the Θ coordinate and the other represents the 0 coordinate. Structures that allow rotation with two degrees of freedom are known.

As in the device according to FIG. 2, the test subject 906 reacts to the occurrence of the test point by actuation a pointer 952 of the type described above. This response is recorded and additional checkpoints are offered.

Although the invention has been described above in connection with various exemplary embodiments, - it is "not restricted to these, but further changes and modifications are possible, all of which fall under the invention.

409836/0898

Claims (1)

Patent claims: 1.) Automatic method for testing the visual field of a living being, in particular a human being, thereby characterized in that the respective direction of view of the test object is determined by machine control, that machine-controlled short-term points of light with a selected stimulus value are offered on a test screen in a test field in relation to the respective viewing direction is centered and that it is determined whether the subject perceives the points of light. 2. The method according to claim Ij, characterized in that the points of light are offered in a machine-controlled manner in a sequence that could not be foreseen for experiments. 3. The method according to claim 1 or 2, characterized in that an indication of the correct perception by the Experimental entity is generated when this has correctly perceived the point of light, and that a display of a false perception is generated when the experimental subject has not correctly perceived the point of light. k. Method according to one of Claims 1 to 3, characterized in that the test being allows the perception of a point of light by operating one by hand 409836/0898 operating device indicates. 5.. The method according to any one of claims 1 to 4, characterized characterized in that the perception of a stimulus by the experimental subject by determining the change in the generated cortex potentials in the occipital center is determined. 6. ' Method according to one of claims 1 to 4, characterized in that the perception of a stimulus by the experimental system by determining the movement of the eye of the experimental system in the direction of the test site, at which the stimulus was perceived is determined. 7 ■ The method according to any one of claims 1 to 4, characterized characterized that the perception of a stimulus by the experimental system by plaguing the change in diameter the pupil is determined. 8. The method according to any one of claims 1 to 7, characterized in that the light points at selected, im Stationary test parts are offered in the test field. 9. The method according to claim 8, characterized in that machine-controlled additional short-term light points with variable stimulus value are offered at the selected test points and that the stimulus values are determined, 409836/0898 24096U in which the experimental system perceived certain points of light. 10. The method according to claim 9> characterized in that the stimulus value of an additional, short-term point of light offered at a specific test point is calculated as a function of the established perceptual behavior of the test being, so that the The threshold value of the stimulus perceived at each selected test site in the test field is determined. 11. The method according to claim 8, characterized in that the threshold value of the stimulus is machine-controlled at each selected test center is offered. 12. The method according to any one of claims 1 to 11, characterized characterized in that the current line of sight of the test object by determining the relative position of the image of a point radiation source is determined on an image of the pupil. 13 · The method according to claim 12, characterized in that ■ a point-like light source lying in infinity is used. Ik. Method according to one of Claims 1 to 11, characterized in that the current viewing direction 409836/0898 2A096H of the experimental system machine-controlled through determination the changes in the horizontal and vertical components of the electric field surrounding the eyeball as a result of the changing corneo-retinal standing potential · is determined. 15. Method according to one of Claims 1 to 14, characterized in that, before the start of the determination, the instantaneous Direction of view of the experimental being - a refraction correction of the eye of the experimental being made will. 16. The method according to any one of claims 1 to 15, characterized characterized in that at the beginning it is determined under machine control which eye of the test object is being examined becomes, and that depending on this plague The pattern of the points of light to be offered is selected. 17 · Method according to one of Claims 1 to 16, characterized in that the offer of the test points is based on the test screen in the test field is centered with respect to the current viewing direction of the test object by a pure translation of the preselected checkpoint coordinates with fixed coordinates with respect to the Direction of view is carried out. 409836/0898 - - 107 - 24096H Ιδ.- Method according to claim 17, characterized in that that a flat test screen is used and that the The stimulus value of the light points changed according to the size and direction of the translation of the test point coordinates will. 19. The method according to claim 18, characterized in that the change by calculating the stimulus value B. one Light point calculated at a shifted light point will after - ~ B ₁ «[ d ² + (AXr + (ΔΥΡ _{3 Bo} d ² where d is the distance of the eye of the test subject from the center of the test screen along a vertical axis on the surface of the test screen, B _{n is} a predetermined one 2 2 Reference square and ( Δ X) + (ΔY) is the square of the distance from the center of the test screen to the location of the moved test point. 20. The method according to any one of claims 1 to 19, characterized in ₉ that an alarm signal is generated and the . The point of light is terminated when the line of sight of the test system deviates from a reference point in the test field by a preselected limit amount. 21. The method according to claim 20, characterized in that the offering of the light point is resumed, 409836/0898 when the viewing direction of the test object returns to the preselected limits. 22. The method according to any one of claims 1 to 21, characterized in that the light points initially on one pre-selected position in the test field and then machine-controlled in a specific direction be moved in the test field. 23 · Method according to claim 22, characterized in that it is determined when the experimental system perceives each point of light. 24. The method according to claim 22 or 23 »characterized in that that the light points are initially offered at a point in the test field that is outside the field of view of the Experimental, and that the points of light are then moved towards the field of vision until perception. 25. The method according to any one of claims 22 to 24, characterized characterized in that the speed of movement of the light points as a function of the distance from the pixel point is changed. 26. The method according to ^ one of claims 22 to 25, characterized in that the point in the test field is determined at which the light point is perceived. 409836/0898 27. The method according to any one of claims 22 to 26, characterized in that depending on the reaction time of the experimental system, the point on the trajectory of a point of light is determined and overflowed before stopping. 28. The method according to any one of claims 22 to 27, characterized in that the light points initially at a distance distributed from each other around the perimeter of the test field ■ Positions offered and then inwards to the position indicated by the direction in which the test is being viewed v / ground the test screen. 29 · The method according to claim 28, characterized in that · that the points distributed around the perimeter of the test field on both sides of imaginary vertical and horizontal lines that divide the test field into four quadrants. 30. The method according to claim 29, characterized in that the perception points for two .sich along adjacent Paths of moving points of light are determined and that another point of light is moved along a path that moves extends substantially perpendicular to a chord between the two points of perception. 51. The method according to claim 30, characterized in that the movement along the vertical path at a predetermined distance from the tendon outward to the circumference of the 4 09836/0898 24096U Test field begins and that the point of light is moved from there towards the tendon. '32. Method according to claim 30 or 31, characterized in that ' that the procedural steps of determining the perception of two points of light and the movement of another Light point along a path perpendicular to the tendon connecting the points of perception of the two light points is repeated until the points of perception of each pair of points of light are within a predetermined distance. 33. The method according to any one of claims 22 to 32, characterized in that initially in an area in the test field, which designates a determined blind spot of the test, offered points of light one after the other moved in a number of directions until the experimental subject perceives them. 3 * f. The method of claim 33> characterized in that the light spots are moved sequentially in four directions that differ from each other by at least 90. 35 · Method according to Claim 33 or J> H, characterized in that the points in the test field are determined at which the test unit perceives each point of light. ' 409836/0898 ■ - in -. 24096U 36. The method according to any one of claims 33 to 35 »thereby characterized in that the two points of perception are determined for two points of light moving along adjacent paths and then another point of light is offered and is moved, which moves along a path that the tendon between the two points of perception in the essentially cuts at a right angle and which begins on one of the pathways that started from one of the previous moving points of light was traversed. 37 · The method according to any one of claims 22 to 36, characterized characterized in that the points of light are offered on a flat screen and their directions of movement and -speeds in a Cartesian coordinate system can be specified. 38. The method according to any one of claims 22 to 36, characterized in that the light points on a hemispherical Umbrella offered and their directions of movement. and speeds in a spherical coordinate system can be specified. su: cm 409836/0898 Blank page