WO1996013195A1

WO1996013195A1 - Method and device for determining horizontal, vertical and/or cyclo-deviations on the eye

Info

Publication number: WO1996013195A1
Application number: PCT/EP1995/004237
Authority: WO
Inventors: Hans-Jörg ETTER; Jakob JÜTZ; Hans-Jörg ZWEIFEL
Original assignee: Interstaatliche Ingenieurschule Neu-Technikum Buchs
Priority date: 1994-10-29
Filing date: 1995-10-29
Publication date: 1996-05-09

Abstract

The invention concerns a device for determining horizontal, vertical and/or cyclo-deviations on the eye of a person (10) to be examined, said device comprising an arrangement for generating a substantially punctiform and/or linear fixation light (3, 15) on a panel (1) disposed in the field of vision of the person. A lens system (24) is provided which enables the fixation light (3, 15) to be mapped as a virtual object point or virtual object line at predetermined positions on the panel (1). Means are provided which prevent the person (10) perceiving the fixation light (3, 15) directly.

Description

METHOD AND DEVICE FOR DETERMINING HORIZONTAL, VERTICAL AND / OR CYCLODEVIATIONS ON THE EYE

Squint (lat. Strabismus) is understood to mean disorders of binocular vision, which are due to disturbed sensorimotor functions of the visual organ, abnormal position of an eye, paralysis of one or more eye muscles or disorders of the balance between the outer eye muscles when the compulsion eases Fusion based. Undisturbed binocular vision is given when all the visual objects located on the so-called horopter circle (circle through the fixation point and the respective nodes of the two eyes) are simultaneously imaged on corresponding retinal sites and when the two retinal images merge into one Image takes place.

This binocular vision is disturbed, for example, if both eyes have different focal lengths, the eyes are then not used in the same way. The brain suppresses the visual impression of an eye, which is then rotated to a different position instead of being directed at the object to be viewed, generally inwards (esotropy, positive squint angle), more rarely outwards (exotropy, negative squint angle).

Another form of squint is caused by paralysis of one or more eye muscles, which is possible after an injury or disease of the central nervous system. The relative deviation of the eyes, the so-called squint angle, increases here if the eye movement includes one of the paralyzed eye muscles.

So-called latent squinting (heterophoria), which is slightly physiological, is based on a disturbance in the balance between the outer eye muscles when the pressure to merge subsides. The eyes only pass proceeding from their primary position, ie the parallel lines of sight.

At the center of all problems associated with dual vision are the fusion and the detection, possibly differentiation and treatment, of their disorders.

A test that allows a quick but rough preliminary examination of nearby binocular vision is the so-called Worth test, in which the two visual impressions of the two eyes are separated - one red, one white and two green dots are closed consider - done by placing a red or green filter. The fusion is not switched off completely, but is weakened.

The determination of the squint angle in all nine viewing directions is carried out, in particular, according to a test method in which a bright, white point is surrounded by a field which has any optotypes, such as lines or other details capable of accommodating or converging. One of the two eyes is covered by a dark red glass, so that the optotypes of the field surrounding the point can no longer be recognized with this eye. The other eye, which does not have a filter, perceives the optotypes and can accommodate or localize them. The fusion is switched off.

Such a test can also be used to distinguish between so-called paralysis and so-called accompanying squint. Paralysis squint is understood to mean all those forms of squinting in which the squint angles are different for different viewing directions. The cause of such a paralysis squint does not have to be paralysis, it can also be an anatomical inflammatory or mechanical disability. In the case of accompanying squinting, however, the squint angle m remains in all so-called ten directions of use, ie 15 ° from the primary position, the same.

Both the so-called Maddox test, which is particularly suitable for the quantitative determination of deviations in the muscular balance in the vicinity, and the test on the so-called Harms wall, which is particularly suitable for the examination of deviations of the binocular, work according to the principle mentioned Seeing at a greater distance is suitable.

The examination device specified by Harms allows the measurement of larger and smaller squint angles with constant removal of the patient from the Harms wall designed as a tangent table. The patient's line of sight can be defined well - which can sometimes be problematic in the case of the corneal reflex determinations customary in other test methods. However, errors can also occur here due to an inaccurate alignment of the forehead projector primary direction (eyes) and, if appropriate, an unsteady posture of the head during the examination, which makes the determination of the squint angle uncertain, particularly in the case of elderly patients or those with signs of paralysis. In addition, if the patient indicates the position of the red dot with a pointing light, trembling movements can make precise localization difficult. Errors in a range of approximately 5 ° have to be accepted.

When testing on the so-called Hess umbrella, the coordinated cooperation between the two eyes is checked in particular. The Hess screen is - just like the Maddox or Harms wall - a tangent screen that is used to examine the close range. Complementary colors are used to separate the two eyes, one eye seeing the fixation points and the other eye a pointer, which the patient tries to align with the fixation points. The object of the present invention is to provide a method and a device which - if necessary in combination with other known test methods - enable the determination of subjective squint angles in all nine viewing directions, the head - regardless of the viewing direction to be examined - remains stabilized and which can be used, in particular, for measurements in the long range, but also for measurements in the close range, if necessary.

This is achieved by means of a method in which the characterizing features of claim 1 or by means of a device in which the characterizing features of claim 3 are realized.

Advantageous or further training is described by the characterizing features of the dependent claims.

The fact that the fixation light, which is used to determine horizontal or Vertical deviations are point-shaped or ring-shaped, are designed as lines or bars to determine cyclodeviations, are provided as a virtual image object, the viewing direction can be changed in a predetermined manner without changing the head posture, which can thus be kept stabilized. Viewing angles in the horizontal and vertical directions of ± 25 ° should thus be able to be checked.

If the covering of an eye with a colored glass, which suppresses the surroundings of the fixation light, is also used for most examination arrangements, as is also known, the eye could also be covered with a polarizing glass, which if necessary also colored st. Due to the fact that means are provided which prevent the person under examination from directly perceiving the fixing light, no disruptive multiple images will influence the measurement result. If the optics include these means as integrated components, possible, intensity-reducing reflections can be reduced or even suppressed due to combination arrangements.

If the fixation light or fixation lights, whether point-shaped or line-shaped, are projected onto the panel via any projection device, the panel can on the one hand be designed as a simple projection screen that can optionally be folded or rolled up, or could be dispensed with entirely if a sufficiently large, free wall surface is available which can then be seen as a "board".

In the sense of the invention, "panel" is to be understood as any essentially flat surface onto which the fixing light can be projected.

However, the fixing light can also be designed to be self-illuminating, as is the case with the classic Harms wall, for example, and can be assigned to the panel. The rotation of the linear fixing light can then be carried out by the patient using a remote control, in accordance with the manner known from the Harms test.

A device for stabilizing the head, for example in the form of a chin and a forehead support, makes it easier for the person to be examined to maintain a constant head position during the examination, which generally comprises several examination steps. The optics, which are preferably housed in the housing on which the device for stabilizing the head is also arranged, should be arranged as close as possible to the eye so that the smallest possible components can be used. Also this makes the part of the device which takes up the optics and, if appropriate, also the projecting direction, more compact and therefore more manageable (the table is also to be regarded as part of the device). The use of the device, for example in medical practices, in which orthoptic examinations only have to be carried out occasionally, is thus more convenient.

If the optics comprises at least one component that is at least partially configured as a tiltable and / or rotatable beam splitter, then - depending on the design of the optical system, i. the type and arrangement of the components used in each case - on the one hand the possibility of perceiving the relevant panel area, and on the other hand the possibility of preventing direct perception of the fixation light. Other optical systems, for example certain systems with prisms, can have the same effect for a certain eye area without the need to use a beam splitter.

An embodiment which is characterized by great compactness, essentially perpendicular impingement of the fixation eye and the use of plane optics comprises a pair of beam splitters, a pair of polarization filters and a pair of delay plates. These optics can also be used for other applications, and always there when an object is intended to prevent direct beam passage, but the object - as a virtual object - should be perceptible in any direction.

If the projection device comprises a slide projector with deflection devices, which can preferably be rotated and / or tilted, then fixation light and, if appropriate, also a

Pointing light can be projected onto the board via a specially designed slide, the deflection device for the The pointing light beam is designed to be rotatable and / or tiltable, which gives the patient the opportunity to position the pointing light on the board according to his subjective visual impression, which - in contrast to a freely guided pointing lamp - enables an exact measurement result.

The fixation light can also be projected onto the blackboard via another projection device, for example the possibility of a laser beam projection is given.

In the same way, the specially designed slide, which has at least one part which can be rotated in the form of a surface section and / or layer part about an axis perpendicular to the slide surface, gives the possibility, via the rotation of this part, of the image of the linear fixing light projected onto the board twist.

In principle, the fixation light (s) and the pointing light could be projected independently of one another; if the disadvantages described can be accepted, the pointing light could be projected onto the board independently of the device by means of a pointing light. However, it is also possible to dispense with a pointing light, particularly if the board has a coordinate cross with grid lines. The patient will then - since the naked eye can perceive this - read the measure of the deviation himself using the markings.

An actuating device for adjusting the optics - depending on the optics used, it may involve rotating and / or tilting mirrors and / or beam splitters or changing the wedge angle of a - for example elastic - prism - should, if necessary, be program-guided ( which is to be understood as a certain sequence of examination steps in the case of differing viewing directions), either allow a purely mechanical or, for example, sensor-controlled adjustment. Is a If a remote control is provided, which is operated, for example, by an orthotist, this can control this actuating device via a suitably designed keyboard. Measuring sensors on the moving parts of the optics make it possible via signals, which are preferably supplied to at least one microprocessor provided in the remote control, to determine the extent of the adjustment by means of which the respective viewing direction is determined. These values are preferably shown on a display on the remote control.

A corresponding control is preferably provided, which is operated by the patient-operated actuating device for the linear fixing light, i.e. twisting the moving part of the slide happens. In the manner shown above, measurement sensors on the moving slide and / or the actuating device - preferably via signals to the microprocessor of the remote control - will also preferably enable the angle of rotation to be determined and its representation on the display of the remote control.

If the pointer is also projected over the slide in the manner shown above, coordinate values are also correspondingly available as a measure of the values to be fixed via the adjustment of the associated deflecting device — if appropriate again via the microprocessor of the remote control representative deviation.

The invention is illustrated below with reference to drawings. Show it:

Fιg.1 a representation of the measurement principle, which is also the basis of the Maddox or the test on the Harms wall; 2 shows a patient with an orthoptist during an examination in front of a harm wall; 3 shows a section through a device according to the invention, with a functional principle for the projection of Fixing light and pointing light, as well as with optics for changing the direction of view; Fig. Is an illustration of a design of the optics for the

Change of viewing direction; 5 shows a variant of the design of the optics for the

Change of viewing direction with deflecting mirrors; 6a and 6b examples of prisms that are possible as components for the optics; 7 shows an embodiment of a slide for the projection of fixation light and pointing light;

8 shows a representation of a control of the projection device for fixing light and pointing light and the optics, and FIG. 9 shows an exemplary representation of the control panel and the display of a remote control.

FIG. 1 shows the measuring principle which is used to determine deviations according to the Maddox or Harms test and which is also the basis of the present invention. A coordinate cross 2 is arranged on a table 1 at a certain distance b from the patient to be examined. A white, point-shaped fixing light 3 is provided in the coordinate center, which is at eye level of the patient. The distances x ^, X2 »X3, .. between the individual markings on the coordinates enable the reading of horizontal and vertical deviations according to the formula ∑x _n = tgα-b. The markings correspond to the projection of degrees of arc onto the vertical and horizontal coordinates, the respective distances therefore increasing from the center to the periphery.

The point-like fixing light 3 is fixed alternately with both eyes, one of the two eyes - in the example of FIG. 1 the left eye 5 - being placed in front of a relatively dark red glass 6. Through the red glass 6, only the fixation light 3 can be recognized with the left eye 5, but not the surroundings of the same - and thus also not the coordinate cross 2. the. The merger is thus switched off. If the patient now sees the red light 8 congruent on the white fixation light 3, the subjective squint angle is zero. In the example in FIG. 1, in which the red light 8 is seen to the left of the white fixation light 3 (the right eye 4 fixes the fixation light 3), it is a manifest esotropy, the marking is a measure of the positive squint angle. If the red light - with the left eye 5 covered in red - is seen to the right of the white fixation light 3, then there is exotropy, the marking is a measure of the negative squint angle. Hypo- or hypertropias (squinting downwards or upwards) can be determined in the same way. The squint angle can either be read directly by the patient using the markings on the coordinate cross 2, or by an orthoptist if the patient is using a

Indicating light indicates the position of the red point 8, or due to a back centering of the red point 8 on the white fixation light 3 via the strength of a prism placed in front of the covered eye.

2 shows an examination on a so-called harm wall 9, which is carried out in accordance with the measuring principle described above. A table, the so-called Harmswand 9, which is at a distance of 2.5 m from the patient 10, carries a coordinate cross 2a with grid lines. The markings correspond to the deviation values of the observed squint angles for the respective viewing directions. The white, mostly point-shaped, fixation light 3 is located in the center of the coordinate cross 2a. A line-shaped or bar-shaped fixation light 15 is - likewise in the center of the coordinate cross 2a - on a remote control 14 in a clockwise and counterclockwise direction rotatable support, for example a circular disk 16, is provided. This line-shaped fixing light 15 is used for measuring cyclodeviations, for the measurement of horizontal and vertical deviations it is extinguished. The patient 10, whose eyes are arranged at the level of the center of the coordinate cross 2a ten fixierlichtes 3 carries a front projector 12 with which, for example, a cross-shaped position light can be projected onto the harm wall 9. This forehead projector 12 can be adjusted on the head of the patient 10, so that when the head of the patient 10 is held straight, which requires the control by a location optician 11, the position light is directed at the center of the coordinate system 2a . This ensures that the line of sight remains unchanged during the respective measuring process. Now one of the two eyes is covered with the red glass in the manner shown above. Since the examination takes place in a slightly darkened environment, the surroundings of the fixation light 3 disappear for the covered eye, which sees a red image of the fixation light 3, whereas the uncovered eye retains this. This prevents the fusion, the two visual impressions no longer match for patients 10 who squint, there is confusion. The patient 10 directs the beam of a pointing lamp 13, which projects a green ring onto the Harmswand, for example, to the point at which he sees the red light. The orthoptist 11 can read the deviation directly on the basis of the markings.

If the head position is the same - control is given via the alignment of the position light - the beam-shaped fixing light 15 is switched on. In the case of cyclotropy, ie a squint position with the rotation of an eye about an anterior-posterior axis, which occurs when the oblique eye muscles are injured and - together with side and height deviations - with certain squint shapes, an eye is used to measure the cyclodeviation covered with a red glass, the other eye is mostly darkened. The patient 10 must now, with the head position held constant, try to use the remote control 14 to set the bar-shaped fixing light 15 again horizontally - subjective visual impression. - 1 2 -

Then the head position is changed, the measure for the rotation of the head in a different direction of view can be controlled via the position light. The measurements are carried out in the manner described above, specifically for certain positions of the rotated or inclined head, for example each spaced 5 ° apart.

3 shows a representation of a device according to the invention, in which the checking of binocular vision with the head held in a fixed position and the measurement of the squint angle over a range of ± 25 ° horizontally and vertically is possible, and with the tremor movements, the perfect reading of the pointing light or could impair the correct positioning of the position light can be excluded.

A housing 17 comprises the projection system 19 for fixation light 3 or 15 and pointing light 27 and an optical system 24 for changing the viewing direction 29 of a patient who has his head in a position on the housing 17 which stabilizes and fixes the position of the head Headrest 18 with chin 18a and forehead support 18b holds.

Using the slide projector 28, fixation light 3 and 15, point or ring-shaped and line-shaped, and pointing light 27 are projected onto a panel 1. The formation of the slide 34 can be seen below in FIG. 7. The slide 34 is designed in two parts, one half possibly being rotatable for itself and representing the positive for the two fixing lights. The other half of the slide is the positive for the pointing light 27, which for the sake of better distinguishability is preferably designed as a green dot. The double beam of rays emanating from the slide projector 28 and passing through the two halves of the slide 34 is deflected by a deflecting mirror 26. As can be seen from the beam paths 20 and 21 for the fixation light and the pointing light, the two beams are directed independently of one another onto a further deflecting mirror 22 or - 1 3 -

23 directed, reflected there and thrown onto the board 1, where fixation light 3 or 15 and pointing light 27 are shown. A coordinate cross can be applied to the panel 1, which is optionally designed as a roll-up projection screen and can thus be well supplied, but it can also be dispensed with, as shown below. A background surrounding the fixation light and perceptible by the uncovered eye is sufficient.

Since the patient's head is fixed to the headrest 18, the viewing direction must be changed. For the testing of binocular vision in the far range - distance table-patient about 2.5 m - then an impractically large table would be necessary. By means of the optics 24, it is possible, as shown schematically in FIG

To deflect the beam in such a way that the eye must be rotated in the viewing direction 29 provided for the respective examination step. The visual impression of the - uncovered - eye is thus based on a virtual image object in the respective viewing direction 29. In the same way, the beam of rays emanating from the pointing light 27 (not shown) is also deflected via the optics 24.

4 shows a possible design for such an optical system 24 for changing the viewing direction. The rays emanating from the fixation light 3 or 15 on the table 1 - the beam path 30 fixation light eye is shown - are deflected by means of two beam splitters 31a and 31b acting as mirrors, since one of the two beam splitters 31a can be rotated and tilted. This in itself becomes the one you want

Change of viewing direction possible. The proportion of reflected and transmitted light should be approximately the same, namely for both beam splitters 31a, 31b in the same way. However, the beam splitters 31a and 31b alone would simultaneously make it possible for the patient to directly perceive fixation light 3 or 15. One pair each of polarization filters 32a, 32b and delay plates 33a, 33b - 1 4 -

express this. The polarization filters can be polarizers of any kind, for example polarization filters are listed. Particularly suitable as delay plates are plates which essentially cause circular polarization of the light. Lambda quarter plates are listed as examples.

The light emanating from the fixation light 3, 15 is linearly polarized when the first polarization filter 32a is passed and circularly polarized after passing through a quarter-wave retardation plate 33a. Only a certain portion of the light passes through the first beam splitter 31a, preferably 50%, the other portion is reflected. The continuous portion passes before the second beam splitter 31b strikes a second quarter-wave retardation plate 33b, which strikes the circularly polarized light in linearly polarized light with one on the oscillation plane of the first quarter-wave retardation plate 33a ¬ transforming the vertical plane of vibration. The radiation component passing through the second beam splitter 31b - again preferably 50% of the incident beam - strikes a second polarization filter 32b, which acts as a barrier for this radiation component. The beam part reflected at the second beam splitter 31b again passes the second lambda quarter delay plate 33b, is circularly polarized, strikes the first beam splitter 31a, is reflected there proportionately and after passing through the second lambda quarter delay plate again 33b is again linearly polarized, namely perpendicular to the plane of oscillation that was present after the first passing through the second quarter-wave retardation plate 33b. The beam part which, after reflection at the two beam splitters 31a, 31b, passes the second beam splitter 31b can pass through the second polarization filter 32b and generate an image in the eye. On the beam splitters

31a, 31b multiply reflected rays can in part 7EP95 / 04237

- 1 5 -

also get into the eye, but are suppressed due to the strong reduction in intensity.

In the arrangement shown in FIG. 4, the lambda quarter plates 33a, 33b are positioned such that their respective fast axes are parallel to one another and are at an angle of 45 ° to the plane of oscillation of the beam polarized by the first polarization filter 32a. A better achromasia is obtained if the two lambda quarter plates 33a, 33b are arranged in such a way that their fast axes are perpendicular to each other and each include an angle of 45 ° with the plane of oscillation of the beam polarized by the first polarization filter 32a. Since the effect of the lambda quarter plates 33a, 33b in such an arrangement is canceled, in this case the second polarization filter 32b must be aligned such that its transmission direction is perpendicular to that of the first polarization filter.

For economic reasons, the two beam splitters 31a, 31b must be chosen to be as small as possible and must therefore be brought as close as possible to the eye in order to cover a sufficiently large field of view. Although it is possible to rotate one of the two beam splitters horizontally and the other beam splitter vertically, this would require a greater distance from the eye and thus a larger dimensioning of the beam splitters 31a, 31b. At the same time, this would necessitate a greater distance between the two beam splitters in order to permit the necessary tilting.

The intensity of the beam reaching the eye is reduced to less than 10% compared to the beam emanating from the fixation light, but is sufficient for correct perception, even when the red glass is placed in front. It may be necessary to use less dark red glass than the Maddox or Harms test. To repeal the Fusion is sufficient if the structure of the background can no longer be seen with the covered eye.

In order to suppress undesirable reflections on polarization filters and / or delay plates, which further reduce the intensity of the transmitted beam, first polarization filter 32a and first delay plate 33a can be joined together or formed as a one-piece component. The second delay plate 33b and the second polarization filter 32b are arranged as close as possible to the second beam splitter 31b, it being possible for the second polarization filter 32b and the second beam splitter 31b to be joined to one another or to be formed as a one-piece component to suppress intensity-reducing reflections.

The orthoptist rotates or tilts the beam splitter 31a (and / or the beam splitter 31b) by the angle required for the respective test step in the horizontal and / or vertical direction. For this purpose, angle encoders - for example in the form of precision potentiometers - are provided, which can be controlled via a remote control - cable-guided or remote-controlled. The beam splitter 31b (and / or the beam splitter 31b) is rotated or tilted by means of a servo drive, the viewing direction is changed by twice the angular amount. The orthoptist can thus determine the viewing direction directly and exactly, the head remains fixed in the headrest. Inaccuracies, as they are the rule in the test on the Harms wall due to restless head posture and uncertain positioning of the projection light projected onto the Harms wall via the forehead projector, are excluded.

FIG. 5 shows another possibility for the formation of an optic 24a which changes the required Direction of view when examining binocular vision according to the principle outlined above. For this purpose, two mirrors 35a and 35b can be rotated and tilted relative to one another. This is no problem for smaller viewing angles. In order to be able to perceive the entire surface of panel 1 at a viewing angle of approximately 25 ° - which is approximately 2.5 m wide and high in accordance with the Harms wall and arranged at a distance of 2.5 m - must be relative large mirrors 35a, 35b can be used. As shown in dashed lines in FIG. 5, so that a part of the panel surface is not covered by the mirror 35b closer to the eye, it must be partially designed (in the case of an arrangement according to FIG. 5 in the upper partial area) as a semi-transparent mirror . This semi-transparent part, which acts as a beam splitter, must not, however, allow a direct view of the fixing light projected onto the board.

6a and 6b show two other possibilities for forming the component causing the change in the viewing direction. Prisms are provided whose refractive angle can be changed. 6a shows a so-called elastic prism 50a, in which between two glass plates 51a and 51b a liquid 52, which has approximately the same refractive index as the glass used to suppress reflections on the inner surfaces of the glass plates, in an elastic membrane 53 is held. Different viewing directions can be determined by rotating at least one of the two glass plates 51a, 51b and / or tilting the prism 50a. The degree of twist, which the orthoptist indicates the direction of view, can - as below based on the

8 - signals supplied via a remote control, which are available via the measuring plates assigned to the glass plates 51a, 51b, are displayed on the remote control.

6b shows a rigid rotating prism 50b, in which two partial prisms 50b1 and 50b2 (actually lenses) against one another can be moved and rotated. The two partial prisms 50b1 and 50b2 are made of the same material.

When using prisms, it must be taken into account that dispersion effects occur.

7 shows the design of the slide 34, which carries a slide half 34a with the positive of the indicator light 27p, for example in the form of a green dot, on a common, essentially transparent plate 36. The other half 34b of the slide 34 can be rotated about an axis 37 defined by the center of the positive of the fixing light 3p, which is ring-shaped here, so that the positive of the bar-shaped fixing light 15p can be rotated. The patient can turn the slide half 34b - corresponding to the illustration in FIG. 2 - again horizontally to turn the light bars, which he may have seen obliquely. The determination of the measure for the cyclodeviation is achieved, for example, by means of FIG described measuring electronics possible. The plate 36 is tinted opaque in the areas which are not covered when the second slide half 34b is rotated. It is possible, during the examination of horizontal and vertical deviations, to insert an essentially U-shaped darkening mask (not shown) which covers the positive of the line-shaped or bar-shaped centering light 15p. For this purpose, a narrow slot on the housing of the slide projector 28 can be provided, in which the cover mask located in this slot can be moved, for example by means of a slide button, either manually or remotely by means of a server motor.

The tracking of the pointing light is illustrated on the basis of FIG. 8, the pointing light representing the subjective visual impression of the patient, since the position of the red dot is thereby indicated. The position of the pointing light can then either be directly on the panel, which may be one of the Harms wall corresponding tangent table is formed with coordinate cross and grid lines, can be read, or also via the measuring electronics, which is provided for the control system for the adjustment of the deflection mirror 23 (Fig.3).

A control button 38 (see also FIG. 3) is arranged on the housing 17 (ergonomic considerations should be considered), which can be moved horizontally / vertically as well as rotated. The control button 38 sits on a plate 43 which is moved horizontally / vertically with the control button 38 and which covers a recess in the housing 17 which enables the movement of the control button 38. A bracket 39 fastened to the inside of the housing 17 with a first pair of rods 40 carries - displaceable along the first pair of rods 40 - a frame 41, which in turn has a second, second, perpendicular to the first pair of rods 40 Rod pair 42 carries. The plate 43 with the control button 38 is arranged on this second pair of rods 42, again displaceably. A first potentiometer 44a is assigned to the frame 41, as a result of which a signal corresponding to the extent of its displacement along the first pair of rods 40 is available and can be supplied to measuring electronics 45 for controlling a servo drive 46. In the same way, a second potentiometer 44b is assigned to the plate 43, which, for example, runs in a recess 45 and is carried along when the frame 41 is displaced and supplies a signal to the measuring electronics 45 corresponding to the amount of displacement of the plate 43. The deflecting mirror 23 for the pointing light can thus be adjusted via the horizontal / vertical movement of the control button 38. Of course, the deflecting mirror 23 can also be adjusted mechanically directly by the person to be examined or by actuating an auxiliary motor.

Angle pickups 47 on the deflecting mirror 23 are used, if appropriate with the interposition of an A / D converter 48 Display 49a of the remote control 49 shows the coordinates of the pointing light 27 projected onto the panel 1 (FIG. 3), which represent a measure of the squint angle.

The control button 38 can, however, also be turned, a potentiometer 44c assigned to the axis of rotation sends a signal corresponding to the angle of rotation to the measuring electronics 45a, by means of which a servo drive 46a causing the rotation of the slide half 34b with the positive of the beam-shaped fixing light 15p can be controlled . The remote control 49 is supplied with the signals corresponding to the dimension and the direction of the rotation via angle pickups 47a on the slide half 34b and possibly via an A / D converter 48a, the value of the cyclodeviation optionally being shown on the display 49a of the remote control 49 becomes.

As already described above, at least one of the beam splitters in FIG. 4 or the mirror arrangement in FIG. 5 can also be rotated or tilted using the remote control 49, for which purpose the desired viewing direction is entered via the keyboard of the remote control 49. In this way, a servo drive 46c is actuated, which carries out the corresponding adjustment of the beam splitter or the mirrors, which can be controlled via angle pickups.

To measure the size of the horizontal / vertical displacements or the angle of rotation, different types of sensors can be used; the potentiometers listed above are to be seen as examples only. The signals available above can be analog or digital signals, an A / D converter may be provided, but the signal processing can also be provided purely analog.

9 shows a possible design of the control panel of a handheld remote control 49. The heart of the remote control 49 is at least one microprocessor with sufficient memory capacity. An application-related program can be loaded via a computer via an interface or is available resident.

The keyboard 49b is - also for hygienic reasons - designed as a membrane keyboard. Several pressure points 54a and 54b represent the nine gaze directions to be measured, the pressure point 54a corresponds to the straight gaze with a straight head posture. A toggle button 55 enables a specific angle to be specified; in the embodiment shown in FIG. 9, 15 ° or 25 ° can be selected, for example, other designs with multiple options are possible, for example for measuring steps that each allow a 5 ° change ¬ Lich. After pressing the pressure point 54b corresponding to the desired viewing direction, the viewing direction is shown on the display 49a using the coordinate values X and Y.

A button 56 can be used to enter a patient-specific test number which is shown on the display 49a. A key 57 enables the type of examination to be carried out to be entered, i.e. whether determination of the horizontal / vertical deviation or the cyclodeviation is made.

A further key 58 is provided, with which the command for storing the values shown on the display 49a is given.

Switching between READ and PLAY mode is possible via a button 59, i.e. between reading the data available via the device and querying data from the memory of the remote control.

Another key 60 enables the deletion of all values for a specific test number. The memory content of the remote control can be transferred to a computer via an interface using a key 61.

The remote control 49 with its user-friendly operating field - which can optionally also be formed on a screen of a computer and can be used in dialog mode - could also be used independently of the device described. Since the arrangement of the pressure points 54a, 54b is a diagram of the tangent table known from the Maddox or Harmstest with its coordinate cross, the selection and setting of the viewing directions is simplified for the orthotist. At the same time, the display shows the possibility of control. Depending on the examination requirements, a different scheme with more or differently arranged pressure points could be provided. In combination with the keys, which can be assigned various input options, this results in a widely replaceable control panel.

Precisely because of its compactness, because of the possibility of inserting different slides into the slide projector, because of the possibility of exchanging the optics in a modular manner, and because of the independence of specially designed panels, the device allows a multiple examination on the eye. For example, the Maddox test checking the convergent convergence of both eyes could be carried out with it, the coordinate cross could then be projected onto the board at the desired distance of approximately 1 m. The Hess and Worth test could also be carried out. It would also be possible to determine the objective squint angle.

Claims

- 23 PATENT CLAIMS

1. A method for determining horizontal, vertical and / or cyclodeviations on the eye of a person to be examined (10), in which - a point or line-shaped fixation light (3, 15) is arranged on a board (1);

- one eye (4, 5) is covered with colored glass (6) which suppresses the surroundings of the fixation light (3, 15) to interrupt the fusion and - the subjective visual impression showing two images is based on the location of the two images (1, 15, 8) on the board (1), if necessary by means of a pointing light (27), characterized in that the fixing light (3, 15) and optionally the pointing light (27) is provided as a virtual object point or virtual object line .

2. The method according to claim 1, characterized in that means (18a, 18b) are provided which hold the head of the person to be examined (10) fixed in position and orientation relative to the table (1).

3. Device for determining horizontal, vertical and / or cyclodeviations on the eye of a person to be examined (10) with a device for generating an essentially point-shaped and / or a linear fixing light (3, 15) on one in the field of vision of the person arranged board (1), characterized in that an optical system (24) is provided which makes the fixation light (3, 15) representable as a virtual object point or virtual object line at predetermined positions on the board (1) and means (35b; 32a, 32b, 33a, 33b) are provided which prevent the person (10) from directly perceiving the fixing light (3, 15).

4. The device according to claim 3, characterized in that the optics (24) comprises the means (35b; 32a, 32b, 33a, 33b) for preventing the direct perception of the fixing light (3, 15).

5. Apparatus according to claim 3 or 4, characterized gekenn¬ characterized in that a - in particular a slide projector (28) comprising - projection device (19) is provided for generating the or the fixation light (s).

6. Device according to one of claims 3 to 5, characterized in that a device (18) for stabilizing the head of the person to be examined (10) is provided, preferably the optics (24) as close as possible to the eyes ( 4,5) is arranged.

7. Device according to one of claims 3 to 6, characterized in that the optics (24) comprises at least one at least partially formed as a beam splitter (31a, 35b) component which can be tilted and / or rotated.

8. Device according to one of claims 3 to 7, characterized in that the means for preventing the direct perception of the fixing light at least one polarization filter (32a, 32b) - in particular two polarization filters - and / or at least one, preferably Delay plate (33a, 33b), in particular two delay plates, designed as a quarter-wave plate.

9. Device according to one of claims 5 to 8, characterized in that the projection device (19) has a slide projector (28) and at least one - in particular two -, preferably rotatable or tiltable, deflection device (s) (22 , 23, 26), preferably in the form of mirrors.

10. Device according to one of claims 3 to 9, characterized in that a device for displaying the subjective visual impression - in particular in the form of a pointer light (27) which can be projected onto the board (1), preferably by means of the projection device - is provided, where appropriate, the optics (24) show the pointing light (27) as a virtual object point on the board (1).

11. The device according to any one of claims 3 to 10, characterized in that a first actuating device is provided for adjusting the optics (24), which is preferably controllable via a remote control (49), the degree of adjustment - in particular via signals that Available via measuring sensors provided on the optics (24) and which are preferably supplied to at least one microprocessor assigned to the remote control (49) - can optionally be determined on a display (49a) of the remote control (49), as a reference value for determining the respective line of sight (29) of the person to be examined.

12. The device according to claim 10 or 11, characterized gekenn¬ characterized in that a second actuating device is provided for adjusting the device for displaying the subjective visual impression, in particular in the form of a control button (38) on one of the optics (24) and the housing (17) accommodating the projection device (19) is provided.

13. The apparatus according to claim 12, characterized in that a - in particular via signals from sensors provided on the second actuating device

(44a, 44b) - a deflection device (22) which effects the projection of the pointing light (27) at least indirectly is adjustable.

14. The device according to claim 12 or 13, wherein the degree of adjustment of the device for displaying the subjective visual impression via signals sent via measuring sensors (44a, 44) provided on the deflecting device (22) and / or on the second actuating device. 44b) are available and are preferably fed to at least one microprocessor assigned to the remote control (49) - can be determined, if appropriate, on a display (49a) of the remote control (49).

15. Slide (34) for use in a device according to one of claims 3 to 14, characterized in that at least a first part (34b) - in the form of a surface section and / or layer part - of the slide (34) an axis (37) can be rotated perpendicular to the slide surface, this axis (37) being defined by the center of a line - which may have a point or a ring in the center as a positive (3p) of the point-like fixing light - which defines the positive ( 15p) of the linear or bar-shaped fixing light.

16. The slide as claimed in claim 15, characterized in that it is formed at least in two parts, a second part (34a) - in the form of a surface section and / or layer part - forming the positive (27p) of the pointing light, and preferably first and second parts (34b, 34a) are arranged next to and / or on top of one another on a common, at least partially transparent, plate (36).

17. Device according to one of claims 12 to 14, with a slide according to claim 15 or 16, characterized in that a third actuating device - in particular associated with the second actuating device - is provided for rotating the first part (34b) of the slide (34), the rotation being controllable in particular via signals from measuring sensors (44c) provided on the third actuating device and the dimension of the Rotation of the first part (34b) of the slide (34) - in particular via sensors assigned to at least one microprocessor assigned to the remote control (49) from the first part (34b) of the slide (34) -, possibly on a display (49a) of the remote control (49), can be determined.

18. Control unit, in particular remote control (49), for a device according to one of claims 11 to 14 or 17, with an operating part, which comprises a keyboard (49b) and preferably a display (49a), characterized in that the keyboard (49b) has at least one area which schematically shows the table (1) with predefined coordinate points, pressure points (54a, 54b) being formed which correspond to these coordinates, and preferably an activated pressure point (54a , 54b) is shown on the display.

19. The control unit according to claim 18, characterized in that at least one key (55, 56, 57, 58, 59, 60) is arranged on the keyboard (49b), via the actuation of which at least one of the following commands can be initiated:

- changing the coordinate values assigned to the pressure points (54a, 54b);

- Deleting an input or a read value; - Save an entered or imported one

Worth;

Assigning a reference number, for example a patient-specific test number;

- Querying a value available in a memory, preferably at least one of these commands and / or the result thereof being able to be shown on the display (49a).