Apparatus and method for determining the location of an object of interest in a patient's eye and ophthalmic apparatus

Abstract

The present invention relates to an apparatus for determining the location of an object of interest within a patient's eye, particularly within the vitreous humor of the eye, and having means for generating at least one optical beam path, with a reference plane located on the opposite side of the object of interest and being set up to determine the conjugate distance between the reference plane and the object of interest at the reference plane.

Description

Technical Field

[0001] The present invention relates to an apparatus for determining the location of an object of interest within a patient's eye, particularly within the vitreous humor of the eye.

[0002] The present invention further relates to an ophthalmic device for performing a treatment on a patient's eye using an ophthalmic microscope.

[0003] The present invention also relates to a method for determining the location of an object of interest within a patient's eye, particularly within the vitreous humor of the eye.

Background Art

[0004] Conventionally, various ophthalmic devices for performing various ophthalmic treatments on patients, such as an ophthalmic microscope for peering into a human eye, are known. Such microscopes are composed of many optical members. The focal plane of this microscope is at its focal length as viewed from the objective lens. An object located in that focal plane will be seen in focus by the doctor. The doctor uses this microscope to examine the anatomical structure within the patient's eye. Some of the intraocular structures are easy to locate and focus on; for example, the iris is in the front part of the eye and most of it is a flat surface, having a distinct color and structure. The retina (which is in the back part of the eye) is also relatively easy to locate and focus on; because it is also mostly flat (when examined through the microscope), colorful, and structured. For structures in the back part of the eye (behind the iris), the doctor needs to examine them via the pupil (the opening inside the iris). This can be done with proper microscope settings and sufficient illumination.

[0005] Other structures, such as the cornea, the lens, and the vitreous humor, or structures within the vitreous humor, cannot be easily distinguished; because they are transparent, or because it is difficult to locate and visualize them within the vitreous humor.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] U.S. Patent Application Publication No. 2014 / 0132931 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] The object of the present invention is to further develop known devices or instruments and methods for ophthalmic examination and / or ophthalmic treatment, and in particular to improve the search for objects in the vitreous humor. [Means for Solving the Problems]

[0008] The object of the present invention is a device for determining the location of a target object in a patient's eye, particularly in the vitreous body of the eye, comprising means for generating at least one optical beam path leading to the target object, and having a reference plane related to the target object, and is achieved by a device set up to determine the object distance between the reference plane and the target object in the reference plane.

[0009] Since the object distance can be determined in a reference plane with a known position, the position of the target object in the eye can also be precisely determined.

[0010] As can be understood, in this device, the reference plane can be generated in various ways so that its location is precisely known. For example, the reference plane can be conveniently specified by reference plane specifying means so that its position is precisely known in this device.

[0011] The reference plane can be formed particularly easily when the reference plane can be formulated using a known reference structure of the patient's eye.

[0012] In this context, the object of the present invention is a device for determining the location of an object of interest within a patient's eye, in particular within the vitreous body of that eye, relative to a known reference structure of that eye, and more particularly for discriminating it relative to a known reference structure of that eye, comprising means for generating at least one optical beam path reaching the object of interest, and being set up to determine the object distance between the reference structure and the object of interest in a reference plane formed by the reference structure.

[0013] Since the actual object distance between the object of interest and a known reference structure, preferably a known reference structure of the human body, and most preferably that of the human eye, can be determined in the reference plane, the position of the object of interest can be determined very easily and reliably.

[0014] Advantageously, by using, as the reference structure, a known structure of the eye which can be easily recognized during an ophthalmic examination, the device can be designed to be very compact and can be easily operated by a physician.

[0015] However, in addition to or instead of this, by means of appropriate technical means, a reference plane can be defined independently of the known eye structure, where the object distance can be determined.

[0016] The means for defining the reference plane can also be provided independently of the device, for example by an ophthalmic treatment device.

[0017] However, if the device has means for defining the reference plane, the device can be provided in a more autonomous operating mode.

[0018] In the sense of the present invention, the term "in the reference plane" means, in particular, that the object distance between the reference plane and the object of interest is determined along the reference plane. This determination can be made within the reference plane and also in the vicinity of the reference plane.

[0019] The present invention relates in particular to structures within the vitreous humor, such as vitreous opacities or floaters. Heretofore, it has been difficult to locate and visualize them. They are usually small, three-dimensional, translucent, and "float" within the vitreous humor. Due to the high magnification of the microscope and thus the insufficient depth of field, the depth perception in the microscope is poor. Therefore, it is difficult to find non-flat structures. Even if a structure is found, it is difficult to determine where it is located relative to other structures of the eye, such as the lens or the retina. This is particularly important in relation to the position along the optical axis. More specifically, even if an object "floating" within the vitreous humor can be focused on and visualized, it is difficult for a doctor to determine how close the object is to the posterior part of the lens or the retina. The insufficient depth of field of the microscope means that the retina appears blurred (out of focus) and ultimately cannot be distinguished. In addition to the same being true for the lens, there is an additional difficulty that it is transparent and not easily visible.

[0020] According to the present invention, in that regard, the object distance, particularly that between the focal plane of the microscope and the object of interest within the eye, can be easily measured.

[0021] And the measurement result can be notified to the doctor and used for other purposes, such as for reporting or machine automation purposes.

[0022] Based on such recognition, the problem of determining the location of the object of interest within the eye, as described above, can be achieved by determining the object distance from a known defined reference plane to the object of interest using the corresponding image group in that reference plane.

[0023] Needless to say, the object distance between the object of interest and the reference structure or that reference plane in the reference plane can be determined in many ways. For example, using a value table or the like can be regarded as a typical example among many.

[0024] It is particularly advantageous to describe the object distance using a geometric ray optical system.

[0025] Particularly precise and thus advantageous for a desirable configuration is, for example, to set up the device such that the object distance is determined by a triangular geometry forming a right triangle located between the object of interest and the reference structure.

[0026] Here, the distance section generated on the reference plane can be set very precisely in relation to the location of the nearby object.

[0027] That is, for example, the course of the distance section can be oriented with respect to the reference plane according to the sense of the present invention, and the reference plane can be formed solely virtually.

[0028] It is particularly advantageous to mutually enclose a right angle between the reference plane of the device and the measurement axis or the optical axis.

[0029] If a right triangle is formed between the reference structure, particularly the reference plane, and the object of interest, the object distance can be determined with the aid of angular functions such as the "Pythagorean theorem" or other trigonometric functions.

[0030] As can be understood, the object distance, the distance section along the reference plane, and the ratios related to at least one of the optical paths mentioned above can be associated in various ways.

[0031] The hypotenuse can be generated very easily and more operably, for example, by at least one of the beam paths mentioned above that crosses the reference structure or the reference plane defined thereby at an angle α≠90° from the light source provided in the generating means towards the object of interest.

[0032] Even if the angle between at least one of the optical beam paths mentioned above and the reference plane is a small one with α = 1° to 5°, the object distance can be successfully determined with the aid of optical beam geometry.

[0033] However, it is preferable that a larger angle α = 10° to 60° is located between at least one of the aforementioned optical beam paths and the reference plane, whereby it becomes possible to more precisely determine the corresponding object distance.

[0034] Here, preferably, the first adjacent side is made the same as the object distance, and the virtual line of the object distance is arranged perpendicular to the reference plane.

[0035] Preferably, the second adjacent side is arranged so that the second adjacent side extends along the reference plane. Advantageously, the second adjacent side can be arranged as a distance section within the reference plane, or can be extended as a distance section parallel thereto.

[0036] Particularly advantageous in this context is to set up the present invention such that at least one of the first adjacent sides of the adjacent sides of the right triangle is defined by the object distance, at least one of the second adjacent sides of the adjacent sides of the right triangle is defined in the reference plane, and the hypotenuse of the right triangle is defined by at least one beam path.

[0037] As described above, with the assistance of the optical beam geometry, the object distance can be determined in various constructive and procedurally simple ways.

[0038] For example, a certain distance section among the distance sections provided according to the sense of the present invention can be defined by two markers generated in relation to the reference plane.

[0039] Thus, by directly and successfully using the means for generating at least one optical beam path of the present apparatus, suitable markers can be generated on the reference plane by one or a plurality of optical beam paths.

[0040] In this way, the means for generating at least one of the aforementioned beam paths, which is provided in the present apparatus, directly becomes the means for generating a marker on the reference plane in a certain distance section.

[0041] It is advantageous for detecting the marker to configure the apparatus to include an imaging system that detects the marker on the reference plane.

[0042] By configuring the imaging system to include a camera, a suitable optical imaging system can be designed in a very simple manner.

[0043] As can be understood, the imaging system provided in any other ophthalmic treatment apparatus can also be used, which has the advantage that the apparatus can be made very simple in design.

[0044] By configuring the optical imaging system to preferably have two, three or more optical beam paths, ideally a plurality of markers can be generated simultaneously, and thus the distance section can be determined with a slight or negligible time delay.

[0045] For this purpose, the optical imaging system can advantageously be configured to include two or more optical imaging devices.

[0046] The optical beam path can be provided by an optical imaging system, such as a camera or the like.

[0047] As can be understood, the means for generating at least one of the above-described optical beam paths, abbreviated as "generating means", can be realized in various ways.

[0048] For example, the generating means can be configured to include a laser light source, and the laser beam can be directed at the target object and thus penetrate the reference plane.

[0049] The optical beam path according to the sense of the present invention can also be generated and provided by a light source such as a laser light source.

[0050] Therefore, it is advantageous to equip the device with suitable technical equipment that can utilize it to generate and provide a corresponding optical beam path.

[0051] That is, by setting up the device such that the object distance can be determined by two markers generated on the reference plane by at least one of the aforementioned optical beam paths passing through the reference plane, and such that these markers are arranged separately from each other in a certain distance section, the object distance can be successfully determined according to the concept of the present invention.

[0052] By simultaneously generating or arranging markers by two or more optically generated beams on the reference plane, the distance section can be determined with almost no time delay. Thereby, it is also possible to determine the object distance in the shortest possible time.

[0053] However, in this design variant, two optical beam path generation sources arranged at intervals along the reference plane are required.

[0054] Here, the device may have two or more generating means, or alternatively, the device may be configured such that a single generating means also has two or more such beam path sources.

[0055] If applicable, the device also has a deflecting device that branches an optical beam path by a single beam path source into at least two optical branched beam paths, enabling several optical beam paths to be used simultaneously in a very simple manner.

[0056] For example, two or more spatially separated markers by a single optical path can be used, especially when the reference plane is moving relative to the object of interest.

[0057] Overlaying or replacing this, an optical beam path group that occurs with a time delay and comes from different angles can also be used.

[0058] That is, advantageously, markers that are spatially separated by a certain distance section can be generated with a certain time offset.

[0059] The advantage of the latter configuration is that a single optical beam path source is sufficient to determine the object distance according to the sense of the present invention.

[0060] In another advantageous design variant, the device is set up such that the object distance can be determined by an image shift related to a marker generated by at least one of the aforementioned optical beam paths passing through the reference plane, and the markers are spatially separated from each other in a certain distance section.

[0061] Those markers generated by the image shift can exhibit various shapes with respect to the reference plane.

[0062] For example, when the markers are suitable and can be represented as image information of the object of interest imaged on the reference plane, the distance section between those markers represents the displacement distance between two sets of image information obtained by imaging from different angles and / or between two sets of image information obtained by imaging at different times.

[0063] It is also possible to include image information or at least its constituent parts in those markers.

[0064] In any case, by setting up the device such that at least one of the aforementioned optical beam paths is arranged at an angle α other than 90° with respect to the reference plane while the direction of the object distance is perpendicular to the reference plane, the geometric beam optical system can be successfully realized by the device. Thereby, the distance section between two markers extends along the reference plane.

[0065] Advantageously, when the present apparatus is provided with an optical imaging system that images a reference plane and images an image of a target object on the reference plane with one or two optical beam paths, the apparatus can be set up such that the object distance is determined by the amount of image shift along the reference plane of the image imaged on the reference plane, or by the distance section formed by two optical markers generated on the reference plane. By doing so, the present apparatus can be configured to easily determine the object distance.

[0066] The object distance can be determined very accurately when the object distance is proportional to the amount of image shift on the reference plane.

[0067] Particularly in this situation, advantageously, the image of the target object imaged on the reference plane can be shifted to the location of a further image when the reference plane is shifted with respect to the target object, and the object distance can be determined based thereon.

[0068] Here, the reference plane is shifted with respect to the target object along a virtual line along the object distance.

[0069] Usefully, the distance section between two markers can be associated with the object distance so that the object distance can be determined by the distance section. A feature of the present invention is also that suitable markers can be generated on the reference plane by at least one of the aforementioned optical beam paths, and the resulting distance section is proportional to the object distance being searched for.

[0070] By setting up the present apparatus so that the focal plane can be arranged at the location of the target object, the object distance can be determined with particularly high operational reliability.

[0071] In order to successfully assist in determining the object distance, it is desirable that the reference plane can be displaced parallel to the focal plane face-to-face, and thus the object distance is arranged to extend orthogonally with respect to both planes.

[0072] Advantageously, the device can be set up such that the optical beam paths in the focal plane can be focused on a common focus.

[0073] Alternatively, the optical beam paths in the focal plane can be focused on separate foci.

[0074] When the device is set up such that at least one of the aforementioned optical beam paths heads towards the object of interest via a reference plane, a marker can be generated more accurately at the location of the reference plane.

[0075] Furthermore, advantageously, the device can be set up such that at least one of the aforementioned optical beam paths is located at an angle α with respect to the object distance, and the object distance can be arranged orthogonally with respect to the reference plane. While also receiving the facilitation thereby, based on the marker generated in relation to the reference plane or the distance section of the related path, the object distance can be determined more accurately.

[0076] To further improve or simplify the configuration of the device, the device can be set up such that the object distance forms a section of the optical axis of the device. For a very simple configuration, the optical axis can be set as the machine direction of the device, and the machine direction can be set as the operating direction of the device.

[0077] Furthermore, when the optical axis of the device forms a section of the optical axis of an ophthalmic observation and / or treatment device, such as the optical axis of an ophthalmic microscope, etc., the device can be successfully further developed.

[0078] When the viewing angle is surrounded by the optical beam paths at least in multiple sections, especially in relation to the reference plane, the object distance can be successfully determined. For example, the viewing angle is surrounded by two optical beam paths passing through the reference plane.

[0079] It is advantageous to arrange the reference plane in front of or behind the focal plane related to the optical imaging device so that the optical marker can be imaged in an easily distinguishable manner in the reference plane.

[0080] The device provided by a certain successful embodiment has an ophthalmic microscope, and the focal length of the microscope is the same as, among other things, the focal length of the aforementioned optical imaging system. By doing so, it becomes possible to determine the object distance in a structurally simple and precise manner.

[0081] Similarly, the object of the present invention is also achieved by an ophthalmic device that performs a treatment on a patient's eye with an ophthalmic microscope and has at least one of the features described in the present application. According to the device of the present invention, the ophthalmic device can be more successfully further developed, and ophthalmic examinations and ophthalmic treatments can be performed more accurately and quickly.

[0082] The object of the present invention is further a method of operating a device for discriminating the location of a target object in a patient's eye, especially in the vitreous body of the eye, wherein at least two optical beam paths intersect with each other in a reference plane at a common intersection point, and with each of the at least two optical beam paths, an intersection point in the reference plane or its vicinity is imaged as a spaced image, and the images are shifted in the reference plane by shifting the intersection point F and the reference plane relative to each other, and the original distance from the intersection point to the reference plane is determined by the amount of the image shift.

[0083] Advantageously, the position of the intersection point and the position of the plane passing through the intersection point can be determined with reference to the reference plane by measuring a corresponding distance section in the reference plane and associating the distance section with the object distance to be determined.

[0084] That is, the object distance extending along the machine direction of the present device is measured not along its actual longitudinal extension line, but by a distance section extending transversely thereto. This distance section is measured along its longitudinal section extension line, that is, an extension line arranged transversely to its machine direction or the object distance.

[0085] This means that the object distance to be searched can be determined very accurately by the distance section in a precisely defined reference plane.

[0086] This is also applicable, in particular, to the device on which the present method is executed.

[0087] Advantageously, by surrounding the viewing angle with at least two of the aforementioned optical beam paths, it is possible to intersect at least two of these optical beams on the reference plane, and further to generate spaced markers.

[0088] Since this viewing angle is a value between 0° and 180°, these optical beam paths can be made to penetrate the reference plane when intersecting at the intersection point later.

[0089] Preferably, by setting the viewing angle to a value between 10° and 90°, a highly reliable determination of the object distance on the reference plane becomes possible.

[0090] What is advantageous in constructing a device with a reference plane more compactly is to set the value of the viewing angle to 30° - 50°, preferably 35° - 45°. Even with such values, an accurate determination of the object distance on the reference plane is possible. Further, these optical beam paths can be arranged satisfactorily within the pupil of the eye.

[0091] This is also advantageously such that the viewing angle can be selected depending on the position of the intersection point with respect to the reference plane.

[0092] The object of the present invention is further a method for operating a device for determining the location of an object of interest in the eye of a patient, in particular in the vitreous body of the eye, generating a reference plane orthogonal to the measurement axis of the device, intersecting at a common intersection point at least one optical path passing through the reference plane with the measurement axis, and generating a marker at the passing point in the reference plane with the at least one optical path, and determining the intersection point-reference plane distance in the reference plane based thereon.

[0093] As described above, the marker can be designed in various ways.

[0094] In order to obtain a distance section that can be measured well and is in the reference plane, it is advantageous to generate additional markers in the reference plane.

[0095] Preferably, the additional marker is also generated by an optical beam path passing through the reference plane.

[0096] In a certain process variant, the optical beam paths are sequentially generated with a certain time offset. This enables the process itself to be operated even with only one means for generating at least one optical beam path, and it is also possible to construct the corresponding device with fewer components.

[0097] By generating the optical beam paths generated in a time-shifted manner in a space-shifted manner and surrounding a certain virtual viewing angle therewith, it is possible to easily generate a distance section between two spaced markers in the reference plane.

[0098] By defining a focal plane at the intersection of two intersecting optical beam paths, the object distance located between the two planes can be determined very reliably.

[0099] In addition or instead of this, in a seemingly advantageous case, one or more focal planes can be defined at a location different from the intersection point defined by the intersecting optical beam paths.

[0100] If the object distance is perpendicular to these two planes, the reference plane and the focal plane are positioned parallel to each other face to face.

[0101] The reference plane can be realized very simply with this device by using process technology, and can also be realized very simply in the design aspect by defining the reference plane with at least one camera unit.

[0102] The task of the present invention is a method for determining the location of a target object in a patient's eye, especially in the vitreous body of the eye, and is also achieved by a method of determining the object distance between the target object and a known reference structure of the eye in the reference plane defined by the reference structure.

[0103] Since it is based on a known reference structure of the eye and the location of the reference plane can be known, the object distance to the target object can be accurately determined in the reference plane.

[0104] Advantageously, the above-mentioned distances, especially the object distance, can be determined by the ratio of the sides and angles of a right triangle.

[0105] The task of the present invention is a special method for determining the location of a target object in a patient's eye, especially in the vitreous body of the eye, in which the target object is located in or near the generated focal plane, and a known anatomical eye structure of the eye is located in the generated reference plane. At least two optical paths are focused in or near the focal plane via the reference plane. When the focal plane and the reference plane are relatively moving, one or more image shifts of at least one image in focus on the focal plane are determined in the reference plane, and the distance between the focal plane and the reference plane is determined by the image shift in the reference plane. This is also achieved by the method.

[0106] As already shown, according to this method, the position or location of the object of interest in the eye can be determined simply and yet precisely. For this purpose, a distance section in the reference plane is determined, and it is carried out based on the measurement of the image shift as described above. The images in that reference plane act as markers.

[0107] According to the sense of the present invention, the term "peripheral" means that the distance from the actual focal plane is less than 10 mm, preferably 5 mm.

[0108] The task of the present invention is a more special method for discriminating the location of the object of interest in the patient's eye, especially in the vitreous body of the eye, in which the object of interest is located within or near the generated focal plane, and the known anatomical eye structures of the eye are located within the generated reference plane. It is achieved by a method in which at least one optical path is focused within or near the focal plane via the reference plane, and the distance section between two markers generated in the reference plane is determined by the at least one optical beam path, and the distance between the focal plane and the reference plane is determined by the distance section determined in the reference plane.

[0109] Also, according to this method, the location of the object of interest in the eye can be accurately measured.

[0110] The distance between the two planes or the object distance determined in this way can also be called the plane interval.

[0111] Based on the object distance determined in this way precisely, the person or doctor can perform ophthalmic procedures.

[0112] According to a certain successful process variant, the determined object distance can be used to automatically operate the treatment machine. This makes it possible to operate the suitable treatment machine more precisely.

[0113] It should also be noted that in the context of the present patent application, indefinite articles and indefinite numerical indications such as "one...", "two...", etc. should generally be understood as "at least" indications, i.e., "at least one...", "at least two", etc., unless it is clear from the specific language or context of the specific clause that they specifically mean "exactly one...", "exactly two", etc.

[0114] In this regard, it should also be mentioned that in the context of the present patent application, the term "especially" should be conventionally understood to introduce additional and suitable features by this expression. This term should not be understood as "in fact" nor as "that is".

[0115] In this regard, it should also be asserted that by supplementing the described methods with further technical features described in the present application, especially by the features of the device, it is possible to successfully further develop those methods and to more precisely express or formulate the details of the methods.

[0116] As can be understood, the features of the solutions described above or described in the claims can be combined as necessary, thereby enabling the advantages and effects achievable in the present application to be embodied in an appropriate cumulative manner.

[0117] In addition, with reference to the attached drawings and the following description in which a leading example of the object positioning device is depicted and described, further features, effects and advantages of the present invention will be explained.

[0118] Members that are at least essentially corresponding in their functional aspects and are in individual drawings can be identified in the present application by having the same reference signs, so they are not necessarily numbered and described in all the figures.

[0119] The following is shown in the drawings below.

Brief Description of the Drawings

[0120]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0121] The device 1 shown in FIGS. 1 and 2 is a first embodiment example I of the present invention, which is for determining the position 2 of a target object 3 in a patient's eye 4 not shown in detail here.

[0122] The object of interest 3 is a foreign object structure, such as a so-called floating object or the like, and is inside the eye 4, more precisely inside the vitreous body 5 of the eye 4.

[0123] The machine axis 6 of the device 1 is along the machine direction 7, and the optical axis 8 of the device 1 can be defined on its longitudinal extension line.

[0124] Furthermore, the device 1 has means 10 for generating two optical beam paths 11 and 12.

[0125] The generating means 10 in this case has two imaging systems 13 and 14 with two camera units 15 and 16.

[0126] The optical axis 8 of the device 1 is here defined by the viewing directions 17 of the imaging systems 13, 14. The viewing directions 17 are on the machine direction 7.

[0127] Furthermore, the device 1 has means 20 for defining a reference plane Y, which can be realized by the imaging systems 13, 14 or the camera units 15, 16.

[0128] Where there is a reference plane Y in this first embodiment is a cross-section (also not numbered) passing through a known eye structure 22. Here, the iris (also not numbered) of the eye 4, which is the known eye structure 22, corresponds to a known reference structure 23.

[0129] A viewing angle θ is enclosed between the two optical paths 11 and 12, and the two optical paths 11 and 12 coming from different directions intersect at a common intersection point F.

[0130] The focal length f of the device 1 is defined by the distance between the imaging systems 13, 14 and the intersection point F.

[0131] In this first embodiment, the focal point F on the focal plane E is defined by the intersection point F.

[0132] In this first embodiment, the intersection point F is selected such that the object of interest 3 is also located there.

[0133] Furthermore, the two optical beam paths 11, 12 and the reference plane Y are aligned with each other such that the two optical beam paths 11 and 12 pass through the reference plane Y.

[0134] In determining the position 2 of the object of interest 3 in the eye 4, first the object distance C between the intersection point F and the reference structure 23, and thus between the focal plane E and the reference plane Y, is determined.

[0135] In particular, FIG. 1 shows a cross-section of the eye 4 and a schematic diagram of the device 1. The two imaging systems 13, 14 of the device 1 are arranged to converge on the intersection point F at the same location, but are separated by the viewing angle θ.

[0136] The two imaging systems 13, 14 in this exemplary embodiment are similar and each comprises an optical member suitable for imaging the focal plane E at the intersection point F.

[0137] Camera units 15, 16 are each added to their respective imaging systems 13, 14 to capture the formed images. By imaging the objects located near the focal plane E with the two imaging systems 13, 14, two similar images O1 and O2 (see also FIG. 2) are obtained, so that these images O1 and O2 share the same content and have similar sizes and spatial arrangements.

[0138] However, for objects located behind or in front of the focal plane E, for example, the iris (object of interest 3) located in front of the focal point F at the object distance C, the images O1 and O2 will be different.

[0139] The two images O1 and O2 still share the same content and have similar sizes and spatial arrangements, but the content is shifted by an amount proportional to the object distance C as detailed in FIG. 2.

[0140] Shown in Fig. 2 is another schematic diagram of the apparatus 1, where the imaging systems 13, 14 and the camera units 15, 16 are removed for simplification, and the diagram is in 3D appearance.

[0141] The two squares A1 and A2 represent the image planes 25 where the reference planes Y of the two imaging systems 13 and 14 are located.

[0142] The imaging systems 13 and 14 produce images of an object (the object O and the thick solid vertical arrow labeled O) located at their common focus F. The two images of O are labeled O1 and O2.

[0143] When the object of interest 3 is moved over the object distance C towards the two imaging systems 13 and 14, it is as shown by the thick dashed arrow labeled O’, and the images O1 and O2 formed by O’ shift on the image plane 25 to form new images located at O’1 and O’2.

[0144] The image shifts are labeled y1 and y2.

[0145] Since the viewing angle θ is fixed, the amounts of the displacements y1 and y2 can be directly related to the object distance C.

[0146] The images O1 and O2 and the shifted images O’1 and O’2 can be regarded as markers 27, 28 located in the reference plane Y, or as locations where appropriate markers 27, 28 in the reference plane Y can be present. These markers 27 and 28 are spatially separated from each other by a distance space B (not shown here, see Fig. 4).

[0147] Therefore, the object distance C can be determined easily and very precisely in the reference plane Y.

[0148] Preferably, the object distance C between the front surface of the iris and the focal plane E of the ophthalmic microscope 150 (see Fig. 3) is determined, but other reference structures 23 of the patient's eye 4 can also be used.

[0149] Next, FIG. 3 shows another exemplary embodiment II of the alternative device 100 for discriminating the location 102 of the object of interest 103 within the patient's eye 104, particularly within the vitreous body 105 of the eye 104. Although similar to the device 1 shown in FIGS. 1 and 2, the device 100 additionally has an ophthalmic microscope 150. More specifically, in this further exemplary embodiment, the alternative device 100 is integrated into the ophthalmic microscope 150.

[0150] The ophthalmic microscope 150 is depicted in FIG. 3 only by its objective lens 151.

[0151] The alternative device 100 also has a machine direction 107, along the longitudinal extension of which the machine axis 106 or the optical axis 108 of the alternative device 100 can be defined.

[0152] FIG. 3 shows a separate schematic view of the cross-section of the alternative device 100 and the patient's eye 104, where the iris is used as the reference structure 123 and thus as the known eye structure 122. The orientation of FIG. 3 is such that the patient (not shown other than the patient's eye 104) is at the top of this FIG. 3.

[0153] In this configuration, two imaging systems 113 and 114 share the objective lens 151 of the microscope and are configured such that their focal planes (not individually numbered) coincide with that of the ophthalmic microscope 150, thus forming a single common focal plane E.

[0154] In this further exemplary embodiment, the imaging systems 113 and 114 are arranged parallel to each other, and the binocular visual path 153 formed by two parallel optical beam paths 111 and 112 of the ophthalmic microscope 150 is separated by a certain beam path distance D.

[0155] The optical beam paths 111, 112 (those generated by the optical beam path generating means 110) are arranged in parallel with respect to the optical axis 108 of the apparatus 100 until reaching the objective lens 151, and in this embodiment, the optical axis 108 of the apparatus 100 is formed by the ophthalmic microscope 150. Due to the refractive power of the objective lens 151, an angular view θ between the two optical beam paths 111 and 112 is generated after the objective lens 151.

[0156] The exact configuration of the alternative apparatus 100, and thus of the imaging systems 113, 114 and the camera units 115, 116, can be variable, and they can be configured to use other beam splitters (not shown) such that light is sampled along the binocular visual path 153, or they can be arranged outside the visual path 153, and their individual optical beam paths 111, 112 may be folded by mirrors (not shown) or other optical members (not shown) so as to achieve fitting within the ophthalmic microscope 150.

[0157] The key point is that the same object near the focal plane E is imaged from different angles by both of them.

[0158] Anyway, two images O1 and O2 (see Figure 2) will be digitized by those camera units 115, 116. Thereafter, those digital images O1 and O2 are processed through the execution of software algorithms and codes by the processor.

[0159] The images O1 and O2 are compared, and the positional differences of the same object in each of the images O1 and O2 are found. By using this positional difference, the object distance C at which the object is located can be determined as seen from the reference plane Y.

[0160] In the above-described apparatuses 1 and 100, two camera units 15, 16 or 115, 116 are used, but it is also conceivable to use only one of the camera units 15 or 16 or 115 or 116 in the apparatus 1 or 100 to collect both images O1 and O2.

[0161] The key points are that two images O1 and O2 are of the same object but are captured from different angles, at least one of the images O1 and O2 needs to form a different angle with the machine axis 6, and thus with the optical axis 8 or 108 of the microscope, and the ophthalmic microscope 150 is movable along that axis 6, 8 or 108, especially.

[0162] Generally, the imaging systems 13, 14 or 113, 114 and the ophthalmic microscope 150 do not necessarily need to share the same focal plane E.

[0163] The focal plane E of those imaging systems 13, 14 or 113, 114 can also be a separate plane located at a more suitable position for imaging a structure of interest in the eye 4 or 104, for example the iris.

[0164] The relative distance C between the planes E and Y can be determined according to software.

[0165] Furthermore, a triangular geometry 155 forming a right triangle 156 is located between the object of interest 103 and the reference structure 123, and by using it, the object distance C can be determined with the help of an angular function. Here, the part of the optical path 111 located behind the objective lens 151 forms an angle α with the machine axis 106 or the optical axis 108.

[0166] The device 100 is integrated into the ophthalmic device 150A together with the ophthalmic microscope 150.

[0167] A further alternative concept will be described based on the following description.

[0168] Shown in Figure 4 is the same device 100 as shown in Figure 3, accompanied by an ophthalmic microscope 150, but instead of the eye 104, an intersection plane, i.e., a reference plane Y, is placed at the location of the iris, which is a known eye structure 122 (see Figure 3).

[0169] In addition, two optical beam paths 111 and 112 are emitted within the ophthalmic microscope 150 and reach the focal plane E.

[0170] Two thin optical beams, represented by these two optical beam paths 111 and 112, are located at a distance D apart between the beam paths at the objective lens 151 and are positioned to intersect at the focal plane E.

[0171] By the light of these two optical beam paths 111 and 112, two spots 157 and 158 are projected and formed on the reference plane Y in a separated state in the distance section B.

[0172] These spots 157 and 158 can be regarded as markers 127, 128, and these markers 127 and 128 are spatially separated from each other in the distance section B on the reference plane Y.

[0173] According to geometry, B has the following mathematical relationship: B = D / F × C ⇒ C = F / D × B and is related to C by this. Therefore, the required object distance C can also be easily determined by the alternative device 100.

[0174] In particular, the imaging systems 113, 114 include camera units 115, 116, optical members such as an objective lens 151, etc., and a computer, and can measure the distance section B between the two spots 157 and 158, and thus the distance between the markers 127 and 128 on the reference plane Y to determine the object distance C.

[0175] Some further notes will be made regarding the design aspects of the devices 1, 100 of the present invention.

[0176] In the configurations of the above-described embodiments, by using two light rays, and thus these two optical beam paths 111, 112, and their relative separation on the reference plane Y (spots 157, 158 and thus markers 127, 128), the object distance C to the reference plane Y in front of the focal plane E is determined. Some alternative configurations can be used instead.

[0177] [Alternative Example 1] Two or more types of light rays, and thus optical beam paths 111, 112, may be used.

[0178] For example, using three or more optical beam paths 111, 112, a greater number of spots than the two spots 157, 158, and thus a greater number of markers than the two markers 127, 128, can be created on the reference plane Y. In this configuration, since the number of measurement values will necessarily be large, it is better to use the average value. One possible advantage of such a configuration is that there is room to handle some small angle or curvature of the reference plane Y, that is, the intersection plane.

[0179] [Alternative Example 2] Instead of two light rays, that is, two optical beam paths 111, 112, a single beam with a size (diameter of the circular cross-section) of A may be used, and the single beam may be focused to produce a small spot on the focal plane E. In this configuration, the measurement value will be the beam size A (diameter of the circular cross-section) on the reference plane Y, that is, the intersection plane, rather than the separation distance B.

[0180] [Alternative Example 3] Instead of a light beam having a circular cross-section (optical beam paths 11, 12; 111, 112), beams of other shapes may be used. For example, beams having a triangular or arrowhead cross-sectional shape. Further noted is that one possible advantage of a beam whose cross-sectional shape is not of symmetry 1 (e.g., triangular) is that the projected image on the reference plane Y will be inverted depending on whether the reference plane Y is behind or in front of the focal plane E.

[0181] [Alternative Example 4] Instead of a light beam having a circular cross-section (optical beam paths 11, 12; 111, 112), a patterned shape (e.g., parallel lines, concentric circles, or other suitable patterns) may be projected onto the reference plane Y. Those patterns may be slightly angled with respect to each other to generate visible fringes (moiré patterns) due to their overlap. High-precision measurement of distance can be performed using those fringes.

[0182] [Alternative Example 5] Instead of converging the two beams 11, 12; 111, 112 to a single point, for example the intersection point or focus F, on the focal plane E, they may be configured to present separated points on the focal plane E. This can be achieved by directing them separately from within the ophthalmic microscope 150. Such a configuration may be advantageous if there is an optimal separation distance section B for the imaging systems 13, 14; 113, 114 for measuring B. If so, the apparatus 1, 100 could be configured such that the distance section B is surely within an optimal range where the object distance C is an appropriate value.

[0183] [Alternative Example 6] The beams (optical beam paths 11, 12; 111, 112) may be focused on a plane other than the focal plane E of the microscope. For example, the plane may be located at the average position of the reference plane Y (during vitreous inspection). One possible advantage of this is that the images (O1 and O2 and O'1 and O'2) produced on the reference plane Y by the beams (optical beam paths 11, 12; 111, 112) will be in sharp focus, thereby potentially improving the distance section B measurement ability of the imaging systems 13, 14; 113, 114.

[0184] Regarding how the apparatus 1, 100 described in the present application can be alternatively designed or supplemented in terms of configuration, other alternative embodiments are schematically shown with reference to FIGS. 5 to 10 below without detailing the apparatuses according to such corresponding alternative concepts.

[0185] The first alternative embodiment III is shown in FIG. 5. This first alternative embodiment is basically based on the horizontal stereoscopic methodology. The basic idea is to take pictures of the same scene at two different positions with a twin camera and reproduce the depth at each pixel. One advantage here is the ability to determine a safe treatment area by measuring the disparity of the images taken by the camera. In this system, good resolution and reproducibility can be achieved by measuring the laser depth perception.

[0186] A second alternative embodiment example IV is shown in FIG. 6. This second alternative embodiment example is basically based on the use of a depth camera that measures time of flight. The object distance C is determined based on the measurement result of the time of flight of the light beam between a device that generates at least one suitable optical beam path and a detector unit, such as a camera unit, that is spatially separated therefrom, as C = (1 / 2) × c × t, where c is the speed of light and t is the time of flight. Using a suitable computer program, the time delay of the light pulse from a laser or LED that has been reflected by a reflective curved surface, such as the cornea, can be taken into account.

[0187] A third alternative embodiment example V is shown in FIG. 7. This third alternative embodiment example is basically based on slit lamp translation tracking, and it is possible to track the movement of the laser delivery head in each direction and automatically (mechanically) sense it with an electrical sensor. By capturing the sensor signal with a CPU and processing it with software, the location can be tracked. One of the advantages is that this configuration is easy to implement. If a step motor module is not incorporated, it can be cost-effective.

[0188] A fourth alternative embodiment example VI is shown in FIG. 8. This fourth alternative embodiment example is basically based on depth perception with a single camera. Focus adjustment is not performed. If the retinal image is in focus, a warning is displayed or a measurement reference point is set. The proximity to the iris can be detected using another or the same camera, and a warning can be issued when it is approximately in focus with the iris. This example has the ability to discriminate a safe treatment area, in particular, by identifying the iris / lens and retina as reference points.

[0189] In another method, there may be one that detects image blur by defocus blur analysis software for depth perception estimation and simultaneously commands the liquid lens to correct the image. By reading the current supplied to the liquid lens for image correction by the software, it is possible to quantify how much the target "eye" has displaced over a depth change. One of the advantages of this is that by performing defocus blur analysis, a strong relationship to depth perception can be provided.

[0190] The fifth alternative embodiment VII is shown in FIG. 9, and this fifth alternative embodiment is basically by printing a pattern on a contact lens or its periphery and focusing a camera on them. One of the advantages of this example is that since a reference mark is provided on the cornea, a strong reference point is detected by the camera and the depth is perceived.

[0191] The sixth alternative embodiment VIII is shown in FIG. 10, and this sixth alternative embodiment is basically for detecting the position of floating objects using OCT (optical coherence tomography) or by ultrasonic A-scan. One of the advantages of this example is that OCT can provide the accuracy and reliability suitable for this purpose.

[0192] None of the above alternative embodiments or concepts solve the problems faced by the present invention even without other features of the present invention.

[0193] However, the described alternative embodiments or concepts can also be combined with those other features to further develop various devices according to the sense of the present invention.

[0194] It should be specified in this regard that the features of the various measures described above or described in the claims and / or the drawings can also be combined as needed, whereby it is possible to implement or achieve the described features, effects and advantages in a suitable cumulative manner.

[0195] As can be understood, the various embodiments described above are only the leading embodiments of the device according to the present invention. Therefore, the embodiments of the present invention are not limited to those embodiments.

[0196] All the features disclosed in this document are claimed to be essential to the present invention as long as they are novel, either individually or in combination, compared with the prior art.

Explanation of Reference Numerals

[0197] 1 Device 2 Location and thus position 3 Object of interest 4 Eye 5 Vitreous body 6 Machine axis and thus measurement axis 7 Machine direction 8 Optical axis 10 Means for generating at least one optical beam path 11 First optical beam path 12 Second optical beam path 13 First imaging system 14 Second imaging system 15 First camera unit 16 Second camera unit 17 Visual direction 20 Means for defining a reference plane 22 Known eye structure 23 Known reference structure 25 Image plane 27 First marker 28 Further markers arranged at intervals 100 Alternative device 102 Location for obtaining materials and thus position 103 Object of interest 104 Eye 105 Vitreous body 106 Machine axis and thus measurement axis 107 Machine direction 108 Optical axis Means for generating at least one optical beam path 111 First optical beam path 112 Second optical beam path 113 First imaging system 114 Second imaging system 115 First camera unit 116 Second camera unit 117 Visual direction 122 Known eye structure 123 Known reference structure 127 First marker 128 Further markers arranged at intervals 150 Ophthalmic microscope 150A Ophthalmic device 151 Objective lens 153 Binocular visual path 155 Triangular geometry 156 Right triangle 157 First spot 158 Further spots f Focal length B Distance section C Object distance D Distance between beam paths E Focal plane F Intersection point Y Reference plane and thus intersection plane θ Visual angle α Angle I Embodiment example II Second embodiment example III First alternative embodiment example IV Second alternative embodiment example V Third alternative embodiment example VI Fourth alternative embodiment example VII Fifth alternative embodiment example VIII Sixth alternative embodiment example

Claims

1. An apparatus (1; 100) for determining the location (2; 102) of a target object (3; 103) within a patient's eye (4; 104), particularly within the vitreous body (5; 105) of the eye (4; 104), the apparatus having means (10; 110) for generating at least one optical beam path (11, 12; 111, 112) and the reference plane (Y) being on the opposite side of the target object (3; 103), the apparatus being set up to determine the object distance (C) between the reference plane (Y) and the target object (3; 103) at the reference plane (Y).

2. The apparatus (1; 100) according to claim 1, characterized in that the reference plane (Y) can be defined by a known reference structure (23; 123) of the patient's eye (4; 104).

3. The apparatus (1; 100) according to claim 1 or 2, characterized in that it is set up such that the object distance (C) can be determined by a triangular geometry (155) forming a right triangle (156) located between the target object (3; 103) and the reference structure (23; 123).

4. The apparatus (1; 100) according to one of claims 1 to 3, characterized in that at least a first adjacent side of the adjacent sides of the right triangle (156) is defined by the object distance (C), at least a second adjacent side of the adjacent sides of the right triangle (156) is defined at the reference plane (Y), and the hypotenuse of the right triangle (156) is defined by the at least one beam path (11, 12; 111, 112).

5. The apparatus (1; 100) according to any one of claims 1 to 4, characterized by comprising at least one optical imaging system (13, 14; 113, 114) for detecting markers (27, 28; 127, 128) formed on the reference plane (Y).

6. The apparatus (1; 100) according to one of claims 1 to 5, the apparatus (1; 100) being set up such that the object distance (C) can be determined by two markers (27, 28; 127, 128) generated on the reference plane (Y) by the at least one optical beam path (11, 12; 111, 112) passing through the reference plane (Y), the markers (27, 28; 127, 128) being arranged separated from each other in a certain distance section (B).

7. The apparatus (1; 100) according to claim 6, characterized in that markers (27, 28; 127, 128) spatially separated by a certain distance section (B) can be generated with a certain time offset.

8. The apparatus (1; 100) according to one of claims 1 to 7, set up such that the object distance (C) can be determined by an image shift related to the markers (27, 28; 127, 128) generated by the at least one optical beam path (11, 12; 111, 112) passing through the reference plane (Y), characterized in that the markers (27, 28; 127, 128) are mutually spatially separated by a certain distance section (B).

9. The apparatus (1; 100) according to one of claims 1 to 8, which images the reference plane (Y) by an optical imaging system (13, 14; 113, 114) and images the image (O1, O2; O'1, O'2) of the object of interest (3; 103) in the reference plane (Y) by one or two optical beam paths (11, 12; 111, 112), set up such that the object distance (C) is determined by the amount of image shift (y1, y2) along the reference plane (Y) of the image (O1, O2; O'1, O'2) imaged in the reference plane (Y), or by the distance section (B) formed by two optical markers (27, 28; 127, 128) generated in the reference plane (Y).

10. The apparatus (1; 100) according to claim 9, characterized in that the object distance (C) is proportional to the amount of image shift (y1, y2) in the reference plane (Y).

11. The apparatus (1; 100) according to one of claims 1 to 10, characterized in that the image (O) of the object of interest imaged in the reference plane (Y) can be shifted to the location of a further image (O') when the reference plane (Y) is shifted with respect to the object of interest (3; 103), whereby the object distance (C) is determined.

12. An apparatus (1; 100) according to any one of claims 1 to 11, characterized in that a distance section (B) between two markers (27, 28; 127, 128) is associated with the object distance (C), and the object distance (C) can be determined by using the distance section (B).

13. An apparatus (1; 100) according to one of claims 1 to 12, characterized in that it is set up such that the focal plane (E) can be arranged at the position of the object of interest (3; 103).

14. An apparatus (1; 100) according to one of claims 1 to 13, characterized in that the optical beam paths (11, 12; 111, 112) can be focused on a common focus (F) within the focal plane (E).

15. An apparatus (1; 100) according to one of claims 1 to 13, characterized in that the optical beam paths (11, 12; 111, 112) can be focused on separate foci within the focal plane (E).

16. An apparatus (1; 100) according to one of claims 1 to 15, characterized in that the at least one optical beam path (11, 12; 111, 112) is set up to be directed onto the object of interest (3; 103) via the reference plane (Y).

17. An apparatus (1; 100) according to one of claims 1 to 16, characterized in that the at least one optical beam path (11, 12; 111, 112) is set up to be located at an angle (α) with respect to the object distance (C), and the object distance (C) is arranged orthogonally with respect to the reference plane (Y).

18. An apparatus (1; 100) according to one of claims 1 to 17, characterized in that the object distance (C) is set up to form a section of the optical axis (8; 108) of the apparatus (1; 100).

19. An apparatus (1; 100) according to one of claims 1 to 18, characterized in that the viewing angle (θ) is surrounded by the optical beam paths (11, 12; 111, 112) at least in a plurality of sections.

20. An apparatus (1; 100) according to one of claims 1 to 19, characterized in that the reference plane (Y) is located in front of or behind the focal plane (E) related to the optical imaging device (13, 14; 113, 114).

21. An apparatus (1; 100) according to one of claims 1 to 20, characterized in that it comprises an ophthalmic microscope (150) having a microscope focal length (f) that is the same as the focal length (f) of the optical imaging device (13, 14; 113, 114), among other things.

22. An ophthalmic device (150A) for performing a treatment on a patient's eye (4; 104) with an ophthalmic microscope (150), characterized in that it is an apparatus (1; 100) according to one of claims 1 to 21.

23. A method of operating an apparatus (1; 100) for determining the location (2; 102) of a target object (3; 103) within a patient's eye (4; 104), especially within the vitreous body (5; 105) of that eye (4; 104), which is a method of operating an apparatus (1; 100) according to one of claims 1 to 21, in which at least two light paths (11, 12; 111, 112) intersect each other in a reference plane (Y) at a common intersection point (F), and with each of said at least two light paths (11, 12; 111, 112), the intersection point (F) in the reference plane (Y) or its vicinity is imaged as a spaced image (O1, O2; O’1, O’2), and the image (O1, O2; O’1, O’2) is shifted relative to another one in the reference plane (Y) by shifting the intersection point (F) and the reference plane (Y) relative to each other, and the original distance (C) from the intersection point (F) to the reference plane (Y) is determined by the amount of those image shifts.

24. The method according to claim 23, characterized in that the at least two optical beam paths (11, 12; 111, 112) enclose each other at a viewing angle (θ).

25. A method for operating a device (1; 100) for discriminating the location (2; 102) of a target object (3; 103) within a patient's eye (4; 104), especially within the vitreous body (5; 105) of the eye (4; 104), which is a method for operating a device (1; 100) according to one of claims 1 to 21, the method comprising generating a reference plane (Y) orthogonal to the measurement axis (6; 106) of the device (1; 100), intersecting at a common intersection point (F) the measurement axis (6; 106) with at least one optical beam path (11, 12; 111, 112) passing through the reference plane (Y), generating markers (27, 28; 127, 128) at the passing points in the reference plane (Y) with the at least one optical beam path (11, 12; 111, 112), and determining based thereon the distance (C) between the intersection point (F) and the reference plane (Y) in the reference plane (Y).

26. A method according to claim 25, characterized in that additional markers (27, 28; 127, 128) are generated in the reference plane (Y).

27. A method according to one of claims 23 to 26, characterized in that the optical beam paths (11, 12; 111, 112) are sequentially generated with a time offset.

28. A method according to claim 27, characterized in that the optical beam paths (11, 12; 111, 112) generated in the time shift manner are also generated in a place shift manner and complementarily enclose a virtual viewing angle.

29. A method according to claims 23 to 28, characterized in that a focal plane (E) is defined at the intersection point (F) by the two intersecting optical beam paths (11, 12; 111, 112).

30. A method according to claims 23 to 29, characterized in that the reference plane (Y) is defined by at least one camera unit (15, 16; 115, 116).

31. A method for discriminating the location (2; 102) of a target object (3; 103) within a patient's eye (4; 104), especially within the vitreous body (5; 105) of the eye (4; 104), the method comprising determining the object distance (C) between the target object (3; 103) and a known reference structure (23; 123) of the eye (4; 104) in a reference plane (Y) defined by the reference structure (23; 123).

32. A method according to one of claims 23 to 31, characterized in that the distance, in particular the object distance (C), is determined by the ratio of the sides and angles of a right triangle (156).

33. A method for discriminating the location (2; 102) of a target object (3; 103) within a patient's eye (4; 104), particularly within the vitreous body (5; 105) of the eye (4; 104), wherein the target object (3; 103) is located within or near the generated focal plane (E), and a known anatomical eye structure (22; 122) of the eye (4; 104) is located within the generated reference plane (Y). The method includes focusing at least two light paths (11, 12; 111, 112) via the reference plane (Y) onto the focal plane (E) or near it, and when the focal plane (E) and the reference plane (Y) are moving relative to each other, determining one or more image shifts of at least one image (O) in focus on the focal plane (E) in the reference plane (Y), and determining the distance (C) between the focal plane (E) and the reference plane (Y) based on the image shift in the reference plane (Y).

34. A method for discriminating the location (2; 102) of a target object (3; 103) within a patient's eye (4; 104), particularly within the vitreous body (5; 105) of the eye (4; 104), wherein the target object (3; 103) is located within or near the generated focal plane (E), and a known anatomical eye structure (22; 122) of the eye (4; 104) is located within the generated reference plane (Y). The method includes focusing at least one optical beam path (11, 12; 111, 112) via the reference plane (Y) onto the focal plane (E) or near it, determining a distance section (B) between two markers generated on the reference plane (Y) by the at least one optical beam path (11, 12; 111, 112), and determining the distance (C) between the focal plane (E) and the reference plane (Y) based on the distance section (B) determined in the reference plane (Y).

35. A method according to one of claims 23 to 34, characterized in that the determined object distance (C) is supplied to operate a treatment machine in an automatic manner.

Images