Operating microscope, operating microscope system and method for observing the posterior segment of an eye

Abstract

An operating microscope (20) is provided with an observation optics (11, 50) providing an observation beam path and an illumination device (41, 43, 45) providing an illumination beam path. The observation optics (11, 50) includes a main objective (50) with an adjustable focal length. The illumination device (41, 43, 45) also includes an optical deflection element (43) by means of which the illumination beam path is directed towards an observation object (30). This deflection element (43) is arranged on the side of the main objective (50) facing the observation object (30). Furthermore, an operating microscope system is provided, comprising such an operating microscope (20) and an attachment module (59) that can be positioned between the main objective and the eye (30) to be observed. To observe the posterior segment (30B) of an eye (30), the attachment module (59) is positioned between the main objective (50) and the eye (30) using the operating microscope system. The attachment module (59) then generates an aerial image of the posterior segment (30B) in an intermediate image plane (62) that can be observed with the operating microscope (20). The focal length of the main objective (50) is adjusted so that the operating microscope (20) is focused on the intermediate image plane (50).

Description

[0001] The present invention relates to an operating microscope. The invention further relates to an operating microscope system comprising an operating microscope and an attachment module for observing the posterior segment of an eye, as is used, for example, in ophthalmic surgery, as well as a method for observing the posterior segment of an eye.

[0002] The surgical microscopes currently used in ophthalmic surgery are stereomicroscopes and often feature the following optical design for their observation optics: On the image side of a fixed, fixed-focal-length main objective, usually an achromatic lens, a magnification changer is arranged, allowing the magnification in the observation beam path to be altered. The magnification changer can be a continuously variable magnification changer, also called a pan-tilt or zoom, or a magnification changer with fixed magnification steps (so-called Galilean changer), in which different lens combinations can be inserted into the observation beam path to adjust the magnification. The magnification changer is generally already part of the stereoscopic beam path, so it has components for the left stereoscopic beam path and components for the right stereoscopic beam path.However, it can also be so large that it is penetrated by both stereoscopic beam paths. Optionally, an optical interface is connected to the magnification changer on the image side, allowing a beam of light to be coupled into or out of the observation beam path. Such an optical interface can be located in each stereoscopic beam path. A binocular tube with tube objectives is then connected to the optical interface(s) on the image side. These objectives generate an intermediate image for each stereoscopic beam path, which is viewed using eyepieces. Alternatively, image sensors can be used instead of the binocular tube. The stereoscopic beam paths are focused onto these sensors, and the images captured by the image sensors are then displayed on one or more screens.

[0003] Furthermore, an operating microscope for ophthalmic surgery has an illumination system for generating an illumination beam path. In addition to a light source and illumination optics for shaping the illumination beam, the illumination system includes a beam splitter, which directs the illumination beam towards the object being examined. The illumination system is usually configured to generate both so-called red-reflection illumination and ambient illumination. With red-reflection illumination, the illumination beam is directed parallel to the optical axis of the main objective or, split into two partial beams, parallel to the stereoscopic observation beam paths towards one eye to illuminate the retina.Light reflected from the retina, which has a predominantly reddish hue due to the retina's blood supply, illuminates the lens from within the eye, allowing lens fragments to be seen, for example, during cataract surgery. The beam splitter is positioned between the main objective lens and the magnification changer.

[0004] If the operating microscope is to be used in posterior segment surgery, a so-called reduction optic is positioned on the object side of the main objective to reduce the focal length. Additionally, an ophthalmic magnifier is placed over the eye, which generates an aerial image of the posterior segment of the eye in the area between the magnifier and the reduction optic. This image can then be observed with the reduced focal length of the operating microscope. The posterior segment includes, in particular, the retina with the fovea and macula, the sclera, the choroid, and the optic nerve head (optic disc). The vitreous humor is also considered part of the posterior segment of the eye.To focus the operating microscope onto the intermediate image plane in which the aerial image is generated, it is generally moved as a whole along its optical axis relative to the ophthalmic loupe, as described, for example, in EP 1 908 398 A1. Such a focusing method can only provide a relatively small focus stroke of less than 100 mm if the working distance of the operating microscope from the eye is not to become so large as to impair ergonomics. Furthermore, such focusing requires precise positioning of the operating microscope relative to the ophthalmic loupe, which places high demands on the focusing system.

[0005] Alternatively, the reducing optics can also have optical components that can be moved relative to each other along their optical axis, allowing the focal length on the object side to be changed. However, this makes the design of the reducing optics more complex and also increases the overall height compared to a fixed focal length reducing optics. Since the space between the ophthalmoscopic loupe and the main objective lens is limited, there are restrictions on the maximum possible height of the reducing optics. Therefore, even a reducing optics with optical components that can be moved relative to each other along their optical axis only allows a relatively small focus stroke of less than 80 mm.

[0006] Furthermore, surgical microscopes featuring a so-called varioscope as the main objective are also known, for example, from DE 10 2005 011 781 A1 and EP 1 889 567 A2. A main objective designed as a varioscope has a fixed lens group and a lens group movably arranged along the optical axis of the varioscope. By moving the movably arranged lens group relative to the fixed lens group, the focal length of the main objective designed as a varioscope can be adjusted, so that the aerial image produced by the ophthalmic loupe can be viewed without having to move the entire surgical microscope relative to the ophthalmic loupe and without the need for a reduction optic. However, in such a configuration, the main objective has a large number of surfaces, which necessitates considerable effort to reduce reflections generated by the illumination beam.That's why such systems are not found in practice.

[0007] The object of the present invention is to provide an advantageous operating microscope, an advantageous operating microscope system, and an advantageous method for observing the posterior segment of an eye, in which the described disadvantages are reduced. This object is achieved by an operating microscope according to claim 1, by an operating microscope system according to claim 9, and by a method for observing the posterior segment of an eye according to claim 10. The dependent claims contain advantageous embodiments of the invention.

[0008] An operating microscope according to the invention comprises an observation optic that provides a beam path suitable for observing an object, such as an eye. The observation optic includes a main objective with an adjustable focal length, which allows the position of the focal plane of the observation optic to be adjusted. The operating microscope also includes an illumination device that provides a beam path for illuminating the object and includes an optical deflection element that directs the illumination beam towards the object. The operating microscope according to the invention is characterized in that the deflection element is arranged on the side of the main objective of the operating microscope facing the object.

[0009] By relocating the deflection element for the illumination beam path from an image-side position of the main objective to an object-side position of the main objective, reflections of the illumination beam at the main objective can be avoided, particularly in the case of 0° illumination, where the illumination beam path runs between the two observation beam paths of the surgical microscope, along the optical axis of the objective towards the observation object, or in the case of stereo-coaxial illumination, where a first and a second illumination beam path are present, which run coaxially or nearly coaxially to the optical axes of the observation beam paths. This allows the main objective to be equipped with more surfaces without having to worry about disruptive reflections from the illumination beam. Relocating the deflection element to a position below the main objective, i.e.,Positioning the lens on the object side of the main objective allows the use of main objectives with variable focal lengths, which, compared to fixed focal length main objectives, have a significantly larger number of potentially reflective surfaces, in conjunction with 0° illumination or coaxial illumination. When using a contact lens or ophthalmic magnifier, the reduction optics in the attachment can then be omitted, so that the attachment only needs to consist of the contact lens or ophthalmic magnifier. Focusing on the aerial image generated by the attachment can be achieved with the main objective. Furthermore, when focusing with a main objective with an adjustable focal length, there is no need to move the operating microscope along the optical axis relative to the ophthalmic magnifier or, if applicable, the contact lens, nor is it necessary to consider the height of a reduction optic.Therefore, focusing with the main objective lens with adjustable focal length allows for a significantly larger focus stroke, ranging from 150 to 400 mm, compared to focusing via the operating microscope or focusing with a reduction optic that has optical components that can be moved relative to each other along its optical axis and is designed to be as low-profile as possible. Consequently, the working space between the eye and the operating microscope is less restricted compared to previous systems. Furthermore, the larger number of lenses in a main objective lens with adjustable focal length, compared to a fixed-focal-length achromatic lens, also reduces aberrations. For example, designing the objective lens as an apochromat reduces chromatic aberration.If the operating microscope is a purely digital operating microscope, the stereo beam path, unlike the current double decentering, can be implemented with only single decentering, which increases the imaging performance. The large focus stroke of the operating microscope according to the invention can also be used to open up further application areas of the operating microscope system, such as gonioscopy or exoscopy.

[0010] The operating microscope can have a transparent end element, with the deflection element positioned between the main objective and the transparent end element. The transparent end element prevents the deflection element from becoming soiled and / or misaligned due to unintentional contact. The transparent end element can be, in particular, a mineral or organic end glass. The operating microscope can, for example, comprise a housing in which both the main objective and the deflection element are located.

[0011] The transparent end element can have a flat surface facing the object, the normal of which runs at an angle greater than 0 degrees to the optical axis of the main objective. In particular, the normal of the flat surface facing the object can run at an angle greater than 10 degrees, and furthermore, in particular, at an angle in the range of 10 degrees to 30 degrees, e.g., at an angle of 10 degrees, 15 degrees, 20 degrees, 25 degrees, or 30 degrees to the optical axis. Angles between these angles are also possible. The transparent end element can, in particular, have two flat surfaces in order to minimize the influence on the observation beam path, which is not parallel at the point of the end element. The flat surfaces can, for example, be arranged parallel to each other.Alternatively, the transparent end cap can be designed as a wedge-shaped transparent end cap with a wedge angle greater than 0 degrees, in particular a wedge angle in the range of 30 arcseconds to 1 degree, and furthermore, in particular a wedge angle in the range of 1 arcminute to 30 arcminutes, between the two planar surfaces. Designing the transparent end cap as a wedge-shaped transparent end cap offers advantages with regard to avoiding aberrations in the observation beam path, for example, with regard to avoiding astigmatism. A suitable wedge angle depends on the refractive index of the material from which the transparent end cap is made, the thickness of the transparent end cap, and the angle between the object-side planar surface and the optical axis of the main objective.

[0012] The deflecting element can have a beam-deflectoring planar surface whose surface normal runs at an angle greater than 30 degrees to the optical axis of the main objective. The surface normal of the beam-deflectoring planar surface can run at an angle in the range of 30 degrees to 60 degrees, and in particular at an angle of 40 degrees to 50 degrees, e.g., at an angle of 45 degrees, to the optical axis of the main objective. In addition to the beam-deflectoring planar surface, the deflecting element can have a further planar surface and be configured as a wedge-shaped deflecting element with a wedge angle greater than 0 degrees, in particular a wedge angle in the range of 30 arcseconds to 1 degree, and in particular a wedge angle in the range of 1 arcminute to 30 arcminutes, between the beam-deflectoring planar surface and the further planar surface.As with the transparent end cap, the wedge shape of the deflecting element offers advantages in terms of avoiding aberrations in the observation beam path, for example, in preventing astigmatism. A suitable wedge angle, as with the transparent end cap, depends on the refractive index of the material from which the transparent deflecting element is made, the thickness of the deflecting element, and the angle between the beam-deflecting surface and the optical axis of the main objective.

[0013] An operating microscope system according to the invention comprises an operating microscope according to the invention and an attachment module that can be positioned between the main objective and an eye as the observation object in the observation beam path. The attachment module is configured to generate an aerial image of the posterior segment of the eye, which can be observed with the operating microscope, when it is positioned in the observation beam path. The focal length of the main objective is adjustable such that the operating microscope is focused on the intermediate image plane.

[0014] In the inventive method for observing the posterior segment of an eye as the object of observation, the eye is observed using an operating microscope system according to the invention. The method comprises the steps - Positioning the attachment module between the main objective and the eye to be observed, in order to generate an aerial image of the posterior segment of the eye in an intermediate image plane, which can be observed with the operating microscope, using the attachment module, and - Focusing the operating microscope on the intermediate image plane by adjusting the focal length of the main objective.

[0015] The properties and advantages of the surgical microscope system and the method according to the invention result from the properties and advantages of the surgical microscope according to the invention.

[0016] Further features, properties and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying figures. Fig. Figure 1 shows a typical operating microscope as used in ophthalmic surgery. Fig. Figure 2 shows a typical digital operating microscope as used in ophthalmic surgery. Fig. Figure 3 shows a main lens with adjustable object depth. Fig. Figure 4 shows an example of an operating microscope which has a main objective with adjustable focal length and a deflection element on the side of the main objective facing the eye, which is set up for observing the anterior segment of the eye. Fig. Figure 5 shows a wedge-shaped end glass in cross-section. Fig. Figure 6 shows the focus stroke of an operating microscope, as described in relation to Fig. 2 has been described, when observing the anterior segment of an eye. Fig. 7 shows the operating microscope from Fig. 4 with a front module for observing the posterior segment of an eye. Fig. Figure 8 shows the focus stroke of an operating microscope, as demonstrated with reference to Fig. 2 has been described, when observing the posterior segment of an eye.

[0017] The following refers to Fig. 1. The typical structure of an operating microscope 2, as used, for example, in ophthalmic surgery, is described. The in Fig. The operating microscope 2 shown in Figure 1 comprises as essential components an objective 5 facing an object field 3, e.g., an eye to be observed, which can be designed in particular as an achromatic or apochromatic objective. In the typical configuration shown, the achromatic objective 5 consists of two cemented partial lenses.

[0018] The object field 3 is positioned in the focal plane of the objective 5, so that it is imaged to infinity by the objective 5. In other words, a divergent beam of rays 7A, 7B emanating from the object field 3 is transformed into a parallel beam of rays 9A, 9B as it passes through the objective 5. The beams 7A, 7b and 9A, 9B define the beam paths of the operating microscope, namely stereoscopic partial beam paths.

[0019] On the observer side of the objective 5, a magnification changer 11 is arranged, which can be configured either as a zoom system for stepless changes in the magnification factor or as a so-called Galilean changer for stepwise changes in the magnification factor. A zoom system, also called a Pankrat, can, for example, be constructed from a lens combination with three lenses, in which the two object-side lenses can be moved to vary the magnification factor. In fact, the zoom system can also have more than three lenses, e.g., four or more lenses, in which case the outer lenses can also be fixed. In contrast, a Galilean changer contains several fixed lens combinations that represent different magnification factors and can be alternately introduced into the stereoscopic partial beam paths defined by the partial beam bundles 9A and 9B.Both a zoom system and a Galilean changer convert an object-side parallel beam of light into an observer-side parallel beam of light with a different beam diameter. In the present exemplary embodiment, the magnification changer 11 is already part of the binocular beam path of the operating microscope 2; that is, it has its own lens combination for each stereoscopic partial beam path 9A, 9B of the operating microscope 2. Setting a magnification factor using the magnification changer 11 is typically accomplished via a motor-driven actuator, which, together with the magnification changer 11, forms part of a magnification changer unit for setting the magnification factor.

[0020] An optional interface arrangement 13A, 13B is connected to the magnification changer 11 on the observer side, allowing external devices to be connected to the operating microscope 2. In the typical setup shown, this arrangement comprises beam splitter prisms 15A, 15B. However, other types of beam splitters can also be used, such as partially reflective mirrors. The interfaces 13A, 13B serve, for example, to couple a beam from the stereoscopic partial beam path 9B of the operating microscope 2 (beam splitter prism 15B) or to couple a beam into the stereoscopic partial beam path 9A of the operating microscope 2 (beam splitter prism 15A).

[0021] In the typical setup shown, the beam splitter prism 15A in the stereoscopic partial beam path 9A serves to reflect information or data for a viewer into the stereoscopic partial beam path 9A of the operating microscope 2 via a display 37, e.g., a digital mirror device (DMD) or an LCD display, and associated optics 39. In the other stereoscopic partial beam path 9B, a camera adapter 19 with an attached camera 21 is arranged at the interface 13B. The camera 21 is equipped with an electronic image sensor 23, e.g., a CCD sensor or a CMOS sensor. An electronic, and in particular a digital, image or video of the object field 3 can be recorded using the camera 21, for example, for documentation purposes or for displaying an image or video on a monitor.

[0022] In the typical setup shown, a binocular tube 27 is connected to the interface 13 on the observer side. This tube has two objective lenses 29A, 29B, which focus the respective parallel beams of light 9A, 9B onto an intermediate image plane 31, thus imaging the observed object 3 onto the respective intermediate image planes 31A, 31B. The intermediate images located in the intermediate image planes 31A, 31B are then imaged to infinity by eyepiece lenses 35A, 35B, so that the observer can view the intermediate image with relaxed eyes. Furthermore, the distance between the two partial beams of light 9A, 9B is increased within the binocular tube by means of a mirror system or prisms 33A, 33B to adjust it to the interpupillary distance of the observer. The mirror system or prisms 33A, 33B also erect the image.

[0023] The operating microscope 2 is also equipped with an illumination device that illuminates the object field 3 with broadband light. For this purpose, the illumination device typically comprises a white light source 41, such as a halogen incandescent lamp, a gas discharge lamp, a white LED, etc. The light emitted from the white light source 41 is directed towards the object field 3 via a deflecting mirror 43, designed as a beam splitter, or a deflecting prism, in order to illuminate it. The illumination device also includes an illumination optic 45, which forms a beam of light and is shown only schematically in the figure.

[0024] It should be noted that the in Fig. The illumination beam path shown in Figure 1 is highly schematic and does not necessarily represent the actual path of the illumination beam. In principle, the illumination beam path can be implemented as so-called oblique illumination. In such oblique illumination, the beam path runs at a relatively large angle (6° or more) to the optical axis of the lens 5, and may even run entirely outside the lens. Alternatively, however, it is also possible for the oblique illumination beam path to pass through an edge region of the lens 5. Another possibility for arranging the illumination beam path is so-called 0° illumination, in which the illumination beam path passes through the lens 5 and is coupled into the lens between the two partial beam paths 9A and 9B, along the optical axis of the lens 5, in the direction of the object field 3.The 0° illumination corresponds to the schematic representation in . Fig. 1. Furthermore, it is possible to implement the illumination beam path as so-called coaxial illumination, in which a first and a second illumination partial beam path are present. The partial beam paths are coupled into the operating microscope via one or more beam splitters coaxially or nearly coaxially to the optical axes of the observation partial beam paths 9A, 9B, so that the illumination is coaxial to the two observation partial beam paths. Coaxial here means that the illumination partial beam paths are positioned without any distance and at an angle of 0° to the stereoscopic observation beam paths. Nearly coaxial, on the other hand, means that the illumination partial beam paths are positioned with a small distance, in particular at a distance of no more than 2 mm, and at a small angle to the stereoscopic observation beam paths, in particular at an angle of no more than 1 degree.

[0025] The following refers to Fig. 2 The typical setup of a digital operating microscope 2', as used in ophthalmic surgery, is described. In the digital operating microscope 2', the main objective 5, the magnification changer 11, which is only an option in the digital operating microscope 2' and therefore not strictly necessary, and the illumination system 41, 43, 45 do not differ from that in Fig. 1. Operating microscope 2 with optical view. The difference lies in the fact that the one in Fig. The operating microscope 2' shown does not include an optical binocular tube. Instead of the tube objectives 29A, 29B, Fig. 1 includes the operating microscope 2' made of Fig. 2 Two focusing lenses 49A, 49B, with which the binocular observation beam paths 9A, 9B are focused onto digital image sensors 61A, 61B in order to generate stereoscopic partial images of the object field 3 at the locations of the image sensors 61A, 61B. The digital image sensors 61A, 61B can be, for example, CCD sensors or CMOS sensors. The images acquired by the image sensors 61A, 61B are sent to digital displays 63A, 63B, which can be designed as LED displays, as LCD displays, or as displays based on organic light-emitting diodes (OLEDs). Displays 63A and 63B can be paired with eyepiece lenses 65A and 65B, as in the present example, which focus the images displayed on the displays 63A and 63B to infinity, allowing the viewer to observe them with relaxed eyes. The displays 63A and 63B and the eyepiece lenses 65A and 65B can be part of a digital binocular tube.They can also be part of a head-mounted display (HMD), such as smart glasses. Although in . Fig. 2. As shown in Figure 2, the images captured by the image sensors 61A, 61B can be transmitted to the displays 63A, 63B of a digital binocular tube via cables 67A, 67B. However, the images can also be transmitted wirelessly to the displays 63A, 63B, particularly when the displays 63A, 63B are part of a head-mounted display. Furthermore, the captured images can be displayed as stereoscopic images on a large monitor, which is viewed by operating room personnel using suitable 3D glasses. To distinguish the stereoscopic sub-images, they can be displayed on the monitor, for example, using different polarizations of the light emitted by the monitor. The 3D glasses then contain switchable polarizers that are switched synchronously with the display of the sub-images on the monitor.Alternatively, it is also possible to alternately switch the left and right lenses of shutter glasses between a transparent and an opaque state in synchronization with the display of a left and a right partial image on a monitor.

[0026] In the Fig. 1 and Fig. In the two operating microscopes 2, 2' shown for ophthalmic surgery, the objective 5 consists solely of a fixed focal length achromatic lens. In contrast, an operating microscope according to the invention uses an objective lens system with multiple lenses, with which the focal length of the objective, i.e., the distance of the object-side focal plane from the vertex of the first object-side lens surface of the objective, can be varied. With such an objective, also called a varifocal objective, an object field 3 arranged in the focal plane is imaged to infinity, so that a parallel beam of light is present on the observer side.

[0027] An example of a lens with an adjustable focal length, hereinafter referred to as a varifocal lens, is shown schematically in Fig. Figure 3 shows the Vario lens 50 comprising a positive element 51, i.e., an optical element with positive refractive power, which is in Fig. 3 is schematically represented as a convex lens. Furthermore, the Vario lens 50 includes a negative element 52, i.e., an optical element with negative refractive power, which is in Fig. Figure 3 schematically depicts a concave lens. The negative element 52 is located between the positive element 51 and the object field 3. In the depicted varifocal lens 50, the negative element 52 is fixed, whereas the positive element 51, as indicated by the double arrow 53, is displaceable along the optical axis OA. When the positive element 51 is in the Fig. When the position shown in dashed lines is moved, the object section width increases. The positive element 51 and the negative element 52 are in Fig. 5 are shown only as individual lenses. However, each of these elements can also be implemented as a lens group or a cemented element, e.g., to make the varifocal lens achromatic or apochromatic.

[0028] Although in Fig. 3. If the positive element 51 is designed to be movable, it is also possible in principle to arrange the negative element 52 so as to be movable along the optical axis OA instead of the positive element 51.

[0029] Fig. Figure 4 shows an exemplary embodiment of a surgical microscope 20, which has a main objective 50 with adjustable focal length and an illumination system 41, 43, 45 with an illumination optic 45 for shaping an illumination beam and with a deflection element 43 for deflecting the illumination beam towards an eye 30. The deflection element 43 is designed as a beam splitter mirror with two parallel planar surfaces 43-1, 43-2 and is arranged on the object side of the main objective 50.

[0030] The operating microscope 20 is a digital operating microscope whose components are largely based on the operating microscope 2'. Fig. 2 or the one in Fig. The main lens shown in section 3 corresponds to 50. Elements of the in Fig. 4 operating microscope 20 shown, which already with reference to Fig. 2 or Fig. 3. As explained above, are in Fig. 4 with the same reference number as in Fig. 2 or Fig. 3 are designated and will not be explained again to avoid repetition.

[0031] The in Fig. The operating microscope shown in section 4 differs from the one in [reference missing]. Fig. 2 operating microscope 2' shown mainly by the fact that (i) a variable objective is used as the main objective 50, (ii) the illumination system 41, 43, 45, in particular the deflection element 43, is arranged on the object side of the main objective 50, and (iii) an optional end element 57 is positioned in front of the deflection element on the object side of the deflection element 43.

[0032] In the present exemplary embodiment, the end element 57 is a plane-parallel end plate 57, whose planar surfaces 57-1, 57-2 run obliquely to the optical axis OA of the main lens 50.

[0033] The end plate can also be referred to as the end glass. In the present exemplary embodiment, the surface normal N of the object-side planar surface 57-1 of the end plate 57 has an angle α > 0 degrees to the optical axis OA of the varifocal lens 50 in order to prevent reflections entering the observation beam path. The angle α is 20 degrees in this exemplary embodiment. Other angles greater than 0 degrees are also possible. However, the angle should preferably be greater than 10 degrees to adequately prevent reflections entering the observation beam path. Typically, the angle is in the range between 10 degrees and 30 degrees.

[0034] Because the end plate 57 is located in the diverging part of the observation beam path, it can induce imaging errors such as astigmatism in the observation beam path. To reduce such imaging errors and ideally avoid them altogether, an end plate 157 with a wedge shape, as shown in [reference], can be used instead of a flat end plate 57. Fig. Figure 5 shows that in the wedge-shaped end plate 157, the planar surfaces 157-1 and 157-2 are arranged at a wedge angle γ greater than 0 degrees to each other. A suitable wedge angle γ can be determined based on the refractive index of the material from which the end plate 157 is made, the thickness of the end plate, and the angle between the object-side planar surface 157-1 and the optical axis OA of the main objective 50. Typical wedge angles are, for example, in the range of 30 arcseconds to 1 degree, preferably in the range between 1 arcminute and 30 arcminutes.

[0035] In the present exemplary embodiment, the beam splitter mirror 43 is arranged such that the surface normal of its object-side planar surface 43-1 forms an angle β of 45 degrees with the optical axis OA of the main objective 50. However, other angles β > 0 degrees are also possible. Preferably, these lie in the range between 30 degrees and 60 degrees, particularly in the range of 40 degrees to 50 degrees. In the present exemplary embodiment, 0° illumination is achieved by means of the beam splitter mirror 43.

[0036] Like the end glass 57, the beam splitter mirror 43, which is also located in the diverging part of the observation beam path, can be designed as a wedge-shaped element instead of as an element with parallel planar surfaces 43-1, 43-2, whose planar surfaces 43-1, 43-2 have a wedge angle > 0 degrees to each other. As with the wedge-shaped end glass 157, a suitable wedge angle can be determined based on the refractive index of the material from which the beam splitter mirror 43 is made, the thickness of the beam splitter mirror 43, and the angle between the object-side planar surface 43-1 of the beam splitter mirror 43 and the optical axis OA of the main objective 50. Typical wedge angles are, for example, in the range of 30 arcseconds to 1 degree, preferably in the range between 1 arcminute and 30 arcminutes.

[0037] The end plate 57 and the beam splitter mirror 43 are preferably arranged in a common housing section of the operating microscope 20. In this way, the beam splitter mirror 43 is shielded from external influences by the housing and the end glass 57, so that misalignment or contamination of the beam splitter mirror 43, for example by accidental contact, can be reliably prevented.

[0038] The variable objective 50 of the operating microscope 20 is associated with a drive 55 for adjusting the object depth. The positive element 51 can be moved by means of the drive 55. Fig. 3 - or another movable lens element - can be moved along the optical axis OA to change the focal length. By moving the positive element 51 along the optical axis OA, a focus stroke FH of 150-400 mm can be achieved for the operating microscope 20. When the operating microscope 20 is positioned as shown in Fig. Figure 4 illustrates how this is used for observing the anterior segment 30A of the eye 30, i.e., for example, the lens, cornea, anterior chamber, posterior chamber, iris, etc. With this focus stroke, reliable focusing on the area of ​​the anterior segment 30A of the eye 30 to be observed can be ensured without having to change the distance between the operating microscope 20 and the eye. In other words, the working distance of the operating microscope 20 can be kept constant during focusing.

[0039] In comparison, the digital operating microscope 2' must be made of Fig. 2 by means of a procedure of the entire operating microscope 2' along the optical axis OA, as described in Fig. Figure 6 is illustrated by the double arrow 60. A maximum travel distance of 70 mm, i.e., a maximum focus stroke FH of 70 mm, is possible in the direction of the eye 30. The use of the variable lens 50 thus significantly increases the usable focus stroke FH. The use of a variable lens 50 is made possible by moving the beam splitter mirror 43 from the Fig. 2 and Fig. 6 shown position above the main lens in the in Fig. The position shown in Figure 4 is shifted below the main lens 50. The increase in the usable focus stroke FH is thus a synergistic effect resulting from the combination of shifting the beam splitter mirror 43 and using the varifocal lens 50. Without shifting the beam splitter mirror 43 to the position below the main lens 50, too many disturbing reflections would occur on the surfaces of the varifocal lens 50 due to the illumination beam of a 0° illumination or the partial illumination beams of a coaxial illumination. This is because, in a varifocal lens 50, both the positive element 51 and the negative element 52 are typically designed as cemented elements and / or comprise several individual lenses, resulting in at least six potentially reflective surfaces within the varifocal lens.

[0040] Fig. Figure 7 shows the operating microscope 20 from Fig. 4, when it is used to observe the posterior segment 30B of the eye 30, for example, the retina, the sclera, the choroid, or the optic nerve head. To view the posterior segment 30B, an attachment module 59 is used, which is positioned between the operating microscope 20 and the eye 30, close to the eye 30. In the present exemplary embodiment, the attachment module 59 is an ophthalmoscopic magnifying lens, which is positioned near the eye 30 without contact with it and which generates an intermediate image of the posterior segment 30B of the eye 30 in an intermediate image plane 62. This intermediate image is magnified and observed using the operating microscope 20. Instead of an ophthalmoscopic magnifying lens, a contact lens that is placed directly on the eye can also be used as the attachment module 59.Since contact with the eye is generally to be avoided, ophthalmoscopic magnifying lenses are usually used, as in the present exemplary embodiment.

[0041] Since the intermediate image plane 62, which contains the intermediate image, is closer to the main objective 50 of the operating microscope 20 compared to the anterior segment 30A of the eye 30, the operating microscope 20 must be refocused to observe the posterior segment 30B of the eye 30. In doing so, the operating microscope 20 is focused on the intermediate image plane 62. With the operating microscope 20 according to the invention, this refocusing is achieved by adjusting the focal length of the variable objective 50 using the drive 55. Since the focus stroke FH is 150-400 mm, such refocusing is possible without moving the operating microscope 20 as a whole. Furthermore, no additional optical components need to be positioned in the beam path between the end glass 57 and the ophthalmoscopic magnifier 59. This gives the treating physician greater flexibility in positioning the operating microscope 20 in the optimal way for him or her.to position them in the most ergonomically advantageous position and to focus from this position on the intermediate image plane 62. Furthermore, the positions of the intermediate image planes 62 can differ between differently designed ophthalmoscopic magnifying lenses 59. Using the variable lens 50, simple focusing on the intermediate image plane 62 of the respective ophthalmoscopic magnifying lens 59 is possible without having to move the operating microscope 20 as a whole.

[0042] In contrast, an operating microscope requires 2', as is the case in Fig. As shown in Figure 2, an additional reducing optic 63 is inserted, which reduces the focal length of the fixed-focal-length main objective 5 to approximately the distance of the intermediate image plane 62 from the main objective 5. This is necessary because otherwise the operating microscope would have to be moved so far away from the eye 30 that ergonomic operation would no longer be possible. However, even when the focal length is adjusted to a specific ophthalmic loupe 59 by means of the reducing optic 63, changing the ophthalmic loupe 59 usually requires refocusing the operating microscope 2' or changing the reducing optic 63.However, since the distance between the eye 30 and the operating microscope 2' in an ergonomic position is subject to narrow limits, and since the height of the reduction optics 63 and the position of the intermediate image plane 62 also limit the scope for movement of the operating microscope 2' towards the eye 30, it is not possible to use an operating microscope 2' as described in reference to . Fig.As described in section 2, with the ophthalmic magnifying lens 59 and the reduction optic 63 inserted, only a relatively small focus stroke of less than 40 mm can be achieved. This severely limits the usable position of the intermediate image plane 62. Even when a reduction optic similar to a varifocal lens with an adjustable focal length is used, this situation changes little. A reduction optic with an adjustable focal length has a greater height than a simple reduction optic, further reducing the space between the ophthalmic magnifying lens and the reduction optic. This can substantially restrict the physician's range of motion during treatment. Therefore, efforts are made to keep the height of a reduction optic with an adjustable focal length low, thus ensuring a small focus stroke FH even when using such an optic.

[0043] The operating microscope, the operating microscope system, and the method according to the invention enable the use of the operating microscope for observing both the anterior and posterior segments of the eye. The operating microscope does not need to be moved and can therefore be positioned and remain in an ergonomically convenient position for the user. Despite this, considerable freedom in focusing is maintained, allowing the use of different ophthalmic lenses while preserving the ergonomic position. Furthermore, when observing both the anterior and posterior segments of the eye, sufficient distance between the eye or the ophthalmic lens on the one hand and the eye-side end of the operating microscope on the other can be ensured.This is made possible by using a varifocal lens for focusing. The use of a varifocal lens is achieved by moving the beam splitter mirror from a position above the main lens to a position below it, thus preventing reflections of the illumination beam from the optical surfaces of the varifocal lens. The increase in the usable focus range is therefore a synergistic effect resulting from the combination of moving the beam splitter mirror and using the varifocal lens.

[0044] The present invention has been described in detail with reference to exemplary embodiments for illustrative purposes. However, a person skilled in the art will recognize that the invention may deviate from the described exemplary embodiments. Therefore, the present invention is not intended to be limited by the exemplary embodiments, but only by the appended claims. Reference symbol list 2.2' Operating microscope 3. Operational field 5 lens 7 divergent beam 9 beams 9A,B stereoscopic partial beam path 11 magnification changers 13A,B Interface arrangement 15A,B Beam splitter prism 19 camera adapters 20 operating microscopes 21 camera 23 Image sensor 27 Binocular tube 29A,B Tube objective 30 Eye 30A Front section 30B Rear Section 31A,B Intermediate image plane 33A,B Prism 35A,B Eyepiece lens 37 Display 39 Optics 40A,B spectral filter 41 White light source 43 Deflection element 45 Lighting optics 47 spectral filters 49 lasers 49A,B Focusing lens 50 Vario lens 51 positive term 52 negative term 53 Displacement path 55 Drive 57 End glass 59 Ophthalmoscopic magnifying glass 60 Focusing using the operating microscope 61A,B image sensor 62 Intermediate image plane 63 Reduction optics 63A,B Display 65A,B Eyepiece lens 67A,B cable 157 End plate 157-1 Plan area 157-2 Plan area FH Focus Hub N1 Surface normal N2 surface normal OA optical axis α angle β angle γ angle QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 1 908 398 A1

[0004] DE 10 2005 011 781 A1

[0006] EP 1 889 567 A2

[0006]

Claims

[1] Operating microscope (20) with - an observation optics (11, 50) providing an observation beam path for observing an observation object (30), which includes a main objective (50) with adjustable object focal length, and - a lighting device (41, 43, 45) providing a beam path for illuminating the object being observed (30), wherein the lighting device (41, 43, 45) comprises an optical deflecting element (43) by means of which the beam path is directed towards the object being observed (30), characterized by , that the deflection element (43) is arranged on the side of the main lens (50) facing the object being observed (30). [2] Operating microscope (20) according to claim 1, characterized by, that it has a transparent end element (57; 157), wherein the deflection element (43) is arranged between the main lens (50) and the transparent end element (57; 157). [3] Operating microscope (20) according to claim 2, characterized by , that the main objective (50) has an optical axis (OA) and the transparent end element (57; 157) has an object-side planar surface (57-1; 157-1) whose surface normal (N1) runs at an angle (α) greater than 0 degrees to the optical axis (OA). [4] Operating microscope (20) according to claim 3, characterized by , that the transparent end element (57; 157) has two planar surfaces (57-1, 57-2; 157-1, 157-2). [5] Operating microscope (20) according to claim 4, characterized by , that the transparent end element (157) is a wedge-shaped transparent end element with a wedge angle (γ) greater than 0 degrees between the two planar surfaces (157-1, 157-2). [6] Operating microscope (20) according to any one of claims 1 to 5, characterized by , that the main objective (50) has an optical axis (OA) to which the surface normal (N2) of a beam-deflecting planar surface (43-1) of the deflecting element (43) runs at an angle (β) greater than 30 degrees. [7] Operating microscope (20) according to one of the preceding claims, characterized by , that the deflecting element (43) has a further planar surface (43-2) in addition to the beam-deflectoring planar surface (43-1) and is designed as a wedge-shaped deflecting element with a wedge angle greater than 0 degrees between the beam-deflectoring planar surface (43-1) and the further planar surface (43-2). [8] Surgical microscope system comprising a surgical microscope (20) according to one of the preceding claims and an attachment module (59) that can be positioned between the main objective (50) and an eye (30) as the observation object in the observation beam path, which is configured to generate an aerial image of the posterior segment (30B) of the eye (30) in an intermediate image plane (62) to be observed with the surgical microscope (20) when it is positioned in the observation beam path, wherein the object focal length of the main objective (50) is adjustable such that the surgical microscope (20) is focused on the intermediate image plane (62). [9] Method for observing the posterior segment (30B) of an eye (30) as an observation object using an operating microscope system according to claim 8, characterized by the steps - Positioning the attachment module (59) between the main objective (50) and the eye (30) in order to generate an aerial image of the posterior segment (30B) of the eye (30) in an intermediate image plane (62) for observation with the operating microscope (20) using the attachment module (59), and - Focusing the operating microscope (20) on the intermediate image plane (62) by adjusting the focal length of the main objective (50).

Images