Ophthalmologic apparatus and tomographic image generation apparatus

Abstract

To acquire a tomographic image of a posterior eye part and an anterior eye part of an eye to be examined with one apparatus.SOLUTION: An ophthalmologic apparatus includes: an objective lens having a first lens group and a second lens group with positive power arranged sequentially from a scanning member side on an optical path of the light from a scanning member to an eye to be examined; and an optical element, which is a lens with positive power or a lens with negative power, and can be inserted into and removed from an optical path between the second lens group and the scanning member. When the optical element is removed from the optical path, the first lens group and the second lens group constitute a first observation optical system, a condensing position in an optical axis direction of the light emitted from a light source is adjusted by the movement of the first lens group or the second lens group on the optical path, and the light scanned by the scanning member is condensed on a first region of the eye to be examined. When the optical element is inserted into the optical path, the first lens group, the second lens group, and the optical element constitute a second observation optical system, and the light scanned by the scanning member is condensed on a second region different from the first region of the eye to be examined.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an ophthalmic apparatus and a tomographic image generating apparatus. [Background technology]

[0002] In an optical coherence tomography apparatus for acquiring a tomographic image of a posterior segment of an eye, such as the fundus of an examinee's eye, it is known that a lens attachment is disposed between an objective lens and the examinee's eye to acquire a tomographic image of an anterior segment of the eye, such as the cornea (Patent Document 1). With this optical coherence tomography apparatus, the use of the lens attachment makes it possible to acquire tomographic images of both the posterior segment and the anterior segment of the examinee's eye with a single apparatus.

[0003] In the conventional optical coherence tomography apparatus described above, the lens attachment is positioned between the subject's eye and the objective lens, so when switching from observing the posterior segment to observing the anterior segment, the alignment between the subject and the imaging device must be readjusted each time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2008 / 106696 Summary of the Invention

[0005] An ophthalmic device of a first aspect of the technology disclosed herein comprises a scanning member for scanning light emitted from a light source, an objective lens having, in order from the scanning member side, a first lens group and a second lens group, the second lens group being a lens group having positive power, and an optical element that can be inserted and removed into an optical path between the second lens group of the objective lens and the scanning member, wherein when the optical element is not inserted into the optical path, the objective lens constitutes a first observation optical system, and light scanned by the scanning member is focused on a first region of the test eye, and when the optical element is inserted into the optical path, the objective lens and the optical element constitute a second observation optical system, and light scanned by the scanning member is focused on a second region different from the first region of the test eye.

[0006] The optical tomographic image generating apparatus according to the second aspect of the technique of the present disclosure is an optical coherence tomography (OCT) imaging apparatus. the objective lens includes, in order from the scanning member side, a first lens group and a second lens group, the second lens group being a lens group having positive power; an optical element that is removably insertable into an optical path between the second lens group of the objective lens and the scanning member; an interference light detector that detects interference light obtained by combining return light from the test eye and the reference light; and an image generating unit that generates a tomographic image of the test eye based on the interference light detected by the interference light detector. When the optical element is not inserted into the optical path, the objective lens constitutes a first observation optical system, and the light scanned by the scanning member is focused on a first region of the test eye. When the optical element is inserted into the optical path, the objective lens and the optical element constitute a second observation optical system, and the light scanned by the scanning member is focused on a second region of the test eye. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of an ophthalmic apparatus according to a first embodiment. [Diagram 2]1 is a schematic diagram illustrating the configuration of a photographing optical system according to a first embodiment. [Diagram 3] FIG. 13 is a schematic diagram of the portion between the scanning unit of the photographing optical system and the subject's eye when the optical module for observing the anterior segment is not inserted in the optical path between the positive first lens group and the positive second lens group. [Figure 4] FIG. 13 is a schematic diagram illustrating the configuration of the portion between the scanning unit of the photographing optical system and the subject's eye when an optical module for observing the anterior segment is inserted in the optical path between the positive first lens group and the positive second lens group. [Diagram 5] FIG. 1 is a diagram showing the basic configuration of a thin-system optical system according to a first embodiment, showing the configuration when no negative lens is inserted in the optical path between two lens groups having positive power (upper part), and the configuration when a negative lens is inserted (lower part). [Figure 6] FIG. 11 is a diagram showing the basic configuration of a thin optical system of a photographing optical system according to a modified example of the first embodiment. [Figure 7] FIG. 11 is a diagram showing the basic configuration of a thin-system optical system according to a second embodiment. [Figure 8] FIG. 11 is a diagram showing the optical configuration of a thin system, illustrating a state in which light is further condensed in the anterior segment of the subject's eye in the imaging optical system of the second embodiment. [Figure 9] FIG. 13 is a thin-system optical configuration diagram showing the basic configuration of a photographing optical system according to a further modified example of the second embodiment. [Figure 10] This is a thin-system optical configuration diagram showing the basic configuration of the photographing optical system of the third embodiment, in which the thin-system optical configuration diagram (upper diagram) shows a state in which the anterior segment can be observed using a negative first lens group and a positive second lens group, and the thin-system optical configuration diagram (lower diagram) shows a state in which a switching lens having positive power is inserted in the optical path between the negative first lens group and the positive second lens group, making it possible to photograph the posterior segment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0009] [First embodiment]

[0010] An ophthalmic apparatus 110 according to a first embodiment of the present invention will now be described with reference to the drawings.

[0011] For ease of explanation, Scanning Laser Ophthalmoscope will be referred to as "SLO" and Optical Coherence Tomography will be referred to as "OCT."

[0012] When the ophthalmic apparatus 110 is placed on a horizontal plane, the horizontal direction is defined as the "X direction", the vertical direction to the horizontal plane is defined as the "Y direction", and the optical axis direction of the photographing optical system 116A is defined as the "Z direction". The apparatus is placed with respect to the subject's eye so that the pupil center of the subject's eye is located on the optical axis in the Z direction. The X direction, Y direction, and Z direction are perpendicular to each other.

[0013] The ophthalmic apparatus 110 includes an imaging device 14 and a control device 16. The imaging device 14 includes an SLO unit 18 for acquiring an image of the fundus 12A of the subject's eye 12, and an OCT unit 20 for acquiring a tomographic image of the subject's eye 12. Hereinafter, a fundus image generated based on SLO data acquired by the SLO unit 18 is referred to as an SLO image. Also, a tomographic image generated based on OCT data acquired by the OCT unit 20 is referred to as an OCT image. The SLO image may also be referred to as a two-dimensional fundus image. Also, the OCT image may also be referred to as a fundus tomographic image or an anterior segment tomographic image depending on the imaging site of the subject's eye 12. The ophthalmic apparatus 110 is an example of the "optical tomographic image generating apparatus" of the technology of the present disclosure.

[0014] The control device 16 includes a computer having a central processing unit (CPU) 16A, a random access memory (RAM) 16B, a read-only memory (ROM) 16C, and an input / output (I / O) port 16D.

[0015] The control device 16 includes an input / display device 16E connected to the CPU 16A via an I / O port 16D. The input / display device 16E has a graphic user interface that displays an image of the subject's eye 12 and receives various instructions from a user. The input / display device 16E may be a touch panel display.

[0016] The control device 16 also includes an image processing device 17 connected to the I / O port 16D. The image processing device 17 generates an image of the subject's eye 12 based on data obtained by the photographing device 14. The image processing device 17 is an example of the "generation unit" of the technology of the present disclosure.

[0017] 1, the control device 16 of the ophthalmic apparatus 110 includes the input / display device 16E, but the technology of the present disclosure is not limited thereto. For example, the control device 16 of the ophthalmic apparatus 110 may not include the input / display device 16E, but may include a separate input / display device that is physically independent from the ophthalmic apparatus 110. In this case, the display device includes an image processing processor unit that operates under the control of the CPU 16A of the control device 16. The image processing processor unit may display an SLO image or the like based on an image signal that is instructed to be output by the CPU 16A.

[0018] The photographing device 14 operates under the control of the control device 16. The photographing device 14 includes an SLO unit 18, a photographing optical system 116A, and an OCT unit 20. The photographing optical system 116A is moved in the X, Y, and Z directions by a photographing optical system driving unit 116M under the control of the CPU 16A. Alignment (positioning) between the photographing device 14 and the subject's eye 12 may be performed, for example, by moving not only the photographing device 14 but also the entire ophthalmic apparatus 110 in the X, Y, and Z directions.

[0019] The SLO system is realized by the control device 16, the SLO unit 18, and the imaging optical system 116A shown in FIG.

[0020] The SLO unit 18 includes a plurality of light sources. For example, as shown in FIG. 1, the SLO unit 18 includes a light source 40 of B light (blue light), a light source 42 of G light (green light), a light source 44 of R light (red light), and a light source 46 of IR light (infrared light (e.g., near-infrared light)). The light emitted from each of the light sources 40, 42, 44, 46 is directed to the same optical path via each of the optical members 48, 50, 52, 54, 56. The optical members 48, 56 are mirrors, and the optical members 50, 52, 54 are beam splitters. The B light is guided to the optical path of the photographing optical system 116A via the optical members 48, 50, 54. The G light is guided to the optical path of the photographing optical system 116A via the optical members 50, 54. The R light is guided to the optical path of the photographing optical system 116A via the optical members 52, 54. The IR light is guided to the optical path of the photographing optical system 116A via the optical members 56 and 52. The light sources 40, 42, 44, and 46 can be LED light sources or laser light sources. An example using a laser light source will be described below. The optical members 48 and 56 can be total reflection mirrors. The optical members 50, 52, and 54 can be dichroic mirrors, half mirrors, etc. The light sources 40, 42, 44, and 46 are examples of the "laser light source" of the technology of this disclosure.

[0021] The SLO unit 18 is configured to be able to switch between various light emission modes, such as a light emission mode in which G light, R light, B light, and IR light are emitted individually, and a light emission mode in which all or some of them are emitted simultaneously. In the example shown in FIG. 1, four light sources are provided: a light source 40 of B light (blue light), a light source 42 of G light, a light source 44 of R light, and a light source 46 of IR light, but the technology of the present disclosure is not limited to this. For example, the SLO unit 18 may further include a light source of white light. In this case, in addition to the various light emission modes described above, a light emission mode in which only white light is emitted may be set.

[0022] The laser light incident on the photographing optical system 116A from the SLO unit 18 is scanned in the X and Y directions by a scanning unit (120, 142) described below. The scanning light passes through the pupil 27 and is irradiated onto the posterior segment (e.g., the fundus 12A) of the subject's eye 12. The reflected light reflected by the fundus 12A is incident on the SLO unit 18 via the photographing optical system 116A. The scanning unit (120, 142) is an example of a "scanning member" of the technology of the present disclosure.

[0023] The light reflected by the fundus 12A is detected by light detection elements 70, 72, 74, and 76 provided in the SLO unit 18. In this embodiment, the SLO unit 18 includes a B light detection element 70, a G light detection element 72, an R light detection element 74, and an IR light detection element 76 corresponding to a plurality of light sources, i.e., the B light source 40, the G light source 42, the R light source 44, and the IR light source 46. The B light detection element 70 detects the B light reflected by the beam splitter 64. The G light detection element 72 detects the G light that passes through the beam splitter 64 and is reflected by the beam splitter 58. The R light detection element 74 detects the R light that passes through the beam splitters 64 and 58 and is reflected by the beam splitter 60. The IR light detection element 76 detects the G light that passes through the beam splitters 64, 58, and 60 and is reflected by the beam splitter 62. An example of the light detection elements 70, 72, 74, and 76 is an avalanche photodiode (APD). The light detection elements 70, 72, 74, and 76 are an example of a "laser light detector" of the technology of the present disclosure.

[0024] Under the control of the CPU 16A, the image processing device 17 generates an SLO image corresponding to each color using signals detected by the B light detection element 70, the G light detection element 72, the R light detection element 74, and the IR light detection element 76. The SLO images corresponding to each color include a B-SLO image generated using a signal detected by the B light detection element 70, a G-SLO image generated using a signal detected by the G light detection element 72, an R-SLO image generated using a signal detected by the R light detection element 74, and an IR-SLO image generated using a signal detected by the IR light detection element 76. In addition, in the case of a light emission mode in which the B light source 40, the G light source 42, and the R light source 44 emit light simultaneously, an RGB-SLO image may be synthesized from the B-SLO image, the G-SLO image, and the R-SLO image generated using the signals detected by the R light detection element 74, the G light detection element 72, and the B light detection element 70, respectively. In addition, in the case of a light emission mode in which the G light source 42 and the R light source 44 emit light simultaneously, an RG-SLO image may be synthesized from a G-SLO image and an R-SLO image generated using the respective signals detected by the R light detection element 74 and the G light detection element 72. In the first embodiment, an RG-SLO image is used as the SLO image, but this is not limited thereto, and other SLO images can be used. As the beam splitters 58, 60, 62, 64, a dichroic mirror, a half mirror, or the like can be used.

[0025] The OCT system is a three-dimensional image acquisition device realized by the control device 16, the OCT unit 20, and the imaging optical system 116A shown in Fig. 1. The OCT unit 20 includes a light source 20A, a sensor (detection element) 20B, a first optical coupler 20C, a reference optical system 20D, a collimator lens 20E, and a second optical coupler 20F. The first optical coupler 20C is an example of a "splitting section" of the technology disclosed herein. The sensor (detection element) 20B is an example of an "interference light detector" of the technology disclosed herein.

[0026] The light source 20A generates light for optical coherence tomography. For example, a super luminescent diode (SLD) can be used as the light source 20A. The light source 20A generates low-coherence light of a broadband light source having a wide spectral width. The light emitted from the light source 20A is split by the first optical coupler 20C. One of the split lights is collimated by the collimating lens 20E as a measurement light, and then enters the photographing optical system 116A. The measurement light is scanned in the X direction and the Y direction by the scanning unit (148, 142) described later. The scanning light is irradiated to the anterior segment of the subject's eye or the posterior segment via the pupil 27. The measurement light reflected by the anterior segment or the posterior segment enters the OCT unit 20 via the photographing optical system 116A, and enters the second optical coupler 20F via the collimating lens 20E and the first optical coupler 20C. In this embodiment, SD-OCT using an SLD as the light source 20A is exemplified, but the present invention is not limited to this, and SS-OCT using a wavelength swept light source instead of an SLD may be adopted.

[0027] The other light beam emitted from the light source 20A and branched by the first optical coupler 20C is incident as reference light on the reference optical system 20D, and passes through the reference optical system 20D to be incident on the second optical coupler 20F.

[0028] The measurement light (return light) reflected and scattered by the subject's eye 12 and the reference light are combined by the second optical coupler 20F to generate interference light. The interference light is detected by the sensor 20B. The image processing device 17 generates a tomographic image of the subject's eye 12 based on the detection signal (OCT data) from the sensor 20B.

[0029] In the first embodiment, the OCT system generates a tomographic image of the anterior or posterior segment of the subject's eye 12.

[0030] The anterior segment of the subject's eye 12 includes, as an anterior segment, the cornea, the iris, the angle, the crystalline lens, the ciliary body, and a part of the vitreous body. The posterior segment of the subject's eye 12 includes, as a posterior segment, the remaining part of the vitreous body, the retina, the choroid, and the sclera. The vitreous body belonging to the anterior segment is the part of the vitreous body on the cornea side with respect to the XY plane passing through the point of the crystalline lens closest to the center of the eyeball as a boundary, and the vitreous body belonging to the posterior segment is the part of the vitreous body other than the vitreous body belonging to the anterior segment. When the anterior segment of the subject's eye 12 is the imaging target site, the OCT system generates, for example, a tomographic image of the cornea. When the posterior segment of the subject's eye 12 is the imaging target site, the OCT system generates, for example, a tomographic image of the retina.

[0031] The posterior segment and the anterior segment are examples of the "first region" and the "second region" of the technology of the present disclosure, respectively.

[0032] 2 shows a schematic configuration of the imaging optical system 116A. The imaging optical system 116A includes an objective lens 130, a beam splitter 178, a horizontal scanning unit 142, a relay lens device 140, a beam splitter 147, vertical scanning units 120 and 148, a focus adjustment device 150, and a collimator lens 156, which are arranged in this order from the subject's eye 12 side. As the beam splitters 178 and 147, for example, a dichroic mirror, a half mirror, or the like can be used.

[0033] The horizontal scanning unit 142 is an optical scanner that horizontally scans the SLO laser light and the OCT measurement light incident via the relay lens device 140. In this embodiment, the horizontal scanning unit 142 is shared by the SLO optical system and the OCT optical system, but this is not limited. A horizontal scanning unit may be provided for each of the SLO optical system and the OCT optical system.

[0034] The collimator lens 156 converts the measurement light emitted from the end 158 of the fiber through which the light emitted from the OCT unit 20 travels into parallel light.

[0035] The focus adjustment device 150 includes a plurality of lenses 152, 154. The focus position of the measurement light on the subject's eye 12 is adjusted by appropriately moving each of the plurality of lenses 152, 154 in the optical axis direction according to the imaging site on the subject's eye 12. Although not shown, when a focus detection device is provided, it is possible to realize an autofocus device by driving the lenses 152, 154 by the focus adjustment device according to the focus detection state to automatically adjust the focus.

[0036] The vertical scanning unit 148 is an optical scanner that scans the measurement light incident via a focus adjustment device 150 in the vertical direction.

[0037] The vertical scanning section 120 is an optical scanner that scans the laser light incident from the SLO unit 18 in the vertical direction.

[0038] The relay lens device 140 includes a plurality of lenses 144, 146 each having a positive power. The relay lens device 140 is configured by the plurality of lenses 144, 146 so that the positions of the vertical scanning units 148, 120 and the horizontal scanning unit 142 are conjugate with each other. More specifically, the relay lens device 140 is configured so that the central positions of the angular scans of both scanning units are conjugate with each other.

[0039] The beam splitter 147 is disposed between the relay lens device 140 and the vertical scanning unit 148. The beam splitter 147 is an optical member that combines the SLO optical system and the OCT optical system, and reflects the SLO light emitted from the SLO unit 18 toward the relay lens device 140, and transmits the measurement light emitted from the OCT unit 20 toward the relay lens device 140. The measurement light emitted from the OCT unit 20 is two-dimensionally scanned by the vertical scanning unit 148 and the horizontal scanning unit 142. In addition, the light emitted from the SLO unit 18 is two-dimensionally scanned by the vertical scanning unit 120 and the horizontal scanning unit 142 that constitute the SLO optical system. The two-dimensionally scanned OCT measurement light and SLO laser light are each incident on the subject's eye 12 via the objective lens 130 that constitutes the common optical system. The SLO laser light reflected by the subject's eye 12 is incident on the SLO unit 18 via the objective lens 130, the horizontal scanning unit 142, the relay lens device 140, the beam splitter 147, and the vertical scanning unit 120. The OCT measurement light that has passed through the subject's eye 12 is incident on the OCT unit 20 via the objective lens 130, the horizontal scanning unit 142, the relay lens device 140, the beam splitter 147, the vertical scanning unit 148, the focus adjustment device 150, and the collimator lens 156.

[0040] As the horizontal scanning unit 142 and the vertical scanning units 120 and 148, for example, a resonant scanner, a galvanometer mirror, a polygon mirror, a rotating mirror, a dowel prism, a double dowel prism, a rotation prism, a MEMS mirror scanner, an acousto-optical element (AOM), or the like is preferably used. In this embodiment, a galvanometer mirror is used as the vertical scanning unit 148, and a polygon mirror is used as the vertical scanning unit 120. Note that when a two-dimensional optical scanner such as a MEMS mirror scanner is used instead of an optical scanner such as a polygon mirror or a galvanometer mirror, the incident light can be two-dimensionally angle-scanned by the reflecting element, so the relay lens device 140 may be eliminated.

[0041] The objective lens 130 includes, in order from the horizontal scanning unit 142 side, a first lens group 134 and a second lens group 132, and at least the second lens group 132 is a positive lens group having a positive power as a whole. In the first embodiment, the first lens group 134 is also a positive lens group having a positive power as a whole. Each of the first lens group 134 and the second lens group 132 includes at least one positive lens. When each of the first lens group 134 and the second lens group 132 includes a plurality of lenses, each of the first lens group 134 and the second lens group 132 may include a negative lens as long as it has a positive power as a whole.

[0042] The first lens group 134 and the second lens group 132 constituting the objective lens 130 are separated by the maximum air gap on the optical axis between the lens surfaces of the objective lens. Even if a glass plate having no power is located between the first lens group 134 and the second lens group 132, the glass plate is not considered as a lens belonging to either the first lens group 134 or the second lens group 132, and the first lens group 134 and the second lens group 132 are considered to be separated by the maximum air gap.

[0043] The photographing optical system 116A includes an optical module 136 for observing an anterior eye segment as an optical module that can be inserted into or removed from the optical path of the objective lens 130, and a sensor 130S for detecting the inserted or removed state of the optical module 136. In the first embodiment, as described in detail later, when the optical module 136 is not disposed in the optical path of the objective lens 130, a posterior eye segment observation optical system 300 (see also FIG. 3) is configured as the observation optical system, and the ophthalmic apparatus 110 thereby obtains an image of the posterior eye segment of the subject's eye 12. On the other hand, when the optical module 136 is inserted into the optical path of the objective lens 130, an anterior eye segment observation optical system 400 (see also FIG. 4) is configured as the observation optical system, and the ophthalmic apparatus 110 thereby obtains an image of the anterior eye segment of the subject's eye 12. In the first embodiment, as described in detail later, the optical module 136 is inserted into or removed from the optical path of the observation optical system manually or automatically by an operator (e.g., an ophthalmologist). The optical module 136 moves on a rail (not shown) or is inserted into or removed from the optical path between the first lens group 134 and the second lens group 132 by rotating a turret. The sensor 130S for detecting the insertion / removal state of the optical module 136 for anterior eye observation may be a sensor that detects either the insertion or removal of the optical module 136 into or from the photographing optical system, or may be a sensor that can detect both. The posterior eye observation optical system 300 is an example of the "first observation optical system" and the "fundus observation optical system" of the technology disclosed herein. The anterior eye observation optical system 400 is an example of the "second observation optical system" and the "anterior eye observation optical system" of the technology disclosed herein.

[0044] Hereinafter, in this embodiment, the case where the subject's eye 12 is observed in a state where the optical module 136 for anterior eye observation is not disposed in the optical path of the photographing optical system is referred to as a posterior eye observation mode (first mode). Also, the case where the subject's eye 12 is observed in a state where the optical module 136 is disposed in the optical path of the photographing optical system is referred to as an anterior eye observation mode (second mode).

[0045] 2, the imaging optical system 116A further includes an optical module 138 different from the optical module 136 for anterior eye observation. The optical module 138 is mainly used in a posterior eye observation mode, and is therefore hereinafter referred to as the optical module 138 for posterior eye observation. The optical module 138 for posterior eye observation includes an optical module body 138H including a fixation lamp, a camera, and an illumination device (not shown), and a beam splitter 178. The beam splitter 178 is disposed in the optical path between the objective lens 130 and the horizontal scanning unit 142, more specifically, between the first lens group 134 and the horizontal scanning unit 142.

[0046] Next, the configuration of each of the imaging optical systems 116A in the posterior eye observation mode and the anterior eye observation mode will be described with reference to Figs. 3 and 4. Fig. 3 shows the posterior eye observation optical system 300 in the posterior eye observation mode. The optical module 136 for anterior eye observation is removed from the optical path of the objective lens 130. Fig. 4 shows the anterior eye observation optical system 400 in the anterior eye observation mode. The optical module 136 for anterior eye observation is inserted in the optical path of the objective lens 130, specifically, in the optical path between the first lens group 134 on the horizontal scanning unit 142 side and the second lens group 132 on the subject's eye side. In the posterior eye observation optical system 300 (Fig. 3), the parallel light beams at three angles supplied from the scanning surface represented by the horizontal scanning unit 142 are shown as being focused on the fundus 12A of the subject's eye 12 through two positive lens groups (the first lens group 134 and the second lens group 132). In addition, in the anterior eye observation optical system 400 (Figure 4), the parallel light beams at the same three angles shared from the horizontal scanning unit 142 are shown as light rays that are focused on the cornea of ​​the test eye 12 by two positive lens groups (the first lens group 134 and the second lens group 132) and an optical element inserted between them (the negative lens 162, described in detail later).

[0047] In the posterior segment observation optical system 300, as shown in FIG. 3 and FIG. 2, the vertical scanning units 120, 148 and the horizontal scanning unit 142 are arranged so as to be conjugate with the pupil position Pp of the subject's eye 12. In the SLO optical system, the SLO laser light scanned by the vertical scanning unit 120 and the horizontal scanning unit 142 is two-dimensionally angularly scanned around the pupil position Pp of the subject's eye 12 via the objective lens 130. As a result, the focal point of the SLO laser light is two-dimensionally scanned on the fundus 12A. Similarly, in the OCT optical system, the measurement light scanned by the vertical scanning unit 148 and the horizontal scanning unit 142 is two-dimensionally angularly scanned around the pupil position Pp of the subject's eye 12 via the objective lens 130. As a result, the focal point of the measurement light is two-dimensionally scanned on the fundus 12A. In a posterior segment observation mode in which an image is acquired using the posterior segment observation optical system 300, a two-dimensional fundus image is acquired by the SLO unit 18, and a tomographic image of the fundus is acquired by the OCT unit 20. As described later, during the period in which the OCT unit 20 acquires the tomographic image of the fundus, the SLO unit 18 continuously acquires two-dimensional images of the fundus successively.

[0048] In the anterior eye observation optical system 400, as shown in FIG. 4, an optical module 136 for anterior eye observation is inserted in the optical path of the objective lens 130, specifically, in the optical path between the first lens group 134 having a positive refractive power and the second lens group 132 having a positive refractive power constituting the objective lens 130. The optical module 136 has an optical element such as a lens therein. In this embodiment, the optical element is a lens 162 having a negative power as a switching lens. When the lens 162 is disposed on the optical axis of the objective lens 130, the lens 162 acts as a switching lens for switching the posterior eye observation optical system 300 to the anterior eye observation optical system 400. Hereinafter, the lens 162 will be referred to as a negative lens 162 or a switching lens 162. When the negative lens 162 is inserted into the optical path of the objective lens 130, the scanning position of the horizontal scanning unit 142 and the pupil position Pp of the subject's eye 12 are not conjugate, and the parallel light from the scanning position of the horizontal scanning unit 142 is focused on the anterior segment. The diameter of the light beam passing through the negative lens 162 is smaller than the diameter of the light beam passing through each of the first lens group 134 and the second lens group 132. Therefore, the effective diameter of the negative lens 162 is smaller than the effective diameter of the lens groups constituting the objective lens 130. The negative lens 162 is smaller than the first lens group 134 and the second lens group 132. Therefore, the optical module 136 can be configured to be small. Note that the optical element is not limited to the negative lens 162, and instead of the negative lens 162, an optical member such as a Fresnel lens or a DOE (Diffractive Optical Element) may be used. 3 and 4, the optical module 136 for anterior eye observation has built-in eye tracking module 160 and dichroic mirror 161 used during anterior eye observation. A plurality of SLO images sequentially acquired by the SLO unit are used by the eye tracking module 160 built in the optical module 136 for anterior eye observation as images for eye tracking during OCT imaging. The eye tracking module 160 further includes a fixation light, a camera, and a lighting device (not shown).

[0049] Next, the optical configurations in the posterior eye observation mode and the anterior eye observation mode will be described. The upper diagram of FIG. 5 shows an overview of the posterior eye observation optical system in the posterior eye observation mode (first mode). The optical module 136 for anterior eye observation is not inserted in the optical path of the objective lens 130. On the other hand, the lower diagram of FIG. 5 shows an overview of the anterior eye observation optical system in the anterior eye observation mode (second mode). The optical module 136 incorporating a negative switching lens 162 is inserted in the optical path of the objective lens 130. Note that in the schematic diagram of the anterior eye observation optical system, for ease of explanation, only the switching lens 162 is shown as the optical module 136.

[0050] The posterior segment observation optical system (upper diagram in FIG. 5) will be described. In the posterior segment observation optical system (upper diagram in FIG. 5), a plurality of lens groups constituting the objective lens 130, i.e., a positive first lens group 134 and a positive second lens group 132, form an afocal system, and the scanning center (Ps in the diagram) in the horizontal scanning unit 142 is conjugate with the pupil position Pp of the subject's eye 12. Here, if the focal lengths of the first lens group 134 and the second lens group 132 are f1 and f2, respectively, the distance (group spacing) d between the first lens group 134 and the second lens group 132 is d=f1+f2. The magnification β is β=-f2 / f1.

[0051] In the posterior eye observation mode (first mode) of the first embodiment, the scanning position Ps of the horizontal scanning unit 142 is conjugate with the pupil position Pp of the subject's eye 12. Parallel light from the scanning position Ps of the horizontal scanning unit 142 passes through the pupil position Pp of the subject's eye 12 as substantially parallel light at a predetermined angle, and is focused on the fundus 12A by the subject's eye 12. The focusing position on the fundus 12A of the measurement light emitted from the OCT unit 20 is determined depending on the scanning position of the vertical scanning unit 120 and the scanning angle at the scanning position (Ps) of the horizontal scanning unit 142. This makes it possible to set a desired scanning position and scanning range in photographing and observing the fundus 12A.

[0052] Next, the anterior eye observation optical system (lower diagram in FIG. 5) will be described. In this observation optical system, a switching lens 162 of an optical module 136 for anterior eye observation is inserted into the optical path of the objective lens .

[0053] In the anterior eye observation mode (second mode), a switching lens 162, which is a negative lens, is inserted between the first lens group 134 and the second lens group 132. In the anterior eye observation mode (second mode), the scanning position Ps of the horizontal scanning unit 142 and the pupil position Pp of the subject's eye 12 are not conjugate, and the parallel light from the scanning position Ps of the horizontal scanning unit 142 is focused on the anterior eye. The focusing position at the anterior eye of the measurement light emitted from the OCT unit 20 is determined depending on the scanning angle at the position (Ps) of the scanning unit. This enables the anterior eye observation.

[0054] Here, the arrangement of the switching lens 162 in the anterior eye observation mode (second mode) will be described. The focal length of the switching lens 162 is f3, the distance between the first lens group 134 and the switching lens 162 is x, the object distance of the switching lens 162 when parallel light is incident on the first lens group 134 from the scanning position Ps is S3, and the image distance is S3'. Note that the image position P3' in the figure is the image position of the scanning position Ps by the switching lens 162 when parallel light is incident on the first lens group 134 from the scanning position Ps, i.e., the conjugate position of the scanning position Ps by the switching lens, and the image position P3' is conjugate with the pupil position Pp of the subject's eye 12. From the imaging equation for the switching lens 162,

[0055]

number

number

[0056] Next, for the second lens group 132, similarly, if the object distance of the second lens group 132 is S2 and the image distance is S2' when parallel light is incident on the first lens group 134 from the scanning position Ps, the imaging equation for the second lens group 132 gives:

number

[0057] Note that S2' is substantially the distance between the second lens group 132 and the eye 12, that is, the so-called working distance WD. As can be seen from FIG. 5, S2=S3'+dx And from this,

[0058]

number

[0059] By substituting the above formula (1) into formula (2), we get

[0060]

number

[0061] By rearranging the above equation (3) with respect to x, we obtain the following equation.

[0062]

number

[0063] By determining the focal length f3 of the switching lens 162, the value of its position x can be found using this formula (4).

[0064] In addition, when the light between the two positive first lens group 134 and the second lens group 132 is parallel light, f2=S2′ holds. Therefore, from the above formula (3), x = f1 + f3 (5) This results in the simple relationship (5).

[0065] Approximately, it is possible to configure the system by placing the switching lens 162 between the first lens group 134 and the second lens group 132 according to this relational expression (5). This relational expression (5) can be said to be a theoretical configuration, although it is the case that the two positive first lens group 134 and the second lens group 132 are completely afocal systems and the light between the two groups is completely parallel light. Needless to say, a practical solution is to appropriately select the shape, thickness, refractive index, etc. of each lens by appropriate aberration calculations in order to achieve a suitable aberration structure in both the posterior eye observation mode (first mode) and the anterior eye observation mode (second mode) while making the system between the two lens groups approximately parallel.

[0066] In the first embodiment, as shown in FIG. 5, the distance (working distance WD) between the second lens group 132 and the subject's eye 12 remains the same whether in the posterior eye observation mode (first mode) or the anterior eye observation mode (second mode). Therefore, there is no need to readjust the alignment between the subject's eye 12 and the photographing optical system 116A in response to a change in each observation mode, and therefore there is no need to force the subject to move. Since it is possible to smoothly and quickly switch between the anterior eye photographing and the posterior eye photographing, the time required for a series of photographing can be reduced. In addition, since the switching lens 162 is small, the insertion and removal mechanism of the switching lens 162 can be realized simply and compactly.

[0067] The ophthalmic apparatus 110 according to the first embodiment described above can provide an apparatus for acquiring three-dimensional image data of both the posterior and anterior segments of the subject's eye 12 using an optical module 136 for observing the anterior segment with a single ophthalmic apparatus.

[0068] Moreover, the ophthalmologic apparatus 110 according to the first embodiment can switch between the posterior eye observation optical system and the anterior eye observation optical system by inserting and removing the optical module 136 for anterior eye observation into and from the optical path between the first lens group 134 and the second lens group 132 constituting the objective lens 130, so that the working distance WD between the objective lens 130 (particularly the second lens group 132) and the subject's eye 12 does not change in each optical system (300, 400). As a result, there is no need to redo the alignment between the subject's eye 12 and the photographing optical system 116A, and therefore switching between the posterior eye observation mode and the anterior eye observation mode can be performed smoothly.

[0069] In the ophthalmic apparatus 110 according to the first embodiment, the optical element of the optical module 136 for anterior eye observation may be a small lens having an effective diameter smaller than that of the objective lens 130 (the first lens group 134 and the second lens group 132), thereby making it possible to miniaturize the optical module 136. Therefore, it is easy to switch between the optical system for posterior eye observation and the optical system for anterior eye observation.

[0070] As described above, in the first embodiment, the convenience of the ophthalmologic apparatus 110 can be improved.

[0071] Next, a modification of the first embodiment will be described.

[0072] In the first embodiment, the switching lens 162 is a negative lens, but the technology of the present disclosure is not limited thereto. The switching lens 162 may be a lens having a positive power (positive lens). FIG. 6 shows a schematic optical configuration of an objective lens, which is a main part of the imaging optical system 116B, which is equipped with the switching lens 162, which is a positive lens. In this case, the position Pc conjugate with the scanning position Ps of the horizontal scanning unit 142 is located on the second lens group 132 side, as shown in FIG. 6. FIG. 6 shows the optical configuration of the anterior eye imaging optical system in the anterior eye observation mode in which the anterior eye is imaged, and corresponds to the lower diagram of FIG. 5 described above. In this configuration, the optical configuration of the posterior eye observation mode (first mode) in which the posterior eye is imaged corresponds to the upper diagram of FIG. 5 (the posterior eye observation optical system 300). In FIG. 6, the lens group is shown as a thin system as in FIG. 5, and an overview of how the parallel light beams at three angles from the scanning position Ps of the horizontal scanning unit 142 are focused on the anterior eye of the subject's eye is shown.

[0073] In the first embodiment, the operator manually removes the optical module 136 for anterior eye from the optical path of the photographing optical system 116A or inserts it into the optical path, but the technology of the present disclosure is not limited to this. For example, a mechanism for automatically removing the optical module 136 for anterior eye from the optical path or inserting it into the optical path is provided. When a posterior eye tomographic image generating button (not shown) is turned on or when an anterior eye tomographic image generating button is turned on, the CPU 16A may control the mechanism to automatically remove the optical module 136 for anterior eye observation from the optical path or insert it into the optical path.

[0074] In the first embodiment, the objective lens 130, the horizontal scanning unit 142, and the relay lens device 140 are configured as a common optical system shared by the SLO optical system and the OCT optical system, in that order from the subject's eye 12, but the technology of the present disclosure is not limited to this. Instead of a configuration in which the horizontal scanning unit 142 is shared by the SLO optical system and the OCT optical system, a horizontal scanning unit and a vertical scanning unit may be provided in each optical system.

[0075] [Second embodiment]

[0076] Next, a second embodiment will be described. Since the configuration of the second embodiment is substantially the same as that of the first embodiment, the same parts are given the same reference numerals and their description is omitted, and the differences will be mainly described.

[0077] 7 shows a schematic optical configuration of an objective lens that is a main part of the photographing optical system 116C of the second embodiment. The photographing optical system 116C differs from the photographing optical system 116A of the first embodiment in the following points.

[0078] The switching lens 162 inserted into the photographing optical system 116C is detachably disposed between the first lens group 134 and the horizontal scanning unit 142, not between the first lens group 134 and the second lens group 132 constituting the objective lens 130. As shown in FIG. 7, the switching lens 162 is a lens having a positive power, and shows the configuration of the anterior eye observation optical system in the anterior eye observation mode. A position Pc conjugate with the scanning position Ps of the horizontal scanning unit 142 is located between the first lens group 134 and the second lens group 132.

[0079] The posterior segment observation optical system in the posterior segment observation mode for fundus photography is the same as that shown in the upper diagram of Fig. 5. In the configuration of Fig. 7 as well, by inserting the switching lens 162, the scanning light of the parallel light beam from the horizontal scanning unit 142 can be focused near the anterior segment of the subject's eye 12. However, in order to completely focus the light on the anterior segment of the subject's eye, it is possible to appropriately focus the light on a required position of the anterior segment of the subject's eye 12 by controlling a focus device, for example, the focus adjustment device 150 shown in Fig. 2, and appropriately converting the light beam incident on the scanning unit into focused light as shown in Fig. 8.

[0080] Next, a modified example of the second embodiment will be described. In the second embodiment, the switching lens 162 is a lens having a positive power, but the technology of the present disclosure is not limited thereto. The switching lens 162 may be a negative lens. FIG. 9 shows an example of an imaging optical system 116D equipped with a lens having a negative power as the switching lens 162. FIG. 9 shows the state of light rays in the configuration of an anterior eye observation mode (second mode) in which a lens having a negative power as the switching lens 162 is inserted between the scanning position Ps of the horizontal scanning unit 142 and the first lens group 134 of the objective lens 130 to capture an image of the anterior eye. As shown in the figure, a parallel light beam incident from the center of the horizontal scanning unit 142 is focused on the cornea as the anterior eye of the subject's eye 12 by the switching lens 162, the first lens group 134 having a positive power, and the second lens group 132 having a positive power. In this anterior eye observation mode (second mode), a virtual image Pv of the position Ps of the horizontal scanning unit 142 is formed between the scanning position Ps of the horizontal scanning unit 142 and the negative switching lens 162 by the switching lens 162, which is a lens having negative power. A position Pc conjugate with the scanning position Ps of the horizontal scanning unit 142 is formed inside the subject's eye 12 by a composite optical system of the lens 162 having negative power, the first lens group 134, and the second lens group 132, but is not limited to this. It goes without saying that if the switching lens 162 is removed from the configuration of the anterior eye observation mode (second mode) shown in Fig. 9, it becomes the posterior eye observation mode (first mode) like the configuration shown in the upper diagram of Fig. 5.

[0081] [Third embodiment]

[0082] Next, a third embodiment will be described. In the configuration of the third embodiment, the parts corresponding to those in the first embodiment shown in Fig. 5 are given the same reference numerals, and the description thereof will be omitted, and mainly the different parts will be described.

[0083] First, in the modified examples of the first and second embodiments, the objective lens 130 is configured by two lens groups having positive power, but the technology of the present disclosure is not limited to this, and the first lens group 134 on the horizontal scanning unit 142 side, i.e., the scanning position Ps side, may be a lens group having negative power.

[0084] As shown in Fig. 10, the imaging optical system 116E of the third embodiment includes a first lens group 134N having negative power instead of the first lens group 134 having positive power in the imaging optical system 116A of the first embodiment. The upper diagram of Fig. 10 shows the configuration of the anterior eye observation optical system in the anterior eye observation mode for photographing the anterior eye, and the lower diagram of the same figure shows the configuration of the posterior eye observation optical system in the posterior eye observation mode for photographing the posterior eye by inserting a switching lens, both of which are thin systems. First, in the configuration shown in the upper diagram of Fig. 10, a parallel light beam from the scanning position Ps of the horizontal scanning unit 142 is condensed at the pupil position Pp of the eye 12 to be examined by the objective lens of a two-group configuration consisting of the first lens group 134N having negative power and the second lens group 132 having positive power. In this state, In the figure, the switching lens 162 is removed from the optical path. Meanwhile, the lower diagram of Fig. 10 shows a state in which the switching lens 162 having positive power is inserted into the optical path between the first lens group 134N having negative power and the second lens group 132 having positive power in the configuration of the posterior eye observation optical system in the posterior eye observation mode. In this state, the first lens group 134N having negative power, the switching lens 162 having positive power, and the second lens group 132 having positive power combine to convert the parallel light beam supplied from the scanning position Ps of the horizontal scanning unit 142 into a parallel light beam at the pupil position Pp of the subject's eye, forming an afocal system as a whole. The scanning position Ps of the horizontal scanning unit 142 and the pupil position Pp of the subject's eye 12 are configured conjugately, and the parallel light beam is angularly scanned at the pupil position Pp of the subject's eye 12 in accordance with the angular scanning of the light beam by the scanning unit, and the condensed light is scanned on the fundus. In the lower diagram of Fig. 10, only the switching lens 162 of the optical module 136 is shown. Here, the position conjugate with the fundus is shown by the broken line Cr, and the conjugate position with the fundus of the subject eye is formed between the inserted lens 162 having positive power and the second lens group 132 having positive power. In the photographing optical system of the third embodiment, the anterior segment can be photographed in the state shown in the upper diagram of Fig. 10 where the optical module 136 is not inserted, and the posterior segment can be photographed in the state shown in the lower diagram of Fig. 10 where the optical module 136 is inserted. Therefore, the optical module 136 in this case is a switching module for the posterior segment.

[0085] In the above-described first embodiment, the modified first embodiment, the modified second embodiment, and the third embodiment, the focus adjustment may be performed as in the second embodiment. Furthermore, in each example, the focus adjustment may be performed by autofocusing as described above. The focus adjustment may be performed by moving at least one of the optical system closer to the light source than the second lens group 132 of the objective lens, for example, the first lens group 134 of the objective lens, the switching lens 162, and the lenses 144 and 146. According to the above-described embodiments, the tomographic image of the anterior segment can be generated without shifting the position of the subject's eye 12 from the time of generating the tomographic image of the posterior segment, and conversely, there is a great advantage that there is no need to change the position of the subject's eye when switching from generating the tomographic image of the anterior segment to generating the tomographic image of the posterior segment, as described above.

[0086] [Further variations] In each of the examples described above, a plurality of optical elements such as switching lenses having different powers may be prepared, and depending on the shape of the anterior segment (e.g., the cornea) acquired in advance, one of the plurality of optical elements may be selected to select an optical element that can focus light at the corneal position depending on the shape of the cornea, etc.

[0087] Furthermore, in each of the examples described above, not only can the position at which an optical element such as a switching lens is inserted be switched between the first lens group 134 and the second lens group 132 or between the horizontal scanning unit 142 and the first lens group 134 depending on the shape of the anterior segment (e.g., the cornea), but it is also possible to select an optical element with a different refractive power from among a plurality of optical elements such as switching lenses with different powers and insert it at the appropriately switched position.

[0088] Further, in each of the above-described examples, the interference light is detected by one detector in both the posterior eye observation mode (first mode) and the anterior eye observation mode (second mode), but the technology of the present disclosure is not limited to this. For example, two detectors with different detection capabilities may be provided, and the interference light may be detected by one of the two detectors in the posterior eye observation mode (first mode), and by the other of the two detectors in the anterior eye observation mode (second mode). [Explanation of symbols]

[0089] 110 Ophthalmological equipment 17 Image Processing Device 20C First optical coupler 40, 42, 44, 46 light source 70, 72, 74, 76 Photodetector element 20B Sensor 132 First lens group 134 Second lens group 142 Horizontal scanning section 148 Vertical Scanning Unit 162 Switching Lens 300 Posterior segment observation optical system 400 Anterior segment observation optical system

Claims

[Claim 1] a scanning member that scans the light emitted from the light source on the subject's eye; an objective lens including a first lens group and a second lens group having a positive power, the first lens group and the second lens group being arranged in this order from the scanning member on an optical path of the light from the scanning member to the eye to be examined; an optical element which is a lens having a positive power or a lens having a negative power and which is insertable into and removable from an optical path between the second lens group and the scanning member; Equipped with When the optical element is removed from the optical path, the first lens group and the second lens group constitute a first observation optical system, and the first observation optical system adjusts a focusing position in the optical axis direction of the light emitted from the light source by the movement of the first lens group or the second lens group on the optical path, and focuses the light scanned by the scanning member on a first region of the subject's eye, When the optical element is inserted into the optical path, the first lens group, the second lens group, and the optical element constitute a second observation optical system, and the second observation optical system focuses light scanned by the scanning member onto a second area of ​​the test eye that is different from the first area.

Images