JP2017158725A - Corneal endothelial cell imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corneal endothelial cell imaging apparatus capable of acquiring a clear image of a corneal endothelial cell without being affected on a form of cornea of an eye to be examined.SOLUTION: A corneal endothelial cell imaging apparatus includes an irradiation system for irradiating a slit light toward the cornea of an eye to be examined, and a light reception system disposed diagonally relative to the irradiation system. The light reception system includes one or more positive lenses, an imaging element, and a negative lens. The imaging element receives a reflection component from the corneal endothelial of the reflection light from the corneal onto which the slit light is irradiated by the irradiation system through the one or more positive lenses. The negative lens is arranged between the one or more positive lenses and the imaging element. An optical center of the negative lens is arranged at a position deviated from an optical axis of at least one of the one or more positive lenses, and an optical axis of the negative lens is arranged inclined relative to the optical axis of the at least one of the one or more positive lenses.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a corneal endothelial cell imaging apparatus.

  The corneal endothelial cell imaging device can irradiate the subject's eye with slit light from an oblique direction, and can receive a reflected component from the corneal endothelium among the reflected light from the cornea irradiated with the slit light to image corneal endothelial cells. It is a possible device. In the corneal endothelial cell imaging device, a sharp image of corneal endothelial cells can be obtained by precisely aligning the imaging optical system in the optical axis direction of the eye to be examined and focusing on the corneal endothelium (Patent Document 1). ).

  In such a corneal endothelial cell imaging device, it is required to acquire a clear image of corneal endothelial cells with high resolving power so as not to hinder diagnosis based on information representing the state of corneal endothelial cells such as cell density. . For example, Patent Document 2 discloses a corneal endothelial cell imaging device in which an asymmetric diaphragm is provided in an irradiation optical system that irradiates slit light or a light receiving optical system that receives a reflection component (reflected light) from a corneal endothelium. . This corneal endothelial cell imaging apparatus obtains a clear image of corneal endothelial cells with high resolving power by shielding light from components that affect the reduction in imaging performance while suppressing a reduction in the amount of light.

JP 2014-239812 A International Publication No. 2013/0665805

  However, in the conventional technology, even when the imaging optical system is precisely aligned with the eye to be inspected, the corneal shape of the eye to be inspected with the slit light irradiates a clear corneal endothelial cell with high resolving power. An image may not be acquired. For example, when the cornea of the eye to be examined is a keratoconus (a cornea in which the central portion protrudes), the focus difference between the corneal apex and the peripheral portion becomes large, and a clear image cannot be acquired.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a corneal endothelial cell imaging apparatus capable of acquiring a clear corneal endothelial cell image without being affected by the shape of the cornea of the eye to be examined. The purpose is to provide.

  The corneal endothelial cell imaging device according to the embodiment includes an irradiation system and a light receiving system. The irradiation system irradiates slit light toward the cornea of the eye to be examined. The light receiving system is disposed obliquely with respect to the irradiation system. The light receiving system includes one or more positive lenses, an image sensor, and a negative lens. The imaging device receives a reflected component from the corneal endothelium through one or more positive lenses among the reflected light from the cornea irradiated with slit light by the irradiation system. The negative lens is disposed between the one or more positive lenses and the image sensor. The optical center of the negative lens is disposed at a position deviated from at least one optical axis of the one or more positive lenses, and the optical axis of the negative lens is inclined with respect to at least one optical axis of the one or more positive lenses. Has been placed.

  According to the present invention, it is possible to provide a corneal endothelial cell imaging apparatus capable of acquiring a clear corneal endothelial cell image without being affected by the shape of the cornea of the eye to be examined.

It is the schematic which shows the structural example of the optical system of the corneal-endothelial-cells imaging device which concerns on embodiment. It is operation | movement explanatory drawing of the corneal-endothelial-cells imaging device which concerns on embodiment. It is operation | movement explanatory drawing of the corneal-endothelial-cells imaging device which concerns on embodiment. It is the schematic which shows the structural example of the processing system of the corneal-endothelial-cells imaging device which concerns on embodiment. It is a flowchart of the operation example of the corneal endothelial cell imaging device which concerns on embodiment. It is operation | movement explanatory drawing of the corneal-endothelial-cells imaging device which concerns on embodiment. It is operation | movement explanatory drawing of the corneal-endothelial-cells imaging device which concerns on embodiment. It is the schematic which shows the structural example of the optical system of the corneal-endothelial-cells imaging device which concerns on the modification of embodiment. It is the schematic which shows the structural example of the processing system of the corneal-endothelial-cells imaging device which concerns on the modification of embodiment. It is a flowchart of the operation example of the corneal endothelial cell imaging device which concerns on the modification of embodiment.

  An example of an embodiment of a corneal endothelial cell imaging apparatus according to the present invention will be described in detail with reference to the drawings. In addition, it is possible to use the description content of the literature referred in this specification, and arbitrary well-known techniques for the following embodiment.

  In the following, the left-right direction as viewed from the subject is the X direction, the up-down direction is the Y direction, and the depth direction (optical axis direction, front-rear direction) of the optical system as viewed from the subject is the Z direction. The X direction and the Y direction may be expressed as the XY direction.

  The corneal endothelial cell imaging device according to the embodiment irradiates a subject eye with slit light, receives a reflected component from the corneal endothelium among reflected light from the cornea of the subject eye irradiated with the slit light, and receives corneal endothelial cells. It is a device that can shoot. The corneal endothelial cell imaging apparatus includes a base, a base portion provided above the base, and a measurement head that can move in the X, Y, and Z directions with respect to the base portion. The measuring head is provided with an optical system for photographing corneal endothelial cells of the eye to be examined. The base is provided with a holding member that holds the chin rest and the forehead support. For example, by using a known alignment method, the optical system can be aligned with the eye to be inspected by moving the measuring head with respect to the subject who puts his chin on the chin rest and holds the forehead on the forehead rest. It is possible (see Patent Document 1).

  Below, the case where the corneal endothelial cell imaging device according to the embodiment acquires an image of a corneal endothelial cell with a wide field of view will be described. The corneal endothelial cell imaging device according to the embodiment acquires images of a plurality of corneal endothelial cells with different imaging ranges, and acquires an image of a wide-field corneal endothelial cell as a panoramic image by combining these images.

[Optical system]
FIG. 1 shows a configuration example of an optical system of a corneal endothelial cell imaging apparatus according to the embodiment. The optical system shown in FIG. 1 is provided in the measurement head. In FIG. 1, illustration of the structure for performing alignment of the optical system with respect to the eye to be examined is omitted.

  The corneal endothelial cell imaging device 1 includes an irradiation system 10 and a light receiving system 20. The irradiation system 10 is provided with an optical system for irradiating slit light toward the cornea C of the eye E. The light receiving system 20 is provided with an optical system for receiving a reflection component from the corneal endothelium among the reflected light from the cornea C of the eye E to which the slit light is irradiated by the irradiation system 10. In the cornea C, the optical axis O2 of the irradiation system 10 (for example, the optical axis of the objective lens of the irradiation system 10) intersects the optical axis O3 of the light reception system 20 (for example, the optical axis of the objective lens of the light reception system 20). Reference numeral 20 denotes an oblique arrangement with respect to the irradiation system 10. That is, when the front axis of the eye E is O1, the irradiation system 10 is provided so that the angle between the axis O1 and the optical axis O2 of the irradiation system 10 is θi (for example, θi = 30 degrees). The light receiving system 20 is provided so that an angle between O1 and the optical axis O3 of the light receiving system 20 is θo. θo may be an angle equal to θi.

(Irradiation system)
The irradiation system 10 includes a light source 11, a collimator lens 12, a field stop 13 in which a slit is formed, an aperture stop 14 in which an opening is formed, and an objective lens 15. The light source 11 includes, for example, an infrared light emitting diode (LED). One or more slits are formed in the field stop 13. The field stop 13 is configured to be able to change the position of the slit in the optical path of the light from the light source 11. In this embodiment, the field stop 13 can be moved by a movement mechanism (movement mechanism 13M described later) (not shown). By moving the field stop 13 by the moving mechanism, the position of the slit in the optical path of the light that has passed through the collimator lens 12 is changed.

  For example, the field stop 13 includes a turret plate that is rotatable about a rotation axis that is provided substantially parallel to the optical path of light from the light source 11. The turret plate is formed with one or more slits along a circumferential direction around the rotation axis. When two or more slits are formed in the turret plate, the moving mechanism moves the turret plate so that a part of one slit and a part of the other slit overlap in the optical path of light from the light source 11. Rotate. When one slit is formed in the turret plate, the moving mechanism is configured so that a part of the slit before the rotation and a part of the slit after the rotation overlap in the optical path of the light from the light source 11. Rotate.

  Alternatively, the field stop 13 may include a slide plate that can slide in a direction that intersects the optical path of the light from the light source 11. The slide plate is formed with one or more slits. When two or more slits are formed on the slide plate, the moving mechanism moves the slide plate so that a part of one slit and a part of the other slit overlap in the optical path of the light from the light source 11. Move. When one slit is formed in the slide plate, the moving mechanism moves the slide plate so that a part of the slit before the movement and a part of the slit after the movement overlap in the optical path of the light from the light source 11. Let

  The field stop 13 is arranged so that the position of the slit in the optical path of the light from the light source 11 is optically substantially conjugate with the corneal endothelium of the eye E to be examined.

  The light output from the light source 11 is converted into a parallel light beam by the collimator lens 12. The light from the light source 11 that has been converted into a parallel light beam is applied to the field stop 13. The light that has been converted into a parallel light beam by the collimator lens 12 passes through the slit formed in the field stop 13 to form slit light. The formed slit light passes through the opening formed in the aperture stop 14 and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated obliquely toward the cornea C. By changing the position of the slit in the optical path of the light from the light source 11, the irradiation area of the slit light in the cornea C can be changed.

(Light receiving system)
The light receiving system 20 includes an objective lens 21, a plano-convex lens 22, a concave lens 23, a diaphragm 24 in which a slit is formed, an imaging lens 25, and an image sensor 26. The objective lens 21, the plano-convex lens 22, and the imaging lens 25 are lenses (positive lenses) having a positive refractive power. The concave lens 23 is a lens (negative lens) that is disposed between the objective lens 21 and the image sensor 26 and has negative refractive power.

  The optical center of the concave lens 23 is disposed at a position deviated from at least one optical axis of the objective lens 21 and the plano-convex lens 22, and the optical axis of the concave lens 23 is relative to at least one optical axis of the objective lens 21 and the plano-convex lens 22. (Tilt shift arrangement). At least one of the objective lens 21 and the plano-convex lens 22 may be tilt-shifted. In other words, the optical center of the objective lens 21 is arranged at a position deviated from the optical axis of the plano-convex lens 22, and the optical axis of the objective lens 21 is inclined with respect to the optical axis of the plano-convex lens 22. Good.

  The diaphragm 24 shields the portion of the reflected light beam from the corneal epithelium in a state where the alignment of the optical system (irradiation system 10 and light receiving system 20) with the eye E is matched, and only the portion of the reflected light beam of the corneal endothelium passes through the slit. Are arranged to be. The imaging lens 25 forms an image of the light that has passed through the concave lens 23 on the imaging surface of the imaging element 26. The image pickup device 26 includes a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

  The diaphragm 24 is arranged such that the position of the slit in the optical path of the reflected light from the cornea C is optically conjugate with the corneal endothelium of the eye E. The imaging surface of the imaging element 26 is disposed so as to be optically substantially conjugate with the corneal endothelium of the eye E to be examined.

  The reflected light of the slit light applied to the cornea C by the irradiation system 10 is guided to the objective lens 21. The reflected light flux includes reflected light fluxes R1, R2, and R3 as shown in FIG. The reflected light beam R1 is a reflected light beam on the corneal surface Ca that is the corneal epithelium of the cornea C. The reflected light beam R2 is a reflected light beam of the corneal endothelium Cb. The reflected light beam R3 is a reflected light beam of the corneal substantial Cc of the cornea C. The reflected light beams R 1, R 2, R 3 pass through the objective lens 21 and pass through the plano-convex lens 22. The plano-convex lens 22 is tilt-shifted so as to correct the aberration characteristics of the light passing therethrough, and corrects the aberration characteristics of the reflected light beams R1, R2, and R3. The light that has passed through the plano-convex lens 22 is refracted by the concave lens 23.

  FIG. 3 schematically shows a change in imaging characteristics due to the concave lens 23. In FIG. 3, the vertical axis represents the MTF (Modulation Transfer Function) value, and the horizontal axis represents the defocus amount. FIG. 3 schematically shows MTF characteristics of light passing through the optical center (one point) of the concave lens 23 and positions near the four corners (four points) with the optical center as a reference.

  The characteristic T1 corresponds to the imaging characteristic of the concave lens 23 when the concave lens 23 is arranged coaxially with the optical axis O3 and the main surface is arranged so as to be orthogonal to the optical axis O3. The characteristic T2 corresponds to the imaging characteristic of the concave lens 23 when the tilt shift arrangement is performed as described above. Since each of the optical center and the optical axis of the concave lens 23 is arranged as described above, the imaging characteristic can be changed from the characteristic T1 to the characteristic T2. Comparing the characteristics T1 and the characteristics T2, the imaging characteristics of the light passing therethrough can be made uniform in the lens surface of the concave lens 23 by arranging the tilt shift. As a result, the focus difference between the corneal apex and its peripheral part can be greatly reduced, so that even if the cornea is a keratoconus, etc. Images can be acquired.

  In FIG. 1, the reflected light beams R 1, R 2, R 3 refracted by the concave lens 23 are irradiated to the diaphragm 24. Of the reflected light beams R1, R2, and R3 irradiated to the diaphragm 24, the reflected light beam R2 passes through the slit and is imaged on the imaging surface of the image sensor 26 by the imaging lens 25. Thereby, a corneal endothelial cell image is formed on the imaging surface of the image sensor 26, and this corneal endothelial cell image is captured.

[Processing system]
FIG. 4 shows a block diagram of a configuration example of a processing system of the corneal endothelial cell imaging apparatus 1. The processing system of the corneal endothelial cell imaging apparatus 1 is configured around the control unit 100.

(Control part)
The control unit 100 controls each part of the corneal endothelial cell imaging apparatus 1. The control unit 100 includes a main control unit 101 and a storage unit 102. The function of the main control unit 101 is realized by a microprocessor, for example. The storage unit 102 stores in advance a computer program for controlling the corneal endothelial cell imaging apparatus 1. This computer program includes a light source control program, an image sensor control program, a data processing program, a user interface program, and the like. When the main control unit 101 operates according to such a computer program, the control unit 100 executes control processing.

  Control of the irradiation system 10 includes control of the light source 11 and control of the driving unit 13D that drives the moving mechanism 13M (control of the field stop 13). Control of the light source 11 includes turning on and off the light source 11 and adjusting the amount of light. As described above, the moving mechanism 13 </ b> M rotates the turret plate that can rotate around a rotation axis that is provided substantially parallel to the optical path of the light from the light source 11. The drive unit 13D is provided with, for example, an actuator that generates a driving force for moving the moving mechanism 13M and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is constituted by a combination of gears, a rack and pinion, for example. The control unit 100 can control the moving mechanism 13M by sending a control signal to the driving unit 13D.

  Control of the light receiving system 20 includes control of the image sensor 26 and the like. The control of the image sensor 26 includes exposure adjustment, gain adjustment, and shooting rate adjustment. The control unit 100 can acquire an output signal (video signal) from the image sensor 26.

  The control unit 100 displays various information on a display device included in a UI unit 120 described later. Information displayed on the display device includes information generated by the control unit 100, information after data processing by the data processing unit 110, and the like.

(Data processing part)
The data processing unit 110 executes various data processing. As an example of data processing, there is processing for image data obtained by the image sensor 26. Examples of this processing include various types of image processing, image analysis processing, and diagnostic support processing such as image evaluation based on image data.

  The data processing unit 110 includes an image composition unit 111 and an analysis unit 112. The image synthesizing unit 111 synthesizes two or more images obtained by the image sensor 26 with the slit positions being different from each other by the movement of the field stop 13 by the moving mechanism 13M to generate a synthesized image (panoramic image). The image composition unit 111 performs alignment processing on the two images obtained so that part of the edge of the image overlaps each other so that the overlapping portion matches, and the two images that have been aligned Two images are synthesized by arranging the images side by side. The image composition unit 111 generates a composite image by repeating such composition processing.

  The analysis unit 112 obtains information representing the state of the corneal endothelial cell based on the output signal from the image sensor 26. For example, the analysis unit 112 identifies the boundary of the corneal endothelial cell by analyzing an image generated based on the output signal from the imaging device 26 and depicting a plurality of corneal endothelial cells, and based on the identified boundary Identify corneal endothelial cells. The analysis unit 112 obtains the area and shape of the specified corneal endothelial cell and obtains information representing the state of the corneal endothelial cell. Information representing the state of corneal endothelial cells includes the number of cells, cell density, minimum cell area, maximum cell area, average cell area, standard deviation of cell area, cell area variation coefficient, cell area histogram, hexagon There are cell appearance rate and shape histogram.

  Note that the image composition unit 111 aligns the two images based on the boundary of the corneal endothelial cells in the overlapping region specified by the analysis unit 112, and arranges the aligned two images side by side. The two images may be combined.

(UI part)
A UI (User Interface) unit 120 has a function for exchanging information between the user and the corneal endothelial cell imaging device. The UI unit 120 includes a display device and an operation device (input device). The display device may include a display unit and may include other display devices. The operation device includes various hardware keys and / or software keys. The control unit 100 can receive an operation content for the operation device and output a control signal corresponding to the operation content to each unit. It is possible to integrally configure at least a part of the operation device and at least a part of the display device. A touch panel display is an example.

  The field stop 13 is an example of a “slit member” according to the embodiment. The objective lens 21 and the plano-convex lens 22 are examples of “one or more positive lenses” according to the embodiment. The concave lens 23 is an example of a “negative lens” according to the embodiment. The imaging lens 25 is an example of a “positive lens” according to the embodiment. The objective lens 21 is an example of a “first positive lens” according to the embodiment. The plano-convex lens 22 is an example of a “second positive lens” according to the embodiment.

[Operation]
The operation of the corneal endothelial cell imaging apparatus 1 according to the embodiment will be described. In the following, the field stop 13 is rotatable about a rotation axis O2 ′ provided substantially parallel to the optical path of light from the light source 11, and 2 in the circumferential direction centering on the rotation axis O2 ′. The turret board in which the above slit is formed shall be included. That is, a panoramic image is generated by arranging two or more acquired images side by side while changing an irradiation area in the cornea C by slit light formed by passing through each of the two or more slits. To do.

  FIG. 5 shows an example of the operation of the corneal endothelial cell imaging device 1 according to the embodiment. FIG. 5 shows a flowchart of an operation example of the corneal endothelial cell imaging device 1 according to the embodiment when acquiring a panoramic image of corneal endothelial cells.

(S1)
The main control unit 101 aligns the optical system with respect to the eye E in the X and Y directions by a known alignment method. For example, the main control unit 101 projects alignment target light onto the eye E to be examined, and forms an image of the reflected light on the imaging surface of the imaging device (or the imaging device 26). Thereby, an image by the Purkinje image of the alignment target light is formed on the imaging surface of the imaging element. The main control unit 101 displays an image of the alignment target light on the display device of the UI unit 120 based on the light reception result of the reflected light of the alignment target light by the image sensor. The user performs XY alignment by moving the measurement head including the optical system in the XY directions by operating the operation device included in the UI unit 120 so as to guide the image into a predetermined alignment mark. When performing XY alignment automatically, the main control unit 101 moves the measurement head in the XY direction so as to cancel the displacement of the image with respect to the alignment mark.

  Next, the main control unit 101 aligns the optical system in the Z direction with respect to the eye E by a known alignment method. For example, the main control unit 101 projects slit light for performing Z alignment onto the eye E. The main control unit 101 receives the reflected light with a line sensor or the like, and moves the measuring head including the optical system in the Z direction so that the light receiving position is determined in advance as a position where the alignment in the Z direction is appropriate. Move to perform Z alignment.

  The main control unit 101 controls the moving mechanism 13M so that a predetermined slit among the two or more slits formed in the field stop 13 is arranged in the optical path of the light from the light source 11.

(S2)
The main control unit 101 causes corneal endothelial cells imaged on the imaging surface of the imaging element 26 to be imaged. The main control unit 101 acquires the video signal obtained by the imaging element 26 and causes the storage unit 102 to store image data (or video signal) based on the video signal.

(S3)
Next, the main control unit 101 controls the driving unit 13D so that a part of the slit before the rotation and a part of the slit after the rotation overlap in the optical path of the light from the light source 11, thereby moving the moving mechanism 13M. To rotate the turret plate. Thereby, the irradiation region of the slit light in the cornea C when the photographing is performed in S2 is moved.

(S4)
The main control unit 101 causes corneal endothelial cells imaged on the imaging surface of the imaging element 26 to be imaged. The main control unit 101 acquires a video signal obtained by the imaging element 26 and causes the storage unit 102 to store image data based on the video signal.

(S5)
The main control unit 101 determines whether or not to perform the next shooting. The number of times of imaging while changing the irradiation area in the cornea C is determined in advance, and the main control unit 101 can determine whether or not to perform the next imaging based on the number of times. Further, the main control unit 101 may determine whether or not to perform the next shooting based on the content of the user operation on the operation device of the UI unit 120. When it is determined that the next imaging is to be performed (S5: N), the operation of the corneal endothelial cell imaging apparatus 1 proceeds to S3. A part of the slit in the optical path of the light from the light source 11 in the second S3 transferred from S5 is arranged so as to overlap with a part of the slit in the optical path of the light from the light source 11 in the first S3.

  6A and 6B are diagrams for explaining operations in S2 to S5 in FIG. For convenience of explanation, FIGS. 6A and 6B schematically show a part of the optical system of FIG. 6A and 6B, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. 6A and 6B, the turret plate is rotatable about a rotation axis O2 ′ provided substantially parallel to the optical path of light from the light source 11, and has a circumference centered on the rotation axis O2 ′. It is assumed that three slits SL1, SL2, and SL3 are formed in the direction. That is, using the first image acquired using the slit light formed by the slit SL1, the second image acquired using the slit light formed by the slit SL2, and the slit light formed by the slit SL3. It is assumed that a panoramic image is generated by arranging at least two of the acquired third images side by side.

  First, in S2, the slit light formed by the slit SL1 is irradiated to the irradiation region SP1 in the cornea C as shown in FIG. 6A. At this time, the reflection component from the corneal epithelium and the reflection component from the corneal endothelium are guided to the image sensor 26. In FIG. 6A, an image IC <b> 1 based on the reflection component from the corneal epithelium among the reflection component from the corneal epithelium and the reflection component from the corneal endothelium is imaged on the imaging surface PS of the imaging element 26.

  Next, in the first S3, the turret plate is rotated about the rotation axis O2 ′ (rotation C1). Thereby, the slit SL2 is disposed in the optical path of the light from the light source 11. At this time, the slit SL2 is arranged such that a part of the slit SL1 and a part of the slit SL2 overlap in the optical path of the light from the light source 11. Thereby, in S4 of the 1st time, as shown to FIG. 6B, the irradiation area | region of the slit light formed by slit SL2 moves to E1, and is irradiated to irradiation area | region SP2 in the cornea C. FIG. A part of the irradiation area SP2 overlaps a part of the irradiation area SP1. At this time, on the imaging surface PS of the imaging element 26, the reflection component from the corneal epithelium and the reflection component from the corneal endothelium move in the D1 direction. As a result, the image IC1 based on the reflection component from the corneal epithelium and the image IC2 based on the reflection component from the corneal endothelium move in the D1 direction and form an image on the imaging surface PS of the imaging element 26.

  Similarly, in the second S3, the turret plate is rotated about the rotation axis O2 ′ (rotation C2). Thereby, the slit SL3 is disposed in the optical path of the light from the light source 11. At this time, the slit SL3 is arranged such that a part of the slit SL2 and a part of the slit SL3 overlap in the light source optical path. Therefore, in the second S4, the slit light formed by the slit SL3 is irradiated to the irradiation region SP3 in the cornea C as shown in FIG. 6B. A part of the irradiation area SP3 overlaps with a part of the irradiation area SP2. At this time, since the irradiation region of the slit light in the cornea C moves in the E1 direction and is irradiated to the irradiation region SP3, the reflection component from the corneal epithelium and the reflection component from the corneal endothelium on the imaging surface PS of the imaging element 26 Further moves in the D1 direction. As a result, the image IC1 based on the reflection component from the corneal epithelium and the image IC2 based on the reflection component from the corneal endothelium move in the D1 direction and form an image on the imaging surface PS of the imaging element 26.

  When it is determined in S5 that the next imaging is not performed (S5: Y), the operation of the corneal endothelial cell imaging device 1 proceeds to S6.

(S6)
When it is determined that the next shooting is not performed (S5: Y), the image composition unit 111 generates a composite image by combining two or more images acquired in S2 and S4.

(S7)
Next, the analysis part 112 calculates | requires the information showing the state of a corneal endothelial cell as mentioned above by analyzing the synthetic | combination image produced | generated in S6.

(S8)
Next, the main control unit 101 displays the information obtained in S7 on the display device of the UI unit 120. At this time, the main control unit 101 can display the information on the display device together with the composite image generated in S6. Thus, the operation of the corneal endothelial cell photographing apparatus 1 is finished (end).

  As described above, the irradiation system 10 includes the field stop 13 in which two or more slits are formed so that a part of one slit overlaps a part of the other slit in the optical path of the light from the light source 11. The field stop 13 is moved by the moving mechanism 13M. Thereby, the sequential irradiation of the slit light to the different irradiation regions of the corneal endothelium can be speeded up. Therefore, it is possible to acquire an image of a corneal endothelial cell necessary for generating a panoramic image in a short time with a very simple configuration.

  For example, since the time required to acquire an image in which new corneal endothelial cells are depicted by changing the fixation target presentation position is at least about 10 to 20 seconds, the eyeball moves during that time. In this case, it is difficult to align the image due to the movement of the eyeball, and it is often impossible to generate a panoramic image. On the other hand, in the embodiment, since the time required for acquiring a new image is 1 second or less (for example, about 0.2 seconds), a panoramic image can be easily acquired without imposing a burden on the subject. It becomes possible.

  In the light receiving system 20, a concave lens 23 is provided between the objective lens 21 and the image sensor 26, and the concave lens 23 is disposed in a tilt-shift manner. As a result, the focus difference between the corneal apex and its peripheral part can be greatly reduced, so that even if the cornea is a keratoconus, etc. Images can be acquired. In addition, since there is little focus difference between any two positions in the acquired image of the corneal endothelial cell, it is easy to align these images, and it is easy to acquire a panoramic image.

<Modification>
The configuration of the optical system of the corneal endothelial cell imaging device 1 according to the embodiment is not limited to the configuration shown in FIG.

  FIG. 7 shows a configuration example of an optical system of a corneal endothelial cell imaging device according to a modification of the embodiment. 7, parts that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

  The configuration of the corneal endothelial cell imaging apparatus 1a according to the modification is different from the configuration of the corneal endothelial cell imaging apparatus 1 in that an irradiation system 10a is provided instead of the irradiation system 10. The irradiation system 10a includes a first slit light output system 30A, a second slit light output system 30B, a third slit light output system 30C, half mirrors HM1 and HM2, an aperture stop 14, and an objective lens 15. .

  The first slit light output system 30A includes a first light source 11A, a first collimator lens 12A, and a first field stop 13A. The first light source 11 </ b> A is the same as the light source 11. A first slit is formed in the first field stop 13A. The first field stop 13A is disposed in the optical path of the light from the first light source 11A.

  The second slit light output system 30B includes a second light source 11B, a second collimator lens 12B, and a second field stop 13B. The second light source 11B is the same as the light source 11. A second slit is formed in the second field stop 13B. The second field stop 13B is disposed in the optical path of the light from the second light source 11B. The second slit is formed such that a part of the irradiation region in the cornea C of the second slit light that has passed through the slit overlaps a part of the irradiation region in the cornea C of the first slit light that has passed through the first slit. ing.

  The third slit light output system 30C includes a third light source 11C, a third collimator lens 12C, and a third field stop 13C. The third light source 11 </ b> C is the same as the light source 11. A third slit is formed in the third field stop 13C. The third field stop 13C is disposed in the optical path of the light from the third light source 11C. The third slit is formed such that a part of the irradiation region in the cornea C of the third slit light that has passed through the slit overlaps a part of the irradiation region in the cornea C of the second slit light that has passed through the second slit. ing.

  The half mirror HM1 couples the optical path of light from the first light source 11A and the optical path of light from the second light source 11B. The half mirror HM2 couples the optical path coupled by the half mirror HM1 and the optical path of the light from the third light source 11C.

  The first field stop 13A is arranged so that the position of the slit in the optical path of the light from the first light source 11A is optically substantially conjugate with the corneal endothelium of the eye E. The second field stop 13B is arranged so that the position of the slit in the optical path of the light from the second light source 11B is optically substantially conjugate with the corneal endothelium of the eye E to be examined. The third field stop 13C is disposed so that the position of the slit in the optical path of the light from the third light source 11C is optically conjugate with the corneal endothelium of the eye E to be examined.

  With the configuration as described above, the irradiation region of the slit light in the cornea C is changed by selectively turning on the first light source 11A, the second light source 11B, and the third light source 11C. The irradiation system 10a can overlap a part of the irradiation area of one slit light in the cornea C with a part of the irradiation area of the other slit light.

  When the first light source 11A is turned on while the second light source 11B and the third light source 11C are turned off, the light output from the first light source 11A is converted into a parallel light beam by the first collimator lens 12A. The light from the first light source 11A, which is a parallel light beam, is applied to the first field stop 13A. The first collimator lens 12A passes through the first slit, and the first slit light is formed by the light converted into the parallel light flux. The first slit light passes through the half mirrors HM 1 and HM 2, passes through the opening formed in the aperture stop 14, and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated obliquely toward the cornea C.

  When the second light source 11B is turned on while the first light source 11A and the third light source 11C are turned off, the light output from the second light source 11B is converted into a parallel light flux by the second collimator lens 12B. The light from the second light source 11B, which is a parallel light beam, is applied to the second field stop 13B. The second slit light is formed by the light that has been converted into a parallel light beam by the second collimator lens 12B through the second slit. The second slit light is reflected by the half mirror HM1, passes through the half mirror HM2, passes through the opening formed in the aperture stop 14, and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated obliquely toward the cornea C.

  When the third light source 11C is turned on while the first light source 11A and the second light source 11B are turned off, the light output from the third light source 11C is converted into a parallel light flux by the third collimator lens 12C. The light from the third light source 11C that has been converted into a parallel light beam is applied to the third field stop 13C. The light made into the parallel light flux by the third collimator lens 12C passes through the third slit to form the third slit light. The third slit light is reflected by the half mirror HM2, passes through the opening formed in the aperture stop 14, and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated obliquely toward the cornea C.

  FIG. 8 shows a block diagram of a configuration example of a processing system of the corneal endothelial cell imaging device 1a according to the modification. 8, parts similar to those in FIG. 4 are given the same reference numerals, and description thereof will be omitted as appropriate.

  The controller 100a controls each part of the corneal endothelial cell imaging device 1a. The control unit 100a includes a main control unit 101a and a storage unit 102a. The function of the main control unit 101a is realized by, for example, a microprocessor, like the main control unit 101. Similar to the storage unit 102, the storage unit 102a stores in advance a computer program for controlling the corneal endothelial cell imaging device 1a. When the main control unit 101a operates according to such a computer program, the control unit 100a executes control processing.

  Control of the irradiation system 10a includes control of the first light source 11A, control of the second light source 11B, control of the third light source 11C, and the like. Control of the first light source 11A includes turning on and off the first light source 11A, adjusting the amount of light, and the like. Control of the second light source 11B includes turning on and off the second light source 11B, adjusting the light amount, and the like. The control of the third light source 11C includes turning on and off the third light source 11C, adjusting the light amount, and the like. The control part 100a can change the irradiation area | region of the slit light in the cornea C by turning on the 1st light source 11A-the 3rd light source 11C alternatively alternatively.

  Similar to the control unit 100, the control unit 100 a can control the light receiving system 20, the data processing unit 110, and the UI unit 120.

  FIG. 9 shows an example of the operation of the corneal endothelial cell imaging device 1a according to the modification. FIG. 9 shows a flowchart of an operation example of the corneal endothelial cell imaging device 1a when acquiring a panoramic image of corneal endothelial cells.

(S11)
The main controller 101a aligns the optical system with respect to the eye E by a known alignment method. S11 is the same as S1.

(S12)
The main control unit 101a turns on the first light source 11A and turns off the second light source 11B and the third light source 11C. Thereby, the light output from the first light source 11A passes through the first collimator lens 12A and passes through the first slit formed in the first field stop 13A, thereby becoming the first slit light. The first slit light passes through the half mirrors HM 1 and HM 2, passes through the opening formed in the aperture stop 14, and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated to a predetermined irradiation region (for example, the irradiation region SP1 in FIG. 6A) in the cornea C.

(S13)
The main control unit 101a causes the corneal endothelial cells imaged on the imaging surface of the imaging element 26 to be photographed. S13 is the same as S2.

(S14)
The main control unit 101a turns on the second light source 11B and turns off the first light source 11A and the third light source 11C. Thereby, the light output from the second light source 11B passes through the second collimator lens 12B, and passes through the second slit formed in the second field stop 13B, thereby becoming the second slit light. The second slit light is reflected by the half mirror HM1, passes through the half mirror HM2, passes through the opening formed in the aperture stop 14, and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated to an irradiation region (for example, the irradiation region SP2 in FIG. 6B) overlapping with a part of the irradiation region of S12 in the cornea C.

(S15)
The main control unit 101a causes the corneal endothelial cells imaged on the imaging surface of the imaging element 26 to be photographed. S15 is the same as S4.

(S16)
The main control unit 101a turns on the third light source 11C and turns off the first light source 11A and the second light source 11B. As a result, the light output from the third light source 11C passes through the third collimator lens 12C and passes through the third slit formed in the third field stop 13C to become third slit light. The third slit light is reflected by the half mirror HM2, passes through the opening formed in the aperture stop 14, and is guided to the objective lens 15. The light guided to the objective lens 15 is irradiated to an irradiation region (for example, the irradiation region SP3 in FIG. 6B) overlapping with a part of the irradiation region of S14 in the cornea C.

(S17)
The main control unit 101a causes the corneal endothelial cells imaged on the imaging surface of the imaging element 26 to be photographed. S17 is the same as the second S4.

(S18)
The image combining unit 111 generates a combined image by combining a plurality of images acquired in at least two of S13, S15, and S17. The image synthesizing unit 111 receives one image obtained by the imaging element 26 that has received the reflection component from the corneal endothelium based on one slit light and the reflection component from the corneal endothelium based on the other slit light. A synthesized image is generated by synthesizing with another image obtained by the image sensor 26. S18 is the same as S6.

(S19)
Next, the analysis part 112 calculates | requires the information showing the state of a corneal endothelial cell as mentioned above by analyzing the synthetic | combination image produced | generated in S18. S19 is the same as S7.

(S20)
Next, the main control unit 101a displays the information obtained in S19 on the display device of the UI unit 120. S20 is the same as S8. Thus, the operation of the corneal endothelial cell photographing apparatus 1a is completed (end).

  As described above, the irradiation system 10a is provided with a plurality of slit light output systems having different irradiation regions in the cornea C, and sequentially irradiates the different regions of the cornea C with the slit light that has passed through the respective slits. Thereby, similarly to the embodiment, it is possible to acquire an image of a corneal endothelial cell necessary for generating a panoramic image in a short time with a very simple configuration. In particular, unlike the embodiment, since it is not necessary to move the field stop, it is possible to simplify the configuration and suppress the generation of operation noise.

  Each of the arbitrary two of the first field stop 13A to the third field stop 13C is an example of a “first slit member” and a “second slit member” according to the embodiment. The half mirror HM1 or the half mirror HM2 is an example of the “optical path coupling member” according to the embodiment.

  In this modification, the case where three slit light output systems are provided has been described, but two slit light output systems or four or more slit light output systems may be provided.

[effect]
The effects of the embodiment will be described.

  The corneal endothelial cell imaging device (corneal endothelial cell imaging device 1) according to the embodiment includes an irradiation system (irradiation system 10) and a light receiving system (light receiving system 20). The irradiation system irradiates slit light toward the cornea (cornea C) of the eye to be examined (eye E). The light receiving system is disposed obliquely with respect to the irradiation system. The light receiving system includes one or more positive lenses (objective lens 21, plano-convex lens 22), an image sensor (image sensor 26), and a negative lens (concave lens 23). The imaging device receives a reflected component from the corneal endothelium through one or more positive lenses among the reflected light from the cornea irradiated with slit light by the irradiation system. The negative lens is disposed between the one or more positive lenses and the image sensor. The optical center of the negative lens is disposed at a position deviated from at least one optical axis of the one or more positive lenses, and the optical axis of the negative lens is inclined with respect to at least one optical axis of the one or more positive lenses. Has been placed.

  According to such a configuration, the imaging characteristics of light passing therethrough can be made uniform within the lens surface of the negative lens. As a result, the focus difference between the corneal apex and its peripheral part can be greatly reduced, so that even if the cornea is a keratoconus, etc. Images can be acquired. In addition, since there is little focus difference between any two positions in the acquired image of the corneal endothelial cell, it is easy to align these images, and it is easy to acquire a panoramic image.

  In the corneal endothelial cell imaging device according to the embodiment, the one or more positive lenses include a first positive lens (objective lens 21) and a second positive lens (plano-convex lens 22). The center may be disposed at a position deviated from the optical axis of the second positive lens, and the optical axis of the first positive lens may be inclined with respect to the optical axis of the second positive lens.

  According to such a configuration, it is possible to acquire an image of a corneal endothelial cell in which aberration is corrected and a focus difference is small at any two positions.

  In the corneal endothelial cell imaging device according to the embodiment, the light receiving system is a positive lens (imaging lens) that is arranged between the negative lens and the imaging element and forms an image on the imaging surface of the imaging element through the light passing through the negative lens. 25) may further be included.

  According to such a configuration, the reflection component from the corneal endothelium can be imaged on the imaging surface of the imaging device in a state where the imaging characteristics are uniform within the lens surface of the negative lens, and thus depends on the form of the cornea A clear corneal endothelial cell image with high resolving power can be obtained without this.

  In addition, the corneal endothelial cell imaging device according to the embodiment may include an analysis unit (analysis unit 112) that obtains information representing the state of the corneal endothelial cell based on an output signal from the imaging element.

  According to such a configuration, it is possible to provide highly accurate information regarding corneal endothelial cells without depending on the form of the cornea.

<Others>
The embodiment described above is merely an example for carrying out the present invention. A person who intends to implement the present invention can make arbitrary modifications, omissions, additions and the like within the scope of the present invention.

  The configuration of the optical system of the corneal endothelial cell imaging apparatus according to the embodiment or its modification is not limited to the configuration shown in FIG. 1 or FIG.

  In the irradiation system of the corneal endothelial cell imaging device according to the embodiment or the modification thereof, the case where the irradiation area of the slit light in the cornea C is changed by using the field stop 13 or the plurality of slit light output systems has been described. The structure which concerns on a form is not limited to this. For example, a correction member (optical element) is provided between the aperture stop 14 and the objective lens 15, and the correction member is inclined with respect to the optical axis O2, and the inclination angle with respect to the optical axis O2 is changed to thereby correct the correction. You may change the irradiation area | region in the cornea C of the slit light which passes a member.

  In the light receiving system of the corneal endothelial cell imaging device according to the embodiment or the modification thereof, the case where the reflection component from the corneal endothelium among the reflected light of the slit light from the cornea C is passed using the diaphragm 24 has been described. The structure which concerns on a form is not limited to this. For example, a correction member (optical element) is provided between the objective lens 21 and the plano-convex lens 22, the correction member is inclined with respect to the optical axis O3, and the inclination angle with respect to the optical axis O3 is changed, thereby changing the corneal endothelium. Only the reflection component from the light may pass through.

DESCRIPTION OF SYMBOLS 1, 1a Corneal endothelial cell imaging device 10, 10a Irradiation system 11 Light source 12 Collimator lens 13 Field stop 13D Drive part 13M Moving mechanism 14 Aperture stop 15 Objective lens 20 Light receiving system 21 Objective lens 22 Plano-convex lens 23 Concave lens 24 Stop 25 Imaging lens 26 Image sensor 100 Control unit 110 Data processing unit 111 Image composition unit 112 Analysis unit C Cornea E Eye to be examined

Claims (4)

An irradiation system for irradiating slit light toward the cornea of the eye to be examined; and
A light receiving system disposed obliquely to the irradiation system;
Including
The light receiving system is
One or more positive lenses,
An image sensor that receives a reflected component from the corneal endothelium through the one or more positive lenses among the reflected light from the cornea irradiated with the slit light by the irradiation system;
A negative lens disposed between the one or more positive lenses and the imaging device;
Including
The optical center of the negative lens is disposed at a position deviated from at least one optical axis of the one or more positive lenses, and the optical axis of the negative lens is relative to at least one optical axis of the one or more positive lenses. A corneal endothelial cell imaging device, wherein the corneal endothelial cell imaging device is arranged to be inclined. The one or more positive lenses include a first positive lens and a second positive lens,
The optical center of the first positive lens is disposed at a position deviated from the optical axis of the second positive lens, and the optical axis of the first positive lens is inclined with respect to the optical axis of the second positive lens. The corneal endothelial cell imaging device according to claim 1, wherein the corneal endothelial cell imaging device is arranged. The light receiving system further includes a positive lens that is disposed between the negative lens and the imaging element and forms an image on the imaging surface of the imaging element of light that has passed through the negative lens. The corneal endothelial cell imaging device according to claim 2. The corneal endothelial cell imaging apparatus according to any one of claims 1 to 3, further comprising an analysis unit that obtains information representing a state of a corneal endothelial cell based on an output signal from the imaging element.

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