JP2004254907A - Fundus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fundus camera with which two or more images of the fundus of an eye imaged from different positions can be obtained without trouble. <P>SOLUTION: The fundus camera which images the fundus of an eye to be examined includes a fixation point presenting means which can change a presentation position of the fixation point with which a line of sight of the eye to be examined is guided, a memory means to memorize two or more presentation patterns of that the presentation position of the fixation point is changed sequentially to a prescribed position corresponding to a case, a selection means which selects the memorized presentation pattern, and a controlling means which controls the above fixation point presenting means to change the fixation point sequentially to the prescribed presentation position in accordance with the selected presentation pattern. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fundus camera that photographs the fundus of a subject's eye.
[0002]
[Prior art]
In the fundus camera, there is known a fundus camera in which an internal fixation target (fixation lamp) that guides the line of sight of the eye to be examined is movable in order to enable photographing of the fundus periphery.
[0003]
As a means for moving the internal fixation target, a method of moving a point light source with a lever or the like, a method of providing a plurality of point light sources at predetermined positions and selectively sequentially lighting them are used. Also, a panoramic image of the entire fundus periphery is created by moving the internal fixation target and joining a plurality of photographed fundus images (see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-9-173298 (3rd, 4th page, 2nd, 5th, 10th and 11th figures)
[0005]
[Problems to be solved by the invention]
However, if you want to obtain panoramic images of the entire fundus periphery or an image of a region where multiple captured fundus images are joined together, you can move the conventional point light source with a lever, etc. In the method of selectively lighting up, the examiner had to designate the position of fixation, etc. one by one.
[0006]
In view of the above prior art, it is an object of the present invention to provide a fundus camera that can easily obtain a plurality of fundus images taken at different positions.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is characterized by having the following configuration.
[0008]
(1) In a fundus camera for photographing the fundus of a subject's eye, a fixation target presenting means capable of changing a presentation position of a fixation target that guides the line of sight of a subject's eye, and a predetermined target that matches the presentation position of the fixation target with a case Storage means for storing a plurality of presentation patterns to be sequentially changed to positions, selection means for selecting the stored presentation patterns, and sequentially changing the fixation target to a predetermined presentation position according to the selected presentation patterns Control means for controlling the fixation target presenting means.
[0009]
(2) In the fundus camera according to (1), after a captured image is obtained, the fundus camera further includes an input unit that inputs a command signal for changing the presentation position of the fixation target to the next presentation position. Each time a command signal is input from the input means, the presenting position of the fixation target is sequentially changed according to the selected presenting pattern.
[0010]
(3) The fixation target presenting means of (1) selectively selects one of the aperture holes by moving the light shielding plate, a light source for fixation, a light shielding plate having a plurality of aperture holes at different predetermined positions, and Drive means arranged in the illumination light path of the fixation illumination light source.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an optical system of a non-mydriatic type fundus camera according to the first embodiment. The optical system is roughly composed of an illumination optical system 1, a photographing optical system 2, an observation optical system 3, and a fixation target presenting optical system 40.
[0012]
<Illumination Optical System> A light beam emitted from a halogen lamp 10 as an observation light source is converted into an infrared light beam through a condenser lens 11 and an infrared filter 12 that transmits infrared light, and then reflected by a half mirror 15. The ring slit 16 having a ring-shaped opening is illuminated. Further, the visible light beam emitted from the flash lamp 13 as a photographing light source passes through the condenser lens 14 and then passes through the half mirror 15 and is coaxially combined with the observation infrared light beam. Illuminate.
[0013]
The light flux from the ring slit 16 forms an intermediate image near the opening of the perforated mirror 21 via the relay lens 17a, the mirror 18, the black spot plate 19 having a small black spot at the center, and the relay lens 17b, and the photographing optical system. Reflected by the peripheral surface of the perforated mirror 21 so as to be coaxial with the optical axis of the system 2. The ring slit light beam reflected by the perforated mirror 21 forms an image once in the vicinity of the pupil of the eye E by the objective lens 20, and then diffuses to uniformly illuminate the fundus of the eye to be examined.
[0014]
<Photographing Optical System> The photographing optical system 2 includes an objective lens 20, a photographing diaphragm 22, a focusing lens 23 movable in the optical axis direction, an imaging lens 24, and a color CCD camera 26 for photographing. Reference numeral 25 denotes a return mirror for the observation optical system, which is moved to a position indicated by a broken line at the time of photographing. The reflected light beam from the fundus once forms an intermediate image of the fundus with the objective lens 20, and then enters the CCD camera 26 through the aperture of the aperture mirror 21, the photographing aperture 22, the focusing lens 23, and the imaging lens 24. Then, a fundus image is formed on the image sensor surface.
[0015]
<Observation Optical System> The observation optical system 3 shares the objective lens 20 to the imaging lens 24 of the photographing optical system 2 and changes the optical path by a return mirror 25 at a position indicated by a solid line except during photographing. 30 is a half mirror, and the ratio of reflection is made larger than that of transmission. A relay lens 31 and an observation CCD camera 32 having sensitivity from the visible range to the infrared range are arranged in the reflection direction optical path of the half mirror 30. The infrared reflected light beam from the fundus reflected by the return mirror 25 is further reflected by the half mirror 30 and then enters the CCD camera 32 via the relay lens 31 to form a fundus image on the image sensor surface. To do. The output of the CCD camera 32 is connected to a color monitor 50 for both black and white, and a fundus image ER is displayed on the screen of the monitor 50.
[0016]
<Fixation Target Presenting Optical System> The fixation target presenting optical system 40 includes a red light source 41, a light shielding plate 42, and a relay lens 37, and an observation optical system from the return mirror 25 to the objective lens 20 via the half mirror 30. 3 optical paths are shared. As shown in FIG. 2A, the light shielding plate 42 includes eight opening holes 42a to 42h. The light shielding plate 42 is attached to the disc plate 46 as shown in FIG. 2B showing the AA cross section of FIG. 2A, and the disc plate 46 is attached to the shaft 43 a of the pulse motor 43. When the disk plate 46 is rotated by the pulse motor 43 and the opening holes 42a to 42h are respectively arranged in front of the light source 41, the fixation target corresponds to the opening holes 42a to 42h as shown in FIG. The eight positions 71L, 71R and 72 to 77 with respect to the optical axis L are presented. The initial rotation position of the disk plate 46 is detected by an optical sensor 45 having a light shielding plate 44 and a light projecting / receiving unit. With these mechanisms, the fundus (gaze direction) of the eye to be examined can be guided in each desired direction according to the case by changing the fixation target presentation position to 8 positions, as shown in FIG. The fundus imaging of the areas 111R, 111L, 112 to 117 can be performed.
[0017]
A reflection mirror 39 is provided in the opposite direction of the relay lens 31 of the observation optical system 3 with the half mirror 30 interposed therebetween. The reflection mirror 39 is positioned substantially conjugate with the imaging surface of the CCD camera 32 via the relay lens 31 and substantially conjugate with aperture holes 42a to 42h arranged on the optical axis L via the relay lens 37. Is set. A part of the light beam of the light source 41 that has passed through the opening holes 42a to 42h is reflected by the half mirror 30 and directed to the reflection mirror 39, and is reflected by the reflection mirror 39 and returns to the original direction. After being transmitted, an image is formed on the imaging surface of the CCD camera 32 by the relay lens 31. As a result, the fixation target image 42 ′ is combined with the fundus image ER and displayed on the monitor 50.
[0018]
FIG. 3 is a block diagram showing the main part of the control system. Outputs from the CCD camera 32 and the CCD camera 26 are input to the image processing unit 51. The image processing unit 51 displays the fundus image from the CCD camera 32 on the monitor 50. The fundus image captured by the CCD camera 26 is stored in the image memory 52 of the image processing unit 51, and then the output from the image processing unit 51 is switched. Is displayed.
[0019]
Connected to the control unit 55 are a switch unit 56 having shooting mode changeover switches 56a to 56c, an image storage unit 57, and a shooting switch 58. The imaging mode changeover switches 56a to 56c are used when setting a single imaging mode for only one imaging, a panoramic imaging mode, and a diabetes test simple imaging mode in accordance with a case. The memory 53 stores a presentation pattern for sequentially changing the fixation target presentation position corresponding to each imaging mode according to the case, and the control unit 55 opens the openings 42a to 42a according to each selected imaging mode. The pulse motor 43 is rotationally driven so that 42h is sequentially arranged on the optical axis L.
[0020]
Further, an external computer 60 can be connected to the control unit 55, and the image data stored in the image storage unit 57 can be transferred and output.
[0021]
The operation of the above configuration will be described. First, the diabetic retinopathy simple imaging mode will be described. The diabetic retinopathy simple imaging mode is a mode in which the fundus of the patient's eye is simply moved in the horizontal direction for imaging regarding the diabetic retinopathy examination.
[0022]
First, the examiner presses the switch 56c to enter the diabetic retinopathy simple imaging mode. When the affected eye is the right eye, the switch 59a is pressed, and when the affected eye is the left eye, the switch 59b is pressed. Here, it is assumed that the affected eye is the right eye and the switch 59a is pressed. When the switch 56 c and the switch 59 a are pressed, the control unit 55 drives the pulse motor 43 based on the fixation target presenting pattern stored in the memory 53 and arranges the opening hole 42 b in front of the light source 41.
[0023]
When the halogen lamp 10 is turned on, the eye image illuminated with infrared light is formed on the CCD camera 32 of the observation optical system 3 and the image is displayed on the monitor 50. The examiner observes the display on the monitor 50 and adjusts the position of the fundus camera body with respect to the eye to be examined. Further, focusing is performed by moving the focusing lens 23.
[0024]
The fixation target is located at the fixation target position 71 </ b> R with respect to the optical axis L as shown in FIG. 5A because the opening hole 42 b is disposed in front of the light source 41. The light flux of the fixation target passes through the relay lens 37, the half mirror 30, the return mirror 25, the imaging lens 24, the focusing lens 23, the photographing aperture 22, the aperture of the perforated mirror 21, and the objective lens 20 and is collected on the fundus of the eye to be examined. The subject visually recognizes the light flux from the opening hole 42b as a fixation target. Thereby, the line of sight of the eye to be examined is guided. The observation and photographing area with this fixation target is an area 111R in FIG.
[0025]
The light beam of the fixation target partially reflected by the half mirror 30 is reflected by the mirror 39, and the reflected light forms an image on the imaging surface of the CCD camera 32 through the half mirror 30 and the relay lens 31. On the screen of the monitor 50, the fundus image ER and the fixation target image 42 'of the eye to be examined are displayed. The examiner observes the fundus image and the fixation target image 42 ′ on the monitor 50, and when the fundus image is confirmed, the examiner presses the photographing switch 58 to perform photographing.
[0026]
When the trigger signal from the imaging switch 58 is input, the control unit 55 retracts the return mirror 25 out of the optical path and emits the flash lamp 13 to illuminate the fundus of the eye to be examined with visible light. Visible reflected light from the fundus travels along the optical path of the photographing optical system 2 and enters the photographing CCD camera 26 to obtain a fundus image.
[0027]
When the captured image of the CCD camera 26 is stored in the image memory 52, the screen of the monitor 50 is switched from the observation screen to the captured image screen by the image processing unit 51, and the still image stored in the image memory 52 is displayed. The The examiner confirms this photographed image, and if it is satisfactory, presses the image storage switch 56d and proceeds to photographing the next part. When the image storage switch 56d is pressed, the image stored in the image memory 52 is transferred to the image storage unit 57 and saved. If the photographed image is not good, the examiner restarts photographing by pressing the cancel switch 56e. When the switch 56d or 56e is pressed, the control unit 55 switches the display on the monitor 50 to the observation image.
[0028]
When the switch 56d is pressed, the control unit 55 drives the pulse motor 43 based on the fixation target presentation pattern stored in the memory 53 in order to change the fixation target to the next presentation position. The opening hole 42c is disposed in front of the light source 41. The fixation target is located at the fixation target position 72 with respect to the optical axis L as shown in FIG. 5A because the opening hole 42 c is arranged in front of the light source 41. The examiner observes the fundus image ER and the fixation target image 42 ′ on the monitor 50, and when the fundus image is confirmed, the examiner presses the photographing switch 58 to perform photographing. The imaging area with this fixation target is an area 112 in FIG. When the image storage switch 56d is pressed, the image stored in the image memory 52 is stored in the image storage unit 57.
[0029]
When the switch 56d is pressed, the control unit 55 drives the pulse motor 43 based on the fixation target presentation pattern stored in the memory 53 to change the fixation target to the next presentation position. 42f is arranged in front of the light source 41. The fixation target is located at the fixation target position 75 with respect to the optical axis L as shown in FIG. 5A because the opening hole 42f is arranged in front of the light source 41. The examiner observes the fundus image ER and the fixation target image 42 ′ on the monitor 50, and when the fundus image is confirmed, the examiner presses the photographing switch 58 to perform photographing. The imaging area with this fixation target is an area 115 in FIG. When the image storage switch 56d is pressed, the image stored in the image memory 52 is stored in the image storage unit 57.
[0030]
When the fundus images 111R, 112, and 115 are obtained, the examiner can confirm the fundus image in the horizontal direction, and can easily examine diabetic retinopathy by viewing the state of peripheral blood vessels on the left and right sides of the fundus. . It is also possible to transfer the fundus images 111R, 112, and 115 to the external computer 60, connect the images on the external computer 60 side to create a panoramic image, and check the horizontal fundus image.
[0031]
Next, the entire fundus photographing mode will be described. To switch to the entire fundus photographing mode, the switch 56b is pressed. When the affected eye is the right eye, the switch 59a is pressed, and when the affected eye is the left eye, the switch 59b is pressed. Here, it is assumed that the right eye is selected by pressing the switch 59a. In the entire fundus imaging mode, as in the above-described diabetic retinopathy simple imaging mode, the control unit 55 performs pulse based on the fixation target presentation pattern stored in the memory 53 as shown in FIG. The motor 43 is driven, and the position of the fixation target is sequentially changed to positions 71R, 72, 73, 74, 75, 76, 77. By storing each captured image in the image storage unit 57, as shown in FIG. 6B, a fundus image 111R at the center of the posterior pole and the fundus images 112 to 117 at the periphery thereof are obtained.
[0032]
With the entire fundus imaging mode, the examiner can confirm the fundus image of the entire fundus and can inspect for diabetic retinopathy in detail. It is also possible to transfer the fundus images 111R and 112 to 117 to the external computer 60, connect the images on the external computer 60 side to create a panoramic image, and check the fundus image of the entire fundus.
[0033]
Next, the single shooting mode for only one shooting will be described. To switch to the single shooting mode, the switch 56a is pressed. When the affected eye is the right eye, the switch 59a is pressed, and when the affected eye is the left eye, the switch 59b is pressed. The control unit 55 drives the pulse motor 43 based on the fixation target presenting pattern stored in the memory 53, and when the affected eye is the left eye and the switch 59b is pressed, the opening hole 42a is arranged in front of the light source 41. Then, the position of the fixation target is set to the position 71L, and when the affected eye is the right eye and the switch 59a is pressed, the opening hole 42b is arranged in front of the light source 41 and the position of the fixation target is set to the position 71R. The examiner observes the fundus image and the fixation target image 42 ′ on the monitor 50, and when the fundus image is confirmed, the examiner presses the photographing switch 58 to perform photographing. The imaging region with this fixation target is the region 111L in FIG. 4B for the left eye, and 111R in FIG. 4B for the right eye. When the image storage switch 56d is pressed, the image once stored in the image memory 52 is stored in the image storage unit 57.
[0034]
Furthermore, a glaucoma observation mode is provided, and a new opening hole is provided in the light shielding plate 42 so that the fixation lamp is arranged so that the optic nerve head is in the center of the screen. May be observed.
[0035]
In this way, by switching the imaging mode, it is possible to perform imaging according to the case, so that the examiner does not need to adjust the position of the fixation target once, and a plurality of images captured at different positions on the fundus Can be obtained without trouble.
[0036]
In the above embodiment, eight fixation target positions 71L, 71R, 72-77 are arranged corresponding to the opening holes 42a-42h as shown in FIG. The target position is not limited to this position and number, and may be changed according to the inspection application. For example, the position of 42a and 42b may be shifted slightly downward, and the central position of the macula may be slightly lowered to devise a balance between the top and bottom of the optic nerve head on the observation / imaging screen.
[0037]
In the above embodiment, the light source 41 of the fixation target is a single color (red). However, the color of the light source 41 is changed when the position of the fixation target is changed, such as by using a multicolor LED. The patient may be alerted.
[0038]
【The invention's effect】
As described above, according to the present invention, a plurality of fundus images taken at different positions can be obtained without trouble.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an optical system of a fundus camera.
FIG. 2 is a diagram showing a fixation target mechanism;
FIG. 3 is a block diagram showing a main part of a control system.
FIG. 4 is a diagram illustrating a moving position of a fixation target and a fundus photographed image corresponding thereto.
FIG. 5 is a diagram showing a moving order of a fixation target and a fundus photographed image corresponding thereto.
FIG. 6 is a diagram illustrating a moving order of a fixation target and a fundus photographed image corresponding thereto.
[Explanation of symbols]
26 CCD camera 40 Fixation target presentation optical system 41 Light source 42 Light blocking plate 43 Pulse motor 46 Disk plate 53 Memory 55 Control unit 56a Switch 56b Switch 56c Switch 56d Switch

Claims (3)

In a fundus camera that images the fundus of the subject's eye, fixation target presenting means that can change the position of the fixation target that guides the line of sight of the subject's eye, and the fixation target presentation position sequentially to a predetermined position that matches the case Storage means for storing a plurality of presentation patterns to be changed, selection means for selecting the stored presentation patterns, and the fixation to sequentially change the fixation target to a predetermined presentation position according to the selected presentation patterns A fundus camera comprising: control means for controlling the sign presentation means. 2. The fundus camera according to claim 1, further comprising an input means for inputting a command signal for changing a fixation target presenting position to a next presenting position after a captured image is obtained, wherein the control means includes: A fundus camera characterized in that each time a command signal is input, the position of the fixation target is sequentially changed according to the selected presentation pattern. The fixation target presenting means according to claim 1 includes a fixation illumination light source, a light shielding plate having a plurality of opening holes at different predetermined positions, and moving the light shielding plate to selectively fix one of the opening holes. And a driving means arranged in the illumination light path of the illuminating light source.

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