JP2006101943A - Fundus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fundus camera which can perform the color photographing and the photofluorography without performing the insertion and the removal of a filter and can perform the color photographing and the photofluorography almost simultaneously with a very small interval of time. <P>SOLUTION: The fundus camera is equipped with a color illumination optical system having a first photographing light source, a visible fluorescence exciting illumination optical system having a second photographing light source, an infrared fluorescence exciting illumination optical system having a third photographing light source, a wavelength separating optical system which separates the reflection light from the fundus of the eye into three wavelengths of red, green and blue elements and further separates one of the separated optical paths into an infrared fluorescent wavelength, three image pickup devices disposed in the separated individual optical paths, a memory to store the captured images, a mode selection means to select a color, a visible fluorescent and an infrared fluorescent modes, and a control means which processes the emission by the individual light sources of the color, the visible fluorescent and the infrared fluorescent illumination optical systems and the image signals from the image pickup devices to be stored in the memory. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fundus camera that performs fundus imaging of a subject's eye.

In fundus photography using a fundus camera, color photography in which the fundus is illuminated with white light and a color image is photographed, and fluorescence photography in which a fluorescent agent circulated in the fundus blood vessel or the like is excited to photograph a fluorescence image are known. Fluorescence photography includes FAG fluorescence photography using a fluorescein fluorescent agent that is visible fluorescence and ICG photography using an indocyanine green fluorescence agent that is infrared fluorescence. Conventionally, during FAG photography and ICG fluorescence photography, each exciter filter is inserted into the optical path of the illumination optical system, and each barrier filter is inserted into the optical path of the photography optical system, and each filter is removed from the optical path during color photography. (For example, see Patent Document 1).
JP 2000-316812 A

However, in the configuration in which the exciter filter and the barrier filter are inserted into and removed from the optical path as described above, when switching between color photography and fluorescence photography, each filter needs to be inserted and removed, which makes the operation complicated. There is a problem.
Further, since the insertion / removal of the filter is performed by a mechanical operation, the insertion / removal operation has a certain time. For this reason, even if color imaging and fluorescence imaging are performed consecutively, the imaging position is likely to shift between the color imaging image and the fluorescence image for the subject's eye with unstable fixation, making it difficult to make a diagnosis by comparing both images. There's a problem.

  In view of the above problems, an object of the present invention is to provide a fundus camera that can perform color photographing and fluorescent photographing without inserting or removing a filter. Another object of the present invention is to provide a fundus camera capable of performing color photography and fluorescence photography almost simultaneously at a minute time interval.

(1) A color illumination optical system that has a first imaging light source and illuminates the fundus with white light, and a second imaging light source that is different from the first imaging light source and has a wavelength for exciting visible fluorescence. A visible fluorescence excitation illumination optical system for illuminating; an infrared fluorescence excitation illumination optical system having a third imaging light source different from the first imaging light source; and illuminating the fundus with light having a wavelength for infrared fluorescence excitation; The reflected light from the light is separated into three wavelengths of a red component, a green component, and a blue component, and one of the separated light paths is further separated into an infrared fluorescence wavelength, and the wavelength separation optical system Three image sensors arranged in each separated optical path, a memory for storing a captured image by the image sensor, mode selection means for selecting a mode of color photographing / visible fluorescent photographing / infrared fluorescent photographing;
The first photographing light source is caused to emit light at the time of color photographing, the image signals from the three image pickup devices are processed and the color image is stored in the memory, and at the time of visible fluorescent photographing, the second photographing light source is caused to emit light and the green component is emitted. The image signal from the image sensor arranged in the separation optical path is processed and the visible fluorescence image is stored in the memory. In the infrared fluorescence photographing mode, the third photographing light source is emitted and disposed in the separation light path of the infrared fluorescence wavelength. And a control means for processing an image signal from the image pickup device and storing an infrared fluorescent image in the memory.
(2) In the fundus camera of (1), the visible fluorescence excitation illumination optical system and the infrared fluorescence excitation illumination optical system share the second imaging light source and the third imaging light source, and are used for the excitation of visible fluorescence and red An exciter filter that transmits only the wavelength for excitation of external fluorescence is disposed in the illumination optical path.
(3) The fundus camera of (1) further includes a continuous shooting mode in which visible fluorescent shooting and color shooting are continuously performed, and in the continuous shooting mode, the control means includes the first shooting light source and the second shooting light source. The switching light emission is performed continuously within at least 100 ms, and the visible fluorescent image and the color image are sequentially stored in the memory by processing the image signal from each image sensor in synchronization with the light emission timing of each photographing light source. And
(4) The fundus camera of (1) further includes a continuous shooting mode in which infrared fluorescent shooting and color shooting are continuously performed, and in the continuous shooting mode, the control means is the first shooting light source and the third shooting light source. Are continuously switched within at least 100 ms, and the image signal from each image sensor is processed in synchronization with the light emission timing of each photographing light source, and the infrared fluorescent image and the color image are sequentially stored in the memory. It is characterized by.

  According to the present invention, color photography and fluorescence photography can be performed without inserting or removing a filter. In addition, color photography and fluorescence photography can be performed almost simultaneously at a minute interval.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an optical system and a control system of a fundus camera according to an embodiment. The optical system is roughly divided into a fundus illumination optical system 10 and a fundus observation / imaging optical system 30.

  The fundus illumination optical system 10 includes a color illumination optical system 10a that illuminates the fundus with white light, and an excitation illumination optical system 10b that illuminates the fundus with excitation light that excites the fluorescent agent circulated on the fundus. Note that the color illumination optical system 10a and the excitation illumination optical system 10b have light sources for photographing and observation, respectively. In this case, the observation light source is used for moving image shooting for performing a follow-up observation of the fundus image, and the shooting light source is a still image shooting for obtaining a clear fundus image by a still image during the follow-up observation by the observation light source. Used for use.

  The color illumination optical system 10a includes an observation light source 11a such as a halogen lamp, a condenser lens 12a, a photographing light source 13a such as a flash lamp, a condenser lens 14a, a ring slit 17 having a ring-shaped opening, a relay lens 18, a mirror 19, and a central portion. A black spot plate 20 having a black spot, a relay lens 21, a perforated mirror 22, and an objective lens 25. Note that the observation light source 11a, the imaging light source 13a, and the ring slit 17 are in a conjugate relationship with the pupil.

  The excitation illumination optical system 10b includes an observation light source 11b such as a halogen lamp, a condenser lens 12b, an imaging light source 13b such as a flash lamp, an exciter filter 15 for excitation illumination, a condenser lens 14b, a half mirror 16, a ring slit 17 to an objective lens 25. Have The half mirror 16 makes the illumination optical axis L1 of the color illumination optical system 10a and the illumination optical axis L2 of the excitation illumination optical system 10b coaxial. Further, the excitation illumination optical system 10b shares the configuration from the ring slit 17 to the objective lens 25 with the color illumination optical system 10a. The observation light source 11b, the imaging light source 13b, and the ring slit 17 are in a conjugate relationship with the pupil. As shown in FIG. 2, the exciter filter 25 includes illumination light for exciting visible fluorescence (for FAG imaging) having a wavelength of about 400 nm to 520 nm, and illumination light for exciting infrared fluorescence (for ICG imaging) having a wavelength of about 700 nm to 820 nm. Has the property of transmitting light. Note that the observation light source 11b and the imaging light source 13b are set to emit a larger amount of light compared to the observation light source 11a and the imaging light source 13a of the color illumination optical system 10a in order to prevent the illumination light amount from being reduced by the exciter filter 25. Has been.

  In the excitation illumination optical system 10b of the present embodiment, the optical system including the imaging light source 13b is changed to a visible fluorescence excitation illumination optical system and an infrared fluorescence excitation illumination optical system by setting the characteristics of the exciter filter 25 as shown in FIG. However, the wavelength selection portion may be separated. For example, a beam splitter is provided between the ring slit 17 and the half mirror 16 to reflect light having a wavelength for exciting infrared fluorescence and transmit visible light, and a wavelength of 790 nm is set as a central wavelength on the separated optical path side. By providing the semiconductor laser, a part of the infrared fluorescence excitation illumination optical system is separated. At this time, if a high-power semiconductor laser is used, it can be used as both an observation light source and a photographing light source.

  The fundus oculi observation / imaging optical system 30 includes an objective lens 25, an imaging diaphragm 31 located near the aperture of the perforated mirror 22, a focusing lens 32 movable in the optical axis direction, an imaging lens 33, and a dichroic as a wavelength separation optical system. A mirror 34, a dichroic mirror 35, and three imaging elements 36a to 36c are provided. The photographing aperture 31 is disposed at a position substantially conjugate with the pupil of the eye E with respect to the objective lens 25. The focusing lens 32 is moved in the optical axis direction by a moving mechanism (not shown) including a motor.

  FIG. 3 is a diagram for explaining the characteristics of the wavelength components of light received by the three image pickup devices 36a to 36c by the wavelength separation optical system (dichroic mirrors 34 and 35). The dichroic mirror 34 has a characteristic of reflecting visible light having a peak of 450 nm in a wavelength range of 380 nm to 520 nm and transmitting light of other wavelength components. Therefore, light having a blue component as a peak is received by the image sensor 36 a disposed in the wavelength separation optical path on the reflection side of the dichroic mirror 34. The dichroic mirror 35 selectively transmits visible light having a peak of 570 nm in the wavelength region of 520 nm to 600 nm and infrared light having a peak of 850 nm in the wavelength region of 800 nm to 900 nm, and a wavelength of 560 nm to 750 nm. It has a characteristic of selectively reflecting visible light having a peak at 600 nm in the region. Therefore, light having a red component as a peak is received by the imaging device 36b disposed in the wavelength separation optical path on the reflection side of the dichroic mirror 35. Further, the image sensor 36c disposed in the wavelength separation optical path on the transmission side of the dichroic mirror 35 receives light having a green component at its peak and infrared light of ICG fluorescence. That is, the image sensor 36c is configured to receive the green component that is the fluorescence wavelength of fluorescein during FAG imaging, and to receive the infrared component that is the fluorescence wavelength of intocyanine green during ICG imaging. With such a configuration, visible fluorescence imaging and infrared fluorescence imaging can be performed by a single image sensor 36c, so that device control is facilitated. Note that the separation optical path of 800 nm to 900 nm for ICG fluorescence imaging may be one of the three imaging elements 36a to 36c.

  The luminous flux emitted from the fundus observation light source 11a of the color illumination optical system 10a illuminates the ring slit 17 through the condenser lens 12a, the imaging light source 13a, the condenser lens 15a, and the half mirror 16. The light transmitted through the ring slit 17 reaches the perforated mirror 22 through the relay lens 18, the mirror 19, the black spot plate 20, and the relay lens 21. The light reflected by the perforated mirror 22 is transmitted through the dichroic mirror 24, and once converged in the vicinity of the pupil of the eye E by the objective lens 25, then diffuses to illuminate the fundus of the eye to be examined. The light beam emitted from the light source 13a for fundus photographing illuminates the eye fundus to be examined through the condenser lens 15a and then through the same optical path as the observation illumination light beam by the light source 11a.

  The light beam emitted from the fundus observation light source 11b of the excitation illumination optical system 10b is selected by the exciter filter 15 through the condenser lens 12b and the imaging light source 13b, and then by the half mirror 16 through the condenser lens 14b. Reflected. After the half mirror reflection, the fundus of the eye to be examined is illuminated through the same optical path as the illumination light beam of the color illumination optical system 10a. Further, the light beam emitted from the light source 13b for fundus photographing illuminates the eye fundus to be examined through the condenser lens 15b and through the same optical path as the observation illumination light beam by the light source 11b.

  As described above, the reflected light from the fundus illuminated by the color illumination optical system 10a and the excitation illumination optical system 10b is the objective lens 25, the aperture of the perforated mirror 22, the photographing aperture 31, the focusing lens 32, and the imaging lens 33. Pass through. After passing through the imaging lens 33, the wavelength is selected by the dichroic mirrors 34 and 35 and reaches the image pickup devices 36a to 36c.

  Outputs of the image sensors 36 a to 36 c are connected to the image processing unit 80. The image processing unit 80 displays a color image on the monitor 8 on the basis of the imaging signals detected from the imaging elements 36a to 36c during color photographing / observation using the color illumination optical system 10a, and to the control unit 81. Imaging data detected from the imaging elements 36a to 36c is transmitted. In addition, the control unit 81 stores the image data of the image sensors 36 a to 36 c at the time of taking a still image in the memory 82. The moving image may be stored in the memory 82.

  Further, the image processing unit 80 displays a fluorescent image on the monitor 8 based on an imaging signal detected from the imaging device 36c at the time of fluorescence imaging / observation, and the imaging detected from the imaging device 36c to the control unit 81. Send data. At this time, the control unit 81 stores the image data detected from the image sensor 36c when the still image is captured in the memory 82.

  Further, a mode selection switch 83 is connected to the control unit 81, and the shooting mode can be switched between ICG shooting, FAG shooting, and color shooting. Further, a substantially simultaneous switch 84 is connected to the control unit, and when the mode selection switch 83 selects the ICG shooting or FAG shooting mode, if there is an input of the switch 84, color shooting and fluorescence shooting ( Switching to a continuous shooting mode (details will be described later) of ICG shooting or FAG shooting). Reference numeral 85 denotes a photographing start switch for generating a photographing start trigger signal. 86a is a switch for finely adjusting the light amount of the observation light source 11a, 86b is a switch for finely adjusting the light amount of the observation light source 11b, 87a is a switch for finely adjusting the light amount of the photographing light source 13a, and 87b is an observation. This is a switch for finely adjusting the light quantity of the light source 13b, and the illumination light quantity can be adjusted according to the individual difference of the eye to be examined.

The operation of the fundus camera having the above configuration will be described.
When the color photographing mode is selected by the mode selection switch 83, moving image observation is performed by the monitor 8 by light emission of the observation light source 11a of the color illumination optical system 10a, and the photographing light source 13a emits light by input of the photographing start switch 85. Color still image shooting is then performed. That is, at the time of color photographing, the control unit 81 emits the photographing light source 13 a by the trigger signal of the photographing start switch 85, and the color signal obtained by processing the image signals from the three imaging elements 36 a to 36 c by the image processing unit 80. The image is stored in the memory 82. When the ICG photographing mode or the FAG photographing mode is selected, moving image observation is performed by the monitor 8 by light emission of the observation light source 11b of the excitation illumination optical system 10b, and the photographing light source 13b emits light by input of the photographing start switch 85. Then, still image shooting is performed. That is, at the time of FAG, the control unit 81 emits the imaging light source 13b by the trigger signal of the imaging start switch 85, and the visible fluorescence image obtained by processing the image signal from the imaging device 36c by the image processing unit 80 is stored in the memory 82. To remember. Similarly, at the time of ICG imaging, the control unit 81 emits the imaging light source 13b by the trigger signal of the imaging start switch 85, and an infrared fluorescent image obtained by processing the image signal from the image sensor 36c by the image processing unit 80 is obtained. Store in the memory 82.

  As described above, according to the configuration of the present embodiment, it is possible to perform color photographing, FAG photographing, and ICG photographing with one apparatus without performing an insertion / removal operation of an exciter filter, a barrier filter, or the like. This eliminates the need for complicated filter insertion / removal operations.

  Further, with the configuration as in the present embodiment, there is no need for an operation for adjusting the light amounts of the photographing light source and the observation light source. That is, the conventional fundus camera has a configuration in which a fluorescent filter such as the exciter filter 15 is inserted and removed. Therefore, in order to prevent a decrease in the amount of illumination light due to the insertion of the fluorescent filter, it is necessary to greatly increase the light amount of the light source during fluorescent photographing. However, according to the configuration of this embodiment, it is not necessary to adjust the light amount when switching between color photographing and fluorescent photographing.

  Next, an operation when the substantially simultaneous continuous photographing mode of color and fluorescence is executed will be described. Color imaging and continuous imaging of FAG imaging when a subject is injected with a fluorescein fluorescent agent will be described. In this case, the FAG shooting mode is set by the mode selection switch 83, and the continuous shooting mode is selected by the input of the switch 84.

  First, moving image observation of the FAG fluorescence image is performed by the monitor 8 by light emission of the observation light source 11b. Thereby, the examiner can observe the FAG fluorescence image. Here, when there is an input from the imaging start switch 84, the control unit 81 causes the imaging light source 13b of the excitation illumination optical system 10b to emit light and causes the imaging device 36c to start a light receiving operation in synchronization with the light emission of the imaging light source 13a. . The image sensor 36c receives the fundus image excited in green by the light emission of the imaging light source 13a, and then outputs FAG fluorescence image data to the image processing unit 80. As a result, the still image of the FAG fluorescence image is stored in the memory 82. Note that the imaging devices 36a to 36c used in the present embodiment were those having 1/30 seconds from the start of the light receiving operation as described above to the end of output to the image processing unit 80.

  Subsequently, when the output of the image data to the image processing unit 80 by the image sensor 36c is completed (after 1/30 seconds from the start of the light receiving operation of the fluorescence image), the control unit 81 switches the photographing light source 13a of the color illumination optical system 10a. The image pickup devices 36a to 36c start a light receiving operation in synchronization with the light emission of the photographing light source 13a. The image sensors 36 a to 36 c receive color fundus images generated by light emission from the imaging light source 13 a and then output color image data to the image processing unit 80. As a result, a still image of a color image is stored in the memory 82.

  As described above, when the fundus color image and the FAG fluorescence image are taken, the difference in photographing time is a slight time difference of 1/30 seconds. That is, it is possible to shoot a color image and a FAG fluorescent image substantially simultaneously. Therefore, when comparing the two images, there is almost no shift in the photographing position between the color photographed image and the fluorescent image, so that it is difficult for the examiner to compare both images. Further, even when the analysis and diagnosis are performed by superimposing the two images after obtaining the color image and the fluorescence image, it is convenient because it is not necessary to correct the shift of the photographing position.

  When performing continuous shooting of ICG shooting, the mode selection switch 83 sets the ICG shooting mode, and the switch 84 selects the continuous shooting mode. Also in the continuous shooting of ICG shooting, the shooting operation is basically the same as that of continuous shooting of FAG shooting, and thus description thereof is omitted. Also in the ICG fluorescence image, the color image and the ICG fluorescence image can be captured almost simultaneously by the same method as described above. In other words, with the configuration as in the present embodiment, it is possible to shoot color images and FAG images at the same time, and color images and ICG images at the same time with a single device without inserting or removing the fluorescent filter. It is. Note that the difference between the photographing times of color photographing and fluorescent photographing is desirably as small as possible in consideration of the characteristics of the image pickup device, but if it is about 100 ms, the influence of fixation micromotion tends to be reduced. Think.

  In the above embodiment, since the exciter filter 25 is capable of visible fluorescence for FAG imaging and infrared fluorescence for ICG imaging, it is not necessary to perform the insertion / removal operation, but visible for FAG imaging. Even if the fluorescent filter and the infrared fluorescent filter for ICG photographing are switched by insertion / removal operation, it is feasible to perform continuous photographing of a color image and a fluorescent image at substantially the same time.

It is a block diagram of the optical system and control system of the fundus camera of the embodiment. It is a figure which shows the characteristic of the exciter filter provided in the excitation illumination optical system of this embodiment. It is a figure explaining the characteristic of the wavelength component of the light received by three image sensors by a wavelength separation optical system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10a Color illumination optical system 10b Excitation illumination optical system 13a Color illumination optical system imaging light source 13b Excitation illumination optical system imaging light source 15 Exciter filter 34, 35 Dichroic mirrors 36a to 36c as wavelength separation optical systems Image sensor 80 Image processing unit 81 Control unit 82 Memory 83 Mode selection switch 84 Almost simultaneous switch

Claims (4)

A color illumination optical system that has a first imaging light source and illuminates the fundus with white light, and a visible light that has a second imaging light source different from the first imaging light source and that illuminates the fundus with light having a wavelength for visible fluorescence excitation. A fluorescence excitation illumination optical system, an infrared fluorescence excitation illumination optical system having a third imaging light source different from the first imaging light source and illuminating the fundus with light having a wavelength for infrared fluorescence excitation, and reflection from the fundus The light is separated into three wavelengths of red component, green component, and blue component, and one of the separation optical paths is further separated by the wavelength separation optical system that separates the infrared fluorescence wavelength and the wavelength separation optical system. Three image sensors arranged in each optical path, a memory for storing an image captured by the image sensor, mode selection means for selecting a mode of color photographing / visible fluorescent photographing / infrared fluorescent photographing;
The first photographing light source is caused to emit light at the time of color photographing, and the image signals from the three image sensors are processed to store a color image in the memory. At the time of visible fluorescent photographing, the second photographing light source is caused to emit light and the green component is emitted. The image signal from the image sensor arranged in the separation optical path is processed and the visible fluorescence image is stored in the memory. In the infrared fluorescence photographing mode, the third photographing light source is emitted and disposed in the separation light path of the infrared fluorescence wavelength. A fundus camera comprising: control means for processing an image signal from the captured image sensor and storing an infrared fluorescent image in the memory. 2. The fundus camera according to claim 1, wherein the visible fluorescence excitation illumination optical system and the infrared fluorescence excitation illumination optical system share a second imaging light source and a third imaging light source, and are for visible fluorescence excitation and infrared fluorescence excitation. An eye fundus camera characterized in that an exciter filter that transmits only a specific wavelength is disposed in an illumination optical path. The fundus camera according to claim 1 further includes a continuous photographing mode in which visible fluorescent photographing and color photographing are continuously performed, and in the continuous photographing mode, the control means sets the first photographing light source and the second photographing light source within at least 100 ms. The fundus is characterized in that the light source is continuously switched and the image signal from each image sensor is processed in synchronization with the light emission timing of each photographing light source, and a visible fluorescent image and a color image are sequentially stored in the memory. camera. The fundus camera according to claim 1 further includes a continuous photographing mode in which infrared fluorescent photographing and color photographing are continuously performed, and in the continuous photographing mode, the control unit sets the first photographing light source and the third photographing light source to at least 100 ms. And switching light emission continuously, and processing the image signal from each image sensor in synchronization with the light emission timing of each photographing light source to sequentially store the infrared fluorescent image and the color image in the memory. Fundus camera.