JPH08173389A - Eyeground camera - Google Patents

Abstract

PURPOSE: To provide an eyeground camera capable of forming a high brightness fluorescent image regardless of individual diflerence or intravenous injection speeds, by receiving fluorescence from the eyeground of an eye to be tested at a light detection means, switching the illuminating light by a switching means based on the detection signal thereof, and switching a barrier filter inserted into the photographing light pass. CONSTITUTION: An illumination optical system is equipped on this eyeground camera by inserting either one specific wavelength range filter selected from a plurality of exciter filters 32 and 32' into an illuminating light pass to irradiate an eyeground EF by illuminating light of the specific wavelength. A photographing optical system for eyeground fluorescent photographing by inserting either one specific wavelength range filter selected from a plurality of barrier filters 41 and 41' is also equipped. In this case, the whole system is constituted so as to judge the changing time in absorbed wavelength of a fluorescent agent intravenously injected based on the light detection signal of a photographing element 49a to detect fluorescence, and when it is judged to be at a changing time, to switch the exciter filter 32 or 32' and the barrier filter 41 or 41' currently inserted respecitvely to the ather ones.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera capable of photographing fluorescence.

[0002]

2. Description of the Related Art Conventionally, as a fundus camera capable of photographing fluorescence, one disclosed in Japanese Patent Application Laid-Open No. 6-11409 is known.

Such a fundus camera includes an exciter filter F1 which transmits infrared light having a wavelength of 780 nm and an exciter filter F2 which transmits infrared light having a wavelength of 805 nm.
Barrier filter B1 that transmits infrared light with a wavelength of 20 nm
And a barrier filter B2 that transmits infrared light having a wavelength of 835 nm.

In fluorescence imaging, first, an exciter filter F1 and a barrier filter B1 are inserted in the illumination optical path and the imaging optical path to illuminate the fundus with infrared light having a wavelength of 780 nm, and to emit light of a wavelength of 820 nm emitted from the fundus. Photograph the fundus with infrared fluorescence. Then, after a lapse of a predetermined time, the exciter filter F2 and the barrier filter B2 are replaced and
The fundus is illuminated with infrared light having a wavelength of 5 nm, and the fundus is photographed by infrared fluorescence having a wavelength of 835 nm emitted from the fundus.

This is because when ICG (Indochia Green), which is a fluorescent agent, is intravenously injected into a subject, albumin in the blood and ICG are bound to each other after a predetermined period of time, and as a result, Absorption wavelength is 780nm to 805nm
The wavelength of infrared fluorescence emitted from the fundus changes to 8
This is because it changes from 20 nm to 835 nm.

[0006]

[Problems to be Solved by the Invention] However, ICG
The time it takes to bind to albumin in blood varies depending on the individual, and the time to bind to albumin in blood varies depending on the speed of intravenous injection. For this reason, even if the elapsed time after the intravenous injection is measured with a timer and the exciter filter F1 and the barrier filter B1 are exchanged and photographed based on the measured time of the timer, the time when the absorption wavelength of the fluorescent agent changes The replacement times of the filters F1 and B1 do not always match. Therefore, there is a problem in that a clear fluorescent image cannot be obtained before and after the time when the absorption wavelength of the fluorescent agent changes.

The present invention has been made in view of the above problems, and its object is always to obtain a clear fluorescent image with high brightness regardless of individual differences in the absorption wavelength of the fluorescent agent and the speed of intravenous injection. It is to provide a fundus camera that can obtain

[0008]

In order to achieve the above object, in the invention of claim 1, an illumination optical system for illuminating the fundus of the eye to be inspected with illumination light of a selected wavelength band among a plurality of illumination lights having different wavelength bands. In a fundus camera including a photographing optical system that inserts a barrier filter having a specific wavelength range selected from among a plurality of barrier filters each having a different specific wavelength range of transmitted light into a photographing optical path and fluorescence-photographs the fundus of the eye to be examined. A light receiving means for receiving fluorescence emitted from the fundus of the eye to be examined, and a switching means for switching the illumination light and switching a barrier filter inserted in the photographing optical path based on the light received by the light receiving means. Is characterized by.

According to the second aspect of the present invention, an exciter filter having a specific wavelength band selected from a plurality of exciter filters having different specific wavelength bands of transmitted light is inserted into the illumination optical path, and illumination light having the selected specific wavelength band is inserted. An illumination optical system that illuminates the fundus of the eye to be inspected, and a barrier filter having a specific wavelength range selected from among a plurality of barrier filters having different specific wavelength ranges of transmitted light are inserted into the imaging optical path to perform fluorescence imaging of the fundus of the eye to be inspected. In a fundus camera equipped with a photographing optical system,
It is characterized in that a light receiving means for receiving the fluorescence emitted from the fundus of the eye to be examined and a switching means for switching the exciter filter and the barrier filter inserted in the optical path based on the light received by the light receiving means are provided.

In the invention of claim 3, an illumination optical system for illuminating the fundus of the eye to be inspected with illumination light of a selected wavelength band among a plurality of illumination lights of different wavelength bands, and a plurality of different specific wavelength bands of the transmitted light. In a fundus camera equipped with a photographic optical system that inserts a barrier filter of a specific wavelength region selected from among the barrier filters of the above into the photographic optical path and performs fluorescence imaging of the fundus of the eye to be examined,
The light receiving means for receiving the fluorescence emitted from the fundus of the eye to be inspected, the judging means for judging the change time of the absorption wavelength of the fluorescent agent injected based on the light received by the light receiving means, and the judging means for the change time of the absorption wavelength. And a switching means for switching the illumination light and switching the barrier filter inserted in the photographing optical path.

According to the sixth aspect of the present invention, an exciter filter of a specific wavelength band selected from a plurality of exciter filters having different specific wavelength bands of light to be transmitted is inserted into the illumination optical path, and the exciter filter of the selected specific wavelength band is inserted. An illumination optical system that illuminates the fundus of the eye to be inspected with illumination light and a barrier filter with a specific wavelength range selected from among multiple barrier filters with different specific wavelength ranges of the transmitted light are inserted into the imaging optical path to fluoresce the fundus of the eye to be examined. In a fundus camera equipped with a photographing optical system for photographing, a light receiving means for receiving fluorescence emitted from the fundus of the eye to be examined, and the time of change of absorption wavelength of the fluorescent agent injected intravenously is judged based on the light received by the light receiving means. When the judgment means and this judgment means judge that it is time to change the absorption wavelength,
A switching means for switching between the exciter filter and the barrier filter inserted in the optical path is provided.

[0012]

According to the first aspect of the invention, the light receiving means receives the fluorescence emitted from the fundus of the eye to be inspected, and the switching means switches the illumination light based on the light received by the light receiving means, and the barrier is inserted into the photographing optical path. Switch the filter.

According to the invention of claim 2, the light receiving means receives the fluorescence emitted from the fundus of the eye to be examined, and the switching means switches the exciter filter and the barrier filter inserted in the optical path based on the light received by the light receiving means. .

According to the third aspect of the invention, the light receiving means receives the fluorescence emitted from the fundus of the eye to be examined, and the judging means judges the timing of change of the absorption wavelength of the fluorescent agent injected based on the light received by the light receiving means. When the determination means determines that it is time to change the absorption wavelength, the switching means switches the illumination light and the barrier filter inserted in the photographing optical path.

According to the invention of claim 6, the light receiving means receives the fluorescence emitted from the fundus of the eye to be examined, and the judging means judges the change timing of the absorption wavelength of the fluorescent agent injected intravenously based on the light received by the light receiving means. However, when the determination means determines that it is the time for the absorption wavelength to change, the switching means switches the exciter filter and the barrier filter inserted in the optical path.

[0016]

Embodiments of the fundus camera according to the present invention will be described below with reference to the drawings.

In FIG. 1, 10 is an illumination optical system of the fundus camera, and 40 is an observation / photographing optical system of the fundus camera.

[Illumination Optical System 10] The illumination optical system 10 includes an observation light source (for example, a halogen lamp) 11, a condenser lens 12, a photographing light source (for example, a xenon lamp) 31,
Exciter filters 32 and 32 'for fluorescence photography that can be inserted into and removed from the illumination optical path indicated by the optical axis O1, the condenser lens 13,
Small-diameter light-shielding plate 14, ring-shaped diaphragm 15, small-diameter light-shielding plate 16,
Relay lens 17, reflection mirror 18, relay lens 1
9, black dot plate 20, relay lens 21, perforated mirror 2
2. The objective lens 23.

The exciter filter 32 transmits infrared light having a wavelength near 780 nm, which is the peak wavelength absorbed by ICG, and cuts light having a longer wavelength than that. The exciter filter 32 'transmits infrared light having a wavelength near 805 nm and cuts light having a longer wavelength than that. The transmission characteristics of these exciter filters 32, 32 'are shown in FIG. A is a transmission curve of the exciter filter 32, and B is a transmission curve of the exciter filter 32 '.

The exciter filters 32, 32 'are inserted or replaced in the illumination optical path by a solenoid (not shown).

The illumination light for observation from the observation light source 11 is
It is projected onto the fundus EF through each optical component from the condenser lens 12 to the objective lens 23. Moreover, the illumination light for photography from the photography light source 31 is projected on the fundus EF through each optical component from the condenser lens 13 to the objective lens 23.

The small-diameter shading plate 14 is conjugated with the cornea EC,
The ring-shaped diaphragm 15 is conjugated with the pupil EP, and the small-diameter light-shielding plate 16 is conjugated with the rear surface of the lens EL. Also, the black dot plate 2
0 indicates that the light reflected on the surface of the objective lens 23 is a perforated mirror 2
This is to prevent the second hole 22a from passing through.

[Observation / Photographing Optical System 40] The observation / photographing optical system 40 includes an objective lens 23 facing the eye E to be inspected, a hole 22a of the perforated mirror 22, and an observation / photographing optical path shown by the optical axis O2 in FIG. It is composed of removable barrier filters 41, 41 ', focusing lens 42, imaging lens 43, reflection mirror 44, mask 45, field lens 46, reflection mirror 47, relay lens 48, and TV camera (video camera) 49. ing. On the extension of the optical axis 02 on the right side of the reflection mirror 44, an optical system for observing the naked eye, a 35 mm camera, etc. are usually arranged, but they are omitted for simplification of description. The reflecting mirror 44 is designed to jump up when observing with the naked eye or when photographing with a 35 mm camera.

The barrier filter 41 has an ICG of 780
It transmits light in the vicinity of 820 nm, which is the peak wavelength of infrared fluorescence emitted by absorbing infrared light having a wavelength of nm, and cuts light having a shorter wavelength than that. The barrier filter 41 'transmits light in the vicinity of 835 nm, which is the peak wavelength of infrared fluorescence emitted by ICG bound to albumin by absorbing infrared light having a wavelength of 805 nm, and cuts light having a shorter wavelength than that. . The transmission characteristics of these barrier filters 41, 41 'are shown in FIG. Note that C is the transmission curve of the barrier filter 41,
D is the transmission curve of the barrier filter 41 '.

A solenoid (not shown) is used to insert or replace the barrier filters 41 and 41 'into the photographing optical path.

The image formed by the reflected light from the fundus EF passes through the objective lens 23, the hole 22a of the perforated mirror 22, the focusing lens 42, and the imaging lens 43, and then the reflection mirror 44 and the mask 4.
An image is formed on a CCD 49a (light receiving means) which is an image pickup device of the television camera 49 through the field lens 46, the reflection lens 47, and the relay lens 48. CCD
The video signal of the image formed on 49a is input to the display means 61 such as a monitor via the control unit 60, and the display means 6 is displayed.
The fundus image F is displayed on the screen 1 in real time.

[Control Unit] As shown in FIG. 3, the control unit 60 includes an arithmetic control circuit 62, an exciter filter 32, and an exciter filter 32.
Solenoid drive circuit 65 for driving a solenoid (not shown) for inserting 32 ', and barrier filters 41, 41
A solenoid drive circuit 66 that drives a solenoid (not shown) that inserts the ‘′, a light emission circuit 67 that lights the observation light source 11, and a light emission circuit 68 that emits the photographing light source 31.
And a recording device 81 for recording the photographed fundus image and the like, a storage unit 80 for storing various data and the like.

The arithmetic control circuit 62 outputs a drive signal to the solenoid drive circuits 65 and 66 in accordance with various conditions (for example, focusing operation and photographing operation) by the operation of the operation unit 69,
A light emission signal is output to the light emitting circuits 67 and 68.

Further, in the fluorescence photographing mode, the arithmetic control circuit 62 obtains the average or the sum of the luminance values of the respective pixels of the fundus image from the video signal output from the CCD 49a, and changes the average luminance and the total luminance with time. Is stored in the storage unit 80, and a peak value is obtained from the temporal change of the stored average luminance or total luminance, and the peak value is compared with the current average luminance or total luminance to obtain a ratio to the peak value. When it is determined that this ratio has decreased to, for example, 50%, that is, when it is determined that the absorption wavelength of the fluorescent agent has changed, the solenoid drive circuits 65 and 66 are operated to operate the filter 32, which is inserted in the optical path. 41 is switched to the filters 32 ', 41'. Then, the arithmetic control circuit 6
2 and the solenoid drive circuits 65 and 66 function as switching means for switching filters.

The arithmetic control circuit 62 has a function as a judgment means for judging the change timing of the absorption wavelength of the fluorescent agent.

Further, the arithmetic control circuit 62 includes a CCD 49
Control is performed to record the fundus image captured in a on the recording device 81 and display the fundus image recorded on the recording device 81 on the display unit 61.

[Visible photography] When the power of the fundus camera body (both not shown) is turned on, first, the arithmetic control circuit 62 activates the light emitting circuit 67 to turn on the observation light source 11. From this state, focusing work including alignment with respect to the fundus EF is performed, and when this focusing work is completed, the illumination light from the observation light source 11 is projected onto the fundus EF via each optical component of the observation illumination optical system 10. Be reflected and reflected.

On the other hand, the reflected light from the fundus EF is composed of optical components from the objective lens 23 of the observing / photographing optical system 40 to the image forming lens 43, a reflecting mirror 44, a mask 45, a field lens 46, a reflecting mirror 47, and a relay lens. It is guided to the CCD 49a of the television camera 49 via 48 and the like, whereby the fundus image F is formed on the CCD 49a, and the fundus image F is formed.
Is displayed on the display means 61 and recorded on the recording device 81.

[Infrared Fluorescence Imaging] When performing infrared fluorescence imaging of the fundus EF, first, ICG (indocyanine green) is intravenously injected. On the other hand, the fluorescence photographing mode is set by operating the operation unit 69. With this setting, the arithmetic and control circuit 62 operates the solenoid drive circuits 65 and 66 to insert the exciter filter 32 and the barrier filter 41 into the illumination optical path and the photographing optical path.

By inserting the exciter filter 32, infrared light having a wavelength in the vicinity of 780 nm is projected on the fundus and the fundus EF is displayed.
When the fluorescent agent appears in the blood vessel, the infrared light is absorbed and infrared fluorescence having a wavelength near 820 nm is emitted from the fundus EF. This infrared fluorescence reaches the CCD 49a of the television camera 49 through the observation / photographing optical system 40, and a fluorescent image is formed on the CCD 49a. Then, the fluorescent image is displayed on the display means 61. The brightness of the fluorescent image changes according to the flow of the fluorescent agent that has entered the blood vessel.

On the other hand, the arithmetic control circuit 62 is composed of the CCD 49a.
The average brightness and the like of each pixel of the fluorescent image is obtained based on the video signal output from the storage unit 80, and the average brightness and the like are stored in the storage unit 80. Average brightness is calculated, for example, every 0.1 seconds,
This is sequentially stored in the storage unit 80. Then, the arithmetic control circuit 62 obtains the peak value of the average brightness from the temporal change of the average brightness stored in the storage unit 80, and compares this peak value with the current average brightness.

When a predetermined time has passed after the intravenous injection of ICG, albumin in the blood and ICG are bound, the absorption wavelength of the fluorescent agent changes from 780 nm to 805 nm, and the wavelength of infrared fluorescence emitted from the fundus EF changes from 820 nm. 835nm
, The brightness of the fluorescent image becomes low. Then, when the average brightness of the fluorescent image is reduced to 50% of the peak value, that is, when the absorption wavelength of the fluorescent agent changes, the arithmetic control circuit 62 operates the solenoid drive circuits 65 and 66 to set the illumination optical path and the imaging optical path. The exciter filter 32 and the barrier filter 41 which are inserted in the switch are switched to the exciter filter 32 'and the barrier filter 41'.

As a result, 83 emitted from the fundus EF.
Since the infrared fluorescence of 5 nm passes through the barrier filter 41 ', the brightness of the fluorescent image formed on the CCD 49a increases.

As a result, even if albumin in blood and ICG are bound, a clear fluorescent image with high brightness can be observed and photographed.

Moreover, when the average brightness of the fluorescent image by the infrared light of 820 nm drops to 50% of the peak value, the arithmetic control circuit 62 operates the solenoid drive circuits 65 and 66, so that the fluorescent agent is absorbed depending on the individual difference. Even if the wavelength changing time is different or the intravenous injection speed is different, the filter is switched to the exciter filter 32 'and the barrier filter 41 at the changing time of the absorption wavelength of the fluorescent agent.
′ Will be surely inserted into the optical path. As a result, it is possible to always obtain a clear fluorescent image with bright brightness even before and after the time when the absorption wavelength of the fluorescent agent changes.

FIG. 4 shows a second embodiment. In this embodiment, the exciter filter 32 'and the barrier filter 41' are switched based on the amount of light received by the light receiving element (light receiving means) 53. is there. Reference numeral 51 is a beam splitter, and 52 is a condenser lens.

FIG. 5 shows an exciter filter 32, 32 '.
Without using a laser light source 91, 92 which is a single wavelength light source
This is an example of using. Laser light source 91 is 7
The laser light source 92 emits infrared light of 80 nm, and the laser light source 92 emits infrared light of 805 nm. Reference numeral 93 is a dichroic mirror that reflects infrared light of 780 nm and transmits infrared light of 805 nm.

In this embodiment, the laser light source 91 is caused to emit light in the initial stage, and when the average luminance of the fluorescent image by infrared light of 820 nm drops to 50% of the peak value, the emission of the laser light source 91 is stopped and The laser light source 92 is caused to emit light. Switching between the laser light sources 91 and 92 is performed by an arithmetic control circuit (switching means) 62.

In all of the above examples, the fluorescent agent I
Injecting CG intravenously, the change in absorption wavelength is 780 nm (short wavelength side)
From 480 to 805 nm (long wavelength side) has been explained, but conversely, it is also possible to use another fluorescent agent to change the absorption wavelength from the long wavelength side to the short wavelength side. Of course.

[0045]

According to the present invention, even when the absorption wavelength of the fluorescent agent changes at different times due to individual differences, and even when the injection speed varies, the absorption wavelength of the fluorescent agent changes before and after the absorption wavelength. In, it is possible to always obtain a bright fluorescent image with bright brightness.

[Brief description of drawings]

FIG. 1 is an optical layout diagram showing an optical system of an embodiment of a fundus camera according to the present invention.

FIG. 2 is a graph showing the transmission characteristics of each filter.

FIG. 3 is a block diagram showing a configuration of a control system of the fundus camera.

FIG. 4 is an optical layout diagram showing a configuration of another embodiment.

FIG. 5 is an explanatory diagram showing an example in which two laser light sources are used.

[Explanation of Codes] 10 ... Illumination optical system 32 ... Exciter filter 32 '... Exciter filter 40 ... Photographing optical system 41 ... Barrier filter 41' ... Barrier filter 49 ... Video camera 49a ... Imaging element 62 ... Arithmetic control circuit 65 ... Solenoid drive Circuit 66 ... Solenoid drive circuit

Claims (8)

[Claims] 1. An illumination optical system for illuminating the fundus of an eye to be inspected with illumination light of a selected wavelength band among a plurality of illumination lights of different wavelength bands.
In a fundus camera equipped with a photographing optical system for inserting a barrier filter of a specific wavelength range selected from a plurality of barrier filters each having a different specific wavelength range of light to be transmitted into a photographing optical path, and a photographing optical system for performing fluorescence photographing of a fundus of a subject eye, A light receiving means for receiving fluorescence emitted from the fundus of the eye to be inspected, and a switching means for switching the illumination light and switching a barrier filter inserted in the photographing optical path based on the light received by the light receiving means. Fundus camera. 2. An exciter filter having a specific wavelength range selected from a plurality of exciter filters each having a different specific wavelength range of transmitted light is inserted into an illumination optical path, and the fundus of the eye to be examined is illuminated with the illumination light having the selected specific wavelength range. An illumination optical system for illuminating,
In a fundus camera equipped with a photographing optical system for inserting a barrier filter of a specific wavelength range selected from a plurality of barrier filters each having a different specific wavelength range of light to be transmitted into a photographing optical path, and a photographing optical system for performing fluorescence photographing of a fundus of a subject eye, A fundus camera provided with light receiving means for receiving fluorescence emitted from the fundus of the eye to be examined, and switching means for switching between an exciter filter and a barrier filter inserted in the optical path based on the light received by the light receiving means. 3. An illumination optical system for illuminating the fundus of the eye to be inspected with illumination light of a selected wavelength band among a plurality of illumination lights of different wavelength bands.
In a fundus camera equipped with a photographing optical system for inserting a barrier filter of a specific wavelength range selected from a plurality of barrier filters each having a different specific wavelength range of light to be transmitted into a photographing optical path, and a photographing optical system for performing fluorescence photographing of a fundus of a subject eye, The light receiving means for receiving the fluorescence emitted from the fundus of the eye to be inspected, the judging means for judging the change timing of the absorption wavelength of the fluorescent agent injected intravenously based on the light received by the light receiving means, and the judging means for the change timing of the absorption wavelength. A fundus camera provided with switching means for switching the illumination light and switching a barrier filter inserted in the photographing optical path when it is determined that there is one. 4. An illumination light in a wavelength range on the short wavelength side and a barrier filter in a specific wavelength range on the short wavelength side are selected in an initial stage of photographing, and the switching means is an illumination light in the wavelength range on the short wavelength side. To the illumination light in the wavelength range on the long wavelength side, and at the same time, the barrier filter in the specific wavelength range on the short wavelength side is switched to the barrier filter in the specific wavelength range on the long wavelength side. . 5. The fundus camera according to claim 1, wherein the light receiving means is an image pickup device of a video camera for picking up an image of the fundus. 6. An exciter filter having a specific wavelength range selected from a plurality of exciter filters each having a different specific wavelength range of transmitted light is inserted into an illumination optical path, and the fundus of the eye to be examined is illuminated with the illumination light having the selected specific wavelength range. An illumination optical system for illuminating,
In a fundus camera equipped with a photographing optical system for inserting a barrier filter of a specific wavelength range selected from a plurality of barrier filters each having a different specific wavelength range of light to be transmitted into a photographing optical path, and a photographing optical system for performing fluorescence photographing of a fundus of a subject eye, The light receiving means for receiving the fluorescence emitted from the fundus of the eye to be inspected, the judging means for judging the change timing of the absorption wavelength of the fluorescent agent injected intravenously based on the light received by the light receiving means, and the judging means for the change timing of the absorption wavelength. A fundus camera, which is provided with a switching means for switching the exciter filter and the barrier filter inserted in the optical path when it is determined that there is one. 7. An exciter filter and a barrier filter of a specific wavelength range on the short wavelength side are selected in an initial stage of photographing, and the switching means switches from the exciter filter and the barrier filter of the specific wavelength range on the short wavelength side to the long wavelength side. 7. The fundus camera according to claim 6, wherein the exciter filter and the barrier filter in a specific wavelength range are switched. 8. The fundus camera according to claim 6, wherein the light receiving means is an image pickup device of a video camera for picking up an image of the fundus.