JP2004081255A - Fundus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent pains from being applied to a subject at the time of a fundus observation which is a previous stage of a fluorescent imaging, and at the same time, to make it possible to pick up a favorable visible fluorescent image. <P>SOLUTION: Until a first period of time has passed since the start of a timer (a step S7), the observation of a fundus image by an infrared ray is selected, and the fundus observation can be performed without applying pains to the subject. When a second period of time passes after the first period of time has passed (a step S9), a fluorescent image appears, and a simultaneous observation of the fundus image by the infrared ray and the fluorescent image by a visible light is selected. Thus, the imaging of a favorable fluorescent image becomes possible, and also, when the fluorescent image appears on the overall fundus after the second period of time has passed, the observation of the fluorescent image by the visible light (stimulating light) can be selected, and an examiner can easily confirm an area required for the imaging, and the sure imaging of the fluorescent image can be performed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fundus camera, more specifically, to simultaneously or selectively irradiate a fundus with visible light including infrared light and excitation light, and to reflect reflected light from the fundus with infrared light and visible light (fluorescent image). The present invention relates to a fundus camera capable of observing a fundus by receiving a light with a CCD camera having sensitivity to light.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a fundus camera capable of photographing visible fluorescence in addition to normal color photographing has been known. In such a fundus camera, in a fundus photographing state before performing a visible fluorescence photographing, a fundus observation is performed with visible light. However, since observation of the fundus with visible light gives the subject the pain of dazzling, an infrared transmission region is provided in an exciter filter used for visible fluorescence, and observation before fluorescence imaging is performed through the exciter filter. It has been proposed to use infrared light (for example, Japanese Patent Application Laid-Open No. 9-1222078).
[0003]
[Problems to be solved by the invention]
However, in a conventional fundus camera capable of performing visible fluorescent imaging, when observing with infrared light, since a fluorescent image with visible light is not observed, although a good fluorescent image is not obtained, However, there has been a problem that fluorescence photography is performed, and it is necessary to perform photography again.
[0004]
An object of the present invention is to solve such a problem, and it is possible to eliminate a pain on a subject at the time of observation of a fundus before the fluorescence imaging, and to capture a good visible fluorescence image. It is to provide a simple fundus camera.
[0005]
[Means for Solving the Problems]
To solve the above problems, according to the present invention,
A fundus camera capable of simultaneously or selectively irradiating the fundus with infrared light and visible light, receiving reflected light from the fundus with a CCD camera having sensitivity to infrared light and visible light, and observing the fundus. ,
An illumination optical system having an exciter filter for visible fluorescence having transmission characteristics at least for excitation light and having transmission characteristics for infrared light,
Having an imaging optical system with a barrier filter for visible fluorescence having a transmission characteristic with respect to fluorescence and infrared light generated by irradiation of the fundus with visible light,
By irradiating the fundus with infrared light or infrared light and visible light simultaneously, it is possible to selectively observe the fundus image with infrared light and simultaneously observe the fundus image with infrared light and the fluorescent image with visible light. The configuration that can be used is adopted.
[0006]
Further, in the present invention, the fundus is irradiated with visible light so that observation of a fluorescent image by visible light can be selected. In this case, the irradiation of the fundus with infrared light is performed by inserting a first filter that transmits infrared light and cuts visible light into the optical path, and the irradiation of the fundus with visible light uses excitation light. This is performed by inserting a second filter that transmits visible light and cuts infrared light into the optical path, and simultaneously irradiates the fundus with infrared light and visible light by using the first and second filters. Both are separated from the optical path, and the excitation light and the infrared light are simultaneously irradiated through an exciter filter.
[0007]
Selection of each observation described above is automatically performed as time elapses by providing a time measuring means (timer). That is, until the first time elapses, the observation of the fundus image by the infrared light becomes possible, and until the second time elapses after the first time, the fundus image by the infrared light is observed. Simultaneous observation of a fluorescent image with visible light is possible, and observation of a fluorescent image with visible light is possible after the second time has elapsed.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail according to embodiments shown in the drawings.
[0009]
FIG. 1 shows the configuration of a fundus camera according to the present invention. In FIG. 1, an observation lamp LA (such as a halogen lamp) is arranged at the center of curvature of a spherical mirror M1 as a light source that generates visible light including infrared light and excitation light. The light from the observation lamp LA and the spherical mirror M1 passes through the condenser lens L1, the filter F1, and the condenser lens L2, is reflected by the total reflection mirror M2, passes through the relay lenses L3 and L4, and is perforated with a hole at the center. After being reflected by the total reflection mirror M3, the light is incident on the fundus Er from the pupil Ep of the eye E through the objective lens L5.
[0010]
In addition, a strobe SR, which is a light source for photographing, is disposed between the filter F1 and the lens L2 for photographing a fundus image on a film F or a CCD1 or CCD2 camera described later. The strobe SR has a light emission characteristic centered on a visible region including excitation light.
[0011]
As shown in FIG. 2A, the filter F1 transmits only illumination light of infrared light in the direction of the subject's eye, and transmits an infrared light region of approximately 800 nm or more. Cut the following visible area. When cutting the infrared light and irradiating the fundus with visible light, a filter F1 'is inserted into the illumination light path instead of the filter F1. As shown in FIG. 2B, the characteristic of the filter F1 ′ transmits a visible light region including excitation light having a wavelength of approximately 800 nm or less and cuts an infrared region beyond the filter region, contrary to the filter F1.
[0012]
In the fluorescent mode, an exciter filter EF is inserted into the illumination optical system between the lens L2 and the total reflection mirror M2 for fluorescent imaging. As shown in FIG. 3A, the exciter filter EF has a transmission characteristic in the vicinity of 450 to 520 nm serving as excitation light, and also has a transmission characteristic in an infrared light region of approximately 800 nm or more similarly to the filter F1. Have. In the fluorescence mode, a barrier filter BF is inserted into the imaging optical system between the mirror M9 and the lens L6. As shown in FIG. 3B, the barrier filter BF has a filter characteristic of transmitting visible fluorescence of 500 to 600 nm generated by irradiating the fundus with excitation light and transmitting infrared light. .
[0013]
The relay lenses L3 and L4 are for the non-mydriatic mode, and are switched to the relay lenses L3 'and L4' in the mydriatic mode and the fluorescent mode. In addition, near the relay lenses L3 and L4, a black spot plate or the like for removing harmful light due to reflection at the boundary surface of the objective lens L5 is disposed as necessary (not shown).
[0014]
The switching operation means 21 includes a switch and necessary driving circuits, and switches between a non-mydriatic illumination system (L3, L4) and a mydriatic illumination system (L3 ', L4'). Is controlled by the switching unit 22 for selecting the output. The switching operation means 21 performs switching (insertion / removal) of the filters F1 / F1 'of the illumination system, insertion / removal of the exciter filter EF and the barrier filter BF necessary for the fluorescence mode, and switching of the return mirrors M4, M5, M6. Also, it controls the turning on and off of the observation light source LA. In addition, a timer (time measuring means) 30 is connected to the switching operation means 21, and when the timer 30 is started, the filters F1 and F1 'are switched according to the time counting of the timer as described later.
[0015]
The reflected light from the fundus Er is received again from the pupil Ep through the objective lens L5, passes through the focusing lens L6 and the imaging lens L7 through the hole of the perforated total reflection mirror M3, and enters the mirror M4. The light reflected by the mirror M4 is reflected by the mirror M5 and is observed by the examiner S through the eyepiece L8.
[0016]
A film F is disposed behind the mirror M4. When photographing a fundus image on the film F, the mirror M4 is removed from the optical path, and the fundus image is guided onto the film F.
[0017]
The mirror M5 is configured to be able to be removed from the optical path. When the mirror M5 is removed from the optical path, the light flux reflected by the mirror M4 is reflected by the mirror M6 and then passed through the lens L9 to the fundus of infrared light. An image is formed on the CCD 2 for observing the image.
[0018]
The mirror M6 is of a flip-up type (or a half mirror is also possible), and an image of the eye to be inspected can be formed on the CCD 1 for capturing a visible light image via a lens L9 '.
[0019]
The CCD 2 is used for infrared light observation (or photographing), simultaneous observation (or photographing) of infrared light and visible light, or observation (or photographing) of a fluorescent image, and is shown in FIG. On the other hand, the CCD 1 is used for visible light observation (or photographing), and is a CCD for color photographing (single plate type or three plate type is possible). ), The specific sensitivities are provided for the wavelengths of the three primary colors R, G, and B. Either of the outputs of the CCD 1 or 2 is selected by a switch 22 controlled by the above-mentioned switching operation means 21 and supplied to a subsequent circuit.
[0020]
An image filing system and a display can be connected to the subsequent stage of the switch 22. In the example of FIG. 1, the display unit 23 and the recording device 24 are connected to the switch 22. The display unit 23 can be constituted by a CRT display or an LCD display, and can display a photographed image of the eye to be inspected by the CCD 1 or the CCD 2 or various related data. The recording device 24 can be composed of an arbitrary external storage device such as a hard disk drive, a CDR, a DVD-RAM, and an MO, and stores a photographed image of the eye to be examined or various related data. FIG. 1 shows a PC (personal computer) 26 as a means for controlling data filing of the recording device 24, but the recording device 24 may be configured as an external storage device built in the PC 26. Data stored in the recording device 24 can be shared (transmitted / received) with another inspection device or PC via the LAN 25.
[0021]
An LED 6 is provided as a light source for a focus dot (FD), and the light of the LED 6 is incident on a mirror M9 disposed between the perforated total reflection mirror M3 and the imaging lens L6 via the lens L10, the mirror M8, and the lens L11. Then, a spot image for focusing is formed on the fundus through the aperture of the perforated total reflection mirror M3 and the objective lens L5. The LED 6 is a light-emitting diode that emits near-infrared light centered around approximately 660 nm.
[0022]
Further, in the fundus camera of the present embodiment, the working dot light source 17 is provided to project a target for alignment between the eye E and the fundus camera. In the present embodiment, the end face of the optical fiber OF whose one end is arranged on the perforated total reflection mirror M3 generates an optical image of a working dot (WD). The working dot light source 17 includes a lens L20 and an LED5. The optical image of the working dot (WD) on the end face of the optical fiber OF is projected onto the cornea of the eye E through the objective lens L5. The end face of the optical fiber OF is arranged at a position where the subject is in focus when the working distance (working distance) between the subject and the fundus camera becomes an appropriate distance. Like the LED 6, the LED 5 is a light-emitting diode that emits near-infrared light centered around approximately 660 nm.
[0023]
In such a configuration, when fundus observation is performed with the eyepiece L8, the filter F1 ′ is inserted into the optical path, F1 is separated from the optical path, the lamp LA is turned on, and the fundus is irradiated with visible light, and the examiner The fundus image is observed through the eyepiece L8. Here, in the fluorescence mode, one of the exciter filter EF or the barrier filter BF is inserted by the user, and in the TV (television) observation mode in which observation is performed through the CCD camera in this state, the filter is not inserted. The existing filter is automatically inserted. This state is shown by steps S1 and S2 in FIG.
[0024]
At this time, since the mode is the TV observation mode (YES in step S3), the return mirror M5 is switched and separated from the optical path (step S4), and the filter F1 is inserted into the optical path instead of the filter F1 '(step S5). Thereby, the infrared light from the observation lamp LA passes through the filter F1 and the exciter filter EF, and the fundus is irradiated with the infrared light. The examiner performs alignment by receiving the fundus image by the infrared light, the working dot and the focus dot by the LEDs 5 and 6 by the CCD 2 via the barrier filter BF, and observing the image on the display unit 23.
[0025]
In the process up to this point, the filter F1 is first inserted in the TV observation mode by infrared light, the fundus image by infrared light and the working dots and focus dots by the LEDs 5 and 6 are received by the CCD 2 and the alignment is almost completed. At this time, the fluorescence mode may be set while the TV observation mode is maintained, and both the exciter filter EF and the barrier filter BF may be inserted to perform the mode.
[0026]
When the fundus is photographed after the alignment is completed in this way, the fluorescent agent is injected intravenously, and the timer 30 is started almost simultaneously with the intravenous injection. At this time, since the determination in step S6 is affirmative, the process proceeds to step S7.
[0027]
The fluorescence appears on the fundus due to the intravenous injection of the fluorescent agent for about 8 to 10 seconds. Therefore, the observation of the fundus image using infrared light is selected until about 7 seconds have elapsed since the timer was started. I have. On the other hand, when it is determined that about seven seconds have elapsed (step S7), the filter F1 is automatically separated from the optical path (step S8). When the filter F1 is detached, the filter F1 'is also detached from the optical path, so that the visible light and the infrared light from the observation lamp LA enter the exciter filter EF, and the exciter filter EF outputs the excitation light and the infrared light. And the fundus is simultaneously irradiated with visible light (excitation light) and infrared light. Fluorescence is generated by the visible light, and a fluorescence image by the visible light (excitation light) and a fundus image by the infrared light pass through the barrier filter BF, are received by the CCD 2, and are simultaneously observed on the display unit 23.
[0028]
As described above, when the fluorescent image is confirmed, the shutter button (not shown) is pressed, the strobe SR emits light, the CCD 2 starts image storage, and captures the fluorescent image. When capturing the fluorescent image, if the observation lamp LA is turned on, good imaging cannot be performed, so that the visible light emitted during observation is blocked. This is performed by turning off the observation lamp LA. Therefore, the examiner performs the alignment using only the working dots and the focus dots.
[0029]
Until about 30 seconds from the start of the timer, continuous photographing for photographing at the beginning of the fluorescence is performed. In this case, by holding down the shutter button, the flash SR is continuously emitted at one-second intervals by a single shutter operation, and a still image of a fluorescent image is taken. Note that the observation lamp LA is turned off even during the continuous photographing, so that the examiner checks whether alignment or focusing is good or not using only dots.
[0030]
After 40 seconds from the start of the timer (YES in step S9), the fluorescent image appears over the entire fundus, so that the filter F1 'is automatically inserted into the irradiation optical path to improve the image contrast (step S10). ). As a result, the fundus image due to infrared light disappears, and a fluorescent image due to visible light (excitation light) is received by the CCD 2 and displayed on the display 23. Therefore, the examiner can observe the fluorescent image by the visible light, and photographs a necessary part while watching the fluorescent image.
[0031]
In addition, in the above-described process, after the timer is started, or when it is desired to observe the fluorescent image with the naked eye (eyepiece) during photographing (interval), the TV observation mode is canceled (steps S11, S12, and S13). YES), the observation lamp LA is turned on, the return mirror M5 is inserted into the optical path (step S14), and observation is enabled by the eyepiece L8, so that the examiner can observe the fluorescent image with the naked eye. When the filter button is pressed in this state, either the exciter filter or the barrier filter is removed according to the user setting, and the fundus observation can be performed.
[0032]
When the fluorescence imaging is completed (YES in step S15), the fluorescence button is pressed to release the fluorescence mode, and both the exciter filter EF and the barrier filter BF are out of the optical path (step S16), and the observation lamp LA is turned on. The color TV observation mode is set.
[0033]
In the above-described embodiment, the observation of the fundus image using infrared light, the simultaneous observation of the fundus image using infrared light and the fluorescence image using visible light (excitation light), Observation of a fluorescent image by light is selected in this order, but the examiner may also select filters F1 and F1 'as appropriate and insert them into the optical path, or remove both from the optical path and select each observation. it can.
[0034]
【The invention's effect】
As is clear from the above description, according to the present invention, at the time of fluorescence imaging, at the time of fundus observation as a preceding stage, observation of the fundus image with infrared light can be selected, without causing pain to the subject From the stage where the fundus observation is possible and the fluorescence image appears, simultaneous observation of the fundus image with infrared light and the fluorescence image with visible light (excitation light) can be selected, so that a good fluorescence image can be taken. . In addition, at the stage where the fluorescent image appears on the entire fundus, observation of the fluorescent image using visible light (excitation light) can be selected, so that the examiner can easily confirm the parts required for imaging, and secure imaging of the fluorescent image is possible. I can do it.
[0035]
When the selection of each of the above observations is performed automatically with the lapse of time, the observation of the fundus image by infrared light becomes possible until the first time elapses, and the first time elapses. Until the second time elapses, simultaneous observation of the fundus image by infrared light and the fluorescent image by visible light (excitation light) is performed, and after the second time elapses, visible light (excitation light) Since the observation of the fluorescent images can be performed, the work of switching the examiner can be omitted, and the efficient fluorescent imaging can be performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an optical configuration of a fundus camera of the present invention.
2A is a diagram illustrating characteristics of a filter F1, and FIG. 2B is a diagram illustrating characteristics of a filter F1 ′.
FIG. 3A is a diagram illustrating characteristics of an exciter filter, and FIG. 3B is a diagram illustrating characteristics of a barrier filter.
FIG. 4A is a diagram showing the relative sensitivity of CCD1, and FIG. 4B is a diagram showing the relative sensitivity of CCD2.
FIG. 5 is a flowchart illustrating a flow of fluorescence imaging.
[Explanation of symbols]
1, 2 CCD
5, 6 LED
21 Switching operation means BF Barrier filter E Eye to be examined EF Exciter filter Ep Pupil Er Fundus F Film F1, F1 'Filter L5 Objective lens L6 Focusing lens L7 Imaging lens LA Observation lamp M3 Perforated total reflection mirror M4, M5, M6 Return mirror

Claims (9)

A fundus camera capable of simultaneously or selectively irradiating the fundus with infrared light and visible light, receiving reflected light from the fundus with a CCD camera having sensitivity to infrared light and visible light, and observing the fundus. ,
An illumination optical system having an exciter filter for visible fluorescence having transmission characteristics at least for excitation light and having transmission characteristics for infrared light,
Having an imaging optical system with a barrier filter for visible fluorescence having a transmission characteristic with respect to fluorescence and infrared light generated by irradiation of the fundus with visible light,
By irradiating the fundus with infrared light or infrared light and visible light simultaneously, it is possible to selectively observe the fundus image with infrared light and simultaneously observe the fundus image with infrared light and the fluorescent image with visible light. A fundus camera characterized by being able to. The fundus camera according to claim 1, further comprising irradiating the fundus with visible light, and selecting observation of a fluorescent image using the visible light. Irradiation of the fundus with infrared light is performed by inserting a first filter that transmits infrared light and cuts visible light into an optical path, and irradiation of the fundus with visible light includes visible light including excitation light. This is performed by inserting a second filter, which transmits infrared light and cuts infrared light, into the optical path. Simultaneously irradiating the fundus with the infrared light and the visible light simultaneously passes the first and second filters through the optical path. The retinal camera according to claim 2, wherein the retinal camera is detached from the camera. A time measuring means is provided, and observation of a fundus image by infrared light is selected until the first time elapses, and the observation by the infrared light is performed until the second time elapses after the first time elapses. 4. The fundus camera according to claim 1, wherein simultaneous observation of a fundus image and a fluorescent image with visible light is selected. 5. The fundus camera according to claim 4, wherein after the second time has elapsed, observation of a fluorescent image by visible light is selected. The fundus camera according to claim 5, wherein the first and second times are configurable. 2. A fundus observation by the CCD camera, and observation through an eyepiece is possible, and when observation through the eyepiece is selected, visible light is applied to the fundus. The fundus camera according to any one of items 1 to 6. The fundus camera according to any one of claims 1 to 7, wherein during fundus photographing, visible light emitted during observation is shut off or a light source that generates visible light is turned off. A continuous photographing mechanism that can continuously photograph a plurality of images at a predetermined time interval with a single shutter operation is provided, and when performing continuous photographing, the visible light irradiated during observation is blocked or visible light is generated. The fundus camera according to any one of claims 1 to 8, wherein the light source is turned off.

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