JPH11113849A - Fundoscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically optimize the light receiving states of light detecting elements. SOLUTION: Information of output voltage of a one-dimensional CCD 42 and photomultipliers 46a, 46b is sent to a light receiving state control part 50 so that the light receiving state control part 50 calculates the appropriate light receiving sensitivities of respective light detecting elements and adjusts the light receiving sensitivities of the respective light detecting elements independently via a CCD light receiving sensitivity control circuit 51 and a photomultiplier light receiving sensitivity control circuit 52. The light receiving state control part 50 calculates the appropriate light quantities of a laser diode 36 and a tracking light source 38 so as to control the light quantities of the laser diode 36 and the tracking light source 38 independently via the laser diode drive circuit 53 and the tracking light source drive circuit 54.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus examination apparatus used particularly for examining the fundus in the field of ophthalmology.

[0002]

2. Description of the Related Art Conventionally, the same part of a blood vessel is irradiated with light of different wavelengths, and the shape of the blood vessel on the fundus is measured by using a light-receiving element that separately receives the reflected light. Japanese Patent Application Laid-Open No. 63-28813 discloses a fundus blood flow meter for measuring the blood flow velocity in a blood vessel by utilizing such methods.
No. 3 publication.

[0003]

However, in the above-mentioned conventional example, the parameters necessary for determining the blood flow can be measured at the same time, but when the eye to be examined is actually measured, the eye to be examined is Due to the large individual differences, the conditions under which the measurements are made have to be changed. In particular, when the retinal reflectance or the transparency of the eye to be examined is different, the light receiving state of the light receiving element changes, which greatly affects the measured value. For this reason, if the light receiving state of the light receiving element is not proper, the measurement of the shape of the blood vessel and the like becomes inaccurate by the obtained signal,
The S / N deteriorates, the Doppler signal becomes unclear, and the value of the blood flow velocity becomes unstable.

Therefore, in order to always obtain proper information,
It is necessary to optimize the light receiving state of each light receiving element, and it is important to adjust the sensitivity of the plurality of light receiving elements and the amount of irradiation light again for each eye to be examined and each measurement site. However, since these adjustments are complicated and time-consuming operations, there is a problem that the amount of light applied to the eye to be examined increases, and at the same time, measurement values become unstable.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a fundus examination apparatus in which a light receiving state of a light receiving element is automatically optimized and a burden on a subject and a burden on a technical person for improving a technical level are reduced.

[0006]

To achieve the above object, a fundus examination apparatus according to the present invention comprises two or more light sources for generating light of different wavelengths, and receives light of each wavelength generated from the light source. An irradiation optical system that irradiates the same target site on the fundus of the optometry, and a light receiving optical system that receives reflected light from the target site,
A fundus examination device having measurement means for measuring predetermined information from the target site based on an output from the light receiving optical system, wherein the light receiving optical system splits reflected light from the target site into light of each wavelength. Spectral means, at least two light receiving means for independently receiving reflected light of each wavelength separated by the spectral means, and light receiving means for independently and automatically adjusting light receiving conditions based on the light receiving state of the light receiving means A condition automatic adjusting means.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 shows a configuration diagram of a fundus blood flow meter according to an embodiment. A condenser lens is provided on an illumination optical path from an observation light source 1 such as a tungsten lamp that emits white light to an objective lens 2 facing the eye E. 3. For example, a field lens 4 with a band-pass filter that transmits only light in the yellow range, a ring slit 5 provided at a position almost conjugate with the pupil Ep of the eye E, and a position almost conjugate with the crystalline lens of the eye E A light-shielding member 6 provided, a relay lens 7, a transmissive liquid crystal plate 8, which is a fixation target display element movable along an optical path, a relay lens 9, and a light-shielding member provided conjugate with the vicinity of the cornea of the eye E to be examined. 10, a perforated mirror 11, and a band-pass mirror 12 that transmits light in the yellow range and almost reflects other light beams are sequentially arranged.

A fundus observation optical system is provided behind the perforated mirror 11, and includes a focus lens 13, a relay lens 14, a scale plate 15, and an optical path switching mirror that can be inserted into and removed from the optical path. 16, eyepiece 17
Are sequentially arranged to reach the examiner's eye e. When the optical path switching mirror 16 is inserted in the optical path, a television relay lens 18 and a CCD camera 19
The output of the CCD camera 19 is connected to a liquid crystal monitor 20.

On the optical path in the reflection direction of the band-pass mirror 12, an image rotator 21, which has a partially cut-out shape polished on both sides and having a rotation axis perpendicular to the plane of the paper, has an eye E to be examined.
Galvanometric mirror 2 conjugated with pupil Ep
2 and a second focus lens 23 in the reflection direction of the lower reflection surface 22a of the galvanometric mirror 22.
Are disposed in the direction of reflection of the upper reflection surface 22b.
4. A focus unit 25 movable along the optical path is provided. The front focal plane of the lens 24 is located on the galvanometric mirror 22.

Above the galvanometric mirror 22, an optical path length compensating meniscus 26, a black spot plate 27 having a light-shielding portion in the optical path, and a concave mirror 28 are arranged concentrically on the optical path and cooperate to form a galvanometric mirror. The upper reflection surface 22b and the lower reflection surface 22a of the mirror 22 are imaged at -1 times,
The light flux passing through the lower reflection surface 22a of the galvanometric mirror 22 without being reflected is
A relay optical system leading to the second upper reflection surface 22b is configured. The optical path length compensating meniscus 26 is used to correct the position of the upper reflecting surface 22b and the lower reflecting surface 22a of the galvanometric mirror 22 in the vertical direction of the drawing caused by the mirror thickness. It works only in the optical path toward the rotator 21.

In the focus unit 25, a dichroic mirror 29 and a condenser lens 30 are sequentially arranged on the same optical path as the lens 24, and a mask 31 and a mirror 32 are arranged on the optical path in the direction of incidence on the dichroic mirror 29.
Are arranged, and the focus unit 25 can be integrally moved in a direction indicated by an arrow.

On the optical path in the incident direction of the condenser lens 30,
Fixed mirror 33, optical path switching mirror 3 retractable from optical path
4 are arranged in parallel, and a collimator lens 35 and a measuring laser diode 36 that emits coherent, for example, red light are arranged on the optical path in the incident direction of the optical path switching mirror 34. Further, on the optical path in the incident direction of the mirror 32, a beam expander 37 composed of a cylindrical lens or the like and a tracking light source 38 that emits, for example, green light different from other high-luminance light sources are arranged.

A focusing lens 23 movable along the optical path and a dichroic mirror 3 are disposed on the optical path in the direction of reflection of the lower reflecting surface 22a of the galvanometric mirror 22.
9, a field lens 40, a magnifying lens 41, and a one-dimensional CCD 42 with an image intensifier are sequentially arranged to form a blood vessel detection system. The imaging lens 4 is provided on the optical path in the reflection direction of the dichroic mirror 39.
3. A pair of mirrors 45a, 45b provided substantially conjugate with the confocal stop 44 and the pupil Ep of the eye E to be examined are arranged, and photomultipliers 46a, 46b are arranged in the reflection directions of the mirror pairs 45a, 45b, respectively. And a light receiving optical system for measurement. For convenience of illustration, all the optical paths are shown on the same plane, but the reflected optical paths of the mirror pairs 45a and 45b, the measuring optical path in the emission direction of the tracking light source 38, and the optical paths from the laser diode 36 to the mask 31 are respectively shown. It is perpendicular to the paper.

Further, a system control unit 47 for controlling the system of the apparatus is provided. The system control unit 47 has input means 48 operated by the examiner, a photomultiplier 46a,
The output of the system controller 47 is connected to a galvanometric mirror control circuit 49 for controlling the galvanometric mirror 22 and the optical path switching mirror 34,
The output of the control circuit 49 is connected to the galvanometric mirror 22.

A light receiving state control unit 50 for controlling the state of the laser beam is provided. The output of the light receiving state control unit 50 is output to a one-dimensional CCD 42 via a CCD sensitivity adjusting circuit 51 for adjusting the light receiving sensitivity of the one-dimensional CCD 42. Are connected to the photomultipliers 46a and 46b via a photomultiplier sensitivity adjustment circuit 52 for adjusting the light receiving sensitivity of the photomultipliers 46a and 46b. Further, the output of the light receiving state control unit 50 is connected to the laser diode 36 via the laser diode driving circuit 53 and to the tracking light source 38 via the tracking light source driving circuit 54. The output of the one-dimensional CCD 42 is connected to a galvanometric mirror control circuit 49 via a blood vessel position detection circuit 55.

In such a configuration, the white light emitted from the observation light source 1 passes through the condenser lens 3 and only the yellow wavelength light is transmitted by the field lens 4 with the band pass filter. Through the relay lens 7 to illuminate the transmissive liquid crystal panel 8 from behind,
Perforated mirror 1 through relay lens 9 and light blocking member 10
1 is reflected and only the wavelength light in the yellow range is a bandpass mirror 3
After passing through the objective lens 2 and passing through the objective lens 2 and once forming a fundus illumination light beam image on the pupil Ep of the eye E, the fundus oculi Ea is almost uniformly illuminated. At this time, a fixation target is displayed on the transmissive liquid crystal plate 8, and the fundus oculi Ea of the eye E to be inspected by the illumination light.
And presented to the subject as an optotype image. In addition,
The ring slit 25 and the light shielding members 6, 10 are for separating the fundus illumination light and the fundus observation light in the anterior segment of the eye E to be inspected. Does not.

The reflected light from the fundus oculi Ea returns along the same optical path, is taken out of the pupil Ep as a fundus observation light beam, passes through the center opening of the perforated mirror 11, the focus lens 13, the relay lens 14, and passes through the scale plate 15 After forming an image as a fundus image Ea ′, the light reaches the optical path switching mirror 16. here,
When the optical path switching mirror 16 is retracted from the optical path, the fundus image Ea 'can be observed by the examiner's eye e via the eyepiece 17. When the optical path switching mirror 16 is inserted in the optical path, the fundus image E formed on the scale plate 15 is displayed.
a 'is the CCD camera 19 by the TV relay lens 18
The image is re-imaged on the screen and projected on the liquid crystal monitor 20.

The examiner performs alignment of the apparatus with the eyepiece 17 or the liquid crystal monitor 20 while observing the fundus image Ea '. At this time, it is preferable to adopt an observation method according to an appropriate purpose. In the case of observation with the eyepiece 17, since the resolution is generally higher and the sensitivity is higher than that of the liquid crystal monitor 20, etc. It is suitable for reading and diagnosing various changes. On the other hand, in the case of observation with the liquid crystal monitor 20, since the field of view is not restricted, the fatigue of the examiner can be reduced. Since it is possible to electronically record the change of the measurement site on the image Ea ', it is extremely effective clinically.

The measurement light emitted from the laser diode 36 is collimated by a collimator lens 35, and is reflected by the optical path switching mirror 34 and the fixed mirror 33 when the optical path switching mirror 34 is inserted in the optical path.
The light passes below the condenser lens 30. When the optical path switching mirror 34 is retracted from the optical path, it passes directly above the condenser lens 30 and passes through the dichroic mirror 29.

On the other hand, the tracking light emitted from the tracking light source 38 has its beam diameter expanded by a beam expander 37 at different magnifications in the vertical and horizontal directions, is reflected by a mirror 32, and is shaped into a desired shape by a shaping mask 31. After that, the light is reflected by the dichroic mirror 29 and is superimposed by the condenser lens 30 with the measurement light which is imaged in a spot shape at a position conjugate with the center of the opening of the mask 31.

Further, the measurement light and the tracking light pass through the lens 24, are reflected once by the upper reflection surface 22b of the galvanometric mirror 22, pass through the black spot plate 27, are reflected by the concave mirror 48, and are returned to the black spot plate 27 and the optical path. After passing through the long compensating meniscus 26, it is returned toward the galvanometric mirror 22. At this time, when the measurement light and the tracking light are reflected in the upper reflecting surface 22b of the galvanometric mirror 22 and returned again, they are incident on the galvanometric mirror 22 in a state of being decentered from the optical path of the objective lens 2. Here, by inserting / retracting the switching mirror 34 in the optical path, the light beam reflected on the back surface of the galvanometric mirror 22 is returned to the notch position of the galvanometric mirror 22, and
To the image rotator 21 without reflection. Then, the measurement light and the tracking light deflected by the band-pass mirror 32 in the direction of the objective lens 2 via the image rotator 21 pass through the objective lens 2 and the eye E to be examined.
To the fundus Ea of the eye.

The scattered reflected light from the fundus oculi Ea is again reflected by the objective lens 2.
And reflected by the band-pass mirror 32, passes through the image rotator 21, is reflected by the lower reflection surface 22a of the galvanometric mirror 22, passes through the focus lens 23, and the measurement light and the tracking light pass through the dichroic mirror 39. Separated.

Here, the tracking light is transmitted through the dichroic mirror 39 and is formed on the one-dimensional CCD 42 by the field lens 40 and the imaging lens 41 as a blood vessel image which is larger than the fundus image Ea 'by the fundus observation optical system. .
Then, based on the blood vessel image picked up by the one-dimensional CCD 42, a movement amount to the center of the blood vessel image is created in the blood vessel position detection circuit 55, and the galvanometric mirror control circuit 4
9 is output. The control circuit 49 drives the galvanometric mirror 22 to compensate for this movement amount.

At this time, because of the spectral characteristics of the band-pass mirror 12, the illumination light from the observation light source 1 is a one-dimensional CCD.
Since the light does not reach the reference numeral 42, the one-dimensional CCD 42 picks up only the blood vessel image Ev 'by the tracking light. In addition, since blood hemoglobin and melanin on pigment epithelium have significantly different spectral reflectances in a green wavelength range, the blood vessel image Ev 'can be captured with good contrast by setting the tracking light to green light.

FIG. 2 shows the blood vessel image Ev 'of the one-dimensional CCD 42 and the indicator T. When a part of the indicator T is overlapped with the measuring blood vessel Ev in a perpendicular state, the line of the blood vessel detecting system arranged in the longitudinal direction of the tracking light is shown. On the one-dimensional CCD 42 composed of a sensor, a blood vessel image Ev 'illuminated and illuminated by the tracking light (indicator T) is captured in an enlarged manner.

The reflected tracking light (indicator T) projected onto the fundus oculi Ea passes through a rotator 41 and a galvanometric mirror 42 at a -n magnification to a one-dimensional CCD 42
Projected to Therefore, regardless of the apparent movement of the indicator T, the indicator T is stationary on the one-dimensional CCD 42,
When the indicator T moves in the longitudinal direction, the blood vessel image E
Only v 'moves on the one-dimensional CCD.

In the blood vessel position detecting circuit 55, the one-dimensional C
One-dimensional CC of the blood vessel image Ev 'based on the received light signal of CD42
The movement amount X of D42 from the reference position 42a is calculated.
Then, the galvanometric mirror 22 is controlled by the galvanometric mirror control circuit 49 based on the movement amount X.
Is driven so that the image receiving position of the blood vessel image Ev 'on the one-dimensional CCD 42 is controlled to be the reference position 42a of the one-dimensional CCD 42.

On the other hand, the measuring light is a dichroic mirror 39.
Are reflected by the mirrors 45a and 45b through the opening of the confocal stop 44, and are received by the photomultipliers 46a and 46b, respectively. The outputs of the photomultipliers 46a and 46b are output from the system controller 4 respectively.
7, and the frequency of the received light signal is analyzed in the same manner as in the conventional example to determine the blood flow velocity of the fundus oculi Ea.

Information on the output voltages of the one-dimensional CCD 42 and the photomultipliers 46a and 46b is transmitted to a light receiving state control unit 50.
Sent to The light receiving state control unit 50 calculates an appropriate light receiving sensitivity of each of these light receiving elements, and
1. The light receiving sensitivity of each light receiving element is independently adjusted through the photomultiplier light receiving sensitivity control circuit 52.

For example, the appropriate light receiving sensitivity is first determined by a one-dimensional CCD.
Assuming that the output is within the unit time as shown by the curve a in FIG. 3 under the condition of the gain G1 and the light quantity I1 which are the light receiving sensitivity, the peak output V1 of the curve a is changed to the peak output as shown by the curve b. Adjust the gain so that V2 output is obtained.

Next, an approximate curve F of the gain G versus voltage V characteristic of the one-dimensional CCD 42 under the light amount I0 as shown in FIG.
(X) On the output V01 corresponding to the gain G1, V1: V2
= V01: V02 is determined as the output V02. Then, the one-dimensional CC is set so that the gain G2 corresponds to V02.
Adjust the light receiving sensitivity of D42. The same method is used for the photomultipliers 46a and 46b.

Further, each of the light receiving elements described above is used as a light meter instead of sensitivity adjustment, and the output light amounts of the laser diode 36 and the tracking light source 38 are automatically adjusted, and the one-dimensional CCD 42 and the photomultipliers 46a and 46b are used. It is also possible to make each of the light receiving elements output an appropriate output.

The output voltage information of the one-dimensional CCD 42 and the photomultipliers 46a and 46b is transmitted to a light receiving state control unit 50.
And the light receiving state control unit 50
6. The appropriate amount of light of the tracking light source 38 is calculated, and the light amount of the laser diode 36 and the tracking light source 38 is independently controlled through the laser diode driving circuit 53 and the tracking light source driving circuit 54, respectively.

The calculation of the appropriate light amount in this case is performed by an approximate curve F 'of the light amount I vs. voltage V characteristic as shown in FIG.
Using (X), the calculation can be performed in the same manner as the calculation of the appropriate light receiving sensitivity described above.

As described above, by automatically optimizing the light receiving state of each light receiving element, an accurate measurement output can be obtained very easily. Therefore, simultaneous or continuous measurement of different information of the same site becomes possible, and a light source and a light receiving element having a wavelength most suitable for a measurement purpose or a measurement target can be freely combined. In addition, independent control using a plurality of these combinations can be easily performed, and multiple measurements such as stabilization of measurement values and improvement of accuracy, improvement of safety for subjects, and reduction of examination time can be performed. The effect can be enhanced. Furthermore, in the irradiation optical system as well as the light receiving optical system, by mixing the light of each wavelength so that they have the same optical path before entering the fundus oculi Ea, it is possible to focus and aim the measurement light with the same mechanism And the operation can be further simplified.

[0036]

As described above, the fundus examination apparatus according to the present invention splits the reflected light from the target part into light of each wavelength, receives the light independently by the light receiving means, and independently receives the light based on the light receiving state. In addition, by automatically adjusting the light receiving conditions, large fluctuations in the fundus reflectance due to differences in the race, age, and medical condition of the subject are suppressed, and the S / N is maintained well and the burden on the subject and the measurer The load of improving the technical level can be reduced. Therefore, it is possible for anyone to easily perform an eye examination without the need for special examination skills, and simplification of the examination technology shortens the examination time, thereby greatly reducing the pain of the subject. It contributes to cost savings for medical institutions.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fundus blood flow meter according to an embodiment.

FIG. 2 is an explanatory diagram of a blood vessel image position on a one-dimensional CCD.

FIG. 3 is a graph showing a light receiving state of a light receiving element.

FIG. 4 is a graph showing gain versus voltage characteristics of a light receiving element.

FIG. 5 is a graph showing a relationship between a light quantity and a voltage characteristic of a light receiving element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Observation light source 11 Perforated mirror 19 CCD camera 20 Liquid crystal monitor 21 Image rotator 22 Galvanometric mirror 25 Focus unit 26 Optical path length compensation meniscus 28 Concave mirror 29, 39 Dichroic mirror 36 Laser diode 38 Tracking light source 42 One-dimensional CCD 46a, 46b Photomultiplier 47 System control circuit 48 Input means 50 Light receiving state control unit 55 Blood vessel position detection circuit

Claims (5)

[Claims] 1. An illumination optical system for irradiating the same target portion of the fundus of an eye to be examined with two or more light sources generating light of different wavelengths, light of each wavelength generated from the light source, In a fundus examination apparatus having a light receiving optical system that receives reflected light and a measuring unit that measures predetermined information from the target site based on an output from the light receiving optical system, the light receiving optical system is configured to receive light from the target site. Spectral means for separating the reflected light into light of each wavelength, at least two light receiving means for independently receiving the reflected light of each wavelength separated by the spectral means, and light receiving conditions based on the light receiving state of the light receiving means And a light receiving condition automatic adjusting means for independently and automatically adjusting the light receiving conditions. 2. The fundus examination apparatus according to claim 1, wherein the light receiving condition automatic adjusting means adjusts light receiving sensitivity of the light receiving means. 3. The fundus examination apparatus according to claim 1, wherein said light receiving condition automatic adjusting means adjusts an output of said light source. 4. The method according to claim 2, wherein the blood vessel shape is measured using the wavelength light near the green light and the line sensor, and the blood flow velocity is measured using the wavelength light near the red light and the light meter. Fundus examination device. 5. The fundus examination apparatus according to claim 2, wherein light beams having different wavelengths are mixed on the same optical axis in the irradiation optical system and irradiated onto the fundus.