JP3636533B2 - Ophthalmic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ophthalmologic diagnostic apparatus that irradiates a fundus of an eye to be examined and measures its ophthalmic characteristics.
[0002]
[Prior art]
Conventional ophthalmic diagnostic apparatuses that measure the characteristics of the eye to be inspected by irradiating a measurement light beam such as laser light into the eye include a fundus blood flow meter and a laser flare cell meter. The fundus blood flow meter measures the blood flow of the fundus blood vessel that can be directly observed in a non-invasive manner, and various fundus blood flow meters using the Doppler principle and speckle phenomenon have been devised by irradiating a measurement light beam.
[0003]
In such a fundus blood flow meter, the movement of the fundus is tracked in order to always irradiate the measurement light beam to the measurement position on the fundus, and further, accurate fixation fixation of the eye to be examined is required. In general, an internal fixation device is provided to present a fixation target, and a necessary part of the fundus is selected by guiding the line of sight of the eye to be examined.
[0004]
As this internal fixation device, there is one LED, an aperture, or a light shielding object, and the examiner controls the fixation target moving means to move the fixation target in a direction that guides the line of sight of the eye to be examined. There are other types, a plurality of LEDs and a transmissive liquid crystal having a plurality of liquid crystal patterns, and the examiner controls the fixation target moving means to selectively present one of them.
[0005]
In addition, as described in, for example, Japanese Patent Publication No. 3-48810, the fundus camera has two fixation targets for the left eye and the right eye, and in conjunction with the left-right movement of the housing of the fundus camera, There is also known one configured so that one fixation target corresponding to the left and right eyes can be selected.
[0006]
[Problems to be solved by the invention]
(1) However, as in the above-described conventional example, in the ophthalmologic diagnosis apparatus having a tracking unit that tracks the movement of the fundus of the eye to be examined and constantly irradiates the measurement light beam to the measurement position on the fundus, the movement of the fundus is large In some cases, the tracking range is exceeded and tracking becomes impossible.
[0007]
(2) In addition, in an internal fixation device such as a fundus blood flow meter, the examiner may come into contact with the fixation target moving means during measurement and the internal fixation target may move.
[0008]
A first object of the present invention is to provide an ophthalmologic diagnosis apparatus that can solve the above-mentioned problem (1) and can continue tracking even when the movement of the fundus is large.
[0009]
The second object of the present invention is to eliminate the above-mentioned problem (2) and to provide an ophthalmic diagnostic apparatus in which the internal fixation target does not move during measurement regardless of the signal from the fixation target moving means. is there.
[0010]
[Means for Solving the Problems]
An ophthalmologic diagnosis apparatus according to a first invention for achieving the above object is provided on a fundus of an eye to be examined. For tracking Irradiate light And follow the movement of the fundus by driving the mirror. Tracking means that always irradiates the measurement light beam to the measurement position on the fundus, and the fundus The measurement position on the Tracking means Driving the mirror Range When it detects that it has exceeded A warning means for issuing a warning
[0011]
An ophthalmologic diagnosis apparatus according to a second invention is Of the eye to be examined To guide the line of sight A fixation target presenting means for presenting the fixation target, and a tracking light beam is applied to the fundus of the subject's eye, and the movement of the fundus is followed by driving a mirror. Tracking means for always irradiating the measurement light beam to the measurement position on the fundus, The measurement position on the fundus is the Tracking means Driving the mirror Range When it detects that it has exceeded Fixation target moving means for changing the presentation position of the fixation target.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail based on the embodiments shown in the drawings.
FIG. 1 is a perspective view of a fundus blood flow meter according to an embodiment. A stage fixing unit 2 and a television monitor 3 are placed on a base 1, and a stage movable unit that is movable back and forth and left and right is placed on the stage fixing unit 2. 4 and the chin support 5 are fixed. A measurement head 6 is placed on the stage movable unit 4, and an operation rod 7, a switch 8, an operation ring 9, a measurement mode selection switch 10, and a blood flow rate display LED 11 are fixed on the examiner side. The measuring head 6 is provided with an operation knob 12, a focus knob 13, and an image rotator knob 14 which are fixation target moving means.
[0014]
FIG. 2 is a configuration diagram of the main part of the fundus blood flow meter built in the measuring head 6, and an objective placed at a position facing the eye E from an observation light source 21 made of a tungsten lamp or the like that emits white light. On the illumination optical path to the lens 22, a condenser lens 23, for example, a field lens 24 with a bandpass filter that transmits only light in the yellow wavelength range, and a ring slit provided at a position substantially conjugate with the pupil Ep of the eye E to be examined. 25, a light-shielding member 26 provided at a position almost conjugate with the crystalline lens of the eye E, a relay lens 27, and a fixation target display element movable along the optical path, and a plurality of dot patterns Q as shown in FIG. Transmissive liquid crystal plate 28, relay lens 29, light shielding member 30 conjugated with the vicinity of the cornea of eye E to be examined, perforated mirror 31, transmits light in the yellow wavelength range and reflects most of the other luminous flux. Bandpass mirror 32 are sequentially arranged, the illuminating optical system is constructed that.
[0015]
The ring slit 25 and the light shielding members 26 and 30 are for separating fundus illumination light and fundus observation light in the anterior segment of the eye E, and the shape of the ring slit 25 and the light shielding members 26 and 30 is as long as it forms a necessary light shielding region. It doesn't matter. Further, in this embodiment, a circular dot pattern Q having a diameter of 0.22 mm is used in which 64 × 64 dots are arranged at a pitch of 0.25 mm, and one of the dot patterns Q is arranged on the transmissive liquid crystal plate 28. However, the shape, size, and total number of the dot pattern Q are not limited to those in the embodiment as long as the eye can be guided to the eye to be examined, and one dot pattern Q may be displayed. Instead, a plurality of dot patterns Q may be displayed such as a cross shape.
[0016]
A fundus observation optical system is formed behind the perforated mirror 31, and includes a first focus lens 33, a relay lens 34, a scale plate 35, which can move along the optical path, and an optical path switching mirror which can be inserted into and removed from the optical path. 36 and the eyepiece 37 are sequentially arranged to reach the examiner's eye e. A TV relay lens 38 and a CCD camera 39 are disposed on the optical path in the reflection direction when the optical path switching mirror 36 is inserted in the optical path, and the output of the CCD camera 39 is connected to the TV monitor 3. .
[0017]
On the optical path in the reflection direction of the bandpass mirror 32, an image rotator 40 and a galvanometric mirror 41 having a rotation axis perpendicular to the paper surface and polished on both sides are disposed. The lower reflection surface 41a of the galvanometric mirror 41 is arranged. A second focus lens 42 that is movable along the optical path is disposed in the reflection direction, and a lens 43 and a focus unit 44 that is movable along the optical path are disposed in the reflection direction of the upper reflection surface 41b. Note that the front focal plane of the lens 43 has a conjugate relationship with the pupil Ep of the eye E, and the galvanometric mirror 41 is disposed on this focal plane.
[0018]
Above the galvanometric mirror 41, an optical path length compensating meniscus 45, a black spot plate 46 having a light shielding portion in the optical path, and a concave mirror 47 are arranged, and are not reflected by the lower reflecting surface 41a of the galvanometric mirror 41. A relay optical system that guides the passing light beam to the upper reflection surface 41 b of the galvanometric mirror 41 is configured. The optical path length compensation meniscus 45 is for correcting the vertical displacement in the drawing caused by the mirror thickness of the positions of the upper reflection surface 41b and the lower reflection surface 41a of the galvanometric mirror 41, and an image rotator. Acts only in the optical path to 40.
[0019]
In the focus unit 44, a dichroic mirror 48 and a condensing lens 49 are sequentially arranged on the same optical path as the lens 43, and a mask 50 and a mirror 51 are arranged on the optical path in the reflection direction of the dichroic mirror 48. The focus unit 44 can be moved integrally in the direction indicated by the arrow. A fixed mirror 52 and an optical path switching mirror 53 that can be retracted from the optical path are arranged in parallel on the optical path in the incident direction of the lens 49. A collimator lens 54 and a coherent lens are disposed on the optical path in the incident direction of the optical path switching mirror 53. For example, laser diodes 55 for measurement that emit red light are arranged. Further, on the optical path in the incident direction of the mirror 51, a beam expander 56 formed of a cylindrical lens or the like, and a high-brightness tracking light source 57 that emits, for example, green light different from other light sources are arranged.
[0020]
A second focus lens 42, a dichroic mirror 58, a field lens 59, a magnifying lens 60, and a one-dimensional CCD 61 with an image intensifier are sequentially arranged on the optical path in the reflection direction of the lower reflective surface 41a of the galvanometric mirror 41. The blood vessel detection system is configured. Further, on the optical path in the reflection direction of the dichroic mirror 58, an imaging lens 62, a confocal stop 63, and mirror pairs 64a and 64b provided substantially conjugate with the pupil Ep of the eye E to be examined are arranged. Photomultipliers 65a and 65b are arranged in the reflection direction of 64b, respectively, and a light receiving optical system for measurement is configured. For the convenience of illustration, all the optical paths are shown on the same plane. However, the reflection optical paths of the mirror pairs 64a and 64b, the measurement optical path in the emission direction of the tracking light source 57, and the optical paths from the laser diode 55 to the mask 50 are respectively shown. It is perpendicular to the page.
[0021]
Further, a system control unit 66 for controlling the entire apparatus is provided. The system control unit 66 includes an operation lever knob 12, a switch 8, a measurement mode selection switch 10, a left and right motion detection means 67, and photomultipliers 65a and 65b. The output of the one-dimensional CCD 61 is connected to a blood vessel position detection circuit 68, and the output of the blood vessel position detection circuit 68 is connected to a control unit 66 and a control circuit 69 that controls the galvanometric mirror 41. The output of the system control unit 66 is connected to the optical path switching mirror 53, the blood flow rate display LED 11, the transmissive liquid crystal plate 28, and the control circuit 69, respectively.
[0022]
FIG. 4 shows the arrangement of each light beam on the pupil Ep of the eye E, I is an area illuminated by yellow illumination light, an image of the ring slit 25, O is the fundus observation light beam, and the aperture of the perforated mirror 31 , V is a measurement / blood vessel received light beam and is an image of an effective portion of the upper and lower reflection surfaces 41b and 41a of the galvanometric mirror 41, and Da and Db are two measurement light beams and are images of the mirror pairs 64a and 64b, respectively. P1 and P1 ′ are measurement light incident positions, which indicate the position of the measurement light selected by switching the optical path switching mirror 53. A region M indicated by a chain line is an image of the lower reflective surface 41a of the galvanometric mirror 41. It is.
[0023]
At the time of measurement, the examiner first fixes the subject's face on the chin support 5 and selects a measurement mode for measuring, for example, a blood vessel near the nipple using the measurement mode selection switch 10. The left and right movement detection means 67 detects the left and right positions of the stage movable table 3 to determine whether the eye E is the left eye or the right eye, and signals from the left and right movement detection means 67 and the measurement mode selection switch 10 are system controlled. Sent to the unit 66. In response to these signals, a predetermined dot pattern Q that is determined in advance on the transmissive liquid crystal plate 28 is displayed as a fixation target, and the observation light source 21 is turned on.
[0024]
The white light emitted from the observation light source 21 passes through the condenser lens 23, and only the yellow wavelength light is transmitted through the field lens 24 with the bandpass filter, and passes through the ring slit 25, the light shielding member 26, and the relay lens 27, and is transmissive liquid crystal. The board 28 is illuminated from behind. Further, the white light is reflected by the perforated mirror 31 through the relay lens 29 and the light shielding member 30, and only the wavelength light in the yellow region is transmitted through the bandpass mirror 32, passes through the objective lens 22, and passes through the pupil Ep of the eye E to be examined. After the image is once formed as a fundus illumination light beam image I above, the fundus Ea is illuminated almost uniformly.
[0025]
At this time, one of the dot patterns Q is displayed on the transmissive liquid crystal plate 28, and this is projected onto the fundus Ea of the eye E by illumination light and presented to the eye E as a visual target image. The examiner operates the operation knob 12 to send a signal to the system control unit 66 to change the position of the presented dot pattern Q so that the right eye of the nipple reaches the approximate center of the visual field. To induce.
[0026]
Reflected light from the fundus oculi Ea returns on the same optical path, is taken out from the pupil Ep as a fundus oculi observation light beam O, passes through the aperture at the center of the perforated mirror 31, the focus lens 33, and the relay lens 34, and is shown on the scale plate 35. As shown in FIG. 5, after forming the fundus oculi image Ea ′, the light path switching mirror 36 is reached. Here, when the optical path switching mirror 36 is retracted from the optical path, the fundus image Ea ′ can be observed through the eyepiece lens 37 by the examiner's eye e, while the optical path switching mirror 36 is inserted in the optical path. At this time, the fundus image Ea ′ formed on the scale plate 35 is re-imaged on the CCD camera 39 by the TV relay lens 38 and displayed on the TV monitor 3.
[0027]
While observing this fundus oculi image Ea ′ with the eyepiece 37 or the television monitor 3, the operation rod 7 and the operation ring 9 are operated to slide the stage movable unit 4 in the XZ plane in the Y direction, and the eye to be examined. Align with E. At this time, it is preferable to adopt an appropriate observation method according to the purpose. In the case of observation with the eyepiece 37, since the resolution is generally higher than that of the television monitor 3 and the like, the fineness of the fundus Ea is small. It is suitable for reading and diagnosing various changes.
[0028]
On the other hand, in the case of observation with the TV monitor 3, the fatigue of the examiner can be reduced because the field of view is not limited, and further, the fundus fundus can be obtained by connecting the output of the CCD camera 39 to an external video tape recorder or video printer. Since it is possible to electronically record changes in the measurement site on the image Ea ′, it is extremely effective clinically.
[0029]
Next, the measurement laser diode 55 and the tracking light source 57 are turned on. The measurement light emitted from the laser diode 55 is collimated by the collimator lens 54, and when the optical path switching mirror 53 is inserted in the optical path, it is reflected by the optical path switching mirror 53 and the fixed mirror 52, respectively. When passing below and the optical path switching mirror 53 is retracted from the optical path, it passes directly above the condenser lens 49 and passes through the dichroic mirror 48.
[0030]
On the other hand, the tracking light emitted from the tracking light source 57 is expanded in beam diameter by the beam expander 56 at different magnifications in the vertical and horizontal directions, reflected by the mirror 51, and then shaped into a desired shape by the shaping mask 50, and then dichroic mirror. The measurement light reflected by 48 is superimposed on the measurement light that is focused in a spot shape at a position conjugate with the center of the opening of the mask 50 by the condenser lens 49.
[0031]
The superimposed measurement light and tracking light pass through the lens 43, are once reflected by the upper reflecting surface 41b of the galvanometric mirror 41, pass through the black spot plate 46, and then are reflected by the concave mirror 47, again, the black spot plate 46, the optical path. It returns to the galvanometric mirror 41 through the long correction meniscus 45. Here, since the galvanometric mirror 41 is arranged at a position conjugate with the pupil Ep of the eye E, the image thereof has a shape indicated by a broken line M in FIG. 4 on the pupil Ep of the eye E. Yes.
[0032]
The concave mirror 47, the black spot plate 46, and the optical path length correcting meniscus 45 are arranged concentrically on the optical path, and relay the image of the upper reflective surface 41b and the lower reflective surface 41a of the galvanometric mirror 41 by -1 times. Since the function of the optical system is given, both light beams reflected at the positions P1 and P1 ′ in FIG. 4 on the back side of the image M of the galvanometric mirror 41 by insertion and retraction of the optical path switching mirror 53 into the optical path are: It will be returned to the positions P2 and P2 'located at the notch of the galvanometric mirror 41, and it will go to the image rotator 40 without being reflected by the galvanometric mirror 41. Then, both light beams deflected toward the objective lens 22 by the band pass mirror 32 through the image rotator 40 are irradiated to the fundus ea of the eye E through the objective lens 22.
[0033]
As described above, the measurement light and the tracking light are reflected in the upper reflection surface 41b of the galvanometric mirror 41, and are incident on the galvanometric mirror 41 in a state of being decentered from the optical axis of the objective lens 22 when returned again. Then, the light beam passing from the position P1 to the position P2 becomes a spot image P, the light beam passing from the position P1 ′ to the position P2 ′ is formed as a spot image P ′, and then the fundus oculi Ea is irradiated in a spot shape.
[0034]
The scattered reflected light from the fundus Ea is collected again by the objective lens 22, reflected by the bandpass mirror 32, passes through the image rotator 40, is reflected by the lower reflective surface 41a of the galvanometric mirror 41, and passes through the focus lens 42. In the dichroic mirror 58, the measurement light and the tracking light are separated.
[0035]
The tracking light passes through the dichroic mirror 58, and is imaged on the one-dimensional CCD 61 as a blood vessel image Ev 'enlarged by the field lens 59 and the imaging lens 60 than the fundus image Ea' by the fundus observation optical system. The measurement light is reflected by the dichroic mirror 58, is reflected by the mirror pair 64a and 64b through the opening of the confocal stop 63, and is received by the photomultipliers 65a and 65b, respectively.
[0036]
At this time, the illumination light from the observation light source 21 does not reach the one-dimensional CCD 61 due to the spectral characteristics of the band-pass mirror 32, and the imaging range is set narrow on the one-dimensional CCD 61. It has become difficult. As a result, only the blood vessel image Ev ′ by the tracking light is captured on the one-dimensional CCD 61. In addition, blood hemoglobin and melanin on the pigment epithelium differ greatly in the spectral reflectance in the green wavelength range, so the blood vessel image Ev 'can be imaged with good contrast by making the tracking light green light. Become.
[0037]
A light beam received by the one-dimensional CCD 61 is a light beam extracted from the measurement / blood vessel light reception light beam V on the pupil Ep of the eye E, and a light beam passing through the measurement light reception light beams Da and Db by the mirror pairs 64a and 64b. The photomultipliers 65a and 65b receive the light. The reason why the measurement / blood vessel received light beam V is larger than the fundus observation light beam O is that the one-dimensional CCD 61 has a larger imaging magnification of the fundus Ea than the CCD camera 39 of the fundus observation optical system. This is because the image plane illuminance on the CCD 61 is difficult to ensure. On the other hand, the influence of flare light generated in the anterior eye part of the eye E due to the increased luminous flux does not pose a problem because the image receiving range is smaller in the blood vessel image receiving optical system. In addition, the interval between the measurement light reception light beams Da and Db on the pupil Ep directly affects the resolution of blood flow velocity measurement, but by increasing the measurement / blood vessel light reception light beam V, the interval between the measurement light reception light beams Da and Db can be sufficiently increased. It is possible to secure.
[0038]
Further, a part of the scattered light reflected by the fundus Ea by the measurement light and the tracking light is transmitted through the bandpass mirror 32 and guided to the fundus observation optical system behind the perforated mirror 31, and the tracking light is incident on the scale plate 35. An image is formed as a rod-shaped indicator T, and the measurement light is formed as a spot image at the center of the indicator T. As shown in FIG. 5, these images are observed together with the fundus image Ea ′ and the target image E projected onto the fundus Ea of the eye E with illumination light via the eyepiece 37 or the television monitor 3. A spot image (not shown) is superimposed on the center of the indicator T, and the indicator T rotates the switch 8 so that the scale S of a perfect circle prepared in advance on the scale plate 35 projected onto the fundus oculi Ea is displayed. The range can be moved one-dimensionally.
[0039]
The examiner rotates the focus knob 13 to focus the fundus image Ea ′. When the focus knob 13 is rotated, the transmissive liquid crystal plate 28, the focus lenses 33 and 42, and the focus unit 44 are interlocked and moved along the optical path by a driving unit (not shown). The liquid crystal plate 28, the scale plate 35, the one-dimensional CCD 61, and the confocal stop 63 are simultaneously conjugated with the fundus oculi Ea.
[0040]
The confocal stop 63 is for focusing on a desired blood vessel Ev. The operation of the confocal stop 63 will be described with reference to FIG. 6. The light beam from the laser diode 55 for measurement enters the mirror 71 from below and is reflected in the left-right direction. Then, the measurement site K1 of the blood vessel Ev on the fundus oculi Ea to be measured is irradiated. The reflected light at the measurement site K1 passes through the opening 72 having the function of determining the light receiving direction equivalent to the mirror pair 64a, 64b, is conjugated to the measurement site K1 by the lens 73, and passes through the small hole 74. Light is received by a photomultiplier (not shown). On the other hand, the reflected light at the measurement site K2 of the blood vessel Ev in the choroid Sc behind the measurement site K1 travels along the optical path indicated by the dotted line and forms an image by the lens 73 in the same manner as the light beam reflected at the measurement site K1 indicated by the solid line. However, since it cannot pass through the small hole 74, it is not received by the photomultiplier.
[0041]
By providing the confocal stop 63 having the same function as the small hole 74 and allowing only the reflected light from the blood vessel Ev at a specific depth to be received by the photomultipliers 65a and 65b, the examiner can change the figure. While viewing the focus state on the fundus image Ea ′ shown in FIG. 5, the depth of the blood vessel Ev to be measured can be set and the fundus image Ea ′ can be focused.
[0042]
After the focusing is completed in this manner, the examiner operates the operation knob 12 to move the visual target image F, guides the line of sight of the eye E, changes the observation area, if necessary. The blood vessel Ev to be moved into the circle S of the scale plate 35 is moved. Then, as shown in FIG. 7, the image rotator 40 is operated by the image rotator knob 14 to rotate the indicator T so that the indicator T is perpendicular to the traveling direction of the blood vessel Ev to be measured.
[0043]
At this time, since the fundus oculi observation light does not pass through the image rotator 40, it is recognized that only the indicator T rotates. Accordingly, the image of each optical member on the pupil Ep shown in FIG. 4 is also rotated by the same angle in the same direction around the origin, and the straight line connecting the centers of the measurement light receiving light beams Da and Db and the spot images P and P ′. The X axis, which is a straight line connecting the centers of the two, coincides with the traveling direction of the blood vessel Ev. Since the blood flow velocity is obtained from the interference signal between the scattered reflected light from the blood vessel wall and the scattered reflected light in the blood, even if the fundus Ea moves in the X axis direction during the measurement, the blood vessel Ev moves in the X axis direction. If it is almost parallel, the measurement results will not be affected.
[0044]
On the other hand, when the fundus oculi Ea moves in the Y-axis direction orthogonal to the X-axis, the light flux from the measurement laser diode 55 deviates from the blood vessel Ev at the measurement site, and the measurement value becomes unstable. In this embodiment, the movement amount of the blood vessel Ev only needs to be detected in the Y-axis direction, and in this embodiment, the blood vessel detection system behind the dichroic mirror 58 and the galvanometric mirror 41 perform tracking in this one direction.
[0045]
In the present embodiment, the elements of the one-dimensional CCD 61 are arranged in the longitudinal direction of the tracking light, and when the angle adjustment of the measurement site is completed as shown in FIG. 7, the longitudinal direction of the indicator T indicating the tracking light. Is orthogonal to the traveling direction of the measurement blood vessel Ev, and the fundus image Ea ′ indicated by the indicator T is enlarged and imaged on the one-dimensional CCD 61 of the blood vessel detection system.
[0046]
After the angle adjustment is completed, the switch 8 is rotated, the indicator T is moved in the direction indicated by the arrow as shown in FIG. 8, and the spot image superimposed on the tracking light is made coincident with the measurement site to set the measurement site. select. Then, after determining the measurement site, the switch 8 is pushed in and the start of tracking is input.
[0047]
When a tracking start command is input from the switch 8 to the control circuit 69 via the system control unit 66, the blood vessel position detection circuit 68 starts from the one-dimensional reference position of the blood vessel image Ev ′ based on the light reception signal of the one-dimensional CCD 61. Is calculated. Then, the galvanometric mirror 41 is driven by the control circuit 69 based on the amount of movement, and the image receiving position of the blood vessel image Ev ′ on the one-dimensional CCD 61 is controlled to be constant.
[0048]
After confirming the start of tracking, the examiner pushes the switch 8 further and starts measurement with the second-stage switch. The system controller 66 inserts the optical path switching mirror 53 into the optical path. First, a light beam incident from the position of the spot image P on the pupil Ep of the eye E is received by the photomultipliers 65a and 65b. The maximum frequency shifts | Δfmax1 | and | Δfmax2 | are obtained by the unit 66. Here, | Δfmax1 | and | Δfmax2 | are the processing results of the output signals from the photomultipliers 65a and 65b, respectively.
[0049]
At this time, the incident light beam is located in the spot image P, and is provided at a position sufficiently displaced with respect to the measurement light receiving light beam Da, Db.
Vmax = {λ / (n · α)} · || Δfmax1 | − | Δfmax2 || (1)
Depending on the position of the blood vessel Ev on the fundus Ea, the true flow rate is
Vmax = {λ / (n · α)} · || Δfmax1 | + | Δfmax2 || (2)
There are cases where it is necessary. Here, λ is the wavelength of the measurement light beam, n is the refractive index of the measurement site, and α is the angle formed by the measurement light beam and the light reception light beam.
[0050]
In this embodiment, first, provisional measurement is performed in this state, and after calculating the maximum speed Vmax according to the above equation (1), the system controller 66 retracts the optical path switching mirror 53 from the optical path, and the eye E Measurement is performed with a light beam incident from the position of the spot image P ′ on the pupil Ep.
[0051]
As shown in FIG. 4, the position of the spot image P ′ on the pupil Ep passes through the center of the other spot image P and has a center on a straight line parallel to the straight line connecting the centers of the measurement light receiving light beams Da and Db. However, in this embodiment, in particular, the distance between the spot images P and P ′ is larger than the distance between the centers of the measurement light receiving beams Da and Db, and the straight lines connecting the midpoints of the two straight lines are the respective centers. Is selected to be orthogonal to the straight line connecting
[0052]
After switching the incident light position from the spot image P to the spot image P ′ thus selected, the system control unit 66 again takes in signals from the two photomultipliers 65a and 65b, and shifts the maximum frequency shift | Δfmax1 ′. |, | Δfmax2 ′ | is calculated, and the maximum speed Vmax is calculated according to the equation (1). The system control unit 66 compares the two maximum velocities Vmax and Vmax ′ to determine an appropriate incident direction of the light flux for obtaining the true maximum flow velocity, and based on this information, sets the optical path switching to an appropriate state. Thus, this measurement is controlled so as to be continuously performed while repeating the calculation of the maximum speed Vmax or Vmax ′ at an appropriate time interval.
[0053]
The maximum blood flow velocity thus obtained is displayed on the blood flow velocity display LED 11, and the measurement of the blood vessel on the right side of the nipple is completed. Although this measurement is performed for about 10 seconds, since the system control unit 66 operates so as not to accept a signal from the operation knob 12 from the start to the end of the measurement, the examiner is careless during the measurement. Even if the operation knob 12 is touched, the position of the visual target image F remains at the measurement start position and does not move.
[0054]
However, in this case, if the fundus oculi Ea of the eye E moves greatly and the measurement site goes out of the circle S, tracking becomes impossible and measurement becomes impossible. In this embodiment, the galvanometric mirror 41 is driven. When the rotation angle of the galvanometric mirror 41 exceeds 1.5 degrees by the signal of the control circuit 69, the system control unit 66 determines that the end of the indicator T is outside the line of the circle S, and the transmissive liquid crystal plate 28 A signal is sent to the display to blink the dot pattern Q displayed as a fixation target to give a warning to the subject so that the line of sight is again directed to the fixation target. This warning may be displayed as a large fixation target by increasing the number of dot patterns Q to be displayed instead of blinking the dot pattern Q. If the LED is a fixation target, the brightness is indicated. It may be increased and a warning may be given by voice.
[0055]
After giving this warning, if the rotation angle of the galvanometric mirror 41 still exceeds 1.5 degrees and the end of the indicator T is outside the line of the circle S, the system control unit 66 will transmit the transmissive liquid crystal plate. A signal is sent to 28, another dot pattern Q is displayed as shown in FIG. 9, the position of the target image F is changed, and the line of sight of the eye E is guided so that the measurement unit is in the center of the circle S. Even if the position of the visual target image F is changed by a signal from the operation knob 12, this control almost eliminates troublesome operations.
[0056]
【The invention's effect】
As described above, the ophthalmologic diagnosis apparatus according to the first aspect of the present invention tracks the movement of the fundus of the eye to be examined. Means mirror drive Range When it exceeds Since a warning is issued to prompt the user to turn his / her line of sight toward the fixation target, tracking can be continued even when the fundus movement is large.
[0057]
An ophthalmologic diagnosis apparatus according to a second invention is The movement of the fundus of the eye to be examined drives the mirror of the tracking means Range When it exceeds , Automatically fixation target Presentation position Change Measurement position Therefore, it is not necessary for the examiner to guide the line of sight of the subject's eye, and tracking can be continued easily.
[Brief description of the drawings]
FIG. 1 is a perspective view of an embodiment.
FIG. 2 is a configuration diagram of a measurement head.
FIG. 3 is an explanatory diagram of a dot pattern.
FIG. 4 is an explanatory diagram of a light beam arrangement on the pupil.
FIG. 5 is an explanatory diagram of a fundus image.
FIG. 6 is an explanatory diagram of a confocal stop.
FIG. 7 is an explanatory diagram of the rotation of the indicator.
FIG. 8 is an explanatory diagram of movement of an indicator.
FIG. 9 is an explanatory diagram of changing the position of a target image.
[Explanation of symbols]
2 Stage fixing part
3 TV monitor
4 Stage movable part
6 Measuring head
7 Operation
12 Operation knob
13 Focus knob
14 Image Rotator Knob
21 Light source for observation
28 Transmission type liquid crystal plate
39 CCD camera
40 Image Rotator
41 Galvanometric mirror
53 Optical path switching mirror
55 Laser diode
57 Light source for tracking
61 One-dimensional CCD
63 Confocal stop
65a, 65b Photomultiplier
66 System controller
69 Control circuit

Claims (5)

A tracking unit that irradiates the fundus of the subject's eye with a tracking light beam and follows a movement of the fundus by driving a mirror to constantly irradiate a measurement light beam on a measurement position on the fundus, and the measurement position on the fundus is the tracking unit. An ophthalmologic diagnosis apparatus comprising: warning means for issuing a warning when it is detected that the mirror driving range is exceeded . A light source that irradiates the fundus of the subject's eye with measurement light, measurement light receiving means that receives reflected light from the fundus of the light beam and converts it into an electrical signal, and a blood vessel in the blood vessel to be measured based on the electrical signal The ophthalmologic diagnosis apparatus according to claim 1, further comprising means for calculating a blood flow . A fixation target presenting means for presenting a fixation target for guiding the line of sight of the eye to be inspected, and a tracking light beam is irradiated on the fundus of the eye to be examined. Tracking means for irradiating a measurement position on the fundus, and a fixation target moving means for changing the presentation position of the fixation target when it is detected that the measurement position on the fundus exceeds the driving range of the mirror of the tracking means; An ophthalmologic diagnosis apparatus characterized by comprising: An operation means for instructing a position for presenting the fixation target to the fixation target presenting means is provided, and an instruction from the operation means is not accepted while the fixation target moving means is operating. The ophthalmologic diagnosis apparatus according to claim 3 . A light source for irradiating a fundus for measurement to the fundus of the eye to be examined, a measuring light receiving means for receiving reflected light from the fundus of the light beam and converting it into an electric signal, and a blood vessel in the blood vessel to be measured based on the electric signal The ophthalmologic diagnosis apparatus according to claim 3, further comprising means for calculating a blood flow .

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