JPH09173299A - Eyeground examination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To newly re-calculate measured data by inputting novel auxiliary data at arbitrary periods before and after measurement. SOLUTION: The luminous flux incident from the spot image position on the pupil of an eye to be examined is detected by photomultipliers 46a, 46b and a system control part 47 calculates the max. frequency shift from the light detection signals and the data and the measured data related to the diameter of a blood vessel are preliminarily inputted to an operation part 51 and the auxiliary data for measuring the blood flow state stored in a memory means 52 is used to operate not only blood flow velocity from the former but also to operate the diameter of a blood vessel and a blood flow rate from the latter. When an analyser alters the auxiliary data to perform re-calculation, new auxiliary data is inputted to the operation part 51 from an input means 53 through a control part 54 and the operation part 51 uses novel auxiliary data to newly calculate blood flow velocity, the diameter of a blood vessel and a blood flow rate.

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 for examining blood vessels on the fundus of an eye to be examined.

[0002]

2. Description of the Related Art Conventionally, in a fundus blood flow meter, the maximum velocity Vmax of blood flow is obtained, the blood vessel diameter of a blood vessel to be measured is further measured from a fundus photograph, and the blood flow rate is obtained from both of them. The maximum velocity Vmax of blood flow is Δfmax1 which is the maximum frequency shift calculated from the received light signals received by the two light receivers.
, Δfmax2, the laser wavelength is λ, the refractive index of the measurement site is n, the angle between the two receiving optical axes in the eye is α, the plane formed by the two receiving optical axes in the eye, and the velocity vector of the blood flow. If the angle formed by is β, it can be obtained from the following equation. Vmax = {λ / (n · α)} · {|| Δfmax1 ｜ − | Δfmax2 || / cosβ} (1)

By performing the measurement from two directions in this way, the contribution of the measurement light in the incident direction is canceled out, and the blood flow at an arbitrary site on the fundus can be measured, and the plane formed by the two light receiving optical axes can be measured. By matching the angle β formed by the line of intersection with the eye fundus with the blood flow velocity vector, β = 0 °, and the true blood flow velocity can be measured.

Among the parameters in the equation (1), λ and n are known constants, and Δfmax1 and Δfmax2 are measured values, while α is the device constant and the refractive error of the subject. Is a parameter calculated by using at least one of the axial length of the eye, the curvature of the cornea.

On the other hand, regarding the blood vessel diameter of the fundus of the eye, one-dimensional C
The provisional blood vessel diameter is calculated from the image signal of the blood vessel imaged by the CD, and any one of the refractive error value, the axial length of the eye, and the corneal curvature 2
The blood vessel diameter is calculated by performing the correction using the Littman method, for example, based on the imaging magnification estimated by using one of them. Further, the blood flow rate is calculated using the maximum blood flow velocity and the blood vessel diameter, assuming that the blood vessel is a cylinder and the blood flow in the blood vessel is Poiseu's flow.

[0006]

However, in the fundus blood flow meter of the conventional example, in order to obtain the calculation result of the blood flow velocity and the like from the measurement data, the necessary refractive error value of the subject,
Auxiliary data such as axial length and corneal curvature are input in advance, or stored as standard values in the device, and the calculation result is obtained only at the time of measurement. It is impossible for the analyst to input these auxiliary data, and the same problem arises when the blood vessel diameter is simultaneously measured to calculate the blood flow. Therefore, in order to measure the blood flow with high accuracy, it is necessary to measure the auxiliary data in advance, and there is a problem that it cannot be dealt with, for example, when performing an urgent measurement.

A first object of the present invention is to solve the above-mentioned problems and to calculate a measurement value from the measurement data of the eye to be examined using the auxiliary data of the subject input by the analyst through the input means. It is to provide a fundus examination device.

A second object of the present invention is to provide a fundus examination apparatus which can newly recalculate measured values by using new auxiliary data input by the analyst at any time before and after measurement by the input means. It is in.

[0009]

A fundus examination apparatus according to a first aspect of the invention for achieving the above object is a detecting means for detecting measurement data of an eye to be inspected, an input means capable of inputting auxiliary data, and the detecting means. A measuring unit for calculating a measured value from the measured data obtained by the means and auxiliary data that can be input by the input unit; and a storage unit for storing the measured data or the measured value together with the auxiliary data. To do.

A fundus examination apparatus according to a second aspect of the present invention includes a detection means for detecting measurement data of an eye to be inspected, an input means capable of inputting auxiliary data, a measurement data obtained by the detection means, and an input by the input means. A calculation unit that calculates a measurement value from possible auxiliary data, a storage unit that stores the measurement data or the measurement value together with the auxiliary data, and new auxiliary data when the new auxiliary data is input from the input unit. Alternatively, the control unit performs control in the calculation unit using the measured value to generate a new measured value.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a configuration diagram of a fundus blood flow meter of an embodiment, in which a condenser lens 3 is provided on an illumination optical path from an observation light source 1 including a tungsten lamp that emits white light to an objective lens 2 facing an eye E to be examined. A field lens 4 with a band-pass filter that transmits only yellow wavelength light, a ring slit 5 that is substantially conjugate with the pupil Ep of the eye E, and a light blocking member 6 provided at a position that is substantially conjugate with the crystalline lens of the eye E. , A relay lens 7, a transmissive liquid crystal plate 8 which is a fixation target display element movable along the optical path, a relay lens 9, a light blocking member 10 which is conjugated with the vicinity of the cornea of the eye E, a perforated mirror 11, a yellow region The band-pass mirrors 12 that transmit the light having the wavelength of 5 and reflect most of the other light flux are sequentially arranged to form an illumination optical system. The ring slit 5 and the light blocking members 6 and 10 are for separating the fundus illumination light and the fundus observation light in the anterior segment of the eye E to be examined, and their shapes are problematic as long as they form a necessary light blocking region. It does not become.

An observation optical system is formed behind the perforated mirror 11, and the first focusing lens 13, the relay lens 14, and the scale plate 1 which are movable along the optical path.
5. An optical path switching mirror 16 that can be freely inserted into and removed from the optical path and an eyepiece lens 17 are sequentially arranged to reach the eye e to be inspected. A television relay lens 18 and a CCD camera 19 are arranged on the optical path in the reflection direction of the optical path switching mirror 16, and
The output of the D camera 19 is connected to the liquid crystal television monitor 20.

On the optical path in the reflection direction of the band-pass mirror 12, the image rotator 21, both the upper and lower surfaces are polished, and the galvanometric mirror 22 having an axis of rotation perpendicular to the paper surface and conjugated to the pupil Ep of the eye E, the optical path. The optical path length compensating meniscus 23 disposed on one side of the concave mirror 2, the black dot plate 24 having a light blocking portion in the optical path, and the concave mirror 25 are sequentially arranged.
5. The black spot plate 24 and the optical path length compensation meniscus 23 are arranged concentrically on the optical path, and cooperate with the upper side of the galvanometric mirror 22 to cooperate with the light flux that passes through the lower reflecting surface 22a of the galvanometric mirror 22 without being reflected. A relay optical system for guiding to the reflection surface 22b is configured. The optical path length correction meniscus 23 includes an upper reflecting surface 22b and a lower reflecting surface 2 which are generated by the mirror thickness of the galvanometric mirror 22.
It is for correcting the vertical displacement of 2a,
It works only in the optical path toward the image rotator 21.

In the incident direction of the upper reflecting surface 22b of the galvanometric mirror 22, the front focal plane is the pupil of the eye E to be examined.
A lens 26 that is conjugate with Ep and a focus unit 27 that is movable integrally along the optical path are arranged. In the focusing unit 27, the same optical path as the lens 26,
A dichroic mirror 28 and a condenser lens 29 are arranged, and a mask 30 and a mirror 31 are arranged on the optical path of the dichroic mirror 28 in the incident direction.

On the optical path in the incident direction of the condenser lens 29,
Fixed mirror 32 and optical path switching mirror 3 capable of retracting from the optical path
3 and 3 are arranged in parallel, and a collimator lens 34 and a laser diode 35 for measurement that emits coherent red light are arranged on the optical path in the incident direction of the optical path switching mirror 33. Further, on the optical path in the incident direction of the mirror 31, a beam expander 36 including a cylindrical lens and the like, and a high-luminance tracking light source 37 that emits green light different from other light sources are arranged.

A second focusing lens 38, a dichroic mirror 39, a field lens 40, a magnifying lens 41, which are movable along the optical path, are provided on the optical path in the reflection direction of the lower reflecting surface 22a of the galvanometric mirror 22.
A one-dimensional CCD 42 with an image intensifier is sequentially arranged to form a blood vessel detection system.

Further, on the optical path in the reflection direction of the dichroic mirror 39, an imaging lens 43, a confocal diaphragm 44, a mirror pair 45a provided substantially conjugate with the pupil of the eye E to be examined,
45b is arranged, and photomultipliers 46a and 46b are arranged in the reflection directions of the mirror pairs 45a and 45b, respectively, to form a measurement light receiving optical system including a blood vessel detection system. Although all the optical paths are shown on the same plane for convenience of illustration, the reflected optical paths of the mirror pairs 45a and 45b, the measurement optical path in the emission direction of the tracking light source 37, and the optical path from the laser diode 35 to the dichroic mirror 28 are shown. Each is orthogonal to the page.

Further, a system control section 47 for controlling the entire apparatus is provided, and the system control section 47 has an input means 48 operated by an examiner and a photomultiplier 46.
a, 46b, outputs of the focus position detecting means 47 are respectively connected, and outputs of the system control unit 47 are respectively connected to a control circuit 49 for controlling the galvanometric mirror 22 and an optical path switching mirror 33. Further, the control circuit 49 is connected to the one-dimensional CCD 4 via the blood vessel position detection circuit 50.
2 outputs are connected.

FIG. 2 shows a block circuit of an algorithm for recalculating blood flow velocity and blood flow using auxiliary data.
One-dimensional CCD 42, photomultipliers 46a, 46
The output of b is connected to the calculation unit 51 via the system control unit 47, and the calculation unit 51 is connected to the storage means 52.
The output of the input unit 53 for inputting auxiliary data is connected to the control unit 54, and the output of the control unit 54 is connected to the calculation unit 51 and the storage unit 52.

FIG. 3 shows the arrangement of the light fluxes on the pupil Ep of the eye E to be examined. The image I of the ring slit 5 in the region illuminated by the yellow illumination light and the aperture of the perforated mirror 11 for the fundus observation light flux. An image O, an image V of the effective part of the upper and lower reflection surfaces of the galvanometric mirror 22 with the measurement / blood vessel received light flux, and images Da and Db of the mirror pairs 45a and 45b with the two measurement received light fluxes are displayed, respectively, and the measurement light incident position The measuring light selected by switching the optical path switching mirror 33 with is the spot light P.
2, P2 ′, and the region M of the lower reflecting surface 22a of the galvanometric mirror 22 is shown by a chain line.

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, and the ring slit 5, the light shielding member 6,
The transmissive liquid crystal plate 8 is illuminated from the back through the relay lens 7, passes through the relay lens 9 and the light blocking member 10, is reflected by the perforated mirror 11, and only the yellow wavelength light is transmitted through the bandpass mirror 12. After passing through the objective lens 2 and once forming a fundus illumination light flux image I on the pupil Ep of the eye E to be examined,
The fundus Ea is illuminated almost uniformly. At this time, a fixation target is displayed on the transmissive liquid crystal plate 8, and the fixation target is projected onto the fundus Ea of the eye E by the illumination light and presented to the eye E as a target image.

The reflected light from the fundus Ea returns through the same optical path, is extracted as a fundus observing light beam O from the pupil Ep, passes through the central opening of the perforated mirror 11, the first focusing lens 13 and the relay lens 14, After the image is formed on the scale plate 15 as a fundus image Ea ′, it 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 through the eyepiece lens 17, and when the optical path switching mirror 16 is inserted in the optical path. The fundus image Ea ′ imaged on the scale plate 15 is re-imaged on the CCD camera 19 by the television relay lens 18 and displayed on the liquid crystal television monitor 20.

The examiner observes the fundus image Ea 'and aligns the apparatus with the eyepiece lens 17 or the liquid crystal television monitor 20. At this time, it is preferable to adopt an appropriate observation method according to the purpose, and in the case of observation by the eyepiece lens 17, since it is generally higher in resolution and sensitivity than the liquid crystal television monitor 20 or the like, the fundus Ea It is suitable for reading and diagnosing minute changes. On the other hand, in the case of observation by the liquid crystal television monitor 20, the examiner's fatigue can be reduced because the field of view is not limited, and the CCD camera 19
By connecting the output of the device to an external video tape recorder or video printer, changes in the measurement site on the fundus image Ea 'can be electronically recorded sequentially, which is extremely effective clinically.

The measuring light emitted from the laser diode 35 is collimated by the collimator lens 34, and when the optical path switching mirror 33 is inserted in the optical path, the measuring light is reflected by the optical path switching mirror 33 and the fixed mirror 32, respectively, and a condenser lens. When it passes below 29, and when the optical path switching mirror 33 is retracted from the optical path, it passes directly above the condenser lens 29 and passes through the dichroic mirror 28.

On the other hand, the tracking light emitted from the tracking light source 37 has its beam diameter expanded by the beam expander 36 at different vertical and horizontal magnifications, is reflected by the mirror 31, and is then shaped into a desired shape by the shaping mask 30. After that, it is reflected by the dichroic mirror 28 and is superimposed on the above-mentioned measurement light. At this time, the measurement light is collected by the condenser lens 2
An image is formed in a spot shape at a position conjugate with the center of the opening of the mask 30 by 9, and the measurement light and the tracking light together pass through the lens 26 and are once reflected by the upper reflection surface 22b of the galvanometric mirror 22. After passing through the black spot plate 24, the light is reflected by the concave mirror 25 and is returned to the galvanometric mirror 22 through the black spot plate 24 and the optical path length correcting meniscus 23 in a state of being decentered from the optical axis of the objective lens 2.

That is, by inserting and retracting the optical path switching mirror 33 into the optical path, the measuring light and tracking light reflected at the positions P1 and P1 'below the image M of the galvanometric mirror 22 as shown in FIG. Is returned to the positions of P2 and P2 ′ located in the cutout portion of the galvanometric mirror 22, so that the bandpass mirror 12 passes through the image rotator 21 without being reflected by the galvanometric mirror 22 and passes through the image rotator 21. Is deflected in the direction of the objective lens 2 to form spot images P2 and P2 'on the pupil Ep, and the fundus Ea of the eye E to be examined is irradiated in a point shape. In this way, various types of flare light can be effectively removed.

The scattered reflected light from the fundus oculi Ea is again reflected by the objective lens 2.
Is condensed by the bandpass mirror 12, passes through the image rotator 21, and is reflected by the galvanometric mirror 2
2 is reflected by the lower reflection surface 22a, passes through the second focusing lens 38, and is separated into measurement light and tracking light by the dichroic mirror 39.

The tracking light is a dichroic mirror 3.
9 through the field lens 40 and the imaging lens 41, and the fundus image by the fundus observation optical system on the one-dimensional CCD 42.
The image is formed as a blood vessel image that is larger than Ea '. And
Based on the blood vessel image picked up by the one-dimensional CCD 42, data indicating the amount of movement of the blood vessel image is created in the blood vessel position detection circuit 50 and output to the system control unit 47, and the system control unit 47 is controlled by the control circuit 49. The galvanometric mirror 22 is driven so as to compensate the movement amount.

Further, the blood vessel image picked up by the one-dimensional CCD 43 is also output to the control unit 57, and the image signal from the one-dimensional CCD 43 is calculated in the calculation unit 51 from the secondary differential value of the image signal. To calculate. On the other hand, the measurement light is reflected by the dichroic mirror 39, passes through the openings of the lens 43 and the confocal diaphragm 44, and is reflected by the mirror pairs 45a and 45b, and photomultipliers 46a and 46, respectively.
The light is received by b, the received light signal is output to the system controller 47, and the frequency is analyzed in the calculator 51.

At this time, because of the spectral characteristics of the bandpass mirror 12, the illumination light from the observation light source 1 is a one-dimensional CCD.
42, and because the imaging range is set narrower, harmful flare light is less likely to be mixed in. As a result, the one-dimensional CCD 42 captures only a blood vessel image by tracking light. Further, since hemoglobin in blood and melanin on pigment epithelium have greatly different spectral reflectances in the wavelength region of green, it is possible to capture a blood vessel image with good contrast by using tracking light as green light.

The light beam received by the one-dimensional CCD 42 is a light beam extracted from the measurement / blood vessel light receiving light beam V on the pupil Ep of the eye E to be examined, and from this light beam, the mirror pair 45a, 45b.
Thus, the measurement received light beams Da and Db are extracted and received by the photomultipliers 46a and 46b. The reason why the measurement / blood vessel received light beam V is made larger than the fundus observation light beam O is that the one-dimensional CCD 42 is used as compared with the CCD camera 19 of the fundus observation optical system.
Has a higher imaging magnification of the fundus, so the one-dimensional CCD4
This is because it is difficult to secure the illuminance on the image plane on 2.

On the other hand, the influence of the flare light generated in the anterior segment of the eye E due to the increased luminous flux does not cause a problem because the image receiving range is smaller in the blood vessel image receiving optical system. Further, the distance between the measurement received 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 received light beam V, the distance between the measurement received light beams Da and Db is sufficiently increased. It is possible to secure.

Part of the scattered and reflected light on the fundus Ea due to the measurement light and the tracking light passes through the bandpass mirror 12,
Guided to the fundus observation optical system behind the perforated mirror 11, the tracking light is imaged as a rod-shaped indicator on the scale plate 15, and the measurement light is imaged as a spot image at the center of this indicator. These images are eyepieces 17
Alternatively, it is observed together with the fundus oculi image Ea ′ and the visual target image via the liquid crystal television monitor 20. At this time, a spot image is observed so as to be superimposed on the center of the indicator, and the indicator is operated by the operating member such as the operating rod of the input means 48 so that the fundus Ea
The top can be moved one-dimensionally.

At the time of measurement, the examiner first focuses the fundus image Ea '. When the focusing knob of the input unit 48 is adjusted, the transmissive liquid crystal plate 8, the first and second focusing lenses 13 and 14, and the focusing unit 27 are interlocked and moved along the optical path by a driving unit (not shown). When the fundus image Ea 'is in focus, the transmissive liquid crystal plate 8,
The scale plate 15, the one-dimensional CCD 43, and the confocal diaphragm 45 simultaneously become conjugate with the fundus Ea.

The confocal diaphragm 45 at this time is for focusing on a desired blood vessel, and the photomultipliers 46a, 4a and 4b only reflect light reflected by a blood vessel at a predetermined depth.
By making 6b receive light, it becomes possible to measure the blood flow velocity of a predetermined blood vessel. In the actual examination, the examiner sets the depth of the blood vessel to be measured while looking at the in-focus state on the fundus oculi image Ea ', and focuses the fundus oculi image Ea'.

After the focusing is completed in this way, the examiner operates the input means 48 to move the visual target image and guide the line of sight of the eye E to change the observation region to be the measurement object. The blood vessel is moved to a predetermined position on the scale plate 15. Then, the image rotator 2 is operated by the operation stick of the input means 48.
1 is operated to rotate the indicator so that the indicator is perpendicular to the traveling direction of the blood vessel to be measured.

At this time, since the fundus observation light has not passed through the image rotator 21, it is recognized that only the indicator rotates. As a result, the pupil Ep shown in FIG.
The image of each optical member above also rotates around the origin in the same direction by the same angle, and the straight line connecting the centers of the measured received light beams Da and Db and the straight line connecting the centers of spot images P1, P1 'and P2, P2' The X axis, which corresponds to, corresponds to the traveling direction of the blood vessel.

This operation corresponds to setting β = 0 ° in the equation (1) for speed calculation described in the conventional example. By setting β = 0 °, the following (a) to (c The advantage of) occurs.

(A) From equation (1), β = 90 °, that is, cosβ =
When it becomes 0, the maximum frequency shift Δfmax1 and Δfm
Although it is not possible to obtain the absolute value of the maximum blood flow velocity Vmax from ax2 alone, it is possible to avoid an unmeasurable position by rotating the fundus image Ea ′ so that β = 0 °.

(B) Since it is not necessary to measure the angle β, error factors are reduced and the operation is simplified.

(C) As described in the conventional example, 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 blood, the fundus in the X-axis direction during measurement. Even if Ea moves, the measurement result is not affected if the blood vessel is made substantially parallel to the X-axis direction.

On the other hand, when the fundus Ea moves in the Y-axis direction which is orthogonal to the X-axis, the luminous flux from the laser diode 37 for measurement deviates from the blood vessel at the measurement site and the measured value becomes unstable. In that case, it is sufficient to detect the moving amount of the blood vessel only in the Y-axis direction, and in this embodiment, the blood vessel detection system behind the dichroic mirror 39 and the galvanometric mirror 22 perform tracking in only this one direction.

In order to perform the tracking and measure the blood flow velocity accurately and quickly for all the blood vessels to be examined, the one-dimensional CCD 42 for detecting the moving amount of the blood vessel image is arranged vertically to the blood vessel to be measured. Then, β = 0 ° also has an advantage that it is not necessary to use a two-dimensional sensor.

In the present embodiment, the elements of the one-dimensional CCD 42 are arranged in the longitudinal direction of the tracking light, and when the angle alignment of the measurement site is completed, the indicator indicating the tracking light is measured in the longitudinal direction. Since it is orthogonal to the traveling direction of, the fundus image Ea 'indicated by the indicator is enlarged and formed on the one-dimensional CCD 42 of the blood vessel detection system. However, it is difficult for the examiner to immediately judge the in-focus state only from the output of the one-dimensional CCD 42.

After the angle adjustment is completed, the operation rod of the input means 48 is operated to match the spot image superimposed on the tracking light with the measurement site and select the measurement site. After determining the measurement site, the input means 48 is operated again to input the start of tracking.

When a tracking start command is input to the control circuit 49 from the input means 48 via the system control section 47, the one-dimensional CCD 4 is detected in the blood vessel position detection circuit 50.
The amount of movement from the one-dimensional reference position of the blood vessel image is calculated based on the light reception signal of 2. Then, the control circuit 49 drives the galvanometric mirror 22 based on this movement amount, and controls so that the image receiving position of the blood vessel image on the one-dimensional CCD 42 becomes constant.

After the examiner confirms the start of tracking,
The measurement switch of the input means 48 is pressed to start the measurement.
The system control unit 47 inserts the optical path switching mirror 33 into the optical path, and first, the spot image P1 on the pupil Ep of the eye E to be examined,
The luminous flux incident from the position of P1 'is the photomultiplier 4
The light is received by 6a and 46b, the received light signal is taken in by the system control unit 47, and the maximum frequency shifts | Δfmax1 | and | Δfmax2 | are calculated by the calculation unit 51.

At this time, since the luminous flux is incident from the positions of the spot images P1 and P1 'and is provided at a position sufficiently displaced with respect to the measured received luminous fluxes Da and Db, the maximum velocity Vmax is normally set.
Is cosβ = 1 in the equation (1) of the conventional example, and Vmax = {λ
/ (N · α)} · || Δfmax1 | − | Δfmax2 ||, but the true flow velocity is Vmax = {λ / (n · α)} · | depending on the position of the blood vessel Ev on the fundus Ea. | Δfmax1 ｜ ＋ ｜ Δfm
There are also cases where you must use ax2 ||. In the present embodiment, first, in this state as a temporary measurement, after calculating the maximum velocity Vmax according to the equation (1), the system control unit 47 causes the optical path switching mirror 33 to retract from the optical path, and the pupil Ep of the eye E to be inspected. The measurement is performed by making a light beam enter from the positions of the spot images P2 and P2 '.

The positions of the spot images P2 and P2 'on the pupil Ep are
As shown in FIG. 2, it is arranged so as to have its center point on a straight line which passes through the centers of the other spot images P1 and P1 ′ and is parallel to the line connecting the centers of the measurement received light beams Da and Db. In the present embodiment, the distance between the spot images P1, P1 'and P2, P2' is larger than the distance between the centers of the measured light beams Da, Db, and a straight line connecting the midpoints of the two straight lines connects the respective centers. Selected to be orthogonal to the straight line.

After the incident light position is switched from the spot images P1 and P1 'to the spot images P2 and P2' thus selected,
Again, the system control unit 47 takes in signals from the two photomultipliers 46a and 46b, and the arithmetic unit 51 causes the maximum frequency shifts | Δfmax1 '| and | Δfmax2' of each.
| Is calculated and the maximum speed Vmax is calculated according to the equation (1).
When the maximum velocity Vmax at this time is set as Vmax ′, the system control unit 47 determines an appropriate incident direction of the light flux for obtaining the true maximum flow velocity by comparing the two maximum velocities Vmax and Vmax ′. The control is obtained so as to make the optical path switching operation into an appropriate state by this information and perform the main measurement. In this measurement, the maximum speed Vmax or Vmax 'is repeatedly calculated at appropriate time intervals and continuously measured.

In this way, for example, the maximum frequency shift in the incident direction determined to be appropriate is | Δfmax1 |, |
If Δfmax2 |, this data and the above-mentioned measurement data relating to the blood vessel diameter are input to the calculation unit 51 in advance,
The blood flow velocity is calculated and displayed from the former measurement data by using the auxiliary data necessary for measuring the blood flow state such as the abnormal refraction value, the axial length of the eye and the corneal curvature stored in the storage means 52 as the standard value. , The blood vessel diameter and blood flow volume corrected by this auxiliary data are calculated and displayed from the latter measurement data.
When the auxiliary data is not input from the input unit 53, the control unit 54 reads the auxiliary data stored in the storage unit 52 and outputs the auxiliary data to the calculation unit 51, and when the auxiliary data is input from the input unit 53. Outputs this auxiliary data to the arithmetic unit 51.

The storage means 52 stores the combination of the measurement data and the auxiliary data, or the combination of the measured value of the blood flow velocity, the blood flow rate and the like and the auxiliary data. When the auxiliary data is changed and recalculated at an arbitrary time later, new auxiliary data is input from the input unit 53 to the calculation unit 51 via the control unit 54 and measured by the calculation unit 51 from the storage unit 52. Issue a command to read the value. When the storage format of the storage unit 52 is a combination with the measurement data, the calculation unit 51 newly calculates the blood flow velocity, the blood vessel diameter, and the blood flow volume using the new auxiliary data. Also, the storage means 5
When the storage format of 2 is a combination with the blood flow velocity, blood vessel diameter, and blood flow measurement values, the auxiliary data that is stored at the same time is used to back-calculate the measurement data from the measurement values, and then input the new data. The auxiliary data is used to newly calculate the blood flow velocity, the blood vessel diameter, and the blood flow rate, and the input values are stored in the storage unit 52.

In this way, the analyst inputs the auxiliary data of the abnormal refraction value, the axial length and the corneal curvature of the subject in advance, or uses the standard values stored in the apparatus to analyze the blood. The flow velocity, the blood vessel diameter, and the blood flow rate can be obtained, and the analyst inputs another auxiliary data from the input means 48 at any time after the measurement to newly obtain the blood flow velocity, the blood vessel diameter, and the blood flow rate. Obtainable. The calculation result is displayed as a measured value on a display (not shown) and is output to a printer as needed. At this time, it is desirable to simultaneously display and output the auxiliary data used for the calculation or the calculation result such as the imaging magnification, and it is possible to confirm under what conditions the measurement result was performed by this display and output. Become.

In the present embodiment, the output signals from the photomultipliers 46a and 46b are directly output to the arithmetic unit 51. However, the system control unit 47 performs fast Fourier transform on the output signals to obtain measurement data. Alternatively, the maximum frequency shift may be obtained and the value may be output to the arithmetic unit 51 as measurement data.

Further, for the image signal from the one-dimensional CCD 43, the system controller 47 may calculate provisional measurement data and output it to the calculator 51.

[0056]

As described above, the fundus examination apparatus according to the first aspect of the present invention inputs the auxiliary data of the subject to the measurement data from the detecting means to calculate the measurement value of the fundus blood vessel of the eye to be examined. As a result, it becomes possible to perform a more accurate and reliable fundus examination for each subject.

In the fundus examination apparatus according to the second aspect of the present invention, storage means for storing a combination of measurement data and auxiliary data or a combination of measurement value and auxiliary data, and when new auxiliary data is input, By providing a control unit to perform recalculation, it is possible to recalculate a new measurement value using the auxiliary data input by the analyst at any time before and after measurement using the input means. More accurate and reliable measurement is possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fundus blood flow meter.

FIG. 2 is an explanatory diagram of a light flux arrangement on a pupil Ep.

FIG. 3 is a block diagram of a block circuit of a measurement value recalculation algorithm.

[Explanation of symbols]

 1 Light Source for Observation 19 CCD Camera 20 LCD TV Monitor 21 Image Rotator 22 Galvanometric Mirror 23 Optical Path Length Correction Meniscus 27 Focusing Unit 35 Laser Diode 37 Tracking Light Source 42 One-dimensional CCD 50 Blood Vessel Position Detection Circuit

Claims (10)

[Claims] 1. A detection unit for detecting measurement data of an eye to be examined, an input unit capable of inputting auxiliary data, a measurement value obtained from the measurement data obtained by the detection unit and auxiliary data inputtable by the input unit. A fundus examination apparatus comprising a calculation unit for calculating and a storage unit for storing the measurement data or the measurement value together with the auxiliary data. 2. The fundus examination apparatus according to claim 1, wherein the auxiliary data is stored in advance in the storage means as a constant. 3. The auxiliary data includes a refractive error value, an axial length,
The fundus examination apparatus according to claim 1, comprising at least one of corneal curvatures. 4. The calculation unit calculates a blood flow velocity, a blood vessel diameter, or a blood flow volume from the measurement data and the auxiliary data.
The fundus examination apparatus according to claim 3. 5. A detection unit for detecting measurement data of an eye to be inspected, an input unit capable of inputting auxiliary data, a measurement value obtained from the detection data obtained by the detection unit, and auxiliary data inputtable by the input unit. When a new auxiliary data is input from the calculating unit, the storage unit that stores the measured data or the measured value together with the auxiliary data, and the new auxiliary data from the input unit, the new auxiliary data or the measured value is used. A fundus examination apparatus comprising: a control unit that performs control in the calculation unit to generate a new measurement value. 6. The fundus examination apparatus according to claim 5, wherein the auxiliary data is stored in advance in the storage means as a constant. 7. The control unit outputs auxiliary data to the arithmetic unit by giving priority to an input value input from the input unit over a value stored in advance in the storage unit as a constant. The fundus examination apparatus according to. 8. A new measurement value is calculated from the auxiliary data of the storage means and the new auxiliary data from the input means when the measured value is stored in the storage means. The fundus examination apparatus according to claim 1. 9. The auxiliary data includes a refractive error value, an axial length,
The fundus examination apparatus according to claim 5, comprising at least one of corneal curvatures. 10. The calculation unit calculates a blood flow velocity, a blood vessel diameter, or a blood flow volume from the measurement data and the auxiliary data.
The fundus examination apparatus according to claim 1.