JPH09327438A - Eye refractometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eye refractometer capable of testing eye refractive power without forcing troublesome motion to a subject and performing the test even in a case positioning has not been properly completed yet. SOLUTION: A CPU 52 measures the refractive power of a tested eye based usually on signals from an optical receiving element part 29 on a measuring and alignment detecting optical system 10 when the position deviation between the optical axis of the tested eye and the optical axis of the optical system 20 is within a prescribed range. When a measurement mode setting switch 55 is ON, the CPU 52 measures the tested eye refractive power regardless of the position deviation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye refractive power measuring device for measuring the eye refractive power of an eye to be examined.

[0002]

2. Description of the Related Art Conventionally, for example, by injecting light that moves in one direction in the pupil of the eye to be examined and observing the movement of the reflected light from the fundus on the pupil, the eye refractive power of the eye to be examined is improved. Measuring methods and measuring devices are known. In such a device, in order to detect a point where the reflected light from the fundus does not move on the pupil, that is, a neutralization point, two photoelectric conversion elements arranged at a slight distance from each other in the moving direction of the incident light. Is configured to move in the optical axis direction as it is. Alternatively, as described in JP-A-55-86437, it is configured to detect the phase difference of slit light incident on two photoelectric light receiving elements arranged apart from each other in the moving direction of incident light. Has been done.

In the eye refractive power measuring device as described above, since the light intensity of the corneal reflected light of the eye to be examined is higher than the light intensity of the fundus reflected light, two photoelectric sensors for measuring the reflected light from the fundus of the eye are used. It is necessary to position the eye to be inspected and the device in the left-right and up-down directions so that the reflected light from the cornea does not enter the conversion element.

In order to easily realize such alignment, a technique as described in Japanese Patent Laid-Open No. 53-125893 has been proposed. The technique disclosed in this publication has four light-receiving sections in which two separately arranged photoelectric light-receiving elements are arranged so that the center of the light-receiving section substantially coincides with the intersection of the optical axis and the light-receiving section. Positioning is realized by providing divided light receiving elements and detecting the amount of light incident on each of the light receiving elements.

The eye-refractive-power measuring device having the above-described alignment function measures the necessary eye-refractive power while the amount of incident light on each of the four light-receiving elements is substantially equal. Is running.

[0006]

However, for example, when the cornea of the eye to be examined has cloudiness, the reflectance of the cornea is so low that sufficient reflected light cannot be obtained. As a result, The amount of light given to the divided light receiving elements may not be sufficient for alignment. Under such circumstances, the eye-refractive-power measuring device cannot properly perform the alignment, and thus there is a problem in that it is impossible to perform the necessary measurement of the eye-refractive power.

[0007] Further, for example, in the eye to be examined suffering from a cataract, the central lens is opaque. On the other hand, when the cornea is normal, the lens is not properly aligned. There was also a problem that the eye refracting power could not be measured properly due to turbidity of the eye. As described above, if the eye refracting power of the eye to be inspected cannot be measured by the eye refracting power measuring device, the subsequent subjective test takes time.

Therefore, in the conventional eye-refractive-power measuring apparatus, the reflected light from the periphery of the pupil or the like is received by the four light-receiving elements and pseudo-positioning is performed to measure the eye-refractive power. However, when such a method is adopted, it is necessary to ask the subject to perform a troublesome operation such as shifting the line of sight.

A first object of the present invention is to perform the measurement of the eye refractive power without requiring the subject to perform a troublesome operation and to perform the measurement of the eye refractive power even when the alignment is not completed properly. It is to provide a refractive power measuring device.

A second object of the present invention is to provide an eye-refractive-power measuring device that allows an observer to set conditions under which measurement can be appropriately performed.

[0011]

SUMMARY OF THE INVENTION A first object of the present invention is to:
A measurement optical system for measuring the eye refractive power of the eye to be inspected, an alignment signal generating means for generating an alignment signal indicating an alignment state between the eye to be inspected and the measurement optical system, and based on the alignment signal, whether measurement is possible or not. A determination means for determining whether or not, when the determination means determines that it is measurable, an eye refractive power measuring device comprising a measuring means for measuring the eye refractive power of the eye to be inspected, wherein the measuring means This is achieved by an eye-refractive-power measuring device characterized by measuring the eye-refractive power of an eye to be inspected in a predetermined case regardless of the judgment of the judging means.

According to the present invention, since the measuring means can measure the eye refractive power of the eye to be examined regardless of the alignment signal in a predetermined case, the lens or the cornea is opaque. It is possible to realize the measurement of the eye refractive power even for the optometry.

A second object of the present invention is to provide a measurement optical system for measuring the eye refractive power of the eye to be inspected and an alignment signal for generating an alignment signal indicating an alignment state between the eye to be inspected and the measurement optical system. Generating means, judging means for judging whether or not measurement is possible based on the alignment signal, and when the judging means judges that measurement is possible,
An eye-refractive-power measuring device including a measuring unit that measures the eye-refractive power of an eye to be inspected, wherein the determining unit includes a changing unit that changes a criterion for determining whether or not measurement is possible. It is also achieved by an eye refractive power measuring device.

According to this, the changing means can change the criterion for determining whether or not the measurement is possible. Therefore, when measuring the eye refractive power of the eye to be examined or the like in which the lens or cornea has opacity. Even if the measurement cannot be performed once, it is possible to obtain the measurable state and change the eye refractive power as desired by changing the determination criteria.

In a preferred aspect of the present invention, the measurement optical system includes an illumination unit for illuminating an eye to be inspected,
A focusing mechanism for performing focusing on an eye to be inspected, wherein the alignment signal is a deviation between an optical axis of the eye to be inspected and an optical axis of the measurement optical system, a deviation of focus on the eye to be inspected, and the illuminating means. Illuminated from, the light amount of the reflected light reflected by the cornea of the subject's eye, and, at least one of the light amount of the reflected light reflected by the fundus of the subject's eye, which is illuminated from the illumination means, the determining means, Whether the deviation of the optical axis is within a predetermined range, whether the focus deviation is within a predetermined range, whether the amount of light reflected from the cornea is within a predetermined range, and the reflected light from the fundus of the eye It is configured to determine whether measurement is possible based on the at least one of whether the light amount is within a predetermined range.

In a further preferred aspect of the present invention, when the determination means determines that measurement is possible,
Either one of a first measurement mode for measuring the eye refractive power of the eye to be inspected and a second measurement mode for measuring the eye refractive power of the eye to be examined regardless of the judgment of the judgment means is set. Equipped with setting means.

In a further preferred aspect of the present invention, whether or not the eye refracting power is measured when the determining means determines that the eye refracting power can be measured together with the eye refracting power data of the eye refracting power measured by the measuring means. Alternatively, it is provided with output means for outputting information indicating whether or not the eye refractive power was measured regardless of the judgment of the judgment means.

According to this embodiment, the observer can know whether the measurement is performed under the normal alignment state or the measurement performed regardless of the alignment state. Becomes

In a further preferred aspect of the present invention, based on the determination means, when it is determined that the measurement by the measurement means is more than a predetermined number of times and the measurement cannot be performed, the measurement means, The measurement of the eye refractive power is executed regardless of the judgment of the judgment means.

In a further preferred aspect of the present invention, the changing means includes: a range of deviation of the optical axis, a range of deviation of the focus, a quantity of light reflected from the cornea, and a quantity of light reflected from the fundus of the eye. At least one of them can be arbitrarily changed.

[0021] In a further preferred aspect of the present invention, when it is determined that the measurement by the measuring means is more than a predetermined number of times and the measurement is impossible, whether the changing means is measurable or not. It is configured to change the judgment standard of.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an eye refractive power measuring device according to an embodiment of the present invention. As shown in FIG. 1, the eye refractive power measurement device 10 includes a measurement and alignment detection optical system 20, a fixation target optical system 30, an observation optical system 40,
And a processing device 50. Of these, the measurement and alignment detection optical system 20 and the fixation target optical system 30
Is almost the same as that of the eye refractive power measuring device disclosed in JP-A-55-86437.

First, the measurement and alignment detection optical system 20 will be described. The measurement and alignment optical system 20 includes an infrared light source 21 that emits infrared light for measurement, a condenser lens 22 for making an infrared light flux from the infrared light source 21 into a substantially parallel light flux, and a plurality of slit-shaped openings 23a.
A rotary drum 23 that is driven to rotate in a fixed direction, a beam splitter 24 that reflects the light beam converted into a slit shape through the rotary drum 23, and a stepping motor (not shown) to intermittently move in a fixed direction. Image rotator 25 that is rotationally driven as a matter of course, and transmits infrared light,
On the other hand, the dichroic mirror 26 that reflects other light
have. Further, as shown in FIG. 1, the measurement and alignment detection optics 20 includes a beam splitter 24.
A condenser lens 27 for condensing light from the diaphragm, a diaphragm member 28 having a slit-shaped opening 28a parallel to the projected slit-shaped luminous flux, and a plurality of photoelectric conversion elements behind it, as will be described later. Has a light receiving element portion 29 in which is arranged.

The image rotator 25 is a stepping motor (not shown) centered on the optical axis A of the infrared light for measurement.
It is configured to be driven to rotate. The position of the diaphragm member 28 preferably coincides with the focal position of the condenser lens 27.

In the measurement and alignment detection optical system 20 thus constructed, the measuring light beam emitted from the infrared light source 21 is converted into a substantially parallel light beam by the condenser lens 22, and further, by the rotating drum 23. It is converted into a slit-shaped light beam. The slit-shaped light flux reaches the eye E through the beam splitter 24, the image rotator 25, and the dichroic mirror 26. The rotary drum 23 having the slit-shaped opening 23a is rotationally driven here, so that the rotary drum 23
Since the light flux from is chopped, the rotating drum 23
The fundus of the eye E to be examined is scanned in accordance with the rotation of.

The reflected light from the eye E is again passed through the dichroic mirror 26, the image rotator 25, the beam splitter 24, the condenser lens 27, and the diaphragm member 28, and
It reaches the light receiving element section 29.

In the light receiving element section 29, as shown in FIG.
A substrate 29a is provided on which two photodiodes 29b, 29c for measuring the refractive power, and
Four photodiodes 29d, 29 for alignment
e, 29f, 29g are attached.

Two photodiodes 2 for measuring the refractive power
9b and 29c are slit-shaped openings 2 of the diaphragm member 28.
On a straight line orthogonal to the longitudinal direction of 8a, they are arranged at equal distances from the intersection of the optical axis of the condenser lens 27 and the substrate 29a.

The four photodiodes 29d, 29e, 29f and 29g for alignment are disclosed in JP-A-55-55.
This is almost the same as that disclosed in Japanese Patent No. 52730.
Each of the photodiodes 29d, 29e, 29f, and 29g has a substantially square shape, and two sides of one photodiode are arranged so as to be substantially in contact with one side of another adjacent photodiode.
Also, four photodiodes 29d, 29e, 29f
And the center O of the conversion element portion consisting of 29 g (see FIG. 2)
At the intersection of the optical axis of the condenser lens 27 and the substrate 29a. These photodiodes 29
The d, 29e, 29f, and 29g receive the reflected light from the cornea of the subject's eye E out of the reflected light from the subject's eye E, and output an electric signal according to the amount of the received light.

On the other hand, the two photodiodes 29b and 29c for measuring the refracting power receive the reflected light from the fundus of the eye to be examined among the reflected light from the eye to be examined E, and according to the quantity of the received light, electricity is received. It is designed to output a signal. The signals output from the photodiodes 29b to 29g described above are provided to the processing device 50.

Next, the fixation target optical system 30 will be described. The fixation target optical system 30 includes a light source 31 and a fixation target 3
2, a collimator lens 33 and a cold mirror 34 are provided. In such a fixation target optical system 30,
The light source 31 illuminates the fixation target 22, the light flux from the fixation target 22 is converted into a substantially parallel light flux by the collimator lens 33, and the parallel light flux is passed through the cold mirror 34 and the dichroic mirror 26. Reach E. The subject will look at this fixation target while measuring the refractive power of the subject's eye. Further, the fixation target 20 is movable in the optical axis direction, and can be appropriately disposed at a position where the fixation target 20 can be fixed with the eye E to be inspected.

Further, the observation optical system 40 includes an infrared light source 41 for observing the extraocular part of the eye to be examined, a mirror 42, a relay lens 43,
It has an imaging lens 45 and an imaging element 45 composed of a CCD. The light flux emitted from the infrared light source 41 illuminates the eye E to be inspected and its peripheral portion. The light flux reflected from the eye to be inspected and its peripheral portion is partially reflected by the dichroic mirror 26. That is, the dichroic mirror 26 transmits infrared light and reflects other light, but part of the infrared light is reflected by the dichroic mirror. The light flux reflected by the dichroic mirror 26 passes through the cold mirror 34 and passes through the mirror 42.
Then, the light beam is deflected by the relay lens 43 and the image forming lens 44, and reaches the image sensor 45. In the image pickup element 45, an electric signal corresponding to the image formed on the image pickup element 45 is obtained, and this signal is given to the processing device 50.

The processing device 50 includes a superimposing circuit 5 that receives an electric signal provided by the image pickup device 45.
1. C for controlling the processing unit 50 and the drive system
The PU 52 and a waveform shaping circuit 53 that receives an electric signal given by the photodiodes 29b to 29g of the light receiving element unit 29 are provided. Further, as will be described later in detail, the CPU 52 is connected to a measurement switch 54 for supporting the start of the measurement of the eye refractive power and a measurement mode switching switch 55 for switching the measurement mode described later.

The superimposing circuit 51 generates image data to be displayed on the screen of the CRT 60 based on the electric signal related to the image of the eye to be inspected and its peripheral portion, which is given by the image pickup device 45. Furthermore, the superimposing circuit 51 follows the instruction from the CPU 52.
An image obtained by superimposing necessary information on the image corresponding to the eye to be inspected and its peripheral portion is displayed on the CRT 60.
Image data including these information is obtained so as to be displayed on the screen. The obtained image data is given to the CRT 60.

Further, the waveform shaping circuit 53 is disclosed in Japanese Patent Laid-Open No. 55-
Similar to the device disclosed in Japanese Patent No. 86437, the electric signals from the measuring photodiodes 29b and 29c are received, and these electric signals are respectively amplified by a built-in tuning amplifier (not shown). The tuning frequency of this tuning amplifier is adjusted to the chopping frequency of the light flux due to the rotation of the rotary drum 23. Next, the waveform shaping circuit 5
Reference numeral 3 shapes the substantially sinusoidal signals from the tuning amplifier into substantially rectangular wave signals. The rectangular wave-shaped signal corresponding to the electric signal from each of the measuring photodiodes 29b and 29c obtained in this way is stored in the CPU 5
2 given.

Similarly, the waveform shaping circuit 53 receives the electric signals from the four alignment photodiodes 29d, 29e, 29f and 29g, and converts them into voltage signals by a built-in amplifier (not shown). C
Give to PU52. The CPU 52 executes the following calculation based on the voltage signals v1 to v4 corresponding to the alignment photodiodes 29d, 29e, 29f and 29g.

First, the CPU 52 has v5 = (v1 + v
3)-(v2 + v4), and v6 = (v1 + v2)
-(V3 + v4) is calculated. The former is x of the corneal reflected light.
The latter is a signal relating to alignment in the direction (see FIG. 2), and the latter is a signal relating to alignment in the y direction (see FIG. 2) of corneal reflected light. Further, the CPU 52 causes the normalized x-direction alignment signal v6 = v5 / (v1 + v2 +).
v3 + v4) and the normalized y-direction alignment signal v7 = v6 / (v1 + v2 + v3 + v4). When v6 and v7 are within a predetermined value range, it is determined that the alignment is properly performed. That is, the alignment photodiode 29
The total voltage signal V8 (= V1 + V2 + V3 + V4) from d, 29e, 29f, and 29g is larger than a predetermined magnitude, and the reflected light from the cornea is located within a predetermined range in the x direction and the y direction. In this case, the alignment state is determined to be appropriate. As described above, in the present embodiment, whether or not the alignment state is appropriate is determined by whether or not there is a deviation between the eye to be inspected and the optical axis of the alignment detection optical system, and the light amount of corneal reflected light is more than a predetermined amount. It is judged by whether it is large or not.

The operation of the eye refracting power measuring apparatus thus constructed will be described below. The eye-refractive-power measuring device according to the present embodiment can operate in two modes according to ON / OFF of the measurement mode setting switch 55. FIG. 3 is a flowchart schematically showing the operation of the eye refractive power measuring device according to the present embodiment.

The process shown in FIG. 3 is started in response to the observer closing the measurement switch 54.

When the apparatus is powered on and a predetermined operation is performed by an observer before this processing is started, the light from the light source 31 is irradiated on the fixation target 22 and further fixed. The luminous flux applied to the target is collimator lens 3
3, the cold mirror 34, and the dichroic mirror 26 reach the eye E to be inspected. On the other hand, the luminous flux for measurement emitted from the infrared light source 21 is
It reaches the eye E through the rotary drum 23, the beam splitter 24, the image rotator 25 and the dichroic mirror 26. The light flux from the infrared light source 21 is partially reflected by the fundus of the eye E to be inspected, or partially reflected by the cornea of the eye E to be inspected, and the dichroic mirror 26, the image rotator 25, the beam splitter 24, and the light condensing unit. The light reaches the light receiving element portion 29 through the lens 27 and the diaphragm member 28. The reflected light from the fundus of the eye E to be examined is received by the photodiodes 29b and 29c for measuring the refractive power, and the reflected light from the cornea is received by the photodiodes 29d, 29e, 29f and 29g for alignment.

Further, the superimposing circuit 51 includes
The light emitted from the infrared light source 41 is reflected by the eye to be inspected and its peripheral portion, and then reaches the image sensor 45 after passing through the dichroic mirror 26, the cold mirror 34, the mirror 42, the relay lens 43, and the imaging lens 44. Based on the electric signal, the superimposing circuit 5
1 is based on this given electric signal, and
According to the command from 52, the image data in which the mark for which the center of the eye to be inspected is aligned is superimposed on the obtained image is generated. This image data is given to the CRT 60, and an eye to be inspected and a mark at a predetermined position are displayed on the screen of the CRT.

The observer moves the device as desired so that the pupil of the eye to be inspected and the mark are aligned with each other.

Next, the observer closes the measurement switch 54 to execute the processing shown in FIG. In the process of FIG. 3, first, the CPU 52 determines whether or not the measurement mode setting switch 55 is open, that is, the state corresponding to the normal measurement mode (step 30).
2). If YES is determined in this step, the device operates under the normal measurement mode.

Next, the CPU 52 determines whether or not the alignment state is appropriate (step 302). More specifically, v6 and v calculated as described above
7 determines whether it is within a predetermined range. At this time, if the alignment state is not appropriate, the CPU 5
2 ends the process.

If YES in step 302, that is, if it is determined that the alignment state is appropriate, the CPU 5
2 executes a predetermined process to measure the eye refractive power. That is, the CPU 52 uses the image rotator 25.
By rotating the photodiode 29b for measuring the refractive power,
Based on the signal given by 29c, data relating to the eye refractive power such as the spherical power, astigmatic power, and astigmatic axial power of the eye E to be examined is calculated, and these data are output to the superimposing circuit 51.

As described above, the superimposing circuit 51 is irradiated with the infrared light source 41 and reflected by the eye to be inspected and its peripheral portion, and then the dichroic mirror 26, the cold mirror 34, the mirror 42, and the relay lens 43. An electric signal based on the light reaching the image pickup element 45 via the image forming lens 44 is given, and the superimposing circuit 51 generates image data according to the given electric signal. Therefore, the superimposing circuit 51 further generates image data obtained by superimposing various information given from the CPU 52 on the obtained image and gives it to the CRT 60 (step 304). FIG. 4 shows an example of an image displayed on the screen of the CRT 60 in this way. In FIG. 4, a spherical power (SPH) "-1.2" is displayed at the bottom of the screen 400.
5 ", astigmatic power (CYL)" -0.75 "and astigmatic axial power (AX)" 160 "are displayed.

It should be noted that, in step 303, it is determined whether or not the alignment state is appropriate, and if it is determined that the alignment state is not appropriate, the measurement is stopped and the process ends. In this case, the device emits a buzzer sound or the like, or displays on the screen of the CRT 60 that the measurement is stopped.
Notify the observer of the suspension of the measurement.

On the other hand, when the observer closes the measurement mode setting switch 55, that is, turns it on, it is determined as NO in step 301, and the process proceeds to step 303. For example, in the normal measurement mode, the eye refractive power of the eye to be inspected was measured, but it is not possible to obtain an appropriate alignment state. By closing the measurement mode setting switch 55, the person can operate the apparatus in the forced measurement mode in which the eye refractive power is measured regardless of the alignment state.

Even under this forced measurement mode, C
The PU 52 rotates the image rotator 25, and based on the signals given by the photodiodes 29b and 29c for measuring the refractive power, the spherical power, the astigmatic power of the eye E,
Data relating to the eye refractive power such as the axial power of astigmatism is calculated, and the data and the data indicating that the measurement is performed in the forced measurement mode are output to the superimposing circuit 51.

Further, under the forced measurement mode, in step 303, it is not judged whether the alignment state is proper or not.

The superimposing circuit 51 is a CPU
Image data that is obtained by superimposing various information given from 52 on the obtained image is generated, and this is generated by the CRT6.
0 (step 304). In this way, CR
An example of the image displayed on the screen of T60 is shown in FIG. In FIG. 5, the spherical power (SP
H) "-1.25", astigmatic power (CYL) "-0.7"
5 "and astigmatism axis (AX)" 160 "are displayed, and" AL-OFF "indicating that the eye refractive power is measured under the forced measurement mode is displayed on the upper part of the screen 400. .

In this way, after measuring the eye refractive power and displaying a predetermined image on the screen of the CRT 60,
The measurement result and information indicating under what mode the measurement is performed are temporarily stored in a memory (not shown) built in the CPU 52. In this embodiment, the right eye and the left eye can be measured a plurality of times, so that the memory stores the measurement result and the mode information for each measurement. .

After the measurement is completed, the observer operates in a predetermined manner to output the measurement result to an output device (not shown) such as a printer. FIG. 6 is a diagram showing an example of a printed material obtained by the eye refractive power measuring device according to the present embodiment. As shown in FIG. 6, the printed matter 600 includes a subject number 601 and a measurement result 60 regarding the right eye.
2. The measurement result 603 for the left eye is displayed. In the measurement result 602 regarding the right eye, in addition to the spherical power (SPH), the astigmatic power (CYL) and the astigmatic axial power (AX), in the rightmost column 604 when measured under the forced measurement mode,
A "?" Mark appears. In the example shown in FIG. 6, it is understood that all six right eye measurements were performed under the forced measurement mode. The measurement result 602 also includes a representative value such as the obtained spherical power. “*” Appears in the rightmost column 605 of the position where these representative values appear.

According to the present embodiment, the observer sets the measurement mode setting switch 55 in a predetermined state so that the eye refractive power is measured regardless of whether the alignment state is proper or not. Therefore, when measuring the subject's eye with a large eccentricity of the pupil, or the subject's eye with opacity in the center of the pupil, such as a cataract, it is not possible to obtain an appropriate alignment state, or easily Even when an appropriate alignment state cannot be obtained, the eye refractive power can be measured.

Next, a description will be given of the eye refractive power measuring device according to the second embodiment of the present invention. The configuration of the eye-refractive-power measuring device according to this embodiment is the same as that of the first embodiment except for the processing by the CPU 52.

The operation of the eye-refractive-power measuring device configured as described above will be described.

In this embodiment, when the measurement mode setting switch 55 is off, the same processing as steps 302 to 304 of the flowchart shown in FIG. 3 of the first embodiment is executed. That is, when the alignment state is appropriate, the eye refractive power is measured, and the measurement result and the like are displayed on the screen of the CRT 60. Also,
During the measurement in step 303, if the alignment state becomes unsuitable, the measurement is stopped.

On the other hand, when the measurement mode setting switch 55 is closed, that is, in the ON state, it operates according to the flowchart shown in FIG.

First, the variable i used in the processing is initialized (step 701), and then this variable i is set to a predetermined number N.
Is determined (step 702). This step 702 will be described later.

Thereafter, it is judged whether or not an appropriate alignment state is obtained (step 703), and if the alignment state is appropriate (YES in step 703), measurement is executed (step 704). , The measurement result is displayed (step 705). If the alignment state becomes unsuitable during the measurement in step 704, the process proceeds to step 706. On the other hand, step 7
If it is judged NO in 03, or step 7
If the alignment state becomes unsuitable during the measurement of 04, the variable i is incremented and step 702
Return to

If the variable i becomes equal to the predetermined number N in step 702, the process proceeds to step 707. This judges whether or not the alignment state cannot be obtained in step 703, or the number of times the alignment state is not appropriate during the measurement in step 704 becomes equal to a predetermined number N. If YES in step 702,
The eye refractive power is measured regardless of the alignment state (step 707). During the measurement in step 707, it is not judged whether the alignment state is proper or not. When the measurement in step 707 is completed, the measurement result and the like are displayed on the CRT 60 (step 705).

According to this embodiment, the observer can
By setting the measurement mode setting switch, the number of times that the alignment state was not appropriate is counted, and when the number of times is equal to the predetermined number, the eye refractive power is measured regardless of the alignment state. It becomes possible to do.

Next, an eye refracting power measuring apparatus according to the third embodiment of the present invention will be described. The eye-refractive-power measuring apparatus according to this embodiment is substantially the same as that of the first embodiment, except for the processing by the CPU 52, which will be described later, and the configuration of the light-receiving element section. Further, in the third embodiment, a focusing mechanism including a lens and the like is provided in the optical path in the measurement and alignment detection optical system of FIG. In this focusing mechanism,
Input device such as joystick (not shown)
By operating, the lens is moved and the focus position can be changed. Further, in the third embodiment, the measurement mode setting switch is omitted.

FIG. 9 is a view showing the arrangement of the light receiving element portion 129 of the eye refractive power measuring device according to this embodiment. FIG.
As shown in FIG.
Above, two photodiodes 129b for measuring the refractive power
And 129c are attached. The positions where the photodiodes 129b and 129c are attached are the photodiodes 2 according to the first embodiment shown in FIG.
It is similar to the positions of 9b and 29c. Also, the substrate 129a
Above are eight alignment diodes, 129d.
-1, 129d-2, 129e-1, 129e-2, 1
29f-1, 129f-2, 129g-1, 129g-
2 are installed.

As shown in FIG. 8, the alignment diodes are four fan-shaped photodiodes 129d-1, 129e-1, 129f-1 and 1 having a central angle of 90 °.
29g-1 and four photodiodes 12 arranged concentrically outside these four photodiodes.
9d-2, 129e-2, 129f-2 and 129g
-2. For example, the set of two photodiodes 129d-1 and 129d-2 corresponds to the photodiode 29d according to the first embodiment shown in FIG.

These photodiodes 129d-1, 1
29d-2, 129e-1, 129e-2, 129f-
The outputs from 1, 129f-2, 129g-1 and 129g-2 are applied to the waveform shaping circuit 53, respectively. In the waveform shaping circuit 53, the received signal is converted into a voltage signal by a built-in amplifier (not shown) and given to the CPU 52.

The operation of the eye refractive power measuring device having the above structure will be described.

Measurement mode setting switch 54 (see FIG. 1)
However, the CPU 52 executes the process shown in FIG. 9 due to the closing. First, an initial value of a condition serving as a criterion for determining whether or not the alignment state is appropriate is set (step 901). Prior to this,
Light from the light source 31 is used by the fixation lamp 22 and the collimator lens 3
3 reaches the eye E to be inspected, and on the other hand, the light emitted from the infrared light source 21 reaches the eye E to be inspected via the condenser lens 22, the rotating drum 23, and the reflection from the fundus. The light is received by the photodiodes 129b and 129c for measuring the refractive power, while the reflected light from the cornea is reflected by the photodiodes 129d-1, 129d-2, 129e-1, 129e for alignment.
2, 129f-1, 129f-2, 129g-1 and 129g-2 are the same as those in the first embodiment.

In this embodiment, the judgment criteria are presence / absence of deviation between the eye to be inspected and the optical axis of the measurement optical system, presence / absence of deviation in focus with respect to the eye to be inspected, and the amount of light reflected from the fundus of the eye being larger than a predetermined amount. And whether the amount of reflected light from the cornea is larger than a predetermined amount.

For example, the presence / absence of deviation between the eye to be inspected and the optical axis of the measurement optical system is determined based on the voltage signal output from the alignment photodiode and applied to the CPU 52 via the waveform shaping circuit 53. Here, the voltage signal output from the photodiode 129d-1 corresponds to V11, the voltage signal from the photodiode 129d-2 corresponds to V12, the voltage signal from the photodiode 129e-1 corresponds to V21, Photodiode 129
The voltage signal from e-2 corresponds to V22, the voltage signal from the photodiode 129f-1 corresponds to V31, the voltage signal from the photodiode 129f-2 corresponds to V32, and the voltage signal from the photodiode 129g-1. The voltage signal corresponds to V41, and the photodiode 129g-
It is assumed that the voltage signal from 2 corresponds to v42. At this time, the CPU 52 determines that v55 = (v11 + v12 + v31
+ V32)-(v21 + v22 + v41 + v42), and v66 = (v11 + v12 + v21 + v22)-
(V31 + v32 + v41 + v42) is calculated, and this v
The presence or absence of the above-mentioned deviation is determined using 55 and v66. That is, if v55 and v66 are within predetermined ranges, it is determined that there is no deviation between the eye to be inspected and the optical axis of the measurement optical system.

Further, the presence / absence of the focus shift with respect to the eye to be inspected can be obtained based on the voltage signal output from the alignment photodiode and applied to the CPU 52 via the waveform shaping circuit 53. More specifically, among the alignment photodiodes, four photodiodes 129d-2, 129e-2, 129f- provided on the outer peripheral portion.
2 and sum of voltage signals corresponding to 129g-2 v77 =
When (v12 + v22 + v32 + v42) is smaller than the predetermined first threshold value, it is determined that there is no defocus.
This is because when there is no focus shift, as shown in FIG. 10, the corneal reflection image IM shows the inside photodiode 129.
d-1, 129e-1, 129f-1, and 129g-
1 is included in the area where it is arranged, and on the other hand, when the focus is deviated, as shown in FIG. 11, the corneal reflection image IM
However, the outer photodiodes 129d-2, 129e-
2, 129f-2 and 129g-2 extend to the area where they are located.

The amount of light reflected from the fundus corresponds to the sum of the voltage signals output from the photodiodes 129b and 129c for measuring the refractive power and given to the CPU 52 via the waveform shaping circuit 53, one of which The amount of light reflected from the cornea corresponds to the sum of the voltage signals output from the eight alignment photodiodes and given to the CPU 52 via the waveform shaping circuit 53. The light quantity of the reflected light from the fundus and the light quantity of the reflected light from the cornea are compared with a predetermined second threshold value and a predetermined third threshold value, respectively.

As described above, whether or not there is a deviation between the eye to be inspected and the optical axis of the measurement optical system, whether or not there is a deviation in focus with respect to the eye to be inspected, whether the amount of light reflected from the fundus is greater than a predetermined amount, and
In order to determine whether the amount of light reflected from the cornea is larger than a predetermined amount, a predetermined range and first to third threshold values are set in step 901 described above.

Then, a condition change flag flg = 0 indicating whether or not a process for changing a condition serving as a judgment standard to be described later should be executed is set (step 902). Further, in a step (step 905) of judging a condition serving as a judgment criterion, which will be described later, i is initialized for storing the number of times it is judged that any of the four conditions is not appropriate (step 903). Further, it is judged whether i has reached a predetermined number N (step 90).
4) If no, then step 905
On the other hand, if YES is determined, the process proceeds to step 906.

In step 905, the presence / absence of deviation between the eye to be inspected and the optical axis of the measurement optical system, the presence / absence of deviation in focus with respect to the eye to be inspected, whether the amount of light reflected from the fundus of the eye is larger than a predetermined amount, and the cornea It is determined whether the light amount of the reflected light from is larger than a predetermined light amount. In this step, if it is determined that any of the above-mentioned conditions is inappropriate, the process proceeds to step 907 and i is incremented (step 907). On the other hand, when it is determined that any of the above conditions is appropriate, the process proceeds to step 908, and the eye refractive power is measured (step 90).
8). The measurement in step 908 is the same as the measurement in step 303 of FIG. 3 and step 704 of FIG. 7.

Even during the measurement in this step 908, it is judged whether or not the condition as the judgment criterion is appropriate, and if any of the above-mentioned conditions is judged to be inappropriate in this judgment, Proceeds to step 907. When the measurement of the eye refractive power is completed, the result is displayed on the CRT 60 (step 909), and the process is completed. CRT60
The image displayed in is similar to that shown in FIG.

On the other hand, if i is incremented in step 907, it is determined in step 904 whether i has reached the predetermined number N, and if yes is determined. If so, go to step 906. That is, in step 905, or during the measurement of the eye refractive power (step 908), when the number of times when the condition serving as the judgment criterion becomes inappropriate reaches a predetermined number N,
Go to step 906.

In step 906, it is determined whether the condition change flag flg is 1. This flag flg
Is set to 0 in step 902, the first time, that is, the first time the process proceeds to step 906, it is determined to be no in step 906, and the condition change flag flg is set to 1 ( Step 910).

At step 910, the observer
By operating an input device (not shown) such as a keyboard, it is possible to newly set a predetermined range indicating presence / absence of deviation between the eye to be inspected and the measurement optical system, and first to third threshold values.

After such new setting, the processing of steps 903 to 908 is executed again. In this case, in step 905, or during measurement of the eye refractive power (step 908), when the condition serving as the determination reference becomes inappropriate, the process proceeds to step 907, i is incremented, and this i is When the predetermined number N is reached (Yes in step 904), the process proceeds to step 906.

When a new setting is made in this way,
Since the condition change flag flg has been set to 1 in step 910, it is determined to be YES in step 906, and the process ends. That is,
When the number of times any of the conditions becomes inappropriate reaches a predetermined number of times, even though the condition serving as the judgment criterion is changed, the process is terminated.

According to the present embodiment, when the eye refraction power is attempted to be measured according to a certain criterion, any one of the conditions included in the criterion is not appropriate, so that the predetermined measurement cannot be performed. , The criteria can be changed.
This allows the observer to more easily and appropriately measure the eye refractive power of the subject's eye.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that this is what is done.

For example, in the first embodiment, whether or not the alignment state is appropriate is determined by whether or not there is a deviation between the eye to be inspected and the optical axis of the alignment detection optical system, and the light amount of the corneal reflected light is predetermined. However, the present invention is not limited to this, and in addition to the above, whether or not the light amount of the fundus reflected light is larger than a predetermined amount, or a combination thereof. You may judge by.

In addition, in the second embodiment,
Although the processing as shown in FIG. 7 is configured to be executed by turning on the measurement mode setting switch 55, the present invention is not limited to this, and the measurement mode setting switch 55 can be removed. The configuration of FIG. 7 may be executed without fail. Further, in the second embodiment, the predetermined number N may be changed by the operation of the observer.

Furthermore, in the first embodiment,
In the normal measurement mode, as in the second embodiment, the number of times the alignment state is not appropriate is counted,
Obviously, when the number of times becomes equal to the predetermined number N, the eye refractive power may be measured regardless of the alignment state.

Further, in the third embodiment, the conditions serving as the judgment criteria are presence / absence of deviation between the eye to be inspected and the optical axis of the measurement optical system, presence / absence of defocus in the eye to be inspected, reflected light from the fundus of the eye. Is greater than a predetermined amount, and whether the amount of light reflected from the cornea is greater than a predetermined amount. 4
However, any one of these four conditions or a combination of any of these conditions may be used.

Furthermore, the first embodiment and the second embodiment
In the embodiment described above, the measurement mode setting switch may be set in a predetermined manner so that the processing according to the third embodiment shown in the flowchart of FIG. 9 can be executed. Further, in the third embodiment, by providing a measurement mode setting switch and setting it, the processing shown in the flowchart of FIG. 9 and the processing shown in the flowchart of FIG. 3 or the processing shown in the flowchart of FIG. 7 are performed. It may be configured to be able to execute either one.

Further, in the present specification, the term "means" does not necessarily mean physical means, but also includes cases where the function of each means is realized by software. Further, the function of one means may be realized by two or more physical means, or the functions of two or more means may be realized by one physical means.

[0090]

EFFECTS OF THE INVENTION According to the present invention, the eye refractive power can be measured even if the alignment is not completed properly without forcing the subject to perform a troublesome operation. It is possible to provide a measuring device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an eye refractive power measurement device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a light receiving element section according to an embodiment of the present invention.

FIG. 3 is a flow chart schematically showing the operation of the eye refractive power measurement device according to the first embodiment.

FIG. 4 is a diagram showing an example of an image displayed on the screen of the CRT according to the first embodiment.

FIG. 5 is a diagram showing an example of an image displayed on the screen of the CRT according to the first embodiment.

FIG. 6 is a diagram showing an example of a printed material obtained by the eye-refractive-power measuring device according to the present embodiment.

FIG. 7 is a flowchart schematically showing the operation of the eye refractive power measurement device according to the second embodiment.

FIG. 8 is a diagram showing a light receiving element portion according to a third embodiment.

FIG. 9 is a flowchart schematically showing the operation of the eye refractive power measurement device according to the third embodiment.

FIG. 10 is a diagram showing an example of a corneal reflection image.

FIG. 11 is a diagram showing an example of a corneal reflection image.

[Explanation of symbols]

 10 Eye Refractive Power Measuring Device 20 Measurement and Alignment Detection Optical System 21 Infrared Light Source 22 Condenser Lens 23 Rotating Drum 24 Beam Splitter 25 Image Rotator 26 Dichroic Mirror 27 Condensing Lens 28 Aperture Member 29 Light-Receiving Element Section 30 Fixation Target Optical System 40 Observation optical system 50 Processing device 51 Superimposing circuit 52 CPU 53 Waveform shaping circuit 60 CRT

Claims (8)

[Claims] 1. A measurement optical system for measuring an eye refractive power of an eye to be inspected, an alignment signal generating means for generating an alignment signal indicating an alignment state between the eye to be inspected and the measurement optical system, and based on the alignment signal. An eye refracting power measuring device comprising a judging means for judging whether or not the measurement is possible, and a measuring means for measuring the eye refracting power of the eye to be inspected when the judgment means judges that the measurement is possible. An eye-refractive-power measuring device, wherein the measuring means measures the eye-refractive power of an eye to be inspected in a predetermined case regardless of the judgment of the judging means. 2. A measurement optical system for measuring an eye refractive power of an eye to be inspected, an alignment signal generating means for generating an alignment signal indicating an alignment state between the eye to be inspected and the measurement optical system, and based on the alignment signal. An eye refracting power measuring device comprising a judging means for judging whether or not the measurement is possible, and a measuring means for measuring the eye refracting power of the eye to be inspected when the judgment means judges that the measurement is possible. The eye refracting power measuring device, wherein the determining means includes a changing means for changing a criterion for determining whether or not measurement is possible. 3. The measurement optical system includes an illumination unit for illuminating an eye to be inspected, and a focusing mechanism for focusing on the eye to be inspected, wherein the alignment signal is an optical axis of the eye to be inspected. Deviation from the optical axis of the measurement optical system, deviation of the focus on the eye to be inspected, illuminated from the illumination means, the amount of light reflected by the cornea of the eye to be inspected, and illuminated from the illumination means, of the eye to be inspected At least one of the light quantity of the reflected light reflected by the fundus of the eye, the determination means, whether the deviation of the optical axis is within a predetermined range, whether the defocus is within a predetermined range, from the cornea Whether the amount of reflected light is within a predetermined range, and whether the amount of reflected light from the fundus is within a predetermined range, based on at least one of the above, it is determined whether measurement is possible. The method according to claim 1 or 2, characterized in that Refractive power measuring device. 4. The eye of the eye to be inspected regardless of the first measurement mode in which the eye refracting power of the eye to be inspected is determined when the determination means determines that the eye is measurable The eye-refractive-power measuring device according to claim 1, further comprising setting means for setting one of the second measurement modes for measuring the refractive power. 5. The eye refractive power is measured when the determining means determines that the eye refractive power is measured together with the eye refractive power data of the eye refractive power measured by the measuring means, or
The eye refractive power measurement device according to claim 1, further comprising an output unit that outputs information indicating whether the eye refractive power has been measured regardless of the determination made by the determination unit. 6. The measuring means, regardless of the judgment of the judging means, when the measuring means judges that the measurement by the measuring means is more than a predetermined number of times and the measurement is impossible. The eye refractive power measurement device according to claim 1, wherein the eye refractive power measurement device is configured to perform measurement of eye refractive power. 7. The changing means includes a range of deviation of the optical axis, a range of deviation of the focus, a light amount of reflected light from the cornea,
The eye refractive power measuring device according to claim 2, wherein at least one of the amounts of light reflected from the fundus can be arbitrarily changed. 8. When the measurement by the measuring means is performed more times than a predetermined number of times and it is determined that the measurement is impossible, the changing means changes the criterion for determining whether or not the measurement is possible. The eye refractive power measuring device according to claim 2.