JPH01129830A - Automatic eye refractive power measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic eye refractive power measuring device for measuring the eye refractive power of an eye to be examined.

(Prior Art) Conventionally, automatic eye refractive power measurement devices for measuring the eye refractive power of the eye to be examined project a pattern image for measuring refractive power onto the fundus of the eye to be examined and measure the fundus reflex image of the eye to be examined. Projected onto a photoelectric element via an optical system.

The signal from this photoelectric element is stored in advance, and the eye refractive power of the subject's eye is calculated and measured based on this stored signal.
There is one in which the values of spherical refractive power S, cylindrical refractive power C1, and cylindrical axis angle θ are displayed on a display unit as measurement data.

(Problems to be Solved by the Invention) This conventional device is configured to display measurement data of eye refractive power on the display section.

Since the measurement pattern image formed and stored on the photoelectric element and used as the basis for refractive power calculation is not displayed as an image, the refractive power may be affected by eyelashes, blinking, the degree of pupil dilation, etc. If an abnormality such as distortion or defect occurs in the measurement pattern image, this cannot be detected, and accurate measurement results cannot be obtained by using measurement data based on such an abnormal refractive power measurement pattern image. First, there is the disadvantage that it is difficult to easily judge whether or not the resulting measurement data is reliable.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an automatic eye refractive power measuring device that can visually determine the reliability of measurement data of the eye to be examined and the measurement state of the eye to be examined. With the goal.

(Means for Solving the Problems) In order to achieve the above object, the automatic eye refractive power measuring device according to the present invention is characterized in that the refractive power measurement pattern image projected onto the fundus of the examinee's eye is reflected in the fundus of the examinee's eye. A photoelectric element on which an image is formed, a storage unit that stores the signal detected by the photoelectric element as an image signal, and a display unit that displays a pattern image for refractive power measurement based on the image signal stored in the storage unit. and an arithmetic unit that calculates the refractive power of the eye to be examined based on the image signal stored in the storage unit.

(Function) In the automatic eye refractive power measuring device according to the present invention, since the pattern image for refractive power measurement for obtaining measurement data is displayed on the display section, it is possible to check whether the obtained measurement data is reliable. You can visually judge whether

(Example) 1-A, Overall Equipment Figure 1 shows the optical arrangement of an optometric apparatus including an automatic eye refractive power measuring apparatus according to the present invention. This optometry device has a keratometry system 1 for measuring the radius of curvature of the cornea C of the eye E to be examined.
, an objective refractive power measurement system 2 for objectively measuring the refractive power of the eye E to be examined, and a fixation target for fixating the eye E to be examined in order to fix the visual axis of the eye E during measurement. A fixation/subjective measurement system 3 that projects an optotype for a subjective test, and an anterior segment 11 of the eye E to be examined.
1rs, an anterior segment [6] and an alignment system 4 for aligning the optical axis of the device and the visual axis of the eye to be examined. Note that a part of the optical path of the anterior ocular segment a detection/alignment system 4 is shared with the optical path of the keratometry system 1.

1-B, ``21 The keratometry system 1 includes a pattern projection system 10 for projecting an annular pattern toward the cornea for measuring the radius of curvature of the cornea, and a size of a corneal reflection image of the annular pattern. and a measurement optical system 11 for measuring the shape and shape.

The pattern projection system 10 includes a pattern plate 101 having an annular aperture 100 and a circle disposed behind the aperture 100 that emits keratometry light with a wavelength of 930 nm to 11000 nm (hereinafter, this keratometry light will be denoted by the symbol a). Annular light source 102
It is composed of. The emitted light from the light source 102 passes through the aperture 100 and is projected onto the cornea C of the eye E to be examined as projection light. The projected light is reflected by the cornea C, creating a virtual image 100' of the aperture 100. The keratometry light a reflected by the cornea C enters the measurement optical system 11 as if it had emitted a virtual image 100'.

The measurement optical system 11 includes an objective lens 110 and a wavelength of 400n.
Visible light of m to 700 nm (hereinafter referred to as C) is reflected and keratometry light a (wavelength of 9301 to 10 nm) is reflected.
A half mirror 111 that transmits light in a long wavelength range of 800n+m or more including 1000n, and a half mirror 111 with a wavelength of 865nm.
a half mirror 112 that transmits infrared light (hereinafter referred to as "infrared light") and reflects infrared light with a wavelength of 900 nm or more, a relay lens 113, and an aperture 114;
A half mirror 115 that transmits red light with a wavelength of 700 nm (hereinafter referred to as the red light) and reflects the keratometry light a, a relay lens 116, and a relay lens 116 that reflects the infrared light and reflects the keratometry light a. It is composed of a half mirror 117 that transmits the and red light d, an imaging lens 118, and an area CCD 5 as a photoelectric element.

Here, as shown in FIG. 3, the diaphragm 114 is
It is divided into two parts: 14a and a central part 114b. Peripheral area 1
14a cuts light with a wavelength of 930 nm or more, and the central part 1
14b is configured to transmit light having a wavelength of 900 nm or more. That is, light of 900 nm or more and 930 nm or less (hereinafter, this light will be denoted by the symbol e) can be transmitted through the entire area of the aperture 114. After the keratometry light a reflected by the cornea C is focused by the objective lens 110,
It passes through the half mirror 111. Then, the keratometry light a is reflected by the half mirror 112, and the relay lens 1
13 and passes through the center portion 114b of the diaphragm 114.

Thereafter, the keratometry light a is reflected by the half mirror 115, and is transmitted to the half mirror 11 by the relay lens 116.
7 and pass through its half mirror 117. The keratometry light a is transmitted to the area CC by the imaging lens 118.
Corneal measurement ring pattern 100' (6th
(see Fig. 7).

Even if the anterior segment (iris) of the subject's eye is illuminated when forming the virtual image 100' of the aperture 100 by projecting the keratometric light a,
Since the reflected light is cut off by the peripheral portion 114a of the aperture 114, it does not reach the area CCD 5, and the corneal pattern 100' is approximately projected onto the area CCD 5.

FIG. 2(a) is an optical path diagram of the pattern projection system 20 shown in FIG.
65n- refractive power measurement light (infrared light b mentioned above) is condensed by a condenser lens 201 and then passed through a conical prism 20.
2, and is irradiated onto a ring pattern 203 for measuring refractive power. The refractive power measurement light passing through the ring pattern 203 is the relay lens 204. The light is irradiated onto a ring aperture 207 via a mirror 205 (see FIG. 1) and a relay lens 206. After the refractive power measurement light passes through the ring diaphragm 207, it is reflected by the reflective surface 208a of the perforated mirror 208. Thereafter, the refractive power measurement light beam is reflected by the mirror 209, passes through the half mirrors 112 and 111 as components of the measurement optical system 11 of the keratometry system 1, and is passed through the objective lens 110 to the fundus E of the eye E to be examined. The ring pattern 203 is projected as an image 203' (see FIG. 2). Here, the light emitting diode 200 and the ring diaphragm 207 are optically conjugate, and the ring diaphragm 207 and the pupil E of the eye E to be examined are located at an optically conjugate position.

C knee 2:' 21 FIG. 2(b) is an optical path diagram of the measurement optical system 21 shown in FIG. 1. The light of the ring pattern image 203' reflected by the fundus E of the eye E to be examined is focused by the objective lens 110. The light passes through the half mirrors 111 and 112, is reflected by the mirror 209, and is reflected by the perforated mirror 208.
The light passes through the opening 208b and passes through the aperture 210.

The refractive power measurement light passes through the diaphragm 210 and passes through the relay lens 21.
Half mirror 21 that transmits visible light C after passing through 1
2 and is irradiated onto an aperture 215 via a relay lens 213 and a mirror 214. As shown in FIG. 4, this diaphragm 215 has a peripheral portion 215b that transmits the refractive power measurement beam having a wavelength of 865 nm, and a central portion 215a that cuts off the refractive power measurement beam.

Moreover, this aperture 215 has a wavelength of 93
The keratometric light a of 0 nm to 11000 nm is not transmitted,
Moreover, it has a property of transmitting visible light C having a wavelength of 400 nm to 700 nm. As a result, the refractive power measurement light is changed to the diaphragm 21.
After passing through the half mirror 217 which reflects only the visible light C through the focusing lens 216 and transmits the refractive power measuring light C, the visible light C passes through only the peripheral part 215b of the corneal measurement system 1 of the keratometry system 1. It is reflected by the half mirror 117, and is imaged by the imaging lens 11g on the area CCD S as a ring pattern image 203' (see FIGS. 6 and 7).

The focusing lens 216 and the aperture 215 are part of the pattern projection system 20
light emitting diode 200. The condenser lens 201, conical prism 202, and ring pattern 203 are housed together in a movable housing 219, and are movable in the optical axis direction as shown by arrow 218 in FIG.

In the measurement optical system 21 described above, the diaphragm 210 is optically conjugate with the position of the pupil E of the eye E to be examined with respect to the objective lens 110, and the light receiving element 5 is located at the position of the pupil E of the eye E to be examined when the eye E is emmetropic (refractive power O Diopter). It is optically conjugate with the intermediate imaging plane A of the ring pattern 203 (see FIG. 2).

Visible light C with a wavelength of 400n- to 700nm emitted by the three light sources 30 at 1-D and °
is condensed by a condenser lens 31 and illuminates a chart board 32.

The chart board 32 has a sunburst chart (fixation chart) 32 as a fixation target, for example, as shown in FIG. 1O.
a, visual acuity chart for subjective testing 32b, astigmatism chart 32c, cross 1J dar chart 32d.

The red and green charts 32e are arranged in a circumferential direction, and each chart is rotated about the axis 34 to be selectively inserted into the optical path.

The images of the charts 32a to 32e are projected onto the eye E by the projection lens 35, are reflected by the mirror 36, are reflected by the half mirror 217, and are merged into the measurement optical system 21 of the objective refractive power measurement system 2. It passes through the diaphragm 215 via the focusing lens 216, the mirror 214, and the relay lens 2.
13 to the half mirror 212, passes through the half mirror 212, and is guided to the barrier pull cross cylinder 37. Visible light C is the barrier pull cross cylinder 37
The light passes through the mirror 38, is reflected by the half mirror 111, is projected onto the subject's eye E by the objective lens 110, and the charts 32a to 32e are observed by the subject's eye.

Further, a plurality of glare light sources 33 for emitting visible light for glare testing are arranged near the chart board 32 near the outer periphery of the insertion positions of the charts 32a to 32e inserted into the optical path. This glare test light 1lJX33
can also be placed near the objective lens 110.

Also, to perform a glare test.

Instead of providing the light source 33, for example, the visual acuity chart 3
It is also possible to adopt a configuration in which the contrast between the viewing table of 2b and the base is changed.

1-E, Anterior Segment Viewing and Alignment System Outside the pattern plate 101 of the pattern projection system 10 of the keratometry system 1, a plurality of light emitting diodes 40 for illuminating the anterior ocular segment are arranged. The emitted infrared light with a wavelength of 900 nm (hereinafter, this infrared light will be referred to as e) illuminates the anterior segment of the eye E to be examined. The infrared light e reflected by the anterior segment of the eye (anterior segment illumination light) is focused by the objective lens 110, passes through the half mirror 111, and is transmitted along the measurement optical system 11 of the keratometry system 1 described above. is propagated through the imaging lens 1.
18 onto the area CCD S.

A plurality of light emitting diodes 41 that emit infrared light with a wavelength of 900r+m are arranged near the outer periphery of the objective lens 110.
The plurality of light emitting diodes 41 are the alignment light source. The alignment light emitted from the alignment light source 41 (hereinafter, the alignment light is denoted by the symbol f) is reflected by the eye E and then condensed by the objective lens 110, in the same manner as the anterior segment illumination light e. Half mirror 111
After passing through, it is guided to the measurement optical system 11 of the keratometry system 1, and is imaged onto the area CCD S by the imaging lens 118.

In front of the half mirror 115 of the measurement optical system 11 of the corneal measurement system 1, an aiming scale projection optical system is arranged. This aiming scale projection system uses red light with a wavelength of 700nun (
This corresponds to the aforementioned light d. A light emitting diode 42 that emits scale light (hereinafter referred to as scale light), a condensing lens 43 that collects scale light d from the light emitting diode 42, and a measuring optical system 1 that reflects the scale light that has passed through the aiming scale 44.
1 and a mirror 45 for merging the two.

The scale light d from the aiming scale 44 is a half mirror.
After passing through the measurement optical system 11, it is imaged onto the area CCD S by its imaging lens 118.

11n 1 sentence FIG. 5 is a block circuit diagram of the present optometric apparatus.

The drive circuit 313 scans the area CCD 5 in response to a command from the arithmetic/control circuit 301, and the received image is sent to the amplifier 5.
' and output as an analog signal.

The arithmetic/control circuit 3 old controls the gate circuit 302 as an analog switch. Gate circuit 302 is area CC
An analog signal from D5, an analog signal from D/A converter 324', or a signal from character circuit 306 having a function to be described later is output to display 305 via display interface 304. Display 3
05 consists of, for example, a CRT, LCD television, or plasma display, and is usually an area (1, CD
5, it displays an anterior segment image EA and an alignment index image 41' (see FIG. 9).

The A/D converter 303 has a function of converting an analog signal from the area CCD 5 into a digital signal. The digital signal is input to frame memory 324. The data of at least one screen of the area CCD 5 is stored in the frame memory 324. Further, the arithmetic control circuit 301 transmits pulses from the pulse generator 312 to the driver circuit 318.
．． 319 and 320, and has a function of counting the number of pulses and outputting the counted value as a signal to the first memory 309, and this first memory 309 stores the counted value. do.

A driver circuit 31g transfers pulses from the arithmetic control circuit 301 to a pulse motor 3 for driving the movable barrel portion of the refractive power measurement system 2.
21 to drive this pulse motor 321. The driver circuit 319 is the chart board 3 of the visual/subjective measurement system 3
Pulses are supplied to the second rotational pulse motor 322 to drive this pulse motor 322.

The driver circuit 320 supplies pulses to a pulse motor 323 for rotating the VCC 37, and drives the pulse motor 323.

The calculation/control circuit 301 also includes driver circuits 314 to 314.
317, 325 to 327 are connected. The driver circuit 314 is connected to the annular light source 102 of the corneal measurement system 1, and supplies power to the annular light source 102 by a power supply circuit (not shown) based on instructions from the arithmetic/control circuit 301. The driver circuit 315 is the light emitting diode 2 of the refractive power measurement system 2.
The driver circuits 314 and 315 are operated simultaneously according to the commands from the calculation and control circuit 301.
That is, the light source 102 and the light emitting diode 200 are configured to turn on and off at the same time.

The driver circuit 316 is the anterior segment observation/alignment system 4
The driver circuit 317 is connected to the anterior eye illumination light source 40, the driver circuit 325 is connected to the aiming scale light source 42, and the driver circuit 327 is connected to the glare light source 33, and the power supply to these is also calculated. - Performed based on commands from the control circuit 301.

Note that the driver circuits 316, 317, and 325 are operated by a common command from the arithmetic and control circuit 301, and the light sources 40.
41 and 42 are configured to turn on and off at the same time. Further, the driver circuit 326 is connected to the light source 30 of the visual/subjective measurement system 3 and supplies power to the light source 30 based on commands from the control circuit 301.

Further, the arithmetic control circuit 301 includes a second memory 31 that stores the measured axis angles of the strong and weak principal meridians and each radius of curvature.
0, spherical power, cylindrical power, based on the measured refractive power,
A third memory 311 that stores the axial angle is connected to each of them. These memories 310 and 311 are the video memory 3.
50. In addition, the axis angle of each strong and weak principal meridian,
Measurement of each radius of curvature, spherical power 1 cylindrical power based on refractive power, and axial angle will be described later.

Connected to the calculation/control circuit 301 are a program memory 307 that stores programs for calculation and control, and a control switch 308 having various switches for starting measurement, selecting a chart at the time of subjective measurement, etc., as shown in FIG. ing. The control switch 308 has a changeover switch 351 for displaying the refractive power measurement pattern image 2031 on the display 305.

Also connected to the arithmetic control circuit 301 is a character circuit 306 that converts the measurement data stored in the memories 310 and 311 into characters and numerical values and outputs them to the display interface 304 via the gate circuit 302.

ru Movement 1) The alignment examiner turns on the power switch 30 of the control switch 308.
811 Turn on. Then, the driver circuits 316 and 317 are activated by the arithmetic and control circuit 304, and the light source 40
゜41, 42, and 30 are lit at the same time. At the same time, the drive circuit 313 is operated by the calculation/control circuit 301,
As a result, the area CCD 5 is scanned. that time,
The arithmetic/control circuit 301 connects the gate circuit 302 to the area CC.
The analog signal from D5 is switched to be sent to display interface 304. This results in
The anterior segment of the eye E to be examined is illuminated with light e from the light source 40, and the alignment light f from the alignment light source 41 is reflected at the anterior segment, and both lights e and f are reflected by the measurement optics of the keratometry system 1. The image passes through the system 11 and is formed on the area CCD 5 as an image of the anterior segment of the eye and as an image of the light source 41 which is an alignment index.

On the other hand, an image of the aiming scale 44 is formed on the area CC opening 5 by the aiming scale light d. These three images are converted into analog signals by the area CCD 5 and output, and the analog signals are input to the display 305 via the display interface 304. As a result, the display 305 displays images as an anterior segment image E^, an aiming scale image 44', and an alignment index image 41', as shown in FIGS. 9(a) and 9(b). Incidentally, instead of the light source 41, a spot projection optical system in which a spot projected image is reflected from the corneal vertex is provided in the area CCD, and the spot projected image is formed on the light beam 5.
It may also be configured to determine whether or not the alignment is successful depending on whether or not the spot projected image is within a predetermined range on the area CCI)5.

The subject uses the fixation chart 32a illuminated by the light source 30 with the fixation/subjective measurement system 3, which is partially shared with the refractive power measurement system 2.
This fixes the visual axis of the subject's eye E.

As shown in FIG. 9(a), when the 7th alignment index image 41' is outside the aiming scale image 44', the examiner places the alignment index image 41' (9th
The entire optical system of the apparatus is moved up and down and left and right so that the optical axis of the eye E and the optical axis of the objective lens 110 are aligned. Further, the entire optical system of the apparatus is moved back and forth to adjust the working distance to a normal distance so that the anterior segment image EA becomes a clear image.

2) When the alignment is completed, the regular inspector turns on the measurement start switch 3082 of the control switch 308. The calculation/control circuit 301 operates the driver circuit 3 according to the command.
Stop commanding 16.317.325 and light source 40.4
42 will be turned off for a short period of time. However, the command to the driver circuit 326 continues, and the light source 30 continues to turn on.

The arithmetic/control circuit 301 instructs the driver circuits 314, 315 to operate during the period when the light sources 40, 41, 42 are turned off, and turns on the light sources 102, 200. Thereafter, the light source 40.
41, 42 and the lighting of the light sources 102, 200 are performed alternately. Note that while the light sources 102 and 200 are on, the 1 indicator 30
Since the anterior segment observation image is not displayed in 5, at this time,
For example, the display 305 may display the words "Measuring". Alternatively, the frame memory 324 may be provided with a memory area for storing the anterior segment image, and the anterior segment image stored in this memory area may be transferred to the light source 1.
02.200 is lit, that is, during measurement, the display 30
5 may be displayed.

The keratometry light a is projected onto the cornea C by light emission from the light source 102 through an annular aperture 100 that is a pattern for keratometry. A virtual image 100' based on the cornea C is formed by the measurement optical system 11 of the keratometry system 1 within the keratometry area 5a at the center of the area CCD 5 (see FIG. 6). At the same time as the light source 102 emits light.

The light emitting diode 200 of the objective refractive power measurement system 2 also emits a refractive power measurement light, and a ring pattern image 200' is projected onto the fundus Ell of the eye E to be examined.
The fundus reflected light passes through the measurement optical system 21 to the area CCD.
It is projected onto the refractive power measurement area 5b in the periphery of 5.

The calculation/control circuit 301 operates the drive circuit 313.

When the area CCD 5 is scanned, its image outputs, that is, the image outputs of the keratometry pattern image 100' and the refractive power measurement pattern 203' are output to the gate circuit 302 and the A/D converter 303. The A/D converter 303 A/D converts the analog signal from the area CCD 5, and the digital signal is input to the frame memory 324. The frame memory 324 stores information for one screen, and the frame memory 324 stores information for one screen.
1 and the D/A converter 324'.

The calculation/control circuit 301 is as shown in FIG.

Reading out memory addresses of the frame memory 324 at predetermined times G1, G2,..., G..., G...
·, G, radially read and scan according to l. As a result, the keratometry pattern image 100' and the refractive power measurement pattern 20 that are simultaneously formed and projected onto the area CCD S.
Data corresponding to two images 3' and 3' are read out and scanned. If the eye to be examined has severe hyperopia, the refractive power measurement pattern image 203' is projected outside area CCD B as shown in FIG. The coordinates of 1tgz,...
Only 14g..., 1i..., and 1n are read out.

In addition, when the eye E to be examined is severely myopic, the pattern image 100' for keratometry and the pattern image 203' for refractive power measurement will be close to each other.

In the case of this rain sound, the calculation/control circuit 301 outputs a command signal to the driver circuit 318, supplies pulses from the pulse generator 312 to the pulse motor 321, moves the movable housing section 219, and adjusts the refractive power. The measurement pattern image 203' is controlled to be projected within the area 5b, and the refractive power measurement pattern image 203' and the corneal measurement pattern image 100' are controlled to maintain an interval of a predetermined interval or more. The focusing lens 216 is moved by this movement of the movable housing 219, but the fixation chart 32a, which is observed by the eye E through the fixation/subjective measurement system 3, is relative to the refractive power of the eye E. It is designed to create a fog vision state of +1.0 to 2.0D.

The number of pulses supplied to the pulse motor 321 to move the movable housing section 219 is determined by the calculation/control circuit 30.
1 is counted by a counting circuit, and the counted value is sent to the movable housing part 2.
This is stored in the first memory 309 as a movement amount of 19.

3) Bi
7 based on the data in the frame memory 324 based on the final image received by the area CCD after moving the movable housing section 219 based on the above rough measurement. As shown, readout scanning G□, G3,..., Gi..., G1..., Gn
The point tgx on the corneal measurement pattern 100' is
-4Kg-...1, g..., 1g#,...
Get the coordinates of Ign. Similarly, points 1g□, Ig□, ...-*g□ on the pattern image 203' for refractive power measurement
, *JCt*...% ++ Obtain the coordinates of gn.

3-1) The arithmetic control circuit 301 calculates the obtained points agu, tlh, .
....

, g...-4Kg, ...-tg++ The elliptical shape of the pattern 100' is calculated from the coordinates. The radius S1 of the long axis (Xa axis) of the ellipse 100' correlates with the radius of curvature R1 of the weak meridian of the cornea C, and the radius Sy of the short axis (Yi axis)
i is correlated to the radius of curvature R2 of the weak meridian, and the angle 0 of the major axis and the angle O12 of the minor axis are the axis angle 01 of the strong principal meridian, respectively.
This corresponds to the axis angle 03 of the 1 weak principal meridian.

The general formula for the ellipse 1001 in the X, -Y coordinate system is:

Ax” +By” +Cxy= 1
...It is expressed as (1).

The radius Sa of the pattern 100' is as shown in FIG. 8, where R is the radius of curvature of the cornea C, the height to the annular aperture 100 is Ω, the working distance is Ω, and the magnification of the entire projection optical system is β. , S pigeon = Y
2) 5st-Sy & can be obtained from equation (3), and the radius of curvature R1 of the strong principal meridian and the radius of curvature R2 of the weak meridian can be similarly obtained from equation (3).

Also, the axis angle θ1 of the strong principal meridian = θki2, and the axis angle θ2 of the weak meridian = θkago. The radius of curvature R□, R2 and the axis angle θ G8 thus obtained are displayed together with the anterior segment image on the display 305 via the character circuit 306 and display interface 304 as shown in FIG. 9(b). and stored in the second memory 310.

3-2) Refractive power measurement pattern image 20 obtained by constant readout scanning
3' point 3g1, lIg□, ..., *gi...12
Based on the coordinates of g, ...1, gn, the general formula of the ellipse 2031 at the x, -yll coordinates is Ax
” +By” +Cxy= 1
-- expressed as (1). This (1)
, From formula (2), calculate S, , S, and the refractive power D1 of the one strong principal meridian and the refractive power D2 of the main meridian are emmetropia (ODiop
Letting ro be the radius of the pattern image of ``tpr),'' in the example shown in FIG. 7, ■ Dx=Dy*=(Sy* ro) (f,
is obtained as (unit m)x D2=D, , = (S,, r,) (f, x is unit m)x. Here, f is the composite focal length of the measurement optical system 21 or the base line length (that is, the radius of the conjugate image of the ring diaphragm at the pupil position of the eye to be examined).

Next, the arithmetic/control circuit 301 calculates the amount of movement of the movable housing section 219 stored in the first memory 309, that is.

The number of pulses corresponding to the amount of movement of the focusing lens 216 is read out, and from this number of pulses, the refractive power correction amount d due to the movement of the focusing lens 216 is determined by the refraction of the strong and weak principal meridians determined by the above equation (5). In addition to force, D2, (D + d), (D, +
Find d). Thereby, the spherical refractive power S, the cylindrical refractive power C1, and the cylindrical axis angle θ of the eye to be examined are determined as S=(D,+d) C=(D+d)−(D2+d) 0=θ cage. The arithmetic/control circuit 301 causes the obtained S and C1θ to be displayed on the display 305 via the character circuit 306 and the display interface 304, and is also stored in the third memory 311.

Here, in order to judge whether or not the refractive power as the obtained measurement data is reliable, the changeover switch 3
When 51 is turned on, under the control of the arithmetic control circuit 301,
Gate circuit 302 outputs the analog signal from D/A converter 324 toward display interface 304 . As a result, a refractive power measurement pattern image 203' is displayed on the display 305, for example, as shown in FIG. 9(c).

In FIG. 9(c), 203A' indicates a portion that is distorted due to the influence of eyelashes and the like. In addition,
In this embodiment, the refractive power measurement pattern image 203' is displayed together with the measurement data as shown in FIG. 9(C), but only the refractive power measurement pattern image 203' is displayed on the display 305. It can also be configured. In addition, this refractive power measurement pattern image 203' is printed on a video printer (
It is also possible to print out the information using a computer (not shown).

Furthermore, it is also possible to provide a configuration in which two frame memories 324 are provided, one stores the refractive power measurement pattern image, the other stores the anterior segment image EA, and both are displayed on the display 305.

4) - Good π1' u C When the designated examiner next turns on the subjective optometry switch 3083 of the control switch 308, the arithmetic/control circuit 301 stops issuing commands to the drivers 314 and 315, and from then on, the light source 1
02.200 stops its emission. Next, the examiner presses the chart selection switch 308 of the control switch 308.
When you select the visual acuity test chart in step 9, the calculation/control circuit 3
01 activates the driver circuit 317 and pulse generator 3
12, a predetermined number of pulses are supplied to the pulse motor 322, the chart board 32 is rotated, and the visual acuity chart 32b (see FIG. 10) is inserted into the optical path of the subjective measurement system 3.

The calculation/control circuit 301 calculates the refractive characteristics S, C10 of the eye E to be examined stored in the second memory 311 and obtained by objective refractive power measurement.
1, O, and calculate the number of pulses necessary to move the focusing lens 216 based on the value of the spherical refractive power S,
The obtained number of pulses is applied to the driver circuit 318.
is supplied to the pulse motor 321 via the movable housing section 2.
19 is moved, and thus the focusing lens 216 is moved.

Next, the calculation/control circuit 301 calculates the number of pulses for rotating the VCC 37 from the cylinder refractive power and the axis angle 0, and the obtained number of pulses is supplied to the pulse motor 323 via the driver circuit 320.

VCC37 is rotated. As a result, the subjective measurement system 3 has undergone optical correction according to the refractive power of the eye E determined by the objective refractive power measurement.

The subject is using the visual acuity display chart 3 inserted into the subjective measurement system 3.
Look at 2b and answer the direction of the break in the Landolt ring.

The examiner determines the subjective visual acuity of the eye E from the response of the examinee,
When it is determined that the corrected visual acuity is not sufficient, the spherical power correction switch 3088 of the control switch 318 is operated. The arithmetic/control circuit 301 transmits pulses from the pulse generator 312 to the driver circuit 3 according to the command from the switch 18.
18 to the pulse motor 321 to re-move the focusing lens to a position where corrected visual acuity is improved. The calculation/control circuit 301 counts the number of pulses when the focusing lens is moved again, and calculates d in equation (6) again from this number of pulses.

Based on this new d, 81, C θ is calculated using equation (6), and the calculated value is displayed on the display 305.

When the examiner next selects the astigmatism chart 3085 with the control switch 308, a predetermined number of pulses are supplied to the pulse motor 322 via the driver circuit 319, the chart board 32 is rotated, and the circuit of the subjective measurement system 3 is The astigmatism chart 32c is inserted into the astigmatism chart 32c.The examinee E looks at the inserted astigmatism chart 32c and answers whether there are any dark lines.When the examinee responds "Yes," the examiner operates the cylinder axis correction switch 3090 of the control switch 318.

Based on the command, the arithmetic/control circuit 301 supplies pulses to the pulse motor 323 via the driver circuit 320, rotates the VCC 37, and corrects the cylinder axis.

The calculation/control circuit 301 counts the number of pulses at this time,
Based on the counted value, the cylinder axis angle θ is corrected, and the corrected cylinder axis angle is displayed on the display 305.

Next, when the examiner selects the cross cylinder chart 3086 of the control switch 308, the control circuit 301 controls the pulse motor 323 to set the currently set cylinder power C of the VCC 37 as a reference, for example, ±0.5D.
Chart 32 is created by alternating the cylinder axis angle difference of
If there is a difference in appearance, the examiner operates the cylinder power correction switch 3089 of the control switch 308, and the arithmetic/control circuit 301 controls VCC 37 based on the command, The power is corrected and the new cylinder power is displayed on the display 305.

Next, when the examiner selects the red green chart 3087 on the control switch 308, the control circuit 301 operates the pulse motor 322, and the red green chart 32e is inserted into the subjective measurement system 3.

The subject answers how the red-green chart 32e looks, and the examiner operates the spherical power correction switch 3088 of the control switch 308 based on the response.

Upon receiving the command, the arithmetic/control circuit 301 operates the pulse motor 321 to move the first focusing lens 216, so that the spherical power S is corrected and the new spherical power is displayed on the display 3.
Displayed on 05.

5) Glare test The examiner then selects glare test 3091 on control switch 30g. Then, the arithmetic/control circuit 301 operates the pulse motor 322 via the driver circuit 319, and the chart board 32 is rotated.
2b is inserted into the optical path of the subjective measurement system 3, the driver circuit 327 is activated and the glare light source 33 emits light.

The subject views the visual acuity display chart 32b in the glare of the glare light source. The examiner can know whether or not the eye E to be examined has a mild cataract based on the examinee's response. Note that a known volume or the like may be added to the glare light source so that its brightness can be varied.

(Effects of the Invention) As explained above, according to the present invention, since the pattern image for refractive power measurement can also be displayed on the display unit, it is possible to visually check whether the obtained measurement data is reliable or not. This has the effect of making it possible to make judgments at a glance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the optical arrangement of an optometric apparatus including an automatic eye refractive power measuring device according to the present invention, FIG. 2 is an optical path diagram of an objective refractive power measuring system, and FIG. Figure 4 shows aperture 2
15 is a plan view, FIG. 5 is a block diagram showing the configuration of the electric circuit, FIG. 6 is a diagram showing the relationship between the image receiving element and the pattern image, and FIG. 7 is the measurement of corneal curvature radius and eye refractive power from the pattern system. A schematic diagram to explain the principle. Figure 8 is a diagram to explain the principle of measuring the radius of curvature. Figures 9 (a), 9 (b), and 9 (c) are the display states of the display. FIG. 10 is a diagram showing an example of a chart for subjective measurement, and FIG. 11 is a diagram showing the switch arrangement of the control switch. 1... Keratometry system, 2... Objective refractive power measurement system, 3... Fixation and subjective measurement system, 4... Anterior segment observation and alignment system, 5... Area CCD, 203 '... Pattern image for refractive power measurement 301... Arithmetic control circuit, 302... Gate circuit 304... Display interface 305... Display unit,
324... Frame memory 324'... D/A converter, 351... Selector switch Fig. 3 Fig. 4 (C) 2o3''A, 203''

Claims (1)

[Scope of Claims] A pattern image for refractive power measurement is projected onto the fundus of the eye to be examined, a reflected image of the fundus of the eye to be examined is projected onto a photoelectric element via a measurement optical system, and based on a signal detected by the photoelectric element. An automatic eye refractive power measurement device that measures the eye refractive power of the eye to be examined, comprising: a storage unit that stores the signal detected by the photoelectric element as an image signal; An automatic eye refractive power measuring device comprising a display unit that displays a measurement pattern image, and a calculation unit that calculates the refractive power of the eye to be examined based on the image signal stored in the storage unit.