JPH08229007A - Optometric - Google Patents

Abstract

PURPOSE: To provide an optometric device which can be futher miniaturized as well as having less number of part items in whole optometric device than usual. CONSTITUTION: Each measurement light is projected on a test eye cornea C and a fundus ER, and the reflected light by the cornea and the reflected light by the fundus of the test eye E are projected on a light receiving element 5 through a measurement optic system 11, and thereby the corneal shape and optic refractory power of the test eye E are measured based on a signal detected by means of the light receiving element 5, in this optometric device. On this occasion, the corneal reflected light and the fundus reflected light are projected on the light receiving element 5 at the same time by the measurement optic system 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometry apparatus for measuring the corneal shape, eye refractive power, etc. of an eye to be examined.

[0002]

2. Description of the Related Art Conventionally, as an optometric apparatus for measuring the corneal shape, eye refractive power, etc. of an eye to be inspected, an index image is projected on the cornea of the eye to be inspected, and the corneal reflected light of the eye to be inspected The reflected light is projected onto each of the light receiving portions that can be photoelectrically converted via the measurement optical system, and the one for calculating the corneal shape and the eye refractive power of the eye to be examined based on the signal detected by each light receiving portion is is there.

[0003]

However, in the conventional device, the light receiving portion for measuring the corneal shape and the light receiving portion for measuring the eye refractive power are separately provided, so that the optical path switching mechanism and the light receiving portion are provided. There is a problem that a part driving circuit, an arithmetic processing system and the like are separately required, the number of parts is increased, and the entire optometry apparatus cannot be downsized. In addition, there is also a drawback that the measurement time becomes long because it is necessary to individually scan each light receiving portion to obtain data relating to corneal measurement and data relating to eye refractive power.

The present invention has been made in view of the above-mentioned problems, and provides an optometry apparatus which can reduce the number of parts of the entire optometry apparatus as compared with the conventional one, and can be further downsized. The purpose is to

[0005]

In order to solve the above problems, a feature of the optometry apparatus according to the first invention of the present application is that the cornea reflected light and the fundus reflected light are simultaneously projected onto the light receiving element. This is where the optical system is constructed.

In the optometry apparatus according to the present invention, the cornea reflected light and the fundus reflected light are simultaneously projected onto one common light receiving element, so that both reflected images are simultaneously detected by one light receiving element.

A feature of the optometry apparatus according to the second invention of the present application is that measurement optics for receiving at least one of the corneal reflected light and the fundus reflected light projected on the eye and the anterior segment image of the eye. The measurement optical system is provided with a common two-dimensional light receiving element that receives at least one of the corneal reflected light and the fundus reflected light and the anterior segment image of the subject's eye, and is detected by the two-dimensional light receiving element. Means for measuring at least one of the corneal shape and the eye refractive power of the subject's eye based on the signal and the means for displaying the anterior segment image recorded in the memory are provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

IA. Overall Optical Arrangement FIG. 1 shows the overall optical arrangement of the optometry apparatus according to the present invention. This optometry apparatus includes a cornea measurement system 1 for measuring the radius of curvature of the cornea C of the eye E, an objective refraction power measurement system 2 for objectively measuring the refraction power of the eye E,
Fixation / awareness measurement system 3 for projecting a fixation target for fixing the eye E to fix the visual axis of the eye E during measurement and a target for subjective test, and an anterior segment of the eye E Observation and anterior ocular segment observation for alignment of the optical axis of the device and the visual axis of the eye
The alignment system 4 is generally included. A part of the optical path of the anterior ocular segment observation / alignment system 4 is shared with the optical path of the corneal measurement system 1.

IB. Corneal Measurement System 1 The cornea measurement system 1 includes a pattern projection system 10 for projecting an annular pattern for measuring the radius of curvature of the cornea toward the cornea, and the size and shape of the corneal reflected light of the annular pattern. Is roughly divided into a measurement optical system 11 for measuring.

The pattern projection system 10 is provided with a pattern plate 101 having an annular opening 100 and a cornea measurement light having a wavelength of 930 nm to 1000 nm (hereinafter, this cornea measurement light is denoted by a symbol a) arranged behind the opening 100. And an annular light source 102 that emits light. Light emitted from the light source 102 passes through the opening 100 and is projected onto the cornea C of the eye E as projection light. The projection light is reflected by the cornea C to form a virtual image 100 ′ of the opening 100. Cornea C
The corneal measurement light a reflected by the beam enters the measurement optical system 11 as if it emitted a virtual image 100 '.

The measurement optical system 11 includes an objective lens 110 and a wavelength 4
Visible light of 00 nm to 700 nm (hereinafter, this visible light is given a reference sign c) is reflected and corneal measurement light a (wavelength 930 nm to 1000 nm)
Including red light with a wavelength of 900 nm or more, Hafmyra-111 that transmits light with a wavelength of 800 nm or more in the long wavelength range and infrared light with a wavelength of 865 nm (hereinafter, this infrared light is denoted by a symbol b) are transmitted. A half mirror 112 that reflects external light, a relay lens 113,
A diaphragm 114, a half mirror 115 that transmits red light having a wavelength of 700 nm (hereinafter, this red light is denoted by reference numeral d) and reflects corneal measurement light a, a relay lens 116, and infrared light b are reflected. A half mirror 117 that transmits the cornea measurement light a and the red light d, an imaging lens 118, and an area as an image receiving element.
It is composed of CCD5.

The diaphragm 114 is divided into a peripheral portion 114a and a central portion 114b, as shown in FIG. The peripheral portion 114a cuts off light with a wavelength of 930 nm or more, and the central portion 114b
Is configured to transmit light having a wavelength of 900 nm or more. That is, light of 900 nm or more and light of 930 nm or less
(Hereinafter, this light will be denoted by the symbol e) can be transmitted through the entire area of the diaphragm 114. The corneal measurement light a reflected by the cornea C is condensed by the objective lens 110, and then passes through the half mirror 111. Then, the cornea measurement light a is reflected by the half mirror 112 and passes through the relay lens 113 to the central portion 114b of the diaphragm 114.
Pass through. After that, the cornea measurement light a is a half mirror.
The light is reflected by 115, guided to the half mirror 117 by the relay lens 116, and passes through the half mirror 117. The cornea measuring light a is formed on the image receiving element 5 by the image forming lens 118, and the cornea measuring ring pattern 100 ″ (see FIGS. 6 and 7).
Is imaged as. Aperture 10 by projection of cornea measurement light a
Even when the anterior eye part (iris) of the eye to be inspected is illuminated when the virtual image 100 ′ of 0 is formed, the reflected light is cut by the peripheral part 114a of the diaphragm 114, and therefore does not reach the image receiving element 5. Corneal pattern
Only 100 ″ will be projected onto the image receiving element.

I-C. Objective Refractive Power Measurement System 2 C-1: Pattern Projection System 20 FIG. 2 (a) is an optical path diagram of the pattern projection system 20 shown in FIG. The refracting power measuring light (wavelength 865 nm) emitted from the light emitting diode 200 has the condenser lens 201.
After being condensed by, the light is refracted by the conical prism 202 and irradiated on the ring pattern 203 for measuring the refractive power. The refracting power measurement light b that has passed through the ring pattern 203 is relay lens 20.
4. The ring diaphragm 207 is irradiated with light through a mirror 205 (see FIG. 1) and a relay lens 206. The refracting power measuring light b passes through the ring diaphragm 207 and then is reflected by the reflecting surface 208a of the perforated mirror 208. Then, after that, the refractive power measuring light b is reflected by the mirror 20.
It is reflected by 9, passes through the half mirrors 112 and 111 which are components of the measurement optical system 11 of the cornea measurement system 1, and the objective lens 11
An image 2 of the ring pattern 203 on the fundus E _{R of the} eye E depending on 0
It is projected as 03 '(see FIG. 2). Here, the light emitting diode 200 and the ring diaphragm 207 are optically conjugate with each other, and the ring diaphragm 207 and the pupil E _{P of the} eye E to be examined are optically conjugate with each other.

C-2: Measuring Optical System 21 FIG. 2 (b) is an optical path diagram of the measuring optical system 21 shown in FIG. Ring pattern image reflected by the fundus E _R of the eye E 2
The light 03 'is condensed by the objective lens 110. Then, the light passes through the half mirrors 111 and 112, is reflected by the mirror 209, passes through the aperture 208b of the perforated mirror 208, and passes through the stop 210. The refracting power measurement light b passes through the diaphragm 210, the relay lens 211, and is reflected by the half mirror 212 that transmits the visible light c.
The diaphragm 215 is illuminated via 14. As shown in FIG. 4, the stop 215 has a peripheral portion 215b through which the refractive power measurement light b having a wavelength of 865 nm is transmitted and a central portion through which the refractive power measurement light b is cut.
215a and.

Further, the diaphragm 215 has a characteristic that the corneal measurement light a having a wavelength of 930 nm to 1000 nm is non-transmissive and the visible light c of 400 nm to 700 nm is transmissive in the entire region thereof. As a result, the refracting power measurement light b is generated in the peripheral portion of the diaphragm 215.
Half mirror 21 that passes only 215b and reflects visible light c and transmits refractive power measurement light b through a focusing lens 216.
After passing through 7, the light is reflected by the half mirror 117 of the measurement optical system 11 of the cornea measurement system 1 and the ring pattern image 203 ″ is formed on the image receiving element 5 by the imaging lens 118 (see FIGS. 6 and 7).
Is imaged as.

The focusing lens 216 and the diaphragm 215 are moved integrally with the light emitting diode 200, the condenser lens 201, the conical prism 202, and the ring pattern 203 of the pattern projection system 20.
It is housed in 219 and is movable in the optical axis direction as indicated by arrow 218 in FIG.

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

I-D. Fixation and subjective measurement system 3 Visible light c emitted by the light source 30 and having a wavelength of 400 nm to 700 nm c
Is condensed by the condenser lens 31, and illuminates the chart plate 32.

On the chart plate 32, as shown in FIG. 10, for example, a sunburst chart (fixation chart) as a fixation target is displayed.
32a, a visual acuity chart 32b for subjective examination, an astigmatism chart 32c, a cross cylinder chart 32d, a red-green chart 32e are arranged in the circumferential direction, and each chart has an axis 3
It is selectively inserted into the optical path by being rotated around 4.

The images of the charts 32a to 32e are projected on the subject's eye E by the projection lens 35. After being reflected by the mirror 36, they are reflected by the half mirror 217 and the measuring optical system of the objective refracting power measuring system 2. 21 merges, passes through a diaphragm 215 through a focusing lens 216, is guided to a half mirror 212 through a mirror 214 and a relay lens 213, passes through a half mirror 212,
Guided to the variable cross cylinder 37. The visible light c passes through the variable cross cylinder 37, is reflected by the half mirror 111 via the mirror 38, is projected on the eye E by the objective lens 110, and the charts 32a to 32e are observed by the eye.

Further, in the vicinity of the chart plate 32, a plurality of glare light sources 33 for emitting visible light for glare test are arranged near the outer periphery of the insertion positions of the charts 32a to 32e inserted in the optical path. The glare test light source 33 may be arranged near the objective lens 110. Further, in order to perform the glare test, instead of providing the light source 33, for example, the contrast between the visual chart of the visual acuity chart 32b and the base may be changed.

IE. Anterior segment observation and alignment system A plurality of anterior segment illumination light-emitting diodes 40 are arranged outside the pattern plate 101 of the pattern projection system 10 of the cornea measurement system 1, and the wavelength of 900 nm emitted from each of the light-emitting diodes 40.
Infrared light (hereinafter, this infrared light is given a reference sign e) illuminates the anterior segment of the eye E to be examined. The infrared light (anterior segment illumination light) e reflected by the anterior segment of the eye is condensed by the objective lens 110, then passes through the half mirror 111, and the cornea measurement system 1 described above is used.
Is propagated along the measurement optical system 11 and is imaged on the image receiving element 5 by the imaging lens 118.

A wavelength of 900 nm is provided near the outer periphery of the objective lens 110.
A plurality of light emitting diodes 41 that emit infrared light are arranged,
The plurality of light emitting diodes 41 are alignment light sources. Alignment light emitted from this alignment light source 41 (hereinafter, this alignment light is given a reference numeral f) is reflected by the eye E to be examined, and then is condensed by the objective lens 110, similarly to the anterior ocular segment illumination light e. After passing through the half mirror 111, it is propagated along the measurement optical system 11 of the cornea measurement system 1 and is imaged on the image receiving element 5 by the imaging lens 118.

An aiming scale projection optical system is arranged in front of the half mirror 115 of the measuring optical system 11 of the cornea measuring system 1. This aiming scale projection system is designed for red light with a wavelength of 700 nm.
(Corresponding to the light d described above; hereinafter referred to as scale light), a light emitting diode 42, a condenser lens 43 that condenses the scale light d from the light emitting diode 42, and a sighting scale.
It is composed of a mirror 45 for reflecting the scale light that has passed through 44 and merging it with the measurement optical system 11. The scale light d from the aiming scale 44 passes through the half mirror 115, and then is imaged on the image receiving element 5 by the imaging lens 118 via the measurement optical system 11.

II. Electric Circuit Configuration FIG. 5 is a block circuit diagram of the optometry apparatus. Drive circuit
313 receives an instruction from the arithmetic / control circuit 301, scans the area CCD as the image receiving element 5, and outputs the received image as an analog signal.

The arithmetic / control circuit 301 controls the gate circuit 302, and the gate circuit 302 converts the analog signal from the image receiving element 5 into the A / D converter 303 or the display interface 304.
Output to and. Display interface
304 receives the analog signal from the image receiving element 5 via the gate circuit 302, and displays the image receiving element 5 on a display unit 305 including, for example, a CRT, a liquid crystal television, or a plasma display.
The received image of.

The A / D converter 303 has a function of converting an analog signal from the image receiving element 5 into a digital signal, and the digital signal is input to the arithmetic control circuit 301.

The arithmetic control circuit 301 is connected to a frame memory 324 which stores data for one screen of the image receiving element which has been converted into a digital signal by the A / D converter 303 or data for several screens. . Further, the arithmetic control circuit 301 has a function of selectively supplying the pulses from the pulse generator 312 to the driver circuits 318, 319 and 320, counts the number of pulses, and uses the counted value as a signal in the first memory 309. The first memory 309 stores the count value.

The driver circuit 318 supplies the pulse from the arithmetic and control circuit 301 to the pulse motor 321 for driving the moving casing of the refracting power measuring system 2 to drive the pulse motor 321. The driver circuit 319 supplies a pulse to the pulse motor 322 for rotating the chart plate 32 of the fixation / awareness measurement system 3 to drive the pulse motor 322. The driver circuit 320 supplies a pulse to the pulse motor 323 for rotating the VCC 37 and drives the pulse motor 323.

The arithmetic / control circuit 301 includes a driver circuit.
314 to 317 and 325 to 327 are connected. Driver circuit 31
Reference numeral 4 is connected to the annular light source 102 of the cornea measurement system 1, and power is supplied to the annular light source 102 by a power supply circuit (not shown) based on a command from the arithmetic / control circuit 301. The driver circuit 315 supplies power to the light emitting diode 200 of the refractive power measurement system 2 based on a command from the arithmetic and control circuit 301. The driver circuits 314 and 315 are configured to operate at the same time according to a command from the arithmetic / control circuit 301, that is, to turn on / off the light source 102 and the light emitting diode 200 at the same time.

The driver circuit 316 is the anterior segment illumination light source 40 of the anterior segment observation / alignment system 4, the driver circuit 317 is the alignment light source 41, the driver circuit 325 is the aiming scale light source 42, and the driver circuit 327 is the glare. Each of them is connected to the light source 33, and the power supply to them is also controlled by the arithmetic / control circuit 301.
Based on the command of. The driver circuits 316, 31
7, 325 are operated by a common command from the arithmetic and control circuit 301, and the light sources 40, 41, 42 are configured to turn on / off at the same time. Further, the driver circuit 326 is connected to the light source 30 of the fixation / awareness measurement system 3, and supplies power to the light source 30 based on a command from the control circuit 301.

Further, the arithmetic control circuit 301 stores the measured axial angle of each strong and weak main meridian and each radius of curvature.
The memory 310 and the third memory 311 that stores the spherical power, the cylindrical power, and the axial angle based on the measured refractive power are connected to each other. The measurement of the axial angle of each strong / weak main meridian, each radius of curvature, the spherical power, the cylindrical power, and the axial angle based on the refractive power will be described later. Further, the arithmetic / control circuit 301 has a program memory 307 that stores arithmetic / control programs.
As shown in FIG. 11, a control switch 308 having various switches for starting measurement and selecting a chart at the time of subjective measurement is connected. 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 is also connected to the control circuit 301.

III. Measurement procedure and operation 1) The alignment examiner turns on the power switch 3081 of the control switch 308.
N Then, the driver circuits 316 and 317 are operated by the arithmetic / control circuit 304, and the light sources 40, 41, 42 and 30 are simultaneously turned on. Together with the arithmetic / control circuit 301, the drive circuit
313 is activated, which causes the image receiving element 5 to scan. At that time, the arithmetic / control circuit 301 switches the gate circuit 302 so that the analog signal from the image receiving element 5 is sent to the display interface 304. As a result, the anterior segment of the eye E to be examined is illuminated with the light e from the light source 40, and
The alignment light f from the alignment light source 41 is reflected by the anterior segment of the eye, and both lights e and f are measured by the measurement optical system 11 of the cornea measurement system 1.
It is formed as an image of the anterior ocular segment and the image of the light source 41 which is an alignment index on the image receiving element 5 through.

On the other hand, an image of the aiming scale 44 formed by the aiming scale light d is formed on the image receiving element 5. These three images are converted into analog signals by the image receiving element 5 and output, and the analog signals are input to the display 305 via the display interface 304. by this,
As shown in FIGS. 9 (a) and 9 (b), the display 305 displays the anterior segment image EA,
Images are displayed as a sighting scale image 44 'and an alignment index image 41'. In addition, a spot projection optical system is provided in place of the light source 41 so that the spot projection image is reflected from the corneal vertex, and the spot projection image is formed on the light receiving element 5, and the spot projection image is formed on the image receiving element 5. May be determined based on whether the alignment is within a predetermined range. The examinee fixes the fixation chart 32a illuminated by the light source 30 in part with the refractive power measurement system 2.
The visual axis of the subject's eye E of the subject is fixed by visual confirmation through the subjective measurement system 3.

When the alignment index image 41 'is outside the aiming scale image 44' as shown in FIG. 9 (a), the examiner finds the alignment index image 41 'in the aiming scale image 44'.
The entire optical system of the apparatus is moved vertically and horizontally so that (see FIG. 9 (b)) is entered, and the optical axis of the eye E to be inspected and the optical axis of the objective lens 110 are aligned. In addition, the entire working optical system is moved back and forth so that the anterior segment image EA becomes a clear image, and the working distance is adjusted to a regular distance.

2) Rough measurement of refractive power After the alignment is completed, the examiner turns on the measurement start switch 3082 of the control switch 308. The arithmetic / control circuit 301 stops the command to the driver circuits 316, 317, 325 according to the command, and turns off the light sources 40, 41, 42 for a short time. However, the command to the driver circuit 326 continues and the light source 3
0 continues to light. The arithmetic / control circuit 301 includes light sources 40, 41, 4
During the extinguishing period of 2, the driver circuits 314 and 315 are instructed to operate and the light sources 102 and 200 are turned on. After that, until the corneal curvature radius and the objective refractive power measurement are completed, the light sources 40, 41,
42 and lighting of the light sources 102 and 200 are performed alternately. Since the anterior ocular segment observation image is not displayed on the display device 305 while the light sources 102 and 200 are lit, the display device 305 may be allowed to display, for example, the character “Measuring” at this time. . Alternatively, a frame memory 324 is provided with a memory area for storing the anterior segment image, and the anterior segment image stored in the memory area is being turned on by the light sources 102 and 200, that is,
You may make it display on the display device 305 during measurement.

The cornea measurement light a is projected by the light emission of the light source 102 onto the cornea C through the circular opening 100 which is a cornea measurement pattern. The virtual image 100 'based on the cornea C is
An image is formed in the central corneal measurement area 5a of the image receiving element 5 (see FIG. 6) by the measurement optical system 11 of the cornea measurement system 1. Simultaneously with the light emission of the light source 102, the light emitting diode 200 of the objective refracting power measuring system 2 also emits the refracting power measuring light b, and a ring pattern image 200 ′ is projected on the fundus E _{R of the} eye E to be examined. The reflected light of the fundus ′ is projected onto the refractive power measurement area 5b in the peripheral portion of the image receiving element 5 via the measurement optical system 21.

The arithmetic / control circuit 301 switches the gate circuit 302, and the analog signal from the image receiving element 5 is input to the A / D converter 303. After that, the arithmetic / control circuit 301 changes to the drive circuit 313.
Is operated to scan the image receiving element 5, and the image output thereof, that is, the image output of the cornea measurement pattern image 100 ″ and the refractive power measurement pattern 203 ″ is output to the A / D converter 303.
The A / D converter 303 converts the analog signal from the image receiving element 5 to A
The D / D converted signal is output to the frame memory 324 via the arithmetic / control circuit 301, and the frame memory 324 stores information for one screen.

As shown in FIG. 7, the arithmetic / control circuit 301 controls the read addresses G ₁ , G ₂ , ..., G _i , ..., G ₁ , ..., G for the predetermined memory addresses of the frame memory 324. Radially read and scan according to _n . As a result, the data corresponding to the two images of the cornea measurement pattern image 100 ″ and the refractive power measurement pattern 203 ″ which are simultaneously image-projected on the image receiving element 5 are read and scanned. When the eye to be inspected has strong hyperopia, as shown in FIG. 6, a refractive power measurement pattern image 203 ″
Is projected to the outside of the image receiving element 5, and therefore, in the above-mentioned readout scanning, the coordinates _K g ₁ , _K g on the cornea measurement pattern 100 ″ are used.
₂ , ..., _K g _i , ..., _K g _l , ..., _K g _n only will be read. When the eye E is strongly myopic, the corneal measurement pattern image 100 ″ and the refractive power measurement pattern image 203 ″ approach each other.

In both cases, the arithmetic / control circuit 301
Outputs a command signal to the driver circuit 318, and the pulse generator 3
The pulse from 12 is supplied to the pulse motor 321 to move the moving casing 219 so that the refractive power measurement pattern image 203 ″ is projected in the area 5b, and the refractive power measurement pattern image 203 ″ is projected. And the cornea measurement pattern image 100 ″ are controlled so as to maintain a predetermined distance or more.
Although the focusing lens 216 is moved by the movement of 9, the fixation chart 32a observed by the eye E through the fixation / awareness measurement system 3 is +1.0 to 2.0 with respect to the refractive power of the eye E. It is designed to be in the D cloudiness state.

The number of pulses supplied to the pulse motor 321 for moving the moving casing 219 is counted by the counting circuit in the arithmetic / control circuit 301, and the counted value is the moving amount of the moving casing 219. Is stored in the first memory 309.

3) Measurement of Corneal Curvature Radius and Precision Measurement of Objective Refractive Power The control circuit 301 controls the moving casing 2 based on the above-mentioned measurement.
Based on the data in the frame memory 324 based on the image received by the final image receiving element 5 after moving 19 as shown in FIG. 7, read scans G ₁ , G ₂ , ..., G _i , ...
_Do G _l ,…, G _n to select points on the corneal measurement pattern 100 ″
Get the coordinates of K _g 1, K _g 2, ..., K _g i, ..., K _g l, ..., K _g n. Similarly, the points on the pattern image 203 ″ for refracting power measurement R _{g
1, R g 2, ...,} R g i, ..., obtained R _g l, ..., the coordinates of R _g n.

3-1) Measurement of Corneal Curvature Radius The arithmetic control circuit 301 uses the obtained points K _g 1, K _g 2, ..., K _g i,
_{..., K g l, ...,} K g n " to calculate the elliptical shape of the. Ellipse 100" pattern 100 from the coordinates of radius _SX K corneal C of the long axis of the _(X K axis)
Correlation with the radius of curvature _R 1 of the weak principal meridian of, and the radius _{SY of the} short axis ( _Y K axis)
K correlates with the radius of curvature _R 2 of the weak main meridian, and the long axis angle θ _K 1 and the short axis angle θ _K 2 correspond to the strong main meridian axis angle θ 1 and the weak main meridian axis angle θ 2, respectively.

The general formula for an ellipse 100 ″ in the _X K− _Y K coordinate system is

[Equation 1]

[Equation 2] Is represented as

The radius _S k of the pattern 100 ″ is the radius of curvature of the cornea C, as shown in FIG.
Up to h, the working distance is l, and the magnification of the entire projection optical system is β,

(Equation 3) Therefore, in the case of the example shown in Fig. 7, _SX K and _SY K are obtained from equations (1) and (2), and the radius of curvature _{R of the} strong main meridian is calculated from equation (3).
1 is

[Equation 4] The radius of curvature _R 2 of the weak principal meridian is

(Equation 5) Can be obtained as

The strong main meridian axis angle θ 1 = θ _K 2, and the weak main meridian axis angle θ 2 = θ _K 1. The curvature radii _R 1 and _R 2 and the axis angles θ 1 and θ 2 thus obtained are displayed together with the anterior segment image on the display 305 through the character circuit 306 and the display interface 304 as shown in FIG. 9 (b). And is stored in the second memory 310.

3-2) Objective refractive power measurement Refractive power measurement pattern image 20 obtained by read-out scanning
Based on the coordinates of the 3 ″ points R _g 1, R _g 2,…, R _g i,…, R _g l,…, R _g n, as in the above equations (1) and (2), _X The general formula of the ellipse 203 ″ in R− _Y R coordinates is

(Equation 6) Is represented as From these equations (1) and (2), _SX R and _SY R are calculated, and the refractive power _D 1 of the strong main meridian and the refractive power _D 2 of the weak strong meridian are emmetropic.
Assuming that the radius of the pattern image 203 ″ of (O Dioptpr) is _r n, in the example shown in FIG.

(Equation 7) Is required. Here, f is the composite focal length of the measurement optical system 21, and x is the base length (that is, the radius of the conjugate image of the ring diaphragm at the pupil position of the eye to be inspected).

Next, the arithmetic / control circuit 301 reads the amount of movement of the moving casing 219 stored in the first memory 309, that is, the number of pulses corresponding to the amount of movement of the focusing lens 216,
From this number of pulses, the refracting power correction amount d due to the movement of the focusing lens 216 is added to the refracting powers D1 and D2 of the strong and weak main radial lines obtained by the above equation (5), and (D1 + d) and (D2 + d) are added. Ask. As a result, the spherical refractive power S, the cylindrical refractive power C, and the cylindrical axis angle θ of the eye to be examined are

(Equation 8) Is required. The arithmetic / control circuit 301 displays the obtained S, C, and θ on the display device 305 via the character circuit 306 and the display interface 304, and also stores them in the third memory 311.

4) Measurement of subjective refractive power When the examiner next turns on the subjective eye examination switch 3083 of the control switch 308, the arithmetic / control circuit 301 causes the drivers 314 and 3 to operate.
The command to 15 is stopped, and thereafter, the light sources 102 and 200 stop their light emission. Next, when the examiner selects a visual acuity test chart with the chart selection switch 3089 of the control switch 308, the arithmetic / control circuit 301 operates the driver circuit 317,
A predetermined number of pulses are supplied from the pulse generator 312 to the pulse motor 322, the chart plate 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 arithmetic / control circuit 301 uses the refraction characteristics S, C, and θ of the eye E to be stored in the second memory 311 and the refraction characteristics of the eye E to be obtained by objective refraction power measurement. S
1, C1 and θ are read out, the number of pulses required to move the focusing lens 216 based on the value of the spherical refractive power S is calculated, and the number of obtained pulses is the driver circuit 31.
It is supplied to the pulse motor 321 via 8 and the moving housing 219
Is moved so that the focusing lens 216 is moved.

Next, the arithmetic / control circuit 301 calculates the number of pulses for rotating the VCC 37 from the cylindrical refractive power and the axial angle θ, and the obtained number of pulses is the driver circuit 32.
It is supplied to the pulse motor 323 via 0, and the VCC 37 is rotated. As a result, the subjective measurement system 3 has made optical correction in accordance with the refractive power of the eye E determined by the objective refractive power measurement.

The subject looks at the visual acuity display chart 32b inserted in the subjective measurement system 3 and answers the direction of the break of the Landolt ring. The examiner determines the subjective visual acuity of the eye E from the response of the examinee, and operates the spherical power correction switch 3088 of the control switch 318 when determining that the corrected visual acuity is not sufficient. The arithmetic / control circuit 301 supplies a pulse from the pulse generator 312 to the pulse motor 321 via the driver circuit 318 in accordance with a command from the switch 18, and moves the focusing lens to a position where corrected vision is improved. Arithmetic / control circuit 301
Counts the number of pulses when the focusing lens is re-moved, and again finds d in equation (6) from this number of pulses.
Based on the above, S1, C1, and θ are calculated by the equation (6), and the numerical values are displayed on the display unit 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 plate 32 is rotated, and the subjective measurement system is operated. The astigmatism chart 32c is inserted in the circuit of 3. The subject E looks at the inserted astigmatism chart 32c and replies whether or not there is a darkly visible line, and when the subject responds with "yes", the examiner makes a columnar axis correction switch 3090 of the control switch 318. To operate.

Based on the command, the arithmetic / control circuit 301 outputs a pulse to the pulse motor 323 via the driver circuit 320.
Supply to and rotate VCC37 to correct the cylinder axis. The arithmetic / control circuit 301 counts the number of pulses at this time, the cylinder axis angle θ is corrected based on the counted value, and the cylinder axis angle after the correction is displayed on the display 305.

Next, when the examiner selects the cross cylinder chart 3086 of the control switch 308, the control circuit 30
1 controls the pulse motor 323 to alternately make a cylinder axis angle difference of, for example, ± 0.5D based on the cylinder degree C currently set at VCC37, and make the difference in the appearance of the chart 32d at that time answered. When there is a difference in appearance, the inspector operates the cylindrical power correction switch 3089 of the control switch 308, and the operation / control circuit 301 makes the VCC37
Is controlled, the cylinder power is corrected, and a new cylinder power is displayed on the display unit 305.

Next, when the examiner selects the red-green chart 3087 of the control switch 308, the control circuit 30
1 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 in response to the response. Upon receiving the command, the arithmetic / control circuit 301 operates the pulse motor 321 to move the focusing lens 216, the spherical power S is corrected, and the new spherical power is displayed on the display 305.

5) Glare test The examiner next checks the glare test 309 of the control switch 308.
Select 1. Then, the arithmetic / control circuit 301 operates the pulse motor 322 via the driver circuit 319, and
32 is rotated, the visual acuity display chart 32b is inserted into the optical path of the subjective measurement system 3, and at the same time, the driver circuit 327 is operated and the glare light source 33 is emitted.

The subject looks at the visual acuity display chart 32b in the glare under the glare light source emission. The examiner can know whether the eye E to be inspected has a slight cataract or not based on the response of the subject. The glare light source may be added with a known volume or the like so that its brightness can be changed.

[0059]

As described above, according to the first aspect of the present invention, the reflected light from the cornea for measuring the shape of the cornea and the reflected light from the fundus for measuring the refractive power of the eye. And are projected onto one light receiving element at the same time
Can detect two reflected lights,
Since the arithmetic processing system can be shared, the optometry apparatus can be downsized. The measurement time can also be reduced.

Further, according to the second invention, when the anterior segment image stored in the memory immediately before the measurement is displayed,
During the measurement, the reliability of the measured value can be confirmed after the measurement.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall optical arrangement of an optometry apparatus according to the present invention.

FIG. 2 is an optical path diagram of an objective refractive power measurement system.

FIG. 3 is a plan view of a diaphragm 114.

FIG. 4 is a plan view of a diaphragm 215.

FIG. 5 is a block diagram showing a configuration of an electric circuit.

FIG. 6 is a diagram showing a relationship between a light receiving element and a pattern image.

FIG. 7 is a schematic diagram for explaining a principle of measuring a corneal curvature radius and an eye refractive power from a pattern system.

FIG. 8 is a diagram for explaining a curvature radius measurement principle.

FIG. 9 is a diagram showing a display state of the display device,
If the alignment index image is outside the aiming scale,
(B) shows the case where the alignment index image is within the aiming scale.

FIG. 10 is a diagram showing an example of a chart for subjective measurement.

FIG. 11 is a diagram showing a switch arrangement of control switches.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Corneal measurement system 2 ... Objective refractive power measurement system 3 ... Fixation and subjective measurement system 4 ... Anterior ocular segment observation and alignment system 5 ... Image receiving element (light receiving element) 11 ... Measuring optical system

Claims (2)

[Claims] 1. A measurement light is projected onto a cornea and a fundus of an eye to be inspected, and corneal reflected light and fundus reflected light of the eye to be inspected are projected onto a light receiving element through a measurement optical system and detected by the light receiving element. An optometry apparatus for measuring a corneal shape and an eye refractive power of the eye to be inspected based on a signal, wherein the measurement optical system simultaneously projects the cornea reflected light and the fundus reflected light onto the light receiving element. And an optometry device. 2. A measurement optical system for receiving at least one of the corneal reflected light and the fundus reflected light projected onto the eye to be examined and the anterior segment image of the eye to be examined, wherein the measurement optical system includes the corneal reflected light. With a shared two-dimensional light receiving element for receiving at least one of the eye fundus reflected light and the anterior segment image of the eye to be inspected,
Means for measuring at least one of the corneal shape and the eye refractive power of the eye to be examined based on the signal detected by the two-dimensional light receiving element and means for displaying the anterior segment image recorded in the memory are provided. Optometry device.