JP3743468B2 - Ophthalmic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention detects a positional relationship between an apparatus main body (apparatus optical system) of an ophthalmologic apparatus such as a non-contact type tonometry apparatus (tonometer) and an eye to be examined, and the apparatus main body based on the detection result. The present invention relates to an ophthalmologic apparatus having an automatic alignment function capable of automatically aligning the apparatus main body with a predetermined position of an eye to be examined by moving the lens.
[0002]
[Prior art]
Conventionally, an ophthalmologic apparatus having a so-called automatic alignment function, that is, the corneal reflection light of the alignment index light projected on the eye to be examined is guided to the optical sensor by the light receiving optical system, and is applied to the eye to be examined based on the output of the optical sensor. An ophthalmologic apparatus that automatically adjusts the alignment of a measurement unit is known.
[0003]
In such an ophthalmologic apparatus, the examiner moves the measurement optical axis to the vicinity of the apex of the cornea of the eye to be examined (coarse alignment adjustment) using a joystick or the like while looking at the viewfinder or the monitor. When the coarse alignment adjustment is completed, automatic alignment adjustment is started based on the output of the optical sensor.
[0004]
[Problems to be solved by the invention]
However, an ophthalmologic apparatus having such an automatic alignment function has a problem that malfunction may occur depending on the operation method, the state of the eye to be examined, and the like.
[0005]
For example, when the subject blinks during automatic alignment adjustment, reflected light from the eyelids or eyelashes may enter the optical sensor. As a result, the automatic alignment adjustment mechanism may move the measurement unit in a direction completely different from the desired direction. When such a malfunction occurred, the examiner had to once move the measurement unit away from the eye to be examined or press the reset switch to cancel the automatic alignment mode.
[0006]
In addition, reflected light from the eyelids and cheeks may enter the optical sensor at the stage of coarse alignment adjustment (which is performed by the examiner manually operating the joystick) before automatic alignment adjustment. The automatic alignment adjustment mechanism may malfunction due to light.
[0007]
[Means for Solving the Problems]
The present invention has been made in view of the above circumstances, and the present invention automatically discriminates such noise light and reflected light from the vicinity of the corneal apex of the subject's eye to effectively prevent malfunction of the automatic alignment adjustment mechanism. It is an object of the present invention to provide an ophthalmologic apparatus that can be prevented.
[0009]
In order to solve the above-described problems, an ophthalmic apparatus according to the present invention includes an apparatus main body, and an alignment in an XY direction along the optical axis to detect an optical axis shift between the apparatus main body and the eye to be examined. the XY-direction alignment indicator light projection means for projecting an index light, wherein for detecting the first light receiving element for detecting the XY direction alignment index light reflected from the examined eye, the distance between the apparatus body and the subject's eye A Z-direction alignment index light projection means for projecting a Z-direction alignment index light onto the eye to be examined from a direction different from the optical axis, a second light receiving element for detecting the Z-direction alignment index light reflected from the eye to be examined, Position of the XY direction alignment index light detected by the first light receiving element on the light receiving element and reception of the Z direction alignment index light detected by the second light receiving element Automatically in ophthalmic apparatus comprising an alignment drive unit, the aligning, the second light receiving and detected light quantity Lxy by the first light receiving element position on the child with respect to the eye the device body based on And a means for stopping the operation of the alignment driving means when a relation of Lxy <Lz is obtained by relatively comparing the light quantity Lz detected by the element.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an intraocular pressure measuring apparatus which is an ophthalmologic apparatus according to an embodiment of the present invention will be described with reference to the drawings.
[0014]
1, 2 and 3 are diagrams showing a configuration of an intraocular pressure measuring apparatus which is an ophthalmologic apparatus according to an embodiment of the present invention. 1, 2, and 3, an intraocular pressure measurement device according to an embodiment of the present invention includes an anterior ocular segment observation optical system 10, an XY direction alignment index light projection optical system 20, an XY direction alignment detection optical system 30, and a Z. A direction alignment index light projection optical system 50, a Z direction alignment light detection optical system 70, and a fixation target projection optical system 80 are provided. The X direction and the Y direction indicate directions parallel to the subject's face (up and down and left and right directions), respectively, and the Z direction indicates a direction perpendicular to the subject's face (front and back). Direction).
[0015]
The intraocular pressure measurement device according to the embodiment of the present invention further includes an injection nozzle 100, an air supply unit 101, an applanation sensor 102, an A / D (analog / digital) converter 103, a control circuit 104, a drive circuit 105, an image. It has a processing circuit 106, a display unit 107, a memory unit 108, an XY direction movement control mechanism 109a, and a Z direction movement control mechanism 109b.
[0016]
The anterior ocular segment observation optical system 10 for observing the anterior segment of the eye E is arranged on the left and right sides of the eye E, and directly illuminates the anterior segment of the eye E with infrared light. , Half mirrors 12 and 14, objective lens 13, and CCD (charge coupled device) camera 16, and half mirrors 12 and 14, objective lens 13, and CCD camera 16 are arranged along optical axis O1. The reflected light from the anterior segment of the eye E illuminated by the anterior segment observation light source 11 is guided to the CCD camera 16 via the half mirror 12, the objective lens 13, and the half mirror 14, and obtained as an anterior segment image. It is done.
[0017]
XY direction alignment index light projection optics for projecting alignment index light used to perform alignment in the XY direction between the apparatus main body (apparatus optical system) of the tonometry apparatus and the eye E to be examined onto the cornea C of the eye E to be examined. The system 20 is arranged on the optical path so that the focal point coincides with the light source 21 that emits infrared light, the condenser lens 22, the aperture stop 23, the pinhole plate 24 that forms the alignment index, the dichroic mirror 25, and the pinhole plate 24. The projection lens 26 and the half mirror 12 are disposed. Infrared light emitted from the light source 21 is collected by the condenser lens 22, passes through the aperture stop 23, and is guided to the pinhole plate 24. The light that has passed through the pinhole plate 24 is reflected by the dichroic mirror 25, becomes a parallel light beam by the projection lens 26, is reflected by the half mirror 12, and is projected onto the cornea C.
[0018]
The XY-direction alignment detection optical system 30 that receives the reflected light of the alignment index light from the cornea C of the eye E to be detected and detects the relative positions of the apparatus main body and the cornea C in the XY directions includes the half mirrors 12 and 14 and the objective lens 13. , And an XY direction alignment detection sensor 31. The alignment index light projected onto the cornea C by the XY direction alignment index light projection optical system 20 and reflected by the cornea C is transmitted through the half mirror 12, focused by the objective lens 13, and partly reflected by the half mirror 14. Then, the light enters the XY direction alignment detection sensor 31. The XY direction alignment detection sensor 31 includes a light receiving element capable of detecting a position such as a PSD (position detector), and for example, a two-dimensional PSD is used. Note that two one-dimensional PSDs may be used.
[0019]
The XY direction alignment detection circuit 91a calculates the relative position in the XY direction between the apparatus main body and the cornea C of the eye E based on the output of the XY direction alignment detection sensor 31, and provides position information 111 indicating the calculation result. Output to the control circuit 104. On the other hand, the light transmitted through the half mirror 14 is guided to the CCD camera 16. The output information 112 of the CCD camera 16 is output to the control circuit 104 and predetermined image processing is performed by the image processing circuit 106. By this image processing, as shown in FIG. 4, the anterior segment image 41 and the bright spot image R of the eye E are displayed on the display screen 107 a of the display unit 107. In FIG. 4, an alignment area 40 is an area where automatic alignment adjustment is possible. The examiner moves the apparatus main body up and down, left and right (XY directions) with a joystick (not shown) so that the bright spot image R indicating the position of the optical axis O1 of the apparatus optical system is located at the center of the alignment area 40, and the apparatus optical system. The measuring unit is moved in a direction in which the optical axis O1 coincides with the eyeball optical axis of the eye E to be examined. When the bright spot image R enters the alignment area 40, the XY direction movement control mechanism 109a is driven. Thereby, the automatic alignment adjustment is started by the XY direction movement control mechanism 109a.
[0020]
The Z-direction alignment index light projection optical system 50 that irradiates the cornea C of the eye E from an oblique direction with slit light for performing alignment in the Z direction between the main body of the intraocular pressure measuring device and the eye E to be examined is red. A light source 51 that emits external light, a condensing lens 52, a slit plate 53, a dichroic mirror 44, an aperture stop 45, and an objective lens 46 are included. Infrared light emitted from the light source 51 is focused by the condenser lens 52 and passes through the slit plate 53. The passing light is reflected by the dichroic mirror 44, passes through the aperture stop 45, is focused by the objective lens 46, and is applied to the cornea C of the eye E to be examined.
[0021]
The Z direction alignment detection optical system 70 that receives the reflected light from the cornea C of the light irradiated by the Z direction alignment index light projection optical system 50 and detects the position in the Z direction includes an objective lens 61, a dichroic mirror 62, and A Z-direction alignment detection sensor 71 is provided. The reflected light from the cornea C of the light illuminated by the Z-direction alignment index light projection optical system 50 is focused by the objective lens 61, guided to the dichroic mirror 62, reflected, and incident on the Z-direction alignment detection sensor 71. The Z-direction alignment detection sensor 71 is composed of a light receiving element such as a line sensor or a one-dimensional PSD. The Z direction alignment detection circuit 91b detects the peak position of the amount of light based on the output of the Z direction alignment detection sensor 71. As a result, the position in the Z direction is detected. The position information 110 is output from the Z-direction alignment detection circuit 91b to the control circuit 104. Based on this detection information, the Z-direction movement control mechanism 109b moves the apparatus main body back and forth (Z direction) with respect to the eye E to ensure a working distance. That is, the Z-direction alignment detection optical system 70 is set so that the working distance is OK when a peak of the amount of received light is detected at a predetermined address of the line sensor constituting the Z-direction alignment detection sensor 71.
[0022]
A fixation target projection optical system 80 for projecting a fixation target image onto the eye E is a fixation target projection light source 81 that emits visible light, a pinhole plate 82, a dichroic mirror 25, a projection lens 26, and the half mirror 12. have. The fixation target light, which is visible light emitted from the fixation target projection light source 81, passes through the pinhole plate 82, passes through the dichroic mirror 25, becomes a parallel light beam by the projection lens 26, and then is reflected by the half mirror 12. And projected onto the eye E. The line of sight of the subject's eye E is fixed by gazing at the fixation target light reflected by the half mirror 12 as a fixation target.
[0023]
The air supply unit 101 deforms the cornea C by injecting an air pulse to the cornea C of the eye E through the injection nozzle 100.
[0024]
The applanation sensor 102 optically detects the cornea C deformed by the air pulse from the injection nozzle 100. Specifically, the cornea C is irradiated with detection light as the air pulse is emitted to the cornea C. This detection light is reflected by the deformed cornea C, and the reflected light is received by the applanation sensor 102 and converted into an electric signal. This electric signal is converted into a digital signal by an A / D (analog / digital) converter 103 and then input to the control circuit 104.
[0025]
The control circuit 104 includes a CPU (central processing unit) 104a and a program memory 104b. The CPU 104a controls / processes the entire tonometry apparatus according to various control / processing programs stored in the program memory 104b.
[0026]
Note that the amount of detection light reflected by the cornea C increases with the start of deformation of the cornea C, and reaches a peak during applanation of the cornea C, so that the intraocular pressure of the eye E to be examined is based on the temporal change in the amount of received light. Is obtained by the CPU 104a.
[0027]
The drive circuit 105 drives the air supply unit 101 when measuring intraocular pressure under the control of the CPU 104a.
[0028]
The memory unit 108 stores setting conditions for executing and stopping automatic alignment adjustment / intraocular pressure automatic measurement, which will be described later.
[0029]
Next, the operation of the intraocular pressure measurement device according to the embodiment of the present invention will be described.
[0030]
In the automatic alignment adjustment / intraocular pressure automatic measurement in the intraocular pressure measurement apparatus according to the present embodiment, the measurement operation is temporarily stopped when three intraocular pressure measurements are completed. This is because when the bright spot image R is present in the alignment area 40, automatic alignment adjustment / intraocular pressure automatic measurement is repeatedly performed, thereby preventing an unnecessary burden on the patient. The intraocular pressure measurement is stopped by switching the RL switch for switching the measurement target of the left and right eye E (for example, switching the intraocular pressure measurement from the left eye to the right eye), switching the front and rear of the observation lens, and clear switch. And the end of printing by the printing unit (not shown) of the intraocular pressure measurement result. Note that the number of times of intraocular pressure measurement until the intraocular pressure measurement operation is temporarily stopped is not limited to three and can be arbitrarily set.
[0031]
FIG. 5 is a diagram showing each measurement site of the cornea of the eye to be measured, in which the XY direction level value and the Z direction level value are actually measured by the intraocular pressure measurement device according to the embodiment of the present invention. 6 is a result of incident light amount conversion level values of the XY direction level value and the Z direction level value actually measured at each measurement site of the cornea of the eye shown in FIG. 5 by the tonometry apparatus according to the embodiment of the present invention. FIG. In FIG. 6, the vertical axis indicates the detection level value (arbitrary level value) of the reflected light from each measurement site of the cornea C of the eye E shown in FIG. 5, and the horizontal axis indicates each measurement site corresponding to the detected reflected light. Is shown.
[0032]
FIG. 6 shows a light amount conversion level value incident on the two-dimensional PSD of the XY-direction alignment detection circuit 91a for detecting the position in the XY direction of the optical axis O1 of the apparatus optical system with respect to the eyeball optical axis of the eye E, and the eye E The light amount conversion level value incident on the one-dimensional PSD of the Z-direction alignment detection circuit 91b for detecting the device operating position (intraocular pressure measurement position) in the Z direction with respect to the apex of the cornea C is shown.
[0033]
These light quantity conversion level values are such that the XY direction level value Lxy is 1200 (arbitrary level value) when the alignment position with respect to the cornea C of the eye E coincides with the alignment origin (reference position) in the XY direction and the Z direction. The Z direction level value Lz is adjusted to 600 (arbitrary level value). In addition, these numerical values are only examples, and it goes without saying that the scope of the present invention is not limited.
[0034]
The alignment of the apparatus main body with respect to the eye E is automatically performed in a state where the subject such as a patient opens his eyes. In this case, the light quantity conversion levels in the XY direction and the Z direction in the vicinity of the corneal apex of the eye E to be examined. In the value, the XY direction level value is larger than the Z direction level value (Lxy> Lz).
[0035]
However, when the subject closes his eyes by blinking or the like, or when the eyelashes are in his eyes, the relationship of Lxy> Lz is not satisfied as is apparent from FIG. The value is smaller than the Z direction level value (Lxy <Lz). Accordingly, the ratio between the XY direction level value and the Z direction level value is obtained, and when it is determined that the cornea C of the eye E is not correctly detected based on this ratio, the apparatus main body aligns with the eye E. Therefore, automatic alignment adjustment and automatic intraocular pressure measurement are stopped.
[0036]
The automatic alignment adjustment and the intraocular pressure automatic measurement can be stopped more reliably by setting a predetermined threshold other than the above-described relationship of Lxy <Lz. For example, the conditions for stopping automatic alignment adjustment and automatic intraocular pressure measurement are set as follows (1) or (2). That is,
(1) Lxy <Lz, or Lxy <500, or Lz <200 (where 500 and 200 are arbitrary level values)
(2) Lxy <aLz, or Lxy <b, or Lz <c (where a, b, and c are arbitrary constants)
The above numerical values can be changed by adjusting the light quantity conversion level value at the alignment origin (reference position).
[0037]
Here, automatic alignment adjustment in the intraocular pressure measurement apparatus according to the embodiment of the present invention will be described with reference to FIG. FIG. 7 is a control flowchart showing automatic alignment adjustment in the intraocular pressure measurement apparatus according to the embodiment of the present invention. This automatic alignment adjustment is performed under the control of the CPU 104a of the control circuit 104.
[0038]
In FIG. 7, in step A1, the XY direction level value Lxy and the Z direction level value Lz detected by the XY direction alignment detection circuit 91a and the Z direction alignment detection circuit 91b are acquired. In the processing after step A2, it is determined whether to execute (continue) or stop the automatic alignment adjustment and the intraocular pressure automatic measurement described above.
[0039]
If Lxy is smaller than Lz in Step A2, Lxy is smaller than 500 in Step A3, or if Lz is smaller than 200 in Step A4, the automatic alignment adjustment operation is stopped (Step A5). Specifically, the operations of the XY direction movement control mechanism 109a and the Z direction movement control mechanism 109b are stopped. At this time, if the intraocular pressure automatic measurement is being performed, the intraocular pressure automatic measurement is also stopped. Specifically, the operation of the drive circuit 105 is stopped.
[0040]
On the other hand, if Lxy is greater than or equal to Lz in step A2, if Lxy is greater than or equal to 500 in step A3, or if Lz is greater than or equal to 200 in step A4, in step A6, the apparatus main body (apparatus optical system) is the eye to be examined. A determination is made as to whether E is aligned. If the apparatus main body is aligned with the eye E in step A6 and is in an alignment OK state, measurement of intraocular pressure is started (step A8).
[0041]
On the other hand, if the alignment is not OK in step A6, the automatic alignment adjustment operation is executed (continue) (step A7). That is, returning to the process of step A1, the process described above is repeated.
[0042]
In addition, since many subjects repeatedly blink once, etc., once automatic alignment adjustment and automatic intraocular pressure measurement are suspended, automatic alignment adjustment and automatic intraocular pressure measurement are suspended until a predetermined time has elapsed. By continuing the state, the intraocular pressure measuring device according to the present invention can be used more effectively.
[0043]
Moreover, since the XY direction level value and the Z direction level value change continuously when the subject closes his / her eyes, if the change in these level values is continuously detected and a threshold is provided, It is also possible to more reliably determine whether or not the examiner's eyes are surely opened, when the examinee's eyes are opened, and the like.
[0044]
Furthermore, the present invention can also be applied to an ophthalmologic apparatus having a self-alignment function that allows the subject himself to perform alignment adjustment himself. In such an ophthalmologic apparatus, by providing a buzzer or the like that generates a signal that prompts the subject to blink from the ophthalmologic apparatus, the subject can close or open the eyelid according to the generation of the signal. As a result, the eye can be inspected reliably at the moment when the eye of the subject opens. It should be noted that an examiner other than the subject may prompt the blinking.
[0045]
Furthermore, although the intraocular pressure measurement device has been described in the present embodiment, the present invention can be applied to other ophthalmologic devices.
[0046]
【The invention's effect】
As described above, according to the present invention, when the eyelid or eyelash of the subject is in the alignment position that is the optical axis of the apparatus optical system, automatic alignment adjustment and automatic intraocular pressure measurement can be reliably stopped. it can. Thereby, it is possible to prevent unnecessary pain from being given to the subject without performing unnecessary automatic alignment adjustment and intraocular pressure measurement.
[Brief description of the drawings]
FIG. 1 is a diagram showing a part of the configuration of an intraocular pressure measuring device which is an ophthalmic device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a part of the configuration of the intraocular pressure measurement apparatus according to the embodiment of the present invention.
FIG. 3 is a diagram showing a part of the configuration of the intraocular pressure measurement device according to the embodiment of the present invention.
FIG. 4 is a diagram showing a display screen such as an anterior segment image displayed on the display unit of the intraocular pressure measurement device according to the embodiment of the present invention.
FIG. 5 is a view showing each measurement site of the cornea of the eye to be measured, in which the XY direction level value and the Z direction level value are actually measured by the intraocular pressure measurement device according to the embodiment of the present invention.
6 shows results of incident light amount conversion level values of XY direction level values and Z direction level values actually measured at each measurement site of the cornea of the eye to be examined shown in FIG. 5 by the intraocular pressure measurement device according to the embodiment of the present invention. FIG.
FIG. 7 is a control flowchart showing automatic alignment adjustment in the intraocular pressure measurement apparatus according to the embodiment of the present invention.
[Explanation of symbols]
E Eye to be examined C Cornea 10 Anterior eye observation optical system 20 XY direction alignment index light projection optical system 30 XY direction alignment detection optical system 50 Z direction alignment index light projection optical system 70 Z direction alignment light detection optical system 80 Fixation target projection Optical system 100 Injection nozzle 101 Air supply unit 102 Applanation sensor 103 A / D converter 104 Control circuit 104a CPU
104b Program memory 105 Drive circuit 106 Image processing circuit 107 Display unit 108 Memory unit 109a XY direction movement control mechanism 109b Z direction movement control mechanism

Claims (1)

The device body,
XY direction alignment index light projection means for projecting XY direction alignment index light onto the eye to be examined along the optical axis in order to detect a deviation of the optical axis between the apparatus main body and the eye to be examined;
A first light receiving element that detects the XY-direction alignment index light reflected from the eye;
Z-direction alignment index light projecting means for projecting Z-direction alignment index light onto the eye to be examined from a direction different from the optical axis in order to detect the distance between the apparatus main body and the eye to be examined;
A second light receiving element for detecting the Z-direction alignment index light reflected from the eye to be examined;
The apparatus main body based on the position on the light receiving element of the XY direction alignment index light detected by the first light receiving element and the position on the light receiving element of the Z direction alignment index light detected by the second light receiving element. Alignment drive means for automatically aligning the eye with the eye to be examined;
In an ophthalmic apparatus comprising:
A means for canceling the operation of the alignment driving means when a relation of Lxy <Lz is obtained by relatively comparing the light quantity Lxy detected by the first light receiving element with the light quantity Lz detected by the second light receiving element. An ophthalmologic apparatus comprising:

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