JP3660145B2 - Ophthalmic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ophthalmologic apparatus used in an ophthalmic clinic or an eyeglass store.
[0002]
[Prior art]
In an ophthalmologic apparatus such as an eye refractive power measurement device, a corneal curvature measurement device, or a non-contact tonometer that measures the characteristics of the eye to be examined, the upper eyelid of the eye to be examined is not sufficiently opened at the time of examination, and the measurement area has an upper eyelid. And accurate inspection is not possible. In order to obtain detailed examination data, an imaging device such as a corneal shape analyzer that analyzes a corneal shape by projecting a large number of platidling images onto a wide area of the cornea of the eye to be examined and capturing a reflection image thereof. It is desirable to shoot with the upper eyelid open as much as possible.
[0003]
For this reason, after examining the anterior eye part of the eye to be examined, the examiner instructed the subject to open his / her eye when the eyelid was not sufficiently opened.
[0004]
[Problems to be solved by the invention]
However, confirmation of how the eyelids open while observing the eye to be examined is left to the judgment of the examiner, and the accuracy depends on the experience of the examiner. For this reason, the inspection (measurement or photographing) may be executed without noticing that the opening of the eyelid is not sufficient, leading to problems such as causing an inspection error and reducing the reliability of the inspection data. In particular, in the case of the corneal shape analyzer as described above, where it is desired to perform the inspection with the eyelids open as much as possible, the subject who is not familiar with the inspection often re-photographs after confirming the image after photographing. Become.
[0005]
In addition, when the eyelids are not sufficiently opened, the subject opens the eyes wide, but when the eye is opened, the alignment may be shifted once, so both alignment and suitability of the eyelids It is not easy for the examiner to judge. With regard to alignment, an alignment detection mechanism can be provided and automation can be started so as to start the inspection according to its suitability. However, if the inspection is automatically started regardless of the opening of the eyelids, a highly reliable inspection is possible. It is difficult to do.
[0006]
In view of the problems of the above-described conventional apparatus, the present invention provides an apparatus that can reduce inspection errors and re-inspection due to inspection with insufficient opening of the eyelids and obtain highly reliable inspection data. Is a technical issue.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is characterized by having the following configuration.
[0008]
(1) An illumination optical system for illuminating the anterior segment of the eye to be examined, an observation optical system for observing the anterior segment of the eye to be examined, and an inspection means for measuring a corneal shape by detecting a platid ring image projected on the cornea of the eye to be examined And an alignment state detection means for detecting the alignment state of the inspection means with respect to the eye to be examined, having a detection surface in the vertical direction of the eye to be examined and arranged at a position substantially conjugate with the eye cornea to be examined Position detecting means for receiving reflected light from the anterior eye portion of the eye to be examined, eyelid position detecting means for detecting the eyelid position of the eye to be examined over time based on an output signal from the position detecting means, and the eyelid On the basis of the detection result of the position detection means, when it is detected that the upward movement of the upper eyelid is almost stopped or has started to fall, the triggering signal of the inspection means is issued on the condition that the alignment state is appropriate. Execute Characterized by comprising a control means.
[0009]
(2) An illumination optical system that illuminates the anterior eye portion of the eye to be examined, an observation optical system that observes the anterior eye portion of the eye to be examined, and an inspection unit that detects the platid ring image projected on the cornea of the eye to be examined and measures the corneal shape And an alignment state detection means for detecting the alignment state of the inspection means with respect to the eye to be examined, having a detection surface in the vertical direction of the eye to be examined and arranged at a position substantially conjugate with the eye cornea to be examined Position detecting means for receiving reflected light from the anterior eye portion of the eye to be examined, eyelid position detecting means for detecting the eyelid position of the eye to be examined over time based on an output signal from the position detecting means, and the eyelid On the condition that the alignment state is appropriate based on the detection result of the position detection means, when the upper eyelid is above the maximum cornea region to be measured, the trigger signal of the inspection means is issued, and the upper eyelid Also involved in Control means for issuing a trigger signal of the inspection means and executing an inspection when detecting that the ascending of the upper eyelid is almost stopped or has started to descend when it does not come above the maximum cornea region to be measured. It is characterized by that.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic optical system of an apparatus according to the present invention, which is an example of an apparatus having a corneal shape measurement system and an eye refractive power measurement system.
[0019]
Reference numeral 1 denotes a plate plate made of a diffusing plate, in which a large number of ring-shaped light transmitting portions and light shielding portions are formed around the optical axis L1. A large number of LEDs 2 that emit red to infrared light are disposed along the ring-shaped light-transmitting portion behind each light-transmitting portion. An anterior ocular segment illumination light source 4 is provided outside the placido plate 1, and the light source 4 illuminates the anterior ocular segment of the eye to be examined from the left and right directions substantially uniformly by near infrared light.
[0020]
In addition, an index projection system 10 and an index detection system 15 for detecting a working distance are provided behind the platide plate 1. The index projection system 10 includes an infrared index projection light source 11 and a lens 12, and light from the light source 11 is converted into a substantially parallel light beam by the lens 12 and passes through an opening opened in the plate 1 to the cornea of the eye E to be examined. Irradiated from an oblique direction. The detection optical axis of the index detection system 15 is provided so as to be symmetric with respect to the projection optical axis of the index projection system 10 with respect to the optical axis L1 on the front surface of the apparatus. A position detection element 17 is arranged. The reflected light from the cornea is incident on the one-dimensional position detecting element 17 through the lens 16 through the opening formed in the plate 1 by the index projection system 10. When the eye E moves in the direction of the optical axis L1, which is the Z direction (front-rear direction), the index image formed on the eye cornea also moves on the position detection element 17, so that the working distance of the eye to be examined is determined from the deviation. An alignment state is detected.
[0021]
A beam splitter 5 is disposed on the optical axis L1 behind the placido plate 1, and an eye refractive power measurement system 20 is disposed behind the beam splitter 5. Reference numeral 21 denotes a beam splitter, and an infrared illumination light source 22, a rotating sector 23, a projection lens 24, and a diaphragm 25 are disposed on an optical axis L2 that is coaxial with the optical axis L1. The rotary sector 23 is formed with two types of slits in a 45 degree direction and a 135 degree direction with respect to the rotation direction. The slit is illuminated by the light source 22, and the slit light beam scanned by the rotation of the rotating sector 23 is condensed near the cornea of the eye E through the projection lens 24, the diaphragm 25, the beam splitter 21, and the beam splitter 5. Projected to the fundus.
[0022]
On the optical axis L1 behind the beam splitter 21, a light receiving lens 26, a diaphragm 27, and a light receiving sensor unit 28 are provided in this order. The diaphragm 27 is disposed at the focal position on the rear side of the light receiving lens 26, and the light receiving sensor unit 28 is disposed at a position substantially conjugate with the eye cornea with respect to the light receiving lens 26. The light receiving sensor unit 28 includes two pairs of light receiving elements (four light receiving elements) arranged symmetrically with respect to the optical axis L1. Each light receiving element is provided at 90 degree intervals with the optical axis L1 as the center, and is arranged so that the refractive power can be measured with a pupil diameter of 2.5 mm. Two types of slit light fluxes having different inclinations are projected onto the fundus of the eye to be examined by the rotation of the rotating sector 23. The eye refractive power is determined from a phase difference signal by each pair of light receiving elements when one slit light beam is scanned and a phase difference signal by each pair of light receiving elements when the other slit light beam is scanned. Is calculated by the control unit 60 (see Japanese Patent Application Laid-Open No. 10-10836).
[0023]
Half mirrors 30, 31, a lens 32, a fixation target 33, and a fixation light source 34 are disposed on an optical axis L3 that is coaxial with the optical axis L1 by the beam splitter 5, and the lens 32 moves in the optical axis direction. Thus, clouding of the eye E is performed. The half mirror 31 reflects light from the light source 36 that projects alignment light from the front. Near-infrared light from the light source 36 is made into a substantially parallel light beam by the lens 35 and projected onto the eye to be examined.
[0024]
A lens 40, a light splitting mirror 41, and a CCD camera 42 are disposed on the optical axis L 4 on the reflection side of the half mirror 30. The CCD camera 42 is used for observing the anterior segment, detecting a bright spot formed on the cornea of the eye by the alignment light source 36, and capturing a platid ring image projected on the anterior segment. On the other hand, a one-dimensional position detection element 45 that is substantially conjugate with the eye cornea to be examined is provided on the reflection side of the light splitting mirror 41 via a lens 40. This position detection element 45 is used as an upper eyelid position detection means, and is arranged so that its detection direction is the vertical direction of the eye E (the vertical direction of the optical axis L1), as shown in FIG. The detection surface has a range extending from at least the center of the cornea to the upper eyelid.
[0025]
FIG. 3 is a block diagram showing a main configuration of the control system. The measuring unit 50 in which the optical system shown in FIG. 1 is arranged is in the X direction (left-right direction) and Y direction (up-down direction) with respect to a movable table 52 that can slide on the base 51 of the apparatus in the horizontal direction. , Driven in the Z direction (front-rear direction) by an X drive system 55, a Y drive system 56, and a Z drive system 57, respectively. The movable table 52 is slid on the base 51 by operating the joystick 53. Each drive system 55, 56, 57 is composed of a motor, a slide mechanism, etc., and its drive is controlled by a control unit 60 that controls the entire apparatus.
[0026]
An image processing unit 61 detects an alignment index image captured by the CCD camera 42 during observation, and inputs the detection result to the control unit 60. The control unit 60 determines the vertical and horizontal alignment states of the device (measurement unit 50) with respect to the eye to be examined based on the input index detection signal. When a shooting trigger signal is input, the image processing unit 61 takes in a platid ring image captured by the CCD camera 42 and performs predetermined image processing for corneal shape analysis. Reference numeral 62 denotes a color display for displaying an anterior ocular segment image for observation taken by the CCD camera 42, analysis results, and the like. The control unit 60 includes a position detection element 45 for detecting the upper eyelid position, a position detection element 17 for detecting the working distance, a sound generation unit 63, a switch unit 64 provided with a switch for selecting a measurement mode, and the like. A force measurement system 20 is connected.
[0027]
Next, the operation of the above apparatus will be described. The apparatus can select an eye refractive power measurement mode or a corneal shape analysis mode by a measurement mode switching switch. Hereinafter, each inspection will be described.
[0028]
<Eye refractive power measurement>
The anterior segment image illuminated by the illumination light source 4 is picked up by the CCD camera 42, and the image is displayed on the display 62. The examiner performs rough alignment by operating the joystick 53 or the like while observing the anterior segment image displayed on the display 62. When the index image formed by the light source 36 is detected by the image processing unit 61, the control unit 60 controls the driving of the X drive system 55 and the Y drive system 56 so that the XY directions are in a predetermined alignment state. Then, the measurement unit 50 is moved. Further, when the index for detecting the working distance can be detected by the position detection element 17, the control unit 60 controls the driving of the Z drive system based on the detection signal so that the Z direction becomes an appropriate state. The measurement unit 50 is moved back and forth. When the alignment states in the XYZ directions become appropriate, a cloud operation (measurement preparation operation) for eliminating the adjustment of the eye to be examined is started. Subsequently, it is determined whether or not the eyelid is open based on a detection signal from the position detection element 45.
[0029]
This suitability determination will be described. The reflected light from the anterior segment illuminated by the anterior segment illumination light source 4 is placed on the optical axis L3 coaxial with the optical axis L1 by the beam splitter 5 on the half mirror 30, the lens 40, and the light dividing mirror 41. Then, the light enters the position detecting element 45. FIG. 2B is a diagram schematically showing a signal output from the position detection element 45 when alignment is completed. As can be seen from the figure, when the anterior eye part is illuminated, the brightness increases in the order of pupil, iris, and upper eyelid, so the upper eyelid part can be detected by comparing each brightness information, and the reference is based on edge detection processing etc. Position information from the position can be obtained. By taking the reference position on the upper, lower, left, and right alignment optical axes, it is easy to determine whether there is a wrinkle in the measurement region through which the measurement light beam passes. That is, in the eye refractive power measurement of this embodiment, the measurement can be performed with a pupil diameter of 2.5 mm. Therefore, if the upper eyelid is located above the measurable region having a radius of 1.25 mm + α, it is determined that the eyelid opening degree is appropriate. If it is less than that, it is determined to be insufficient.
[0030]
If the eyelids are not sufficiently opened, the voice generation unit 63 gives a voice instruction such as “please open your eyes wide”. Further, since the fact is displayed on the display 62, the examiner may instruct the subject. When the subject opens the eye and it is determined that the eyelid is properly opened (the movement in the XYZ directions is also automatically performed during this period), the control unit 60 automatically generates a trigger signal, and the eye Measurement by the refractive power measurement system 20 is executed. During execution of this measurement, the upper eyelid may fall to the above measurable region due to fatigue of the subject. In this case, the control unit 60 interrupts the measurement, gives an instruction to call attention to the subject from the voice generation unit 63, and puts the measurement in a standby state. When it is detected that the upper eyelid has moved above the measurable area, the measurement is automatically resumed (or the measurement is restarted).
[0031]
In addition, since the eye refractive power measurement is normally performed a plurality of times (about 3 to 5 times) continuously with the same eye, the control unit 60 automatically tracks the measurement unit according to the XYZ alignment detection information, and the position detection element. The suitability of the upper eyelid position detected by 45 is determined each time measurement is performed. FIG. 4 is a diagram showing the detection position of the upper eyelid in time series, and is an example of a subject whose upper eyelid is drooping. In the case of such a subject, the eyelid is raised by an instruction to open the eye, but after a while, the eyelid falls due to fatigue. Therefore, the continuous measurement is performed between P1 and P2 where the upper eyelid is located above the measurable position D shown in the figure. If the expected number of times is not reached, the eye opening instruction is given again. Additional measurement is performed between P3 and P4.
[0032]
In this embodiment, the measurement is performed by automatically generating a trigger signal by detecting the alignment in the XYZ directions, but the alignment is performed by operating the joystick 53 while observing the reticle and the alignment bright spot displayed on the display 62. Then, the measurement start switch 54 may be pressed to generate a measurement start trigger signal. In this case, after the control unit 60 performs the cloud fog operation, which is a preparation operation for measurement, if the position of the upper eyelid is before P1 in the example shown in FIG. 4, the measurement execution is in a standby state and the upper eyelid can be measured. Measurement is started when it is detected that the position has moved above the correct position D. In this way, the occurrence of measurement errors can be reduced without missing the measurement timing.
[0033]
<Cornea shape analysis>
The description will focus on the differences from the eye refractive power measurement (see FIG. 6). As in the case of eye refractive power measurement, the apparatus automatically performs alignment in the XYZ directions based on the alignment detection information. When the alignment is completed, it is determined whether or not the upper eyelid position detected by the position detection element 45 is a position suitable for imaging. If it is determined that imaging is possible, imaging of the anterior segment image on which the placido ring is projected ( The image processing unit 61 automatically captures the still image as a still image. In the corneal shape analysis by projection of platid rings, a corneal region having a maximum diameter of about 11 mm is measured. Therefore, if there is a crease above this region (radius 5.5 mm + α), it is determined that measurement is possible. However, depending on the subject, it may be difficult to position the eyelid above this region even if an eye opening instruction is given. In this case, the movement of the upper eyelid is monitored, and photographing is performed by detecting that the eyelid is at the uppermost position.
[0034]
The detection of the uppermost position of the upper eyelid will be described with reference to FIG. FIG. 5 is a diagram showing the position in time series when the upper eyelid moves in response to an eye opening instruction. The control unit 60 samples and stores the upper eyelid position over time (at regular time intervals), while the upper eyelid position P (n) at the sampled time t (n) is one immediately before. The change with respect to the upper eyelid position P (n-1) at the sampling time t (n-1) is sequentially obtained. Here, if P (n) −P (n−1) ≧ m, it can be considered that the bag is moving upward, and if P (n) −P (n−1) <m, The movement of the upper arm can be regarded as almost stopped (or turned down). However, m is a predetermined change amount set to determine the movement of the upper eyelid and is a constant of m> 0.
[0035]
Therefore, it can be determined whether or not the upper eyelid has come to the uppermost position for the subject based on whether or not the change in the position data sampled at regular time intervals is greater than or less than the predetermined change amount. When the shape analysis is performed by projecting the placido ring onto the cornea, it is desirable to obtain a ring image over the wide range of the cornea as much as possible, so when the apparatus detects that the upper eyelid has reached the top position, At that timing, a trigger signal is automatically generated to perform shooting. As a result, a photographed image with the uppermost eyelid opened for the subject can be obtained with good timing.
[0036]
The photographed image is taken into the frame memory, and the edge of the placido ring image is detected by the image processing unit 61. The controller 60 performs a predetermined calculation process based on the detection data and analyzes the corneal shape. The analysis result is displayed on the display 62 as a topograph, for example.
[0037]
As described above, since the position of the upper eyelid that needs to be opened differs depending on the type of measurement, it is convenient to be able to detect the position of the eyelid from the reflected light of the anterior segment illumination because the degree of freedom of the apparatus is increased. In particular, in the case of a configuration in which different measurements are performed by one apparatus as in the present embodiment, it is preferable that the eyelid position detection system can be shared.
[0038]
In the case of corneal shape analysis, the position of the upper eyelid may be detected from the state of reflected light of the placido ring image projected onto the cornea. That is, when the upper eyelid is applied to the placido ring image, the ring pattern image is not detected, and the position of the upper eyelid can be determined from the detected ring pattern image.
[0039]
The above embodiment can be further variously modified. For example, the CCD camera 42 for observation can be used in place of the position detecting element 45 for detecting the upper eyelid position. Since the CCD camera 42 alternately outputs odd field and even field video signals every 1/60 seconds, one of the signals is stored in the memory, and the position of the eyelid is detected as needed from the luminance change. . In this case, since signals in all regions are not required, the vertical direction has a range that can cover the upper eyelid from the center as in the position detection element 45, and the horizontal direction has a range of several pixels across the center. . The eyelid position may be detected by averaging the luminance signals in the horizontal direction.
[0040]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce inspection errors and inspection re-execution due to inspection execution in a state where the opening of the eyelid is insufficient, and it is possible to obtain highly reliable inspection data.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic optical system of an apparatus according to the present invention.
FIG. 2A is a diagram showing an arrangement of position detection elements for detecting an upper eyelid position.
(B) It is the figure which showed typically the signal output from a position detection element when alignment is completed.
FIG. 3 is a block diagram showing the configuration of the main part of the control system. FIG. 4 is a diagram showing the detection position of the upper eyelid in time series.
FIG. 5 is a diagram showing a position in time series when the upper eyelid moves in response to an eye opening instruction.
FIG. 6 is a diagram showing a flowchart in corneal shape analysis.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Platide board 4 Light source for anterior ocular segment illumination 20 Eye refractive power measurement system 42 CCD camera 45 Light source for anterior ocular segment illumination 60 Control unit 61 Image processing unit

Claims (2)

An illumination optical system that illuminates the anterior eye portion of the eye to be examined, an observation optical system that observes the anterior eye portion of the eye to be examined, an inspection means that detects a platid ring image projected on the cornea of the eye to be examined, and a corneal shape; An ophthalmologic apparatus comprising an alignment state detection unit that detects an alignment state of the inspection unit with respect to an optometry , has a detection surface in the vertical direction of the eye to be examined, and is disposed at a position substantially conjugate with the eye cornea to be examined. Position detecting means for receiving reflected light from the anterior optometric eye part , eyelid position detecting means for detecting the eyelid position of the eye to be examined over time based on an output signal from the position detecting means, and eyelid position detecting means Based on the detection result of the above, when it is detected that the upward movement of the upper arm is almost stopped or has started to descend, the control is performed by issuing a trigger signal of the inspection means on condition that the alignment state is appropriate Ophthalmologic apparatus characterized by comprising: a stage, a. An illumination optical system that illuminates the anterior eye portion of the eye to be examined, an observation optical system that observes the anterior eye portion of the eye to be examined, an inspection means that detects a platid ring image projected on the cornea of the eye to be examined, and a corneal shape; An ophthalmologic apparatus comprising an alignment state detection unit that detects an alignment state of the inspection unit with respect to an optometry, has a detection surface in the vertical direction of the eye to be examined, and is disposed at a position substantially conjugate with the eye cornea to be examined. Position detecting means for receiving reflected light from the anterior optometric eye part, eyelid position detecting means for detecting the eyelid position of the eye to be examined over time based on an output signal from the position detecting means, and eyelid position detecting means On the condition that the alignment state is appropriate based on the detection result of the above, when the upper eyelid is above the maximum cornea region to be measured, the trigger signal of the inspection means is issued, and the upper eyelid is detected over time. Nevertheless Control means for generating a trigger signal of the inspection means and executing an inspection when it is detected that the ascending of the upper eyelid has almost stopped or has started to descend when it does not go above the maximum corneal region the ophthalmic apparatus according to claim.

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