JP2008073415A - Ophthalmologic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently measure the cornea shape of the examined eye with good accuracy. <P>SOLUTION: This ophthalmologic apparatus for measuring the cornea shape and the refracting power of the examined eye includes: a measurement mode select means for selecting either a cornea shape measuring mode or an eye refracting power measuring mode; an alignment detecting means for detecting the alignment state of the measuring part to the examined eye; and a control means for measuring the eye refracting power of the examined eye using an eye refracting power measuring optical system based on the detection result detected by the alignment detecting means before the cornea shape of the examined eye is measured using a cornea shape measuring optical system in the state where the cornea shape measuring mode is selected by the measurement mode select means, and changing the presenting position of a fixed mark in the optical axis direction based on the measurement result using a presenting position changing means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ophthalmologic apparatus for measuring a cornea shape and eye refractive power of an eye to be examined.

  An ophthalmologic apparatus capable of measuring the cornea shape and eye refractive power of an eye to be examined with one apparatus is known. In the case of such an apparatus, a predetermined pattern (for example, a balloon) is applied to a fixation target to be fixed to the eye for the purpose of applying fog to the eye during the eye refractive power measurement mode. Is used, and the display position of the fixation target is moved according to the eye refractive power of the eye to be examined.

  However, the presenting position of the fixation target is moved only in the eye refractive power measurement mode, and the presenting position of the fixation target is not moved in the corneal shape measurement mode. Therefore, if the eye to be examined is close to the normal eye, fixation can be performed by looking at the fixation target.However, when measurement is performed on a strong myopic eye, etc., the eye to be examined does not know where to look. The movement of the optometry may become unstable, resulting in a decrease in measurement accuracy and variations in measurement results.

Further, in the above-described composite apparatus, the corneal shape measurement is performed after adjusting the fixation state of the eye to be inspected. After the measurement switch is pressed, the eye refractive power measurement is first performed to fix the fixation target. Is disclosed in which the corneal shape is measured from the second time (see Patent Document 1).
JP-A-7-241274

  However, it is troublesome for the examiner to perform eye refractive power measurement for fixation adjustment by the first measurement switch input, and to measure the corneal shape from the second measurement switch input, which increases the measurement time. . Further, when trying to perform these in a series of operations by inputting a single measurement switch, however, in the case of the apparatus of Patent Document 1, until the position of the fixation target is moved after the measurement switch is pressed, It is necessary to open the eye to be examined extra. Therefore, there is a high possibility that the subject's eye will blink when measuring the corneal shape (particularly in the case of dry eye or the like), and there is a high possibility of a measurement error.

  In view of the above problems, an object of the present invention is to provide an ophthalmologic apparatus that can accurately and efficiently measure the corneal shape of an eye to be examined.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) Corneal shape measurement optical system for measuring the corneal shape of the eye to be examined, eye refractive power measurement optical system for measuring the eye refractive power of the eye to be examined, and fixation target presentation for presenting a fixation target to the eye to be examined A measuring unit having an optical system, and a presentation position changing means for changing the presentation position of the fixation target presented to the eye to be examined in the direction of the optical axis, and measuring the corneal shape and refractive power of the eye to be examined. In the ophthalmic device to perform,
Measurement mode selection means for selecting one of a corneal shape measurement mode and an eye refractive power measurement mode;
Alignment detection means for detecting the alignment state of the measurement unit with respect to the eye to be examined;
Based on the detection result detected by the alignment detection unit before measuring the corneal shape of the eye to be examined using the corneal shape measurement optical system in a state where the corneal shape measurement mode is selected by the measurement mode selection unit. Control means for measuring the eye refractive power of the eye to be examined using the eye refractive power measuring optical system, and changing the presentation position of the fixation target in the optical axis direction using the presentation position changing means based on the measurement result And.
(2) In the ophthalmic apparatus according to (1),
It is characterized by comprising notifying means for notifying that the operation for stabilizing the fixation state of the eye to be examined has been completed by the control means.
(3) In the ophthalmologic apparatus according to (1), the control unit changes the presentation position of the fixation target in the optical axis direction before the alignment of the measurement unit with respect to the eye to be examined is completed. .

  According to the present invention, it is possible to accurately and efficiently measure the corneal shape of the eye to be examined.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external configuration diagram of an ophthalmologic apparatus according to the present embodiment. The ophthalmologic apparatus according to the present embodiment is a so-called stationary ophthalmologic apparatus, and includes a base 1, a face support unit 2 attached to the base 1, and a movable base that is movably provided on the base 1. 3 and a measurement unit (measurement unit) 4 that is movably provided on the movable table 3 and accommodates an optical system to be described later. The measuring unit 4 is moved in the left and right direction (X direction), the up and down direction (Y direction), and the front and rear direction (Z direction) with respect to the eye E by an XYZ driving unit 6 provided on the moving table 3. The movable table 3 is moved in the X direction and the Z direction on the base 1 by operating the joystick 5. Further, when the examiner rotates the rotary knob 5 a, the measurement unit 4 is moved in the Y direction by the Y drive of the XYZ drive unit 6. On the top of the joystick 5, a measurement start switch 5b is provided. A display monitor 40 is provided on the movable table 3.

  FIG. 2 is a schematic configuration diagram illustrating the configuration of the optical system and the control system of the ophthalmologic apparatus according to the present embodiment. On the transmission optical path O1 of the dichroic mirror 15 in front of the eye E, an eye refractive power measurement optical system 10 that measures the eye refractive power of the eye to be examined is arranged.

  The measurement optical system 10 includes a projection optical system 10a that projects a spot-like measurement index on the fundus oculi Ef of the eye E via the pupil central portion of the eye E, and fundus reflected light reflected from the fundus oculi Ef via the pupil periphery. And a light receiving optical system 10b for picking up a ring-shaped fundus reflection image on the two-dimensional imaging device.

  The projection optical system 10 a includes a measurement light source 11, a relay lens 12, a hall mirror 13, and a measurement objective lens 14 disposed on the optical path O <b> 1 of the measurement optical system 10. In the light receiving optical system 10b, the objective lens 14 and the hall mirror 13 of the projection optical system 10a are shared, and the relay lens 16, the total reflection mirror 17, the light receiving diaphragm 18, the collimator lens 19, the ring lens 20, and the two-dimensional imaging element 22 are used. including.

  Further, an objective lens 24 for observing the eye E, a dichroic mirror 25, and a total reflection mirror 29 are arranged in the reflection direction of the dichroic mirror 15. Further, on the optical path O <b> 2 in the reflection direction of the mirror 29, a fixation target that includes a fixation target presentation visible light source 51, a fixation target 52, and a projection lens 53, and presents the fixation target 52 to the eye E to be examined. A sign presentation optical system 50 is arranged. In addition, by moving the light source 51 and the fixation target 52 in the optical axis direction, the presentation position (distance) of the fixation target 52 is changed in the optical axis direction. 58 is a pulse motor for moving the light source 51 and the fixation target 52 in the optical axis direction. That is, the fixation target 52 is placed at an arbitrary presenting position by driving the motor 58.

  Further, on the optical path O3 in the reflection direction of the dichroic mirror 25, an anterior ocular segment observation optical system 28 that includes an imaging lens 26 and a two-dimensional image sensor 27 and captures an anterior ocular segment image to be examined is arranged.

  Further, in front of the anterior segment of the eye E, a corneal shape measurement index projection optical system 30 for projecting a corneal shape measurement index (for example, a ring index R) on the cornea of the eye to be examined, and the eye E The working distance index projection optical system 31 that emits near-infrared light for detecting the alignment state in the working distance direction with respect to the eye to be examined is projected symmetrically with respect to the observation optical axis by projecting the infinity index onto the cornea Ec. ing. The index projection optical system 30 is also used as anterior segment illumination that illuminates the anterior segment of the eye E.

  The dichroic mirror 15 transmits light having a wavelength emitted from the measurement light source 11 of the measurement optical system 10, and reflects light having a wavelength and visible light emitted from the index projection optical system 30 and the working distance index projection optical system 31. It has the characteristic to do. The dichroic mirror 25 has a characteristic of transmitting visible light and reflecting infrared light.

  Here, the light from the index projection optical system 30 and the working distance index projection optical system 31 is projected onto the eye cornea Ec to be examined. Then, the anterior ocular segment image including the corneal luminescent spot is imaged by the imaging device 27 via the dichroic mirror 15, the objective lens 24, the dichroic mirror 25, and the imaging lens 26.

  The control unit 70 performs a calculation for obtaining the corneal shape of the eye E based on the shape of the ring index image R imaged by the image sensor 27. That is, the index projection optical system 30 and the observation optical system 28 function as a corneal shape measurement optical system that measures the corneal shape of the eye to be examined. In addition, the calculation for obtaining the eye refractive power is performed based on the output signal from the light receiving element 22 of the measurement optical system 10. The anterior segment image obtained by the image sensor 27 is combined with the measurement result, the reticle mark LT, etc., and then displayed on the screen of the display monitor 40 (see FIG. 3). In addition, the control unit 70 also includes a memory 75 for storing data such as measurement results, a joystick 5, a rotary knob 5a, a measurement start switch 5b, an XYZ drive unit 6, various settings relating to inspection (measurement mode switching and alignment mode). For example, an operation switch unit 45 for switching is connected. The operation switch unit 45 is provided with, for example, a measurement mode selection switch 45a for selecting one of a corneal shape measurement mode and an eye refractive power measurement mode.

  The operation of the apparatus having the above configuration will be described. Here, a corneal shape measurement mode in which the corneal curvature radius and the axial angle of the eye to be examined are obtained as a measurement result is selected by the mode switch 45a. In addition, the alignment mode changeover switch is set so that the triggering input for the alignment of the measuring unit 4 with respect to the eye to be examined and the measurement start is performed by manual operation of the eye to be examined. In addition, the presenting position of the fixation target 52 in the initial state is arranged at a position corresponding to 0D according to the normal eye.

  Here, the control unit 70 uses the eye refractive power measurement optical system 10 based on the alignment detection result detected by a predetermined method before measuring the cornea shape of the eye to be examined using the cornea shape measurement optical system. The eye refractive power of the eye to be examined is measured, and the presentation position of the fixation target 52 is changed in the optical axis direction based on the measurement result. That is, the eye position of the eye to be examined is automatically and automatically measured in advance before the trigger signal for starting the corneal shape measurement is issued, and the fixation position that matches the eye refractive power of the eye to be examined according to the result After the fixation target 52 is moved, the corneal shape measurement is started.

  A more specific operation will be described below. The examiner fixes the subject's face to the face support unit 2 and instructs the fixation target 52 to fixate, and then operates the joystick 5 to perform alignment with the eye to be examined. As a result, the anterior segment of the eye to be examined is photographed by the image sensor 27, and the anterior segment image, the reticle mark LT, the ring index image R projected by the index projection optical system 30, and the working distance projection on the display monitor 40. The infinity index image M projected by the optical system 31 is displayed (see FIG. 3A).

  Then, the examiner operates the joystick 5 while viewing the ring image R displayed on the display monitor 40, and adjusts the position of the measurement unit 4 in the vertical and horizontal directions so that the ring image R and the reticle mark LT are concentric. To do. Thereafter, the position of the measuring unit 4 in the working distance direction is adjusted with reference to the indicator (or so that the ring image R becomes the thinnest).

  When the rough alignment is completed, the control unit 70 detects the alignment state of the measurement unit 4 with respect to the eye to be inspected based on the imaging signal from the imaging device 27 (see the flowchart in FIG. 4). In this case, the control unit 70 obtains an alignment state in the vertical and horizontal directions with respect to the eye to be examined based on the center coordinates of the ring index R. In addition, when the measuring unit 4 is displaced in the working distance direction, the control unit 70 changes the image interval of the ring index R in the predetermined meridian direction while the interval of the infinity index M hardly changes. The alignment state in the working distance direction with respect to the eye to be examined is obtained by using the characteristic (refer to Japanese Patent Laid-Open No. 6-46999 for details).

  Here, the control unit 70 determines whether or not the alignment state of the measurement unit 4 with respect to the eye to be examined is appropriate depending on whether or not the alignment states in the XYZ directions are within a predetermined allowable range. If so, a trigger signal (measurement start signal) is automatically issued to start eye refractive power measurement. At this time, predetermined blink detection means for detecting blink of the eye to be examined may be provided, and whether or not the trigger signal is automatically issued may be added as a determination condition.

  The controller 70 turns on the light source 11 based on the trigger signal (see FIG. 2). The measurement light emitted from the light source 11 passes through the dichroic mirror 15 through the relay lens 12 to the objective lens 14 and is then projected onto the fundus of the eye E through the pupil of the eye to be examined. Then, the reflected light from the fundus is collected by the objective lens 14 through the pupil of the eye to be examined and the dichroic mirror 15, and collected again on the aperture of the light receiving diaphragm 18 through the hall mirror 13 to the total reflection mirror 17. The collimator lens 19 generates a substantially parallel light beam (in the case of a normal eye), is extracted as a ring-shaped light beam by the ring lens 20, and is received by the image sensor 22 as a ring image. Then, the control unit 70 calculates the eye refraction value of the eye to be examined based on the image position of the ring image captured by the image sensor 22.

  Next, the control unit 70 presents the fixation target 52 according to the eye refraction value of the eye to be examined so that the fixation target 52 is located at a position conjugate with the fundus of the eye to be examined. Move. This makes it possible to stabilize the fixation state even if the subject has high myopia or hyperopia. When the presenting position of the fixation target 52 is changed, the control unit 70 notifies (displays) that the operation for stabilizing the fixation state of the eye to be examined has been completed (displayed) (FIG. 3B). reference). In this case, after the fixation target is moved, the notification time may be delayed until the fixation state of the subject's eye is stabilized (for example, about 1 to 2 seconds).

  The examiner who has received this notification tells the subject to fixate the fixation target 52, and after making fine adjustments or confirmation of the alignment, confirm that there is no blinking of the subject's eye and perform measurement. Press the start switch 5b. Then, the control unit 70 continuously measures the corneal shape of the eye E based on the input of the trigger signal from the measurement start switch 5b, and each time the measurement of the corneal shape is completed, the number of measurements and the measurement result The contents are updated (see FIG. 3C). The measurement is continued until a predetermined number (for example, three) of measurement values excluding the measurement error is obtained.

  When a predetermined number of measurement values are obtained, the control unit 70 determines that the measurement result satisfies a predetermined measurement end condition, and ends the measurement. Then, the control unit 70 displays the characters “FINISH” indicating the end of the measurement of one eye on the display monitor 40 (see FIG. 3D).

  As described above, it takes time to measure the corneal shape (especially continuous measurement) by performing the operation to stabilize the fixation state of the eye before the trigger signal for starting the corneal shape measurement is input. Since it does not become longer than this, the occurrence of blinking during measurement of the corneal shape can be suppressed, and measurement errors can be prevented. In addition, it is possible to measure with high accuracy by measuring the fixation state of the eye to be measured stably.

  Further, by automatically performing eye refractive power measurement that is measured in advance in order to stabilize the fixation state of the eye to be examined, the examiner can smoothly measure the corneal shape. Therefore, even if the subject's eye is difficult to perform automatic measurement, such as the subject's eye with many blinks or the subject's eye with an abnormal corneal shape (for example, keratoconus), the subject's eye is stabilized. In addition, the corneal shape can be accurately measured based on the experience of the examiner by manual operation. In the above description, the eye refractive power measurement is a configuration in which the measurement is automatically performed, but the measurement is only preliminary and if the fixation state of the eye to be examined can be stabilized, Special accuracy is not required.

  In the above description, the control unit 70 completes the above-described operation for stabilizing the fixation state of the eye to be inspected before the alignment of the measuring unit 4 with respect to the eye to be inspected by manual operation of the examiner is completed. As described above, the eye refractive power measurement optical system 10 and the fixation target presentation optical system 50 may be operated.

  For example, an allowable range for alignment determination in eye refraction measurement may be set wider (for example, ± 2 mm vertically and horizontally from the alignment reference). In this case, the allowable alignment range may be such that the measurement light beam emitted from the eye refractive power measurement optical system 10 is not greatly vignetted due to the iris of the eye to be examined. Then, the control unit 70 automatically issues a trigger signal for measuring the eye refractive power and moves the fixation target 52 based on the measurement result before the alignment adjustment by the examiner's operation is completed. In this way, corneal shape measurement can be started more smoothly.

  In the above description, the corneal shape measurement optical system is configured to measure the corneal curvature and axial angle of the eye to be examined. However, the present invention is not limited to this, and a projection is performed by projecting a placido index on the eye cornea to be examined. The present invention can be applied even to an apparatus that measures the corneal shape of the eye to be examined in a wide range and in detail by capturing the platide image.

  In the above apparatus, a case where the eye refractive power is obtained as a measurement result (for example, an eye refractive power measurement mode) will be briefly described. When the measurement start switch 5a is pressed after completion of the alignment, the control unit 70 first performs preliminary measurement of the eye refractive power, and based on the result, the fixation target 52 is positioned at a position conjugate with the fundus of the eye to be examined. After moving the presenting position of the fixation target 52, it is further moved so as to be clouded by an appropriate diopter. Then, the control unit 70 continuously performs eye refractive power measurement until a predetermined number (for example, three) of measurement values excluding measurement errors is obtained in a state where the eye E is clouded. Then, the measurement result is displayed on the display monitor 40.

  In the above description, the configuration for stabilizing the fixation state of the eye to be examined in corneal shape measurement has been described. However, a measurement optical system that optically measures the eye characteristics of the eye to be examined, such as corneal thickness measurement and intraocular pressure measurement. If so, the present invention can be applied.

It is an external appearance block diagram of the ophthalmologic apparatus which concerns on this embodiment. It is a schematic block diagram explaining the structure of the optical system of the ophthalmic apparatus which concerns on this embodiment, and a control system. It is a figure which shows the display screen of the monitor in a cornea shape measurement. It is a flowchart explaining operation | movement of the ophthalmologic apparatus which concerns on this embodiment.

Explanation of symbols

Reference Signs List 4 measurement unit 10 eye refractive power measurement optical system 28 anterior ocular segment observation optical system 30 cornea shape measurement index projection optical system 40 display monitor 45a measurement mode selection switch 50 fixation target presentation optical system 51 visual light source for fixation target presentation 52 fixation Target 70 control unit

Claims (3)

A corneal shape measuring optical system for measuring the corneal shape of the eye to be examined; an eye refractive power measuring optical system for measuring the eye refractive power of the eye to be examined; a fixation target presenting optical system for presenting a fixation target to the eye to be examined; And an ophthalmologic apparatus for measuring the corneal shape and refractive power of the eye to be examined, and a measurement unit for changing the presentation position of the fixation target presented to the eye to be examined in the optical axis direction. In
Measurement mode selection means for selecting one of a corneal shape measurement mode and an eye refractive power measurement mode;
Alignment detection means for detecting the alignment state of the measurement unit with respect to the eye to be examined;
Based on the detection result detected by the alignment detection unit before measuring the corneal shape of the eye to be examined using the corneal shape measurement optical system in a state where the corneal shape measurement mode is selected by the measurement mode selection unit. Control means for measuring the eye refractive power of the eye to be examined using the eye refractive power measuring optical system, and changing the presentation position of the fixation target in the optical axis direction using the presentation position changing means based on the measurement result An ophthalmologic apparatus comprising: The ophthalmic device according to claim 1.
An ophthalmologic apparatus comprising an informing means for informing that the operation for stabilizing the fixation state of the eye to be examined has been completed by the control means. The ophthalmologic apparatus according to claim 1, wherein the control unit changes the presentation position of the fixation target in the optical axis direction before the alignment of the measurement unit with respect to the eye to be examined is completed.

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