JP2005103069A - Ocular adjusting function measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ocular adjusting function measuring instrument with which the state of an ocular adjusting function is measured more precisely. <P>SOLUTION: The ocular adjusting function measuring instrument is provided with: a right eye refraction detection means and a left eye refraction detection means respectively having a measuring optical system for detecting the refraction variation of the right eye and the left eye; a right eye fixation mark optical system and a left eye fixation mark optical system respectively having a fixation mark which can move in a distance direction with respect to the right eye and the left eye; and an adjusting function measuring means for obtaining the states of the adjusting function of the respective right eye and left eye based on the aging of the refraction detected by the right eye refraction detection means and the left eye refraction detection means at a position obtained by moving the right and left fixation marks by the portion of the same diopter with distant refraction from which adjustment of the right eye and the left eye is respectively removed as reference. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an eye accommodation function measuring apparatus that objectively measures the accommodation function of an eye to be examined.

In ophthalmology clinics, etc., an eye refractive power measuring device that objectively measures eye refractive power is generally used, and a subjective value test is performed based on the objective refractive power value obtained thereby. The prescription frequency is determined. However, subjects who have accommodation tension in their eyes tend to cause eyestrain such as headaches and stiff shoulders when looking close. For this reason, the method and apparatus which measure accommodation tension are proposed by the following nonpatent literature 1 and patent documents 1. In these methods and apparatuses, paying attention to the fact that there is a certain correlation between the degree of accommodation tension and the appearance frequency of the high-frequency component of accommodation fine movement, a fixation target (stimulus target) is set every 0.5D steps from a distance. The time-dependent change of the refractive power data when the fixation target is stopped at each of the eight positions is sampled for 20 seconds, and a predetermined high-frequency component of the time-dependent change of the sampled refractive power data is sampled. By determining the appearance frequency, the accommodation function of the eye to be examined is objectively measured.
JP-A-2003-70740 Seiko Suzuki and two others, “Evaluation of regulation function by high-frequency component of accommodation fine movement”, Visual Science, Japanese Society of Ophthalmology, September 2001, Vol. 22, No. 3, p. 93-97

However, in the conventional apparatus, the adjustment function state is measured for each eye. Since a person sees things with both eyes, the conventional method of measuring one eye at a time cannot always say that an accurate adjustment function state is measured. In particular, there is a problem that measurement in a state where the fixation target is correctly viewed cannot be performed because measurement for each eye does not involve convergence during binocular vision.
In addition, as a method for measuring the refractive power, there is a measuring method in which a reflected light beam from the fundus is received by a two-dimensional sensor as a ring image, and this is image-analyzed to obtain the refractive power. For this reason, it is not suitable for an apparatus for obtaining an adjustment function state from a change in refractive power with time.

  An object of the present invention is to provide an eye accommodation function measuring device capable of measuring a more accurate eye accommodation function state in view of the above prior art. It is another object of the present invention to provide an eye accommodation function measuring device capable of measuring the accommodation function state with sufficient accuracy even when the measurement optical system of the image analysis method is employed.

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

(1) Right eye refractive power detection means and left eye refractive power detection means each having a measurement optical system for detecting a change in refractive power of the right eye and the left eye, and movable in the distance direction with respect to the right eye and the left eye The right and left eye fixation target optical systems having the fixation target respectively, and the right and left eye fixation target optical systems, and the distance power from which the adjustment of the right eye and the left eye has been removed are used as a reference. Adjustment function for obtaining right and left eye adjustment function states based on temporal changes in refractive power detected by the right eye refractive power detection means and left eye refractive power detection means at a position moved by the same diopter amount And measuring means.
(2) In the eye accommodation function measuring apparatus according to claim 1, when the left and right fixation targets are moved to a near position, the left and right fixation axes are guided in order to guide the binocular visual axis to a convergence state according to the fixation target presentation distance. Convergence means for converging the optical axes of the measurement optical system and the fixation target optical system is provided.
(3) The apparatus for measuring an eye accommodation function according to claim 2, further comprising an interpupillary distance determining means for detecting or inputting a distance between pupils of the right eye and the left eye in distance vision, wherein the convergence means includes the right and left fixation targets. The convergence is executed by determining the angle at which the optical axis of the fixation target optical system is converged based on the presenting distance when the lens is moved near and the distance between the pupils in distance vision.
(4) In the eye accommodation function measuring apparatus according to (2), the alignment detection means for detecting the alignment states of the right and left measurement optical systems and the fixation target optical system for the right eye and the left eye, respectively, and the congestion caused by the convergence means At the same time, it comprises an alignment adjustment means for adjusting the alignment of the right and left measurement optical systems and the fixation target optical system based on the detection result of the alignment detection means.
(5) In the eye accommodation function measuring apparatus according to (1), the right eye fixation target optical system and the left eye fixation target optical system each present a fixation target having a parallax according to a presentation distance. And
(6) The refractive power detection means of (1) includes a measurement optical system that projects a light beam on the fundus of the subject's eye and receives the reflected light beam from the fundus as a ring image on a two-dimensional light receiving element, and receives the light by the light receiving element. It is characterized in that a change in refractive power with time is detected by analyzing a part of the ring image.
(7) A refractive power detection unit that detects a change in refractive power of the eye to be examined and a fixation target optical system having a fixation target that is movable in the distance direction with respect to the eye to be examined. In the eye accommodation function measuring device for obtaining the accommodation function state of the eye to be examined based on the change with time of the refractive power detected by the refractive power detection means at the presentation position where the fixation target is moved to give, the refractive power detection The means includes a measurement optical system that projects a light beam on the fundus of the subject's eye and receives a reflected light beam from the fundus as a ring image on a two-dimensional light receiving element, and partially analyzes the ring image received by the light receiving element. Thus, it is characterized in that a change in refractive power with time is detected.

  According to the present invention, since the eye accommodation function state can be measured in a binocular vision state, a more accurate measurement result can be obtained. Even when the measurement optical system of the image analysis method is employed, the adjustment function state can be measured with sufficient accuracy.

  The best mode of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an eye accommodation function measuring apparatus according to the present invention. The apparatus includes a right eye measurement unit 10R and a left eye measurement unit 10L in which optical systems for measuring the adjustment function states of the subject's right eye ER and left eye EL are arranged. The right eye measurement unit 10R and the left eye measurement unit 10L are mounted on the fixed base 2 so as to be movable in three-dimensional directions up and down (Y direction), left and right (X direction), and front and rear (Z direction) with respect to the subject's eyes ER and EL, respectively. Has been. 11R is a three-dimensional drive unit that moves the right eye measurement unit 10R in a three-dimensional direction, and 11L is a drive unit that moves the left eye measurement unit 10L in a three-dimensional direction. The drive units 11R and 11L are configured by a slide mechanism or a motor in each direction. The measurement units 10R and 10L may be configured to move in a three-dimensional direction while being suspended from an arm or the like. Reference numerals 12R and 12L denote position detection units that detect the positions of the left and right measurement units 10R and 10L in the X direction, and the detection information is used to detect the interpupillary distances of the eyes ER and EL to be examined.

  The right eye measurement unit 10R and the left eye measurement unit 10L include eye refractive power measurement optical systems 20R and 20L, observation optical systems 50R and 50L that are also used for alignment position detection, fixation target presentation optical systems 55R and 55L, and alignment. Index projection optical systems 45R and 45L and movable mirrors 15R and 15L for deflecting the light beam in the left-right direction (X direction) are arranged, respectively.

  FIG. 2 is a diagram illustrating an optical system configuration arranged in the right eye measurement unit 10R. The eye refractive power measurement optical system 20R includes a projection optical system that projects a spot-like light beam from the center of the pupil of the eye to be examined to the fundus and a light receiving optical system that extracts the reflected light from the periphery of the pupil in a ring shape. The projection optical system includes an infrared point light source 21R such as an LED or SLD arranged on the optical axis L1, a relay lens 22R, a hall mirror 23R, and a measurement objective lens 24R, which are arranged in this order toward the eye to be examined. Yes. The light source 21R is in a conjugate relationship with the eye fundus of the eye to be examined. A movable mirror 15R is arranged in front of the subject's right eye ER, and the direction of the light beam is changed by the movable mirror 15R. Between the movable mirror 15R and the measurement objective lens 24R, there is disposed a beam splitter 19R that reflects the reflected light of the anterior segment of the eye to the observation optical system 50R and guides the light beam of the fixation target optical system 55R to the eye to be examined. Has been.

  The light receiving optical system shares the measurement objective lens 24R and the hall mirror 23R of the projection optical system, and is arranged on the optical path in the reflection direction of the relay lens 25R, the mirror 26R, and the mirror 26R arranged in the optical path in the reflection direction of the hall mirror 23R. The light receiving stop 27R, the collimator lens 28R, the ring lens 29R, and a two-dimensional light receiving element 30R such as a CCD are provided. The light receiving aperture 27R and the light receiving element 30R have a conjugate relationship with the fundus of the eye to be examined.

  As shown in FIGS. 3A and 3B, the ring lens 29R has a lens part 32 in which a cylindrical lens is formed in a ring shape on a flat plate, and a light shielding material in which a coating for shielding light is applied in addition to the lens part 32. The unit 33 is configured. A ring-shaped opening is formed by the light shielding portion 33. The ring lens 29R is provided in the light receiving optical system so that the light-shielding portion 33 is in a conjugate position with the eye pupil (the conjugate position does not need to be strictly conjugate, but the accuracy required in relation to the measurement accuracy. As long as it is conjugate). For this reason, the reflected light from the fundus is extracted in a ring shape with a size corresponding to the light shielding portion 33 from the periphery of the pupil. When a parallel light beam enters the ring lens 29R, a ring image having the same size as the ring lens 29R is condensed on the light receiving element 30R arranged at the focal position. The light shielding portion 33 having a ring-shaped opening may be formed of a separate member in the vicinity of the ring lens 29R. Further, the light source 21R, the light receiving aperture 27R, the collimator lens 28R, the ring lens 29R, and the light receiving element 30R can be moved integrally in the direction of the optical axis L1 as a movable unit. By moving this movable unit in accordance with the spherical refraction error (spherical refractive power) of the eye ER to be examined, the spherical refraction error is corrected, and the light source 21R, the light receiving diaphragm 27R and the light receiving element 30R are optically applied to the fundus of the eye to be examined. To be conjugated.

  An observation optical system 50R and a fixation target presenting optical system 55R are arranged in the direction of the optical axis L2 that is coaxial with the optical axis L1 by the beam splitter 19R. The observation optical system 50R includes an observation system objective lens 51R, a half mirror 52R, a photographing lens 53R, and a CCD camera 54R that is an imaging element. The anterior segment image of the eye to be examined is imaged on the imaging element surface of the camera 54R via the movable mirror 15R, the beam splitter 19R, the objective lens 51R, the half mirror 52R, and the photographing lens 53R, and the observation image is displayed on the monitor described later. Is done. The observation optical system 50R also serves as an optical system that detects each index image formed on the eye cornea to be examined.

  In the fixation target presenting optical system 55R, an observation system objective lens 51R, a half mirror 52R, a mirror 56R, a lens 57R, a fixation target 58R, and a visible light source 59R are sequentially arranged from the eye ER side. The fixation target 58R performs clouding of the eye ER to be examined by moving in the optical axis direction.

  45R is an optical system for projecting the alignment index, and has two sets of first projection optical systems arranged symmetrically with respect to the optical axis L1, and an optical axis arranged at a narrower angle than the first projection optical system. Two sets of second projection optical systems arranged symmetrically with respect to the optical axis L1 are provided. The first projection optical system has point light sources 46aR and 46bR that emit near-infrared light, and collimator lenses 47aR and 47bR, and projects an infinite index onto the eye ER to be examined by light of substantially parallel light flux. On the other hand, the second projection optical system has point light sources 46cR and 46dR that emit near-infrared light, and projects a finite index onto the eye E to be examined by a divergent light beam.

  The movable mirror 15R is rotationally driven by the motor 16R so as to cope with the convergence during near vision, and changes the direction of the light beam toward the eye ER and the reflected light beam from the eye ER in the left-right direction.

  Since the right eye measurement unit 10R and the left eye measurement unit 10L are basically symmetric, the optical system configuration arranged in the left eye measurement unit 10L is the optical member arranged in the right eye measurement unit 10R described above. “R” is replaced with “L”, and the description thereof is omitted. The fixation target 58R of the right eye measurement unit 10R and the fixation target 58L of the left eye measurement unit 10L have the same target. Therefore, even in the binocular simultaneous measurement, the subject can fuse the fixation targets 58R and 58L presented at the same time and view them as one fixation target.

  FIG. 4 is a control system block diagram of this apparatus. Outputs of the cameras 54R and 54L of the right eye measurement unit 10R and the left eye measurement unit 10L are connected to the control unit 70 via image processing units 71R and 71L, respectively. The control unit 70 detects the alignment state with respect to the subject's eyes ER and EL based on the alignment index image analyzed by the image processing units 71R and 71L. The anterior segment image captured by the cameras 54R and 54L is displayed on the monitor 7 by switching display or two screens. The outputs of the light receiving elements 30R and 30L of the measurement units 10R and 10L are also connected to the control unit 70 via the image processing units 72R and 72L, respectively, and the control unit 70 is analyzed by the image processing units 72R and 72L. The refractive power is obtained based on the ring image. Further, the control unit 70 includes driving units 60R and 60L for moving the fixation targets 58R and 58L presented to the right eye ER and the left eye EL in the optical axis direction, and motors 16R and 16R for driving the driving mirrors 15R and 15L, respectively. 16L, a switch unit 80 having various input switches, a joystick 81 for manually moving the right eye measurement unit 10R and the left eye measurement unit 10L in the XZ direction, a right eye measurement unit 10R and a left eye measurement unit 10L A rotary switch 82, etc. for moving in the direction by manual operation is connected.

  The operation of the apparatus having the above configuration will be described. First, the objective distance measurement will be described.

  The face of the subject is fixed with a face support unit (forehead, chin rest, etc.) (not shown), and the right eye measurement unit 10R and the left eye measurement unit 10L are aligned with the eye ER and EL, respectively. The examiner observes the subject's eyes ER and EL displayed on the monitor 7, and uses the joystick 81 and the rotation switch 82 so that the four index images by the alignment index projection optical systems 45R and 45L appear on the screen. The eye measurement unit 10R and the left eye measurement unit 10L are moved in the XYZ directions by the drive units 11R and 11L, and are roughly aligned. The right eye measurement unit 10R and the left eye measurement unit 10L can be moved simultaneously or separately by operation with the joystick 81 and the rotary switch 82. When moving separately, the individual movement is set by a switch arranged in the switch unit 8.

  When four alignment index images from the eye ER to be examined are picked up by the camera 54R, the control unit 70 drives and controls the drive unit 11R based on the index image and automatically moves the right eye measurement unit 10R. Perform auto alignment. The alignment state in the YZ direction is obtained from the deviation information between the center position of the two index images and the position of the optical axis L1 by the first projection optical system that projects the infinity index. The right eye measurement unit 10R is moved in the YZ direction so as to enter. The alignment state in the X direction (working distance direction) is detected by comparing the distance A between the two infinity index images by the first projection optical system and the distance B between the two finite index images by the second projection optical system. . This is because when the corneal reflection elephant is formed by an infinite light source and a finite light source, the elephant height of the corneal reflection elephant by the infinity light source does not change even if the working distance changes, but the elephant height by the finite light source does not change. This utilizes the characteristic that it changes as the working distance changes (refer to Japanese Patent Laid-Open No. 6-46999 for details). The right eye measurement unit 10R is moved in the X direction so that the deviation of the alignment in the X direction falls within a predetermined allowable range.

  Similarly, when four alignment index images from the eye to be examined EL are picked up by the camera 54L, the control unit 70 drives and controls the drive unit 11L based on the index images, and automatically controls the left eye measurement unit 10L. Execute auto alignment to move to.

  Regarding the alignment, rough alignment can be simplified by keeping wide observation ranges by the left and right cameras 54R and 54L. In addition, when an adult, a child, or the like is selected by a switch operation so that rough rough alignment can be automatically performed, usability is improved.

  In the above alignment, the fixation target having the same target in both the right eye ER and the left eye EL by the fixation target presentation optical system 55R of the right eye measurement unit 10R and the fixation target presentation optical system 55L of the left eye measurement unit 10L. Marks 58R and 58L are presented simultaneously. In the distance measurement, the movable mirrors 15R and 15L are not rotated, and the visual axes of both eyes are guided parallel to the front direction.

  The refractive power measurement will be described. When the alignment of both the right eye measurement unit 10R and the left eye measurement unit 10L is completed, the control unit 70 automatically issues a trigger signal and starts measurement of the left and right eyes simultaneously (the examiner presses a measurement start switch not shown). , Trigger signal may be input). The infrared light emitted from the light source 21R of the right eye measurement unit 10R is reflected by the drive mirror 15R via the relay lens 22R, the hall mirror 23R, the objective lens 24R, and the beam splitter 19R, and is spot-shaped on the fundus of the eye to be examined. A point light source image is projected. The point light source image projected onto the fundus is reflected and scattered to exit the eye to be examined, reflected by the drive mirror 15R, and then collected by the objective lens 24R, via the hall mirror 23R, relay lens 25R, and mirror 26R. The light is condensed again on the light receiving aperture 27R and reaches the ring lens 29R via the collimator lens 28R. A reflected light beam is extracted from the fundus by the ring lens 29R as a ring light beam and then received by the light receiving element 30R. The ring image formed on the light receiving element 30R is taken into the image processing unit 71R.

  The control unit 70 obtains the refractive power from ring coordinates in a certain angular direction (for example, the horizontal direction) of the ring image detected and processed by the image processing unit 72R as a preliminary measurement. Based on the refractive power, the fixation target 58R is moved in the optical axis direction, the fundus and the fixation target 58R are placed at a conjugate position, and then moved away by an appropriate diopter, thereby fogging the eye to be examined. In this state, the distance refracting power is measured based on the ring image taken into the image processing unit 72R in the same manner as described above. The image processing unit 72R scans in the circumferential direction, for example, every 10 degrees from the center position of the ring image (for example, coordinates corresponding to the measurement optical axis position of the light receiving element 30R), and extracts data exceeding a predetermined threshold value. Thus, the ring image coordinates in each angular direction are detected. The shape of the ring image is obtained by elliptically approximating the detected ring image coordinates in all directions by a process such as a least square method. Then, the refraction values of S, C, and A of the right eye are obtained from the shape of the ring image.

  Similarly, in the left eye measurement unit 10L, the measurement is performed in a state where the subject eye EL is clouded, and the refraction values of S, C, and A of the left eye are obtained based on the output from the light receiving element 30L.

  Next, the measurement of the adjustment tension for obtaining the adjustment function state will be described. The human eye is subjectively perceived to be in a static refractive state when staring at a stationary target, but it can be adjusted by observing objective refractive power over time. A sine wave-like vibration called fine movement is observed. It is considered that the high-frequency component of accommodation fine movement is caused by the vibration of the refractive power of the crystalline lens and indicates the activity state of the ciliary muscle. As the load on the ciliary muscle increases, the frequency of appearance of the high-frequency component of accommodation fine movement also increases. The degree of accommodation tension of the eye to be examined can be estimated by examining the appearance frequency (hereinafter referred to as HFC) of the accommodation fine movement high frequency component.

  When the adjustment tension measurement mode is selected by the mode switching switch arranged in the switch unit 80, the distance refractive power measurement of both eyes is performed in the state where the left and right eyes are simultaneously fogged in the same manner as described above, and the measurement is performed. The result is stored in the memory 84. Then, both eyes are set so that the refractive power value (S value) obtained by this distance measurement is a distance farther by 0.5D than the reference (this reference position can be regarded as the far point position of the eye to be examined). The fixation targets 58R and 58L are moved, and the temporal change in refractive power at a predetermined time T (for example, 20 seconds) is sampled while the fixation targets 58R and 58L are stopped, and stored in the memory 84. Thereafter, the fixation targets 58R and 58L of both eyes are sequentially moved in the vicinity at the same time in steps of 0.5D, and the refractive power lapses at a predetermined time T in a state where the fixation targets 58R and 58L are stopped. Changes are sampled and stored in memory 84. The moving positions of the fixation targets 58R and 58L are, for example, eight positions that are changed in a 0.5D step from + 0.5D to -3.0D on the basis of the S value in the distance measurement. By causing the subject's eye to see the fixation targets 58R and 58L moved in the vicinity, an adjustment load is applied to the subject's eye. When moving the fixation targets 58R and 58L to the next designated position, a 5-second break is taken.

  Here, as the fixation targets 58R and 58L move to the near positions, the drive mirrors 15R and 15L of the left and right measurement units 10R and 10L are moved by the control unit 70 by the amount corresponding to the amount of convergence of the eye to be examined at each position. Driven by rotation.

FIG. 5 is a diagram for explaining the driving of the drive mirrors 15R and 15L according to the amount of convergence of the eye to be examined. The distance from the eyeball rotation point O to the corneal vertex Cp of the eye ER and EL to be examined is a, Assuming that the distance to the fixation target presenting position is b and the distance between the pupils in far vision is d, the deflection angle α (half of the convergence angle θ) of the visual axis of one eye for far vision is
α = tan ⁻¹ (d / (2a + 2b))
Is required. If the incident angle of the optical axis L1 (the optical axis of the eye refractive power measurement optical system and the fixation target presenting optical system) with respect to the drive mirrors 15R and 15L at this time is β,
β = (90 ° −α) / 2
It becomes. The inter-pupil distance d in far vision is detected by the two detection units 12R and 12L when the alignment of the measurement units 10R and 10L is completed at the time of measuring the refractive power for distance, so that information can be used. Alternatively, the distance measured by the interpupillary distance meter may be input using the switch of the switch unit 80.

  In the present embodiment, the fixation target position is moved farther by 0.5D with reference to the refractive power obtained by the distance power measurement, and then closer to the nearer in 0.5D steps. When each fixation target position to which the adjustment load is applied at this time is converted into the distance b, it is as shown in FIG.

  The control unit 70 obtains the rotational drive amounts of the drive mirrors 15R and 15L at the respective fixation target positions so that the visual axes of both eyes are in a convergence state according to the fixation target presentation distance, and the motor 16 , 16L, the drive mirrors 15R, 15L are respectively rotated. Further, as the drive mirrors 15R and 15L are rotated, the measurement units 10R and 10L are respectively adjusted in alignment. As described above, alignment adjustment of the measurement units 10R and 10L is performed by driving and controlling the drive units 11R and 11L based on the four alignment index images detected by the cameras 54R and 64L, respectively.

  By this convergence mechanism and alignment adjustment mechanism, the visual axis of both eyes is guided to be in a convergence state corresponding to the fixation target presentation distance, and the subject can continue to look at the fixation target in a natural congestion state. it can. Therefore, it is possible to accurately measure the accommodation tension of both eyes.

  Also during the adjustment tension measurement, the ring images formed on the left and right light receiving elements 30R and 30L are taken into the image processing units 71R and 71L, respectively, and a change in refractive power with time is obtained by image analysis of the ring images. However, in the adjustment tension measurement, in order to calculate the appearance frequency (HFC) of the high-frequency component from the change in refractive power, it is necessary to sample the refractive power data with a short period of 0.1 second or less. If the ring shape is obtained by image analysis of all directions of the ring image that is an index image received by the light receiving element 30R (30L) as in the case of distance refractive power measurement, it takes time and it becomes difficult to detect adjustment fine movement. Therefore, in the adjustment tension measurement, refractive power is obtained by using partial information of the index image received by the light receiving element 30R (30L). For example, two coordinates only in a specific direction are detected such as a horizontal meridian direction based on the center of the ring image, and the refractive power in that direction is detected from the interval. This makes it possible to detect a change in refractive power with time and to calculate an HFC with sufficient accuracy. If the processing time is within 0.1 seconds, detection in another direction such as the vertical direction may be added, but it is sufficient that at least the refractive power in the meridian direction is obtained.

  In the adjustment tension measurement, when the temporal change of the refractive power sampled at each of the eight positions where the position is moved is stored in the memory 84, the control section 70 analyzes the adjustment tension. This analysis will be briefly described. First, if there is blinking of the eye to be examined, the refractive power data has a significantly different value, and this is removed. Data loss and disturbance due to blinking are corrected with a cubic spline function. Next, frequency analysis is performed using fast Fourier transform (FFT) to obtain a power spectrum. The power spectrum is calculated for each section of time T (20 seconds). Each section is set to be shifted by a certain time (for example, 1 second) within the time T, and the time in each section is the same (for example, 8 seconds). The calculated power spectrum is converted into a common logarithm and analyzed. From this power spectrum, an average power spectrum (unit: dB) in a section of high frequency components of 1.0 to 2.3 Hz is obtained and evaluated as an appearance frequency (HFC) of the adjusted fine movement high frequency component.

  When the HFC is calculated, the adjustment tension measurement result is displayed on the monitor 7. FIG. 7 is a display example of the measurement result of the right eye. You may display the measurement result of both eyes on the monitor 7 simultaneously. As the measurement result, the three elements of the fixation target (stimulus target) position, the adjustment response amount, and the HFC are graphically displayed as a three-dimensional graph using a color code map. The graph shows the adjustment response amount (refractive power D) on the vertical axis and the fixation target position on the horizontal axis. At each fixation target position, the change in the adjustment reaction amount corresponding to the elapsed time within the predetermined time T is represented by a bar graph. Has been. The HFC is color-coded in seven levels as an example. For example, when the HFC is less than 50, it is displayed in green, and when it is 70 or more, it is displayed in red, and the interval is displayed in gradation from green to yellow via yellow. An eye to be examined with less accommodation tension has a low HFC value in far vision and exhibits a green color in the color code map. On the other hand, the eye to be examined having a large amount of accommodation tension has a high HFC value as a whole, and the color code map shows a red color, indicating that the ciliary muscle is in tension. Further, in this example, a graphic line FS indicating the S value obtained by the distance measurement is displayed on the graph in association with the amount of adjustment reaction at each fixation target position, and the S value of the distance measurement is displayed. Whether the adjustment reaction amount of each fixation target position is on the + side can be easily understood visually.

  The embodiment described above can be variously modified. For example, the drive mirrors 15R and 15L can be driven two-dimensionally, and the reflection direction can be changed not only in the left-right direction but also in the up-down direction, and fixedly fixed so as to look down slightly in near vision. Measurement may be performed while presenting the mark. By doing so, it is possible to create a more natural visual state of near work, and to perform adjustment tension more accurately.

  The fixation targets 58R and 58L are image displays such as an LCD that can freely change the target and present images with parallax corresponding to the distance of near vision to the left and right eyes, respectively. The target with a three-dimensional feeling can be seen. For example, as shown in FIG. 8, the fixation target 58L to be presented to the left eye is drawn with a circular symbol 100 at the center and a bar figure 101L separated vertically on the right side, and the fixation target 58R to be presented to the right eye By drawing the round symbol 100 and the bar symbol 101R separated vertically on the left side, the central circle symbol 100 and the surrounding fixation target frame become fusion stimuli on the left and right, and the rod symbols 101R and 100L become one. The three-dimensional image appears to be positioned in front of the round symbol 100. The bar symbols 101R and 101L change the distance to the central circle symbol 100 in relation to the parallax according to the distance of near vision. By presenting a fixation target that provides a three-dimensional effect, measurement in a state closer to natural vision becomes possible.

  In addition, as a convergence mechanism for the measurement optical axis and the fixation target presenting optical axis in near vision, a mechanism for rotating the left and right measurement units 10R and 10L in the horizontal direction is provided instead of driving the drive mirrors 15R and 15L. A corresponding configuration may be used.

  The measurement optical system that measures the change in refractive power projects a light beam from the periphery of the pupil, projects a ring light beam on the fundus, extracts the reflected light beam from the center of the pupil, and rings it on a two-dimensional light receiving element (imaging device). An optical system that receives light as an image may be employed. Also in this case, in the image analysis of the ring image, the temporal change in refractive power can be sampled with a sufficiently short period by performing partial image analysis.

It is a block diagram of the eye accommodation function measuring device concerning the present invention. It is a figure explaining the optical system structure arrange | positioned at a right eye measurement unit. It is a figure explaining the structure of a ring lens. It is a control system block diagram of this apparatus. It is a figure explaining the drive of the left-right drive mirror according to the amount of convergence of the eye to be examined. It is a figure which shows the fixation target presentation distance with respect to each fixation target position where adjustment load is given. It is an example of a display of the measurement result of adjustment tension measurement. It is a figure which shows the example of the fixation target which gave the parallax.

Explanation of symbols

10R Right eye measurement unit 10L Left eye measurement unit 15R, 15L Movable mirror 20R, 120L Eye refractive power measurement optical system 45R, 45L Alignment index projection optical system 55R, 55L Fixation target presentation optical system 58R, 58L Fixation target 30R, 30L Light receiving element 29R, 29L Ring lens 11R, 11L Three-dimensional drive unit 12R, 12L Position detection unit 70 Control unit 71R, 71L Image processing unit 72R, 72L Image processing unit

Claims (7)

Right eye refractive power detection means and left eye refractive power detection means each having a measurement optical system for detecting a refractive power change of the right eye and the left eye, and a fixation target movable in the distance direction with respect to the right eye and the left eye Right eye fixation target optical system and left eye fixation target optical system, respectively, and the right and left eye fixation targets are separated from each other with the same diopter separation. Adjustment function measuring means for obtaining right and left eye adjustment function states based on temporal changes in refractive power detected by the right eye refractive power detection means and the left eye refractive power detection means at a position moved only by An eye accommodation function measuring device comprising: 2. The eye accommodation function measuring apparatus according to claim 1, wherein when the left and right fixation targets are moved to a near position, the left and right measurements are performed in order to guide the visual axes of both eyes to a convergence state corresponding to the fixation target presentation distance. An eye adjustment function measuring apparatus comprising: a converging unit for converging the optical axes of the optical system and the fixation target optical system. 3. The eye accommodation function measuring apparatus according to claim 2, further comprising an interpupillary distance determining means for detecting or inputting a distance between pupils of the right eye and the left eye in distance vision, wherein the converging means displays the right and left fixation targets in the near field. An eye adjustment function measuring device that performs convergence by determining an angle for converging the optical axis of the fixation target optical system based on a presentation distance when moving to a distance and a distance between pupils in distance vision . 3. The apparatus for measuring an eye accommodation function according to claim 2, wherein the alignment detection means detects the alignment states of the right and left measurement optical systems and the fixation target optical system with respect to the right eye and the left eye, respectively, and the alignment at the same time as the convergence by the convergence means. An eye adjustment function measuring apparatus comprising: an alignment adjusting unit that adjusts the alignment of the right and left measurement optical systems and the fixation target optical system based on a detection result of the detection unit. 2. The eye accommodation function measuring apparatus according to claim 1, wherein the right eye fixation target optical system and the left eye fixation target optical system each present a fixation target having a parallax according to a presentation distance. Adjustment function measuring device. The refractive power detection means according to claim 1 includes a measurement optical system that projects a light beam on the fundus of the eye to be examined and receives a reflected light beam from the fundus as a ring image on a two-dimensional light receiving element, and the ring received by the light receiving element. An apparatus for measuring an eye accommodation function, characterized in that an image is partially analyzed to detect a temporal change in refractive power. A refractive power detecting means for detecting a refractive power change of the eye to be examined; and a fixation target optical system having a fixation target that is movable in the distance direction with respect to the eye to be examined. In the eye accommodation function measuring device for obtaining the accommodation function state of the eye to be examined based on the temporal change of the refractive power detected by the refractive power detection means at the presentation position where the fixation target is moved, the refractive power detection means comprises: A measuring optical system that projects a light beam onto the fundus of the subject's eye and receives a reflected light beam from the fundus as a ring image on a two-dimensional light receiving element, and partially refracts the ring image received by the light receiving element by image analysis An apparatus for measuring an eye accommodation function, which detects a change in force over time.

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