JP5011144B2 - Ophthalmic measuring device - Google Patents

Description

  The present invention relates to an ophthalmologic measurement apparatus. In particular, the present invention relates to an ophthalmologic measurement apparatus that can evaluate the characteristics of an eye to be examined at the time of occlusion and is useful for finding oblique positions.

  In recent years, with the spread of personal computers and video games, opportunities to abuse the eyes regardless of age are increasing. Such so-called VDT work often involves gazes at a relatively close distance with both eyes for a long time, resulting in eye symptoms such as eye pain, blurred vision, glare, and redness, and systemically May be accompanied by headache, stiff shoulders and sometimes nausea. This is called eye strain. There are several possible causes of eye strain, one of which is nervous tension due to the oblique position. The oblique position means that there is a fundamental shift in the positions of the left and right eyes with respect to the gaze target when viewing with both eyes, and is also referred to as latent strabismus. When viewing with both eyes open, the eyes of both eyes are concentrated, but since the original eye position is not completely correct, the object looks double as it is. Together, you will endeavor to see the objects together. If the degree of oblique position is strong, the fusion effort must always be exerted strongly, so that the nerves become tense for a long time and induce eye strain. On the other hand, the ciliary body, which is a muscular tissue, expands and contracts the lens in coordination with the lens and adjusts the focus, but this function is also related to the autonomic nerve, and the ciliary muscle is tense during long-term close-up work etc. Continuation of the state (regulatory tension) that causes eye strain causes a cause of eye strain.

  The oblique position is often left unattended because it is unlikely to be noticed in appearance unlike the perspective view. However, there are cases where it is necessary to detect and deal with early, and establishment of a quantitative inspection method is desired. The cover-uncover test is generally used for the oblique inspection. In this method, one eye is shielded with an opaque plate or the like, and the oblique position is screened by observing the eye position when the shielding is removed. With this method, quantitative evaluation cannot be performed, and minute changes may be overlooked. When correcting oblique positions, wearing several types of prism lenses and looking at the test target, the test is conducted subjectively, but the objective test and the measuring instrument used therefor have not been realized. It was. The rotation of the eyeball (convergence, divergent) is closely related to the regulation function. There are functions referred to as regulatory convergence in which congestion is induced when a regulatory stimulus is applied, and vergence adjustment in which a regulatory response is induced when a congestion stimulus is applied. Although the oblique eye is shielded and faces the original eye position (resting position), the adjustment is not known. It is known that regulation is correlated with the response of both eyes by the action of autonomic nerves. When both eyes are shielded, the adjustment is also in a resting position. However, when one eye is opened, there is a possibility that it is affected by the opened eye. As described above, the eye has a function of accommodation convergence, and when the adjustment of one-eye occlusion does not indicate a resting position, the position of the oblique eye does not face the resting position due to the accommodation convergence. there is a possibility. The inventor of the present application, because the original characteristic appears by shielding the visual field of the oblique position, useful data can be obtained by simultaneously measuring the eye with the visual field shielded and the open eye simultaneously, We found that diagnostic criteria were obtained. The present invention was created based on this discovery.

However, when such a measuring apparatus is realized, eye adjustment cannot be measured because light is not incident on the eye whose field of view is shielded. Further, even if an attempt is made to measure a change in eye accommodation based on such an idea, since the change is small, a technique capable of accurately detecting the change in accommodation is required. For this reason, a measuring apparatus that accurately finds an eye with an abnormal eye position such as an oblique position has not been realized.
In addition to these measurements, the present invention also enables measurement of spherical aberration and measurement of higher order aberrations including vertical coma aberration for viewing the dry eye condition, which are related to accommodation tension.

  The present invention is capable of evaluating the accommodation characteristics of an eye whose line of sight is occluded, and more precisely evaluating the ocular adjustment before and after occlusion, and accurately detecting an abnormal eye position such as an oblique position. The purpose is to realize a measuring device capable of

  In order to achieve the above object, the ophthalmologic measurement apparatus according to the first embodiment of the present invention irradiates the eye 14 of a subject with visible light and non-visible light for measurement as shown in FIG. An ophthalmologic measurement apparatus 1 that receives the reflected light beam from the retina F of the subject's eye that is invisible, and measures the adjustment of the subject's eye based on the received light reception signal; A shielding unit 81 that can be controlled so as to shield or transmit a light beam applied to the eye 14 and a light flux control unit 82 that controls the shielding unit 81 are provided, and the shielding unit 81 is disposed in front of the eye 14 of the subject. And has a wavelength selection characteristic that shields visible light and transmits non-visible light for measurement at the time of shielding, and the light beam control unit 82 allows the subject to view the gaze object 12 in both eyes. After that, the visible light to one eye (14R or 14L) of the subject is blocked. The shielding unit 81 is configured to transmit the visible light to the subject's one eye 14R after the one-eye view so as to shield the visible light to the one eye 14R of the subject. The adjustment measurement unit 30 is configured to measure the adjustment of the eye 14 of the subject before and after the shielding of visible light or before and after transmission.

  Here, “visible light” is light having a wavelength in a range that can be detected by human eyes. The “invisible light” is light having only light having a wavelength outside the range that can be detected by the human eye, and is preferably near infrared light. “Adjustment” refers to a function of focusing an object to be focused on the retina F of the eye to be examined, and is expressed by the reciprocal of the distance. For example, it is expressed as 1 diopter for a gaze distance of 1 m and 2 diopters for a gaze distance of 0.5 m. “Adjustment before and after the shielding of visible light” means that the visible light when gazing at a gaze target object 12 with both eyes in a short time is shielded in a short time, and adjustment before and after shielding. It means that. In addition, the time immediately after the shielding further includes a temporal change in the adjustment after the shielding. On the other hand, “before and after transmission of visible light” means that the visible light to one eye is shielded, and in this state, the gaze target 12 is gazeed with one eye, and then in a short time. Say to release the ray of the other eye. Note that “shielding” means reflection and absorption of visible light and blocking transmission.

  That is, the ophthalmologic measurement apparatus according to the first embodiment of the present invention switches the binocular vision and the monocular vision by abruptly switching the shielding / transmission of visible light, and adjusts the eye before and after the switching. The measurement is performed using invisible light, and a wavelength selection member (filter) is used for a visible light shielding portion. Because of this configuration, it is possible to measure eye accommodation even when no visible light is incident on the eye, so it is possible to accurately measure the characteristics of one-eye vision including accommodation. It can contribute to visual research and diagnosis.

  Preferably, in the ophthalmic measurement apparatus according to the present invention, for example, as shown in FIG. 3, the adjustment measurement unit 30 includes an irradiation unit (such as 126) that emits invisible light, and an eye retina F (see FIG. 1). It is comprised so that the light-receiving part (131 grade | etc.,) Which receives the reflected light beam from may be included.

  Since it is configured in this way, the measurement light source and the light receiving part are integrated, so that handling is easy. In particular, the alignment of the optical axis and the adjustment of the light receiving position are facilitated, and quick and accurate measurement is possible.

  Preferably, in the ophthalmologic measurement apparatus according to the present invention, for example, as shown in FIG. 1, the adjustment measurement unit 30 further applies the visible light to one eye that is not shielded from visible light by the shielding unit 81. It is configured to be able to measure the adjustment of one eye before and after light shielding or before and after transmission.

  Since it is comprised in this way, since adjustment can be measured also about the one eye which is not obstruct | occluded visible light, the correlation of the adjustment between both eyes can be grasped | ascertained temporally. Regarding the regulation, it is said that there is a correlation between the fluctuations of both eyes due to the control by the autonomic nerve. It can be performed.

  The ophthalmologic measurement apparatus 2 as the second embodiment of the present invention further includes, for example, a gaze direction measurement unit that measures the gaze direction of the eye 14 of the subject before and after shielding visible light, as shown in FIG. 33 is provided.

  Eyes with oblique positions are said to be swayed in the line of sight, and the present invention can measure sway in the line of sight in addition to the change in adjustment before and after the shielding of visible light. This makes it possible to perform accurate and precise measurements and to obtain data useful for finding oblique positions.

  Preferably, the ophthalmic measurement apparatus according to the present invention compares, for example, as shown in FIG. 1, the measurement results of the adjustment of the eye 14 of the subject before and after the shielding of the visible light or before and after the transmission. And a comparison / determination unit 40 that determines the magnitude of the change in the characteristic of the eye 14 of the subject.

  Here, “comparison of adjustment” means (a) comparison of changes in the adjustment of the one eye that is shielded before and after the shielding, and (b) adjustment of the one eye that is not shielded and the one eye that is shielded before and after the shielding. And (c) a combination of a change in adjustment of one eye that is not shielded before and after shielding when the other eye is shielded in one eye that is not shielded. Furthermore, those time transitions are included. These comparison data are displayed on the display unit 41, or output to an external device (not shown) for further detailed data processing, or stored in a memory (not shown).

  Since it has such a configuration, it is possible to process the measured values obtained without human intervention, and to facilitate diagnosis etc. by applying an expert system etc. in which the knowledge of specialists such as doctors is databased, for example Can do.

  The present invention uses non-visible light as measurement light, uses a shielding portion 81 that transmits the wavelength of the measurement light and shields visible light, and adjusts the eye 14 of the subject who is viewing with one eye. Since the variation can be measured, the correlation between the variation in the adjustment of the non-shielded eye and the shielded eye can be quantitatively known. Moreover, since the change of the gaze direction of the eye 14 of the subject can be measured by switching the visible light from transmission to shielding (or vice versa) in a short time, the magnitude of the oblique position of the shielding eye can be known. it can. Furthermore, it is possible to compare the positions of the binocular vision and the one-eye vision of the non-shielded eye, thereby knowing the size of the perspective of the non-shielded eye.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Moreover, what added an alphabetic character after a number like "14R" and "14L" is meant to include what is partly different from the structure of 14, although most of the structure is common. When it is not necessary to distinguish between 14R and 14L, they are collectively referred to as “14”.

[First embodiment]
[Constitution]
With reference to FIG.1 and FIG.2, the ophthalmologic measurement apparatus 1 as the 1st Embodiment of this invention is demonstrated. FIG. 1 shows a subject's eye 14 (one of the two eyes is 14R and 14L, respectively) (see FIG. 2), a gaze target 12, and an ophthalmologic measurement apparatus 1 according to the present invention. is there. The gaze target 12 is placed at a predetermined distance D with respect to the eye 14 of the subject. By moving the position of the gaze target 12, the characteristics of the eye when the subject is viewed at various distances with respect to the subject's eye 14 can be measured. Further, the gaze target 12 may form a virtual three-dimensional image, and the distance of the gaze target 12 may be changed by virtual means. The ophthalmic measurement apparatus 1 includes a dichroic mirror 190, a shielding unit (filter) 81, a light flux control unit 82, an adjustment measurement unit 30, and a comparison determination unit 40. The comparison determination unit 40 analyzes the measurement result of the adjustment measurement unit 30, and displays or outputs it. In FIG. 1, a configuration including the display unit 41 in the comparison determination unit 40 is shown, but the display unit 41 may be separate from the comparison determination unit 40.

  The subject 50 (see FIG. 2) gazes at the gaze target 12 with both eyes or one eye through the dichroic mirror 190 and the shielding unit 81. The gaze target 12 is illuminated with natural light or is a light emission image by natural light. The dichroic mirror 190 is installed with an inclination of 45 ° with respect to the line of sight of the eye 14 of the subject when the gaze target 12 is viewed. The shielding unit 81 is a wavelength-selective member that transmits the wavelength of the measurement light transmitted and received by the adjustment measurement unit 30 described later, but blocks visible natural light. The shielding unit 81 is controlled by a command from the light beam control unit 82. In front of the eye 14 of the subject, for example, it is moved and set to a state where the shield 81 is attached or not attached. This operation is set sufficiently short with respect to the eye adjustment speed.

  FIG. 2 shows a state in which measurement is performed using the ophthalmic measurement apparatus 1. As shown in the figure, a shielding part 81 is provided at a position about 10 mm to 15 mm away from the cornea of the eye 14 of the subject so that visible light can be completely shielded. The shielding part 81 is provided independently for each eye. Further, the dichroic mirror 190 is disposed at both eyes so as to be 45 ° with respect to the line of sight. The subject 50 gazes at the gaze target 12 placed at an appropriate distance via the shielding part 81 and the dichroic mirror 190. The adjustment measuring units 30R and 30L are arranged substantially perpendicular to the line of sight 15 of the subject 50.

  The adjustment measurement unit 30 includes a measurement optical system 103 that generates near infrared rays, a wavefront measurement unit 125, and the like, and the measurement light emitted from the measurement light projection light source 126 is applied to the eye 14 of the subject via the dichroic mirror 190. Light incident and reflected by the eye retina F is received by the light receiving element 131 (see FIG. 3). The adjustment measurement unit 30 is provided for each eye (30L, 30R). The adjustment measurement unit 30 is supported on the gantry 10 by the support unit 20. The support part 20 can be rotated around its axis and moved in the XYZ directions, whereby the optical axis of the measurement light of the adjustment measurement part 30 can be set at the center of the eye 14 of the subject. The measurement result from the adjustment measurement unit 30 is sent to the comparison judgment unit 40, where necessary data processing and result display are performed.

  FIG. 3 shows the configuration of the adjustment measurement unit 30. As shown in the figure, the adjustment measurement unit 30 includes a wavefront measurement unit 125, a measurement optical system 103 that guides the measurement light beam to the wavefront measurement unit 125, a light receiving element 131 that receives the measurement light, and a video image that is an output from the light receiving element 131. A calculation unit 132 that calculates the movement adjustment amount and wavefront aberration of the wavefront measurement unit 125, an adjustment calculation unit 180 that calculates an adjustment value from the calculation result, and a control unit 140 that controls each unit of the ophthalmic measurement apparatus 1 are included. Note that the control of the control unit 140 can be performed by manual operation in addition to receiving and controlling the result of the calculation unit 132.

  The wavefront measuring unit 125 is movable with respect to the incident / exit optical axes AX1 and AX2 (Z-axis direction in FIG. 2) with respect to the dichroic mirror 190. The measurement optical system 103 does not move with respect to the optical axis. The movement of the wavefront measuring unit 125 is performed by setting the Hartmann plate 130 at a position conjugate with the position of the pupil of the eye 14 of the subject so that the received light beam becomes a parallel light beam, and is controlled by the control unit 140.

  The measurement optical system 103 includes an objective lens 170, a rotating prism 117, a polarizing beam splitter 118, a relay lens 119, an iris diaphragm 120, relay lenses 121 and 122, a half mirror 123, and a relay lens 124.

  The wavefront measuring unit 125 includes a measuring light projection light source 126 and a measuring light receiving optical system 127. The measurement light projection light source 126 propagates in the order of the relay lens 121, the iris diaphragm 120, the relay lens 119, the polarization beam splitter 118, the rotating prism 117, the objective lens 170, the dichroic mirror 190, and the shielding unit 81, and the eye of the subject. The optical system which irradiates 14 with a light beam is comprised. The iris diaphragm 120 is in a conjugate position with the pupil of the subject's eye 14, and the measurement light projection light source 126 is in a conjugate position with the eye retina F to be examined. The wavelength of the measurement light projection light source 126 is a non-visible light region, and since it does not adversely affect the eye, it is preferably a near infrared ray. Since the shielding unit 81 transmits the wavelength of the measurement light, the light of the measurement light projection light source is always incident on the eye 14 of the subject regardless of the shielding / transmission control state of the shielding unit 81 with respect to the visible light.

  The iris diaphragm 120 is for supplying an appropriate amount of light to the eye 14 of the subject, and is controlled manually or by the control unit 140 based on the intensity of light received by the light receiving element 131. The rotating prism 117 always rotates around the optical axis AX3 during the measurement, so that the rotating light beam is incident on the eye 14 of the subject to reduce the influence of nonuniformity in the beam surface of the measuring light projection light source 126. When the light is reflected by the eye 14 of the subject and passes through the rotating prism 117 again, the light beam is stationary by receiving the rotation opposite to the previous rotation. As a result, a light reception signal averaged in the retina F is obtained, and more accurate measurement is possible. The drive control of the rotating prism 117 is performed by the control unit 135.

  The measurement light reflected by the retina F of the eye to be examined propagates in the order of the shielding unit 81, the half mirror 190, the objective lens 170, the rotating prism 117, the polarization beam splitter 118, the relay lens 122, the half mirror 123, and the relay lens 124. The light enters the wavefront measuring unit 125.

  The wavefront measuring unit 125 includes a variable cross cylinder 128, an imaging lens 129, a Hartmann plate 130, and a light receiving element 131 as a light receiving unit. When the eye 14 of the subject is an astigmatic eye, for example, correction is performed using an optical element such as a variable cross cylinder 128.

  The variable cross cylinder 128 includes a cylindrical lens having a convex surface (positive power) and a cylindrical lens having a concave surface (negative power). The two cylindrical lenses are driven by a driving device such as a pulse motor, and are independently rotated about the optical axis AX3 of the measuring optical system 103. When the two cylindrical lenses are rotated in opposite directions, the astigmatism power is changed, and when the two cylindrical lenses are integrally rotated in the same direction, the astigmatic axis angle is changed. Drive control is performed by the control unit 135.

  As the light receiving element 131, for example, a CCD element is suitable. The imaging lens 129 functions as an optical member for making reflected light from the eye 14 of the subject into parallel rays. The Hartmann plate 130 is provided with a large number of microlenses having the same focal length on the surface thereof. The Hartmann plate 130 divides the light flux from the imaging lens 129 into a plurality of light fluxes corresponding to the microlenses, and each receives the light received by the light receiving element 131. Focus on the surface.

  FIG. 4 shows an example of the lens array image 131 '. If the light incident on the Hartmann plate 130 is a parallel light beam, the spots formed by all the microlenses are focused according to the arrangement of the microlenses on the Hartmann plate, and the microlenses are arranged at equal intervals. On the light receiving element 131, a plurality of equally spaced lens array images 131 ′ shown in FIG. 4 are formed. The spot interval of this lens array image 131 'is equal to the interval of the minute lenses. In FIG. 4, the horizontal axis x corresponds to, for example, the horizontal direction of the subject's eye 14, and the vertical axis y corresponds to, for example, the vertical direction of the subject's eye 14. I (xi, yi) is the light intensity of the lens array image 131 'at the point (xi, yi). As will be described later, rough characteristics such as the sphericity, cylindricality, and cylindrical axis angle of the subject's eye 14 are obtained from the light intensity distribution, and the spherical aberration is obtained from the point image position of the lens array 131 ′. A precise value of the eye 14 adjustment can be calculated. In the figure, PE indicates the range of the pupil of the eye 14 of the subject. For the measurement of the fourth-order Zernike coefficient, the Hartmann plate is preferably divided into at least 17 beams to form at least 17 lens array images 131 '. Thus, the wavefront measuring unit is formed by the Shack-Hartmann wavefront sensor that divides the beam into at least 17 beams.

  When the light beam incident on the Hartmann plate 130 is not a parallel light beam, the interval between the spot images of the lens array image 131 ′ is deviated from the case of the parallel light beam incident. When the subject 50 is myopic, the measurement light beam from the eye 14 of the subject is narrowed by parallel rays, the spot interval is narrower than the microlens interval, and conversely, the subject 50 is hyperopic. In this case, the spot image interval of the lens array image 131 ′ is wider than the interval of the minute lenses. For this reason, it is necessary to move the entire wavefront measuring unit 125 in the optical axis Z direction so as to be parallel rays on the Hartmann plate surface in accordance with individual differences. The movement control for this is performed by the control unit 140. Details of the movement control will be described later.

  FIG. 5 shows the configuration of the calculation unit 132 and the control unit 135. The light reception output of the light receiving element 131 is input to the calculation unit 132. The calculation unit 132 includes a calculation unit 133 that performs a predetermined calculation and a memory unit 134 that stores a video signal that is a light reception output. The output of the arithmetic unit 133 is output to the control unit 135 and the adjustment calculation unit 180.

  The control unit 135 includes a control unit 140 and first to third drive units (136, 137, 138). Each unit receives the result of the calculation unit 132 and operates based on processing in the control unit. The first drive unit 136 drives the variable cross cylinder 128 to correct astigmatism. The second drive unit 137 drives the wavefront measuring unit 125 and sets the received light beam to be a parallel beam on the surface of the Hartmann plate 130. The third drive unit 138 drives the rotational movement of the rotating prism 117. Here, an example in which each unit operates in accordance with a command from the control unit 140 has been described, but the present invention is not limited to this. For example, the unit may be manually operated by a measurer. Further, it may be operated by a command signal from an external device (not shown). Further, a lighting drive signal is output from the control unit 140 toward the measurement light projection light source 126, and thereby the measurement light projection light source 126 is appropriately turned on as necessary.

[Operation]
Next, the operation of the ophthalmic measurement apparatus 1 according to the present invention will be described. The following is assumed as the measurement mode of this measuring apparatus.
(A) After gazing in both eyes, the temporal transition of the adjustment of each eye when moving to the monocular vision is measured. This mode evaluates the temporal change of each eye and the correlation between the eyes. (Mode A).
(B) After a gaze in one eye, the temporal transition of the adjustment of each eye when shifting to the binocular vision is measured. In this case, a mode (mode B) for evaluating the temporal change of each eye itself and the correlation between both eyes.
Here, the operation will be described by taking the case of (a) as an example.

FIG. 6 shows the overall operation of this measuring apparatus. It consists of steps 1-5. Hereinafter, the operation will be described with reference to FIGS. 1 to 5 as appropriate. The detailed contents of each step will be described by subdividing each part with the drawings (FIGS. 7 to 9, 13, and 14) to be referred to later. For convenience of reference, a flow diagram to be referred to on the right side of each step in FIG. 6 and the number of the diagram are shown.
First, in step 1, the alignment adjustment between the ophthalmologic measuring apparatus 1 and the eye 14 of the subject is performed. This adjustment is performed by aligning the optical axis of the measurement light with the eye 14 of the subject, and when the subject 50 has a normal eye that is neither myopic nor hyperopic, and the position where the parallel light beam enters the Hartmann plate 130. The wavefront measuring unit 125 is set at (reference position).
In step 2, characteristics such as the spherical power of the subject's eye 14 are measured (coarse measurement mode), and the reference position is precisely reset. In addition, correction of astigmatism is performed. That is, precise setting according to individual differences is performed.
In step 3, the shielding part 81 is opened and closed to shield / transmit visible light.
In step 4, a precise measurement (accurate measurement mode) of adjusting the eye 14 of the subject is performed. Step 3 and Step 4 are repeated as appropriate.
In step 5, evaluation is performed based on the obtained adjustment data.

  Variations in the eye accommodation that is the subject of this measurement device are generally small and have rapid changes. Therefore, in order to detect the change precisely and at high speed, wavefront aberration measurement (step 4) is used in the present invention. In the wavefront aberration measurement, as is well known, the deviation from the plane wave is detected from the positional deviation of the point image generated by the Hartmann plate, thereby measuring the wavefront aberration of the eye 14 of the subject. It is necessary for the incident light to be a parallel light. This precise setting is performed in step 2. The present invention is characterized in that the steps 2 and 4 can be realized by the same hardware.

  The contents of step 1 and step 2 will be described with reference to FIG. Note that the steps in the flowchart may be further divided into other flowcharts. In this case, the frame indicating the step is a double line, and the step number to be referred is surrounded by <>.

  First, the gaze target 12 is presented in front of the subject 50, and the shielding portion 81 is mounted in front of the subject's eye 14R or 14L to be shielded. The mounting position of the shielding portion 81 may be anywhere as long as it blocks the view, but if it is mounted at a position of 10 mm to 15 mm from the cornea, it is effective because the ratio of blocking the view is increased. The shielding unit 81 is controlled so that the gaze target 12 can be seen from the subject.

  Next, alignment adjustment of the eye 14 of the subject is performed (S11). Specifically, the position and angle of the subject's eye 14 and the adjustment measurement unit 30 and the position and angle of the dichroic mirror 190 are adjusted, and the light beam of the measurement light projection light source is correctly incident on the subject's eye 14. In addition, the light receiving element 131 is set so that the reflected light can be sufficiently received. Next, the position of the wavefront measuring unit 125 is set to the reference position by the second drive unit 137 (S12). Here, the reference position is a position where the incident light on the Hartmann plate 130 becomes a parallel light when the eye 14 of the subject is an average normal eye. Since this distance varies among individuals, as will be described later, in step 2, it is precisely controlled to be optimal (see S13 to S17).

  Next, the measurement light reflected by the eye retina F is incident on the light receiving element 131, and a video signal that is an output of the light receiving element 131 is input to the calculation unit 132. Here, the number of pixels of the light receiving element 131 is N in the horizontal direction (x direction) and M in the vertical direction (y direction). The received light intensity values I (xi, yj) of the pixels (xi: 1 to N, yj: 1 to M) of the light receiving element 131 are stored in the memory unit 134 (S13).

  Next, the calculation unit 132 determines whether or not the number of spot point images (hereinafter sometimes simply referred to as “point images”) of the lens array image 131 ′ can perform wavefront aberration measurement with sufficient accuracy. The process proceeds to (S21 to S30: see FIG. 8) (S14). Since the setting adjustment is not sufficient at the beginning of measurement, S15 to S17 are executed in a normal case, and the setting adjustment is repeated. When the setting is completed and the number of spot point images is equal to or greater than a predetermined value, S18 to S20 are executed, and wavefront aberration measurement, which is final precision measurement, is performed.

  The contents of the position detection determination flow will be described with reference to FIG. Ideal point image position (the eye 14 of the subject) of the kth microlens on the Hartmann plate 130 (a series number is assigned to all microlenses and the kth one, where the total number of microlenses is L). (The position of each point image formed on the light receiving element 131 in the case of normal) is expressed as (Hxk, Hyk) on the basis of the pixel arrangement order.

ここで、αは被検者の眼１４の瞳に対するレンズアレイ像１３１’の倍率、ｄ_ｘ、ｄ_ｙは、それぞれｘ方向、ｙ方向の微小レンズアレイのレンズ間距離、ｐはレンズアレイ像１３１’を取得するピクセルのサイズ（ピクセル形状を正方形とした場合の一辺の長さ）である。即ち、式１は、各点像の理想位置（完全な平行光線が入射した時のスポット位置）の周りで実際に受光される点像をサーチし、その強度の総和をｃｄとして算出するものである。ｃｄの値が閾値より大きいか否かを判断し（Ｓ２４）、大きい場合は、ｇの値を１つインクリメントする（Ｓ２５）。この処理を全ての微小レンズについて繰り返す（Ｓ２６→Ｓ２７→Ｓ２３→Ｓ２６）。この結果、ｇの値は、閾値以上の受光強度の点像の総数となっている。ここで得られたｇの値を設定値ｇｔｈと比較し（Ｓ２８）、設定値ｇｔｈ以下の場合は所定の数の点像が検出不可能と判断してフーリエ変換利用の球面度数測定（Ｓ３２〜Ｓ３６）（図９参照）に移行し（Ｓ２９）、波面測定ユニット１２５の再設定のための工程２を繰り返す。設定値ｇｔｈより大きい場合は所定の数より多い数の点像が検出可能（即ち、波面収差測定可能）として、遮蔽部の制御工程（工程３、Ｓ１８）及び、眼球の波面収差測定（工程４、Ｓ１９）（図７参照）に移行する（Ｓ３０）。 First, the threshold value Ith of the light intensity I of the point image is set. The Ith is set for evaluating whether the light is sufficiently incident on the eye 14 of the subject by distinguishing between low intensity and high intensity. Whether or not such a state is present is determined by whether or not there are a predetermined number or more of point images equal to or greater than the threshold value Ith. This is because in the wavefront aberration measurement described later, it is necessary to secure a certain number of point images, and therefore the number of point images gth that can be detected is set (S21). gth is set to about 5. Next, as the initial value of the micro lens number, the micro lens number k and the number of point images g are set to 1, 0, respectively (S22). Next, the arithmetic unit 133 uses Equation 1 to determine how many point images with which the received light intensity equal to or greater than the threshold is obtained for all the microlenses (k: 1 to L) (S23 to S27).

Here, α is the magnification of the lens array image 131 ′ with respect to the pupil of the eye 14 of the subject, d _x and _dy are the inter-lens distances of the micro lens array in the x direction and y direction, respectively, and p is the lens array image 131. 'Is the size of the pixel to acquire (the length of one side when the pixel shape is a square). In other words, Equation 1 searches for a point image actually received around the ideal position of each point image (a spot position when a completely parallel light beam is incident), and calculates the sum of the intensities as cd. is there. It is determined whether or not the value of cd is larger than the threshold value (S24). If it is larger, the value of g is incremented by one (S25). This process is repeated for all the microlenses (S26 → S27 → S23 → S26). As a result, the value of g is the total number of point images having a received light intensity equal to or greater than the threshold value. The value of g obtained here is compared with the set value gth (S28). If the value is less than the set value gth, it is determined that a predetermined number of point images cannot be detected, and spherical power measurement using Fourier transform (S32 to S32). The process proceeds to S36 (see FIG. 9) (S29), and Step 2 for resetting the wavefront measuring unit 125 is repeated. When it is larger than the set value gth, more than a predetermined number of point images can be detected (that is, wavefront aberration can be measured), and the shielding portion control step (step 3, S18) and eyeball wavefront aberration measurement (step 4). , S19) (see FIG. 7) (S30).

  Hereinafter, with reference to FIG. 9, spherical power measurement using Fourier transform in step 2 will be described. The calculation unit 132 sets the pupil analysis range PE shown in FIG. 4 (S32). This pupil analysis range PE is a range in the lens array image 131 ′ corresponding to the pupil range of the eye 14 of the subject. Next, if the position (xi, yj) of the point image is outside the analysis range PE, I (xi, yj) = 0 is set (S33). The reason for this is to prevent the accuracy from being lowered with measurement data outside the pupil range. Here, the subscript i is a natural number from 1 to N, and the subscript j is a natural number from 1 to M. The pupil analysis range PE can be obtained from the spread of the lens array image 131 ′. However, if the diameter is set to 2 mm for clear vision and 6 mm for night vision, the pupil analysis range PE is a value suitable for most subjects.

ここで、ｍ：０〜Ｍ−１，ｎ：０〜Ｎ−１、である。
図１０にフーリエ変換された空間周波数像１３１’’の例を示す。 Next, the arithmetic unit performs a discrete Fourier transform on I (xi, yj) based on Equation 2 to obtain a spatial frequency image R (ui, uj) (S34).

Here, m: 0 to M-1, n: 0 to N-1.
FIG. 10 shows an example of a spatial frequency image 131 ″ subjected to Fourier transform.

Next, the calculation unit 133 executes the nearest center-of-gravity point calculation process among the point images existing in the spatial frequency axes u and v directions (S35 in the flowchart of FIG. 9).
FIG. 11 is an explanatory diagram showing an example of the center-of-gravity point calculation process, and is an enlarged view of the vicinity of the center point of the UV space shown in FIG. As shown in the figure, the center O of R (ui, uj) is set as the origin of the (u, v) coordinate (S41 in FIG. 13). If the point images closest to the origin are Pv and Pu, the position Mv of the maximum coordinate value of the maximum luminance value at that point is calculated (S45), and the barycentric point Gv is calculated from the pixels near Mv (S46). A distance Δv between Gv and the center point O is calculated (S47).

ここで、ＦＴｘ，ＦＴｙは、各々ｘ，ｙ方向の離散フーリエ変換時の格子数、ｆはハルトマンプレート１３０の焦点距離、αは被検者の眼１４の瞳に対するレンズアレイ像１３１’の倍率である。
次に、演算ユニット１３３は、球面度数Ｓｆを下記の式５に基づき算出し、メモリユニット１３４に保存する（Ｓ５３）。

次に、演算ユニット１３３は、バリアブルクロスシリンダ１２８を適宜駆動して乱視度数Ｃを式６に基づき算出してメモリユニット１３４に保存する（Ｓ５４）。

更に、演算ユニット１３３は、乱視軸Ａを式７に基づき算出してメモリユニット１３４に保存する（Ｓ５５）。

そして、演算ユニット１３３は、球面度数Ｓｆ、乱視度数Ｃ、乱視軸Ａの測定結果（粗測定結果）を出力する（Ｓ１６）（図７参照）。 As described above, since Δu and Δv are obtained, the spherical power DIOP is calculated.
FIG. 9 shows a flowchart of spherical power measurement. The arithmetic unit 133 calculates the lateral spherical power DIOPx and the vertical spherical power DIOPy by Expressions 3 and 4 (S51, S52).

Here, FTx and FTy are the number of lattices at the time of discrete Fourier transform in the x and y directions, f is the focal length of the Hartmann plate 130, α is the magnification of the lens array image 131 ′ with respect to the pupil of the eye 14 of the subject. is there.
Next, the arithmetic unit 133 calculates the spherical power Sf based on the following equation 5 and stores it in the memory unit 134 (S53).

Next, the arithmetic unit 133 appropriately drives the variable cross cylinder 128 to calculate the astigmatism power C based on the equation 6, and stores it in the memory unit 134 (S54).

Further, the arithmetic unit 133 calculates the astigmatism axis A based on Expression 7 and stores it in the memory unit 134 (S55).

Then, the arithmetic unit 133 outputs the measurement result (coarse measurement result) of the spherical power Sf, the astigmatic power C, and the astigmatic axis A (S16) (see FIG. 7).

  FIGS. 15 and 16 are graphs showing the measurement results and power maps of the spherical power Sf, the astigmatism power C, and the astigmatism axis A thus obtained. When the sign of the myopic eye, that is, the spherical power Sf is negative, the interval between the point images is narrower than the distance between the minute lenses of the Hartmann plate 130, whereas when the sign of the hyperopic eye, that is, the spherical power Sf is positive, the interval between the point images. Becomes wider than the interval of the microlenses. The absolute value of the astigmatism degree C increases as the difference between the u direction and the v direction increases.

  Next, returning to FIG. The arithmetic unit 133 moves and sets the measurement unit 125 from the reference position in the optical axis Z direction (see FIG. 3) so that the spherical power Sf obtained by the measurement unit 125 becomes 0 in the control unit 135. The position of the variable cross cylinder 128 is set so that the astigmatic degree C becomes 0 (S17).

  The arithmetic unit 133 repeats the processes of S13 to S17 until the number of point images is detected greater than the predetermined number gth. In S14, it is determined whether or not the position of the point image can be detected. If it is determined that the position of the point image can be detected, the process proceeds to shielding unit control (step 3, S18) and eyeball wavefront aberration measurement processing (step 4, S19).

  Wavefront aberration measurement is performed by photographing a point image generated by the Hartmann plate 130 and detecting its position. That is, when the adjustment of the eye 14 of the subject fluctuates, the position of the point image changes, so that the wavefront aberration can be obtained from the change in the position. Since the calculation by the wavefront aberration measurement process is known (for example, Japanese Patent Application Laid-Open No. 2004-73395), the description thereof is omitted.

  First, the shield 81 is not worn from the subject's eye 14 (S18), and then the spherical aberration of the eyeball is measured in this state (S19). Next, visible light is shielded by a signal from the light flux controller 82 as a state where the shield is attached (S18). The wavefront aberration of the eyeball that is shielded immediately after the shielding is measured, and the temporal transition is stored. The measurement of the temporal transition of the wavefront aberration may be started from the state where the shielding part 81 is not worn from the eye 14 of the subject, and the measurement may be continued and stored while the shielding part 81 is worn.

  Then, the adjustment calculation unit 180 calculates the true adjustment position (adjustment) of the subject's eye 14 that is the focus position on the visual axis from the measured value of the wavefront aberration of the subject's eye 14.

  Next, the comparison determination unit 40 compares the adjustment values of the eyes with and without the visible light being shielded, and displays them on the display unit 41. Alternatively, the adjustment value before and after the shielding eye is shielded is output from the comparison determination unit 40 to the external device (S20). This completes the measurement.

  What has been described above is the case of mode A in which the shielded eye is measured when shifting from binocular vision to monocular vision, but on the contrary, transition from monocular vision to binocular vision is performed. In the case of mode B, the same measurement can be performed except when the shielding procedure of the shielding unit is reversed. It is also possible to measure the one eye that is not shielded. Thereby, it is possible to know the influence of the adjustment due to the occlusion and the magnitude of the correlation between the adjustment of the non-occluded eye and the occluded eye viewed with one eye. In addition, it is possible to know the original characteristics of an unshielded eye that is viewed with one eye.

  Furthermore, since the adjustment of one eye when the binocular vision is always performed without performing the shielding by the shielding unit can be measured independently, the configuration of the present invention can be used in such a case.

  As described above, in the first embodiment of the present invention, when precise measurement by wavefront aberration measurement processing cannot be performed, the wavefront measurement unit 125 is moved in the optical axis direction, and then precise measurement by wavefront aberration is performed. Therefore, it is possible to measure the optical characteristics of a wide range of eyes without adopting a special structure that adds an optical system for precise measurement of optical characteristics and an optical system for rough measurement. And cost reduction.

[Second Embodiment]
FIG. 17 shows the configuration of an ophthalmologic measuring apparatus 2 according to the second embodiment of the present invention. This ophthalmic measuring apparatus 2 is obtained by adding a gaze direction measuring unit 33 to the ophthalmic measuring apparatus 1 according to the first embodiment. The line-of-sight measurement unit 33 detects the line-of-sight direction of the eye 14 of the subject and detects how the line-of-sight direction changes due to shielding. There are a scleral reflection method, a cornea detection method, and the like as the detection method of the line of sight.

  FIG. 18 shows a configuration example to which the scleral reflection method is applied, which utilizes the difference in reflectance between the cornea (black eye) and the sclera (white eye). As shown in FIG. The near-infrared ray is irradiated on the eyeball, and the intensity of the reflected light from the eye is measured by the two photodetectors 150a and 150b. In FIG. 18B, the intensity of the two photodetectors is substantially the same, but in FIG. 18C, the output of the detector 150a is larger than that of the photodetector 150b. The level difference is processed by the line-of-sight direction measurement unit 33, and the comparison / determination unit 40 compares the level difference as in the case of wavefront aberration measurement.

  FIG. 19 (a) shows the principle of the corneal reflection method. The corneal reflection method uses the fact that the center of curvature of the cornea and the center of rotation of the eyeball are different to measure the relative movement of the virtual image inside the cornea of the spotlight incident on the eyeball as the eyeball moves. is there. As shown in the figure, a spotlight virtual image is observed at the position Q1 with respect to the eyeball indicated by a solid line. Here, a virtual image of the spotlight inside the cornea is observed at the position Q2 when the eyeball is rotated by θ (see the dotted line). This virtual image is observed by the image sensor 151 as shown in FIG. 19B, the change is processed by the line-of-sight direction measurement unit 33, and the comparison judgment unit 40 compares the same as in the case of wavefront aberration measurement.

  The gaze direction measurement data by the gaze direction measurement unit 33 may be an evaluation item separately from the adjustment by the wavefront measurement unit described above, or may be evaluated using both.

The whole block diagram of the measuring apparatus of the 1st Embodiment of this invention. The figure which shows the mode of the measurement by this invention. The figure which shows the structure of an adjustment measurement part. The example of the light reception image in a light receiving element. The figure which shows the structure of a calculating part and a control part. The figure which shows operation | movement of this measuring apparatus simply. The figure which shows the detail of operation | movement of this measuring apparatus. The position detection determination flowchart of a point image. The spherical power measurement flow diagram. Example of Fourier transformed spatial frequency image It is explanatory drawing which shows an example of a gravity center calculation process, Comprising: The enlarged view of the center point vicinity part of UV space shown in FIG. It is explanatory drawing which shows an example of a gravity center calculation process, Comprising: The enlarged view of the maximum point vicinity part of UV space shown in FIG. The flowchart of a gravity center calculation process. The flowchart of a spherical power calculation process. It is the figure which displayed on the screen an example of the eye refractive power value obtained by rough measurement mode, and its power map. It is the figure which displayed on the screen the other example of the eye refractive power value obtained by rough measurement mode, and its power map. The whole block diagram of the measuring apparatus of the 2nd Embodiment of this invention. The principle diagram of the scleral reflection method. The principle diagram of a corneal reflection system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ophthalmological measurement apparatus 10 Base 12 Gaze object 14 Subject's eye 15 Line of sight 20 Support part 30 Adjustment measurement part 33 Gaze direction detection part 40 Comparison judgment part 41 Display part 50 Subject 81 Shield part 82 Light flux control part 103 Measurement Optical system 117 Rotating prism 118 Polarizing beam splitter 119 Relay lens 120 Iris stop 121 Relay lens 122 Relay lens 123 Half mirror 124 Relay lens 125 Wavefront measuring unit 126 Measuring light projection light source 127 Measuring light receiving optical system 128 Variable cross cylinder 129 Imaging lens 130 Hartmann plate 131 Light receiving element 131 ′ Lens array image 131 ″ Fourier transformed spatial frequency image 132 Operation unit 133 Operation unit 134 Memory unit 135 Control unit 136 First drive unit 137 Second drive unit 138 3 the drive unit 140 control unit 150 photodetector 170 objective lens 180 adjusted calculator 190 dichroic mirror

Claims (7)

In an ophthalmic measurement device that irradiates the subject's eyes with visible light and non-visible light for measurement:
An adjustment measurement unit that receives the reflected light beam from the retina of the eye to be inspected, and measures the adjustment of the eye based on the received light reception signal;
A shielding part that can be controlled to shield or pass a light beam applied to the eye of the subject;
A light flux control unit for controlling the shielding unit;
The shielding part is disposed in front of the subject's eye, and has a wavelength selection characteristic that shields the visible light and allows the non-visible light for measurement to pass at the time of shielding,
The luminous flux control unit is configured to shield visible light on one eye of the subject after viewing the subject's gaze target with both eyes, or to one eye of the subject. After viewing one eye so as to shield visible light, the shielding unit is controlled to transmit visible light to one eye of the subject,
The adjustment measurement unit measures the adjustment of the eye to be examined before and after the shielding of the visible light or before and after transmission.
Ophthalmic measuring device. The adjustment measurement unit includes an irradiation unit that emits the invisible light, and a light receiving unit that receives a reflected light beam from the eye retina.
The ophthalmic measurement apparatus according to claim 1. Further, the adjustment measurement unit measures the adjustment of the one eye before and after the visible light shielding or before and after the transmission for one eye that is not shielded from the visible light by the shielding unit.
The ophthalmologic measurement apparatus according to claim 1 or 2. Furthermore, a gaze direction measuring unit that measures the gaze direction of the eye to be examined before and after shielding the visible light is provided.
The ophthalmologic measurement apparatus according to claim 1. A comparison / determination unit that determines the magnitude of the change in the characteristics of the eye of the subject by comparing the adjustment of the subject's eye before and after the shielding of the visible light or before and after the transmission,
The ophthalmologic measurement apparatus according to claim 1. The adjustment measurement unit has a wavefront measurement unit including a Hartmann plate, and can also measure high-order aberrations of the eye.
The ophthalmic measurement apparatus according to claim 1. The wavefront measurement unit has a Shack-Hartmann wavefront sensor that divides into at least 17 beams.
The ophthalmologic measurement apparatus according to claim 6.

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