JP7024228B2 - Ophthalmic equipment and ophthalmic equipment control program - Google Patents

Description

The present disclosure relates to an ophthalmic apparatus for inspecting an eye to be inspected and an ophthalmic apparatus control program.

Cataract surgery is performed for cataracts in which the visual acuity deteriorates due to the opacity of the crystalline lens inside the eye. In conventional cataract surgery, an intraocular lens (IOL) is inserted instead of the opaque crystalline lens. In this IOL, there is an adjusted IOL in which the spherical power changes according to the adjustment of the eye to be inspected.

Japanese Unexamined Patent Publication No. 2009-34451

W. Neil Charman1 and David A. Atchison, Age-dependence of the average and equivalent refractive indices of the crystalline lens, Biomed Opt Express 2014 Jan 1; 5 (1): 31-39

However, in a conventional ophthalmic apparatus, it is not possible to confirm the relationship between the movement of the crystalline lens or IOL during accommodation of the eye and the change in the refractive power at that time, and it is easy to evaluate the accommodation IOL, for example. It wasn't.

In view of the conventional problems, it is a technical subject of the present disclosure to provide an ophthalmic apparatus capable of measuring an ophthalmologic refractive power according to the movement of the crystalline lens or the IOL during accommodation, and an ophthalmic apparatus control program.

In order to solve the above problems, the present disclosure is characterized by having the following configurations.

(1) An ophthalmologic device that inspects an eye to be inspected , which is an axial length that is the distance from the anterior surface of the corneal surface of the eye to be inspected to the retina. , And the intraocular distance measuring means for measuring the intraocular distance including the thickness of the crystal body, the refractive power measuring means for measuring the refractive power of the eye to be inspected, and the intraocular distance measuring means and the refractive power measuring means. The control means comprises a control means for simultaneously measuring the axial length and the crystal thickness and the refractive power under the regulatory stimulus, and the control means includes the measurement results of the axial length and the crystal thickness and the refractive power. It is characterized in that the measurement results of the above are displayed side by side on the display means .
(2) An ophthalmic device control program used in an ophthalmic device that inspects an eye to be inspected, and is executed by a processor of the ophthalmic device to project an accommodative stimulus optotype on the eye to be inspected. Intraocular distance measurement, which measures the intraocular distance including the axial length, which is the distance from the anterior surface of the corneal to the retina of the eye to be inspected, and the thickness of the crystalline body under the accommodative stimulus by the step and the accommodative stimulus projection step, and the above-mentioned. A control step for simultaneously performing a refractive force measurement for measuring the refractive force of the eye to be inspected, a display step for displaying the measurement result of the axial length and the crystal body thickness, and the measurement result of the refractive force side by side on a display means. Is executed by the ophthalmic apparatus .

It is a schematic diagram which shows the internal structure of an apparatus. It is a flowchart which shows the control operation of a device. It is a figure which shows an example of the anterior eye part observation image. It is a figure which shows an example of a ring image. It is a figure for demonstrating the calculation of the axial length. It is a figure which shows an example of the result display screen. It is a figure which shows an example of the result display screen. It is a figure which shows an example of the tomographic image before distortion correction. It is a figure which shows an example of the tomographic image after distortion correction. It is a figure for demonstrating ray tracing.

<First Embodiment>
The first embodiment according to the present disclosure will be described. The first embodiment is an ophthalmic apparatus (for example, an ophthalmic apparatus 1000) for inspecting an eye to be inspected. The ophthalmic apparatus includes an adjustable stimulus projection unit (for example, a fixation target optical system 10), an intraocular distance measuring unit (for example, an OCT optical system 100), and a refractive power measuring unit (for example, a refractive power measuring optical system 400). , A control unit (for example, a control unit 70) is mainly provided.

The accommodative stimulus projection unit projects, for example, an accommodative stimulus optotype on the eye to be inspected. For example, the accommodation stimulus projection unit gives an accommodation stimulus to the eye to be inspected by changing the presentation distance of the optotype. The intraocular distance measuring unit measures, for example, the intraocular distance of the eye to be inspected. The intraocular distance is, for example, axial length, corneal thickness, anterior chamber depth, lens thickness, vitreous thickness, and the like. The refractive power measuring unit measures, for example, the refractive power of the eye to be inspected. The control unit controls the intraocular distance measuring unit and the refractive power measuring unit, and simultaneously measures the intraocular distance and the refractive power under accommodative stimulation. Here, "simultaneous" includes performing in parallel and alternately performing one or several measurements. By providing these configurations, the ophthalmic apparatus of the first embodiment can confirm the change in the refractive power and the intraocular distance before and after the accommodation of the eye to be inspected.

The control unit may display the measurement result of the intraocular distance and the measurement result of the refractive power side by side on the display unit (for example, the display unit 75). This makes it easy to compare the intraocular distance with the change in refractive power. The control unit may display the measurement result of the intraocular distance and the measurement result of the refractive power in real time.

The intraocular distance measuring unit and the refractive power measuring unit may perform measurement with infrared light having different wavelengths from each other. As a result, noise due to the influence of each other's measurement light can be suppressed.

When measuring the intraocular distance and the refractive power, the control unit may measure the elapsed time. For example, the control unit may determine the progress of disease or aging of the crystalline lens (for example, the degree of hardening) based on the time required for the adjustment of the eye to be inspected. Further, the control unit may display the change with time of the intraocular distance and the refractive power on the display unit. In this case, the control unit may display the change with time of the intraocular distance and the refractive power in different colors according to the amount of change.

The processor of the control unit may execute the ophthalmologic device control program stored in the storage unit (for example, the memory 74). The ophthalmic apparatus control program includes, for example, a regulatory stimulus projection step and a control step. The accommodative stimulus projection step is, for example, a step of projecting an accommodative stimulus optotype on the eye to be inspected. The control step is a step in which the intraocular distance measurement for measuring the intraocular distance of the test eye and the refractive power measurement for measuring the refractive power of the test eye are simultaneously performed under the control stimulus by the control stimulus projection step.

<Second Embodiment>
Next, a second embodiment according to the present disclosure will be described. The ophthalmic apparatus of the second embodiment (for example, the ophthalmic apparatus 1000) includes an imaging unit (for example, OCT optical system 100), a refractive power measuring unit (for example, a refractive power measuring optical system 400), and a control unit (for example, control). Part 70) and mainly.

The photographing unit photographs the anterior eye portion and the fundus portion of the eye to be inspected, or the entire eyeball. The photographing unit may be, for example, an interference optical system that acquires a tomographic image of the eye to be inspected based on an interference state between the measurement light reflected by the eye to be inspected and the reference light corresponding to the measurement light. Further, the photographing unit may be a Scheimpflug camera, an ultrasonic photographing camera, or the like. The imaging unit mainly captures tomographic images. The refractive power measuring unit measures the refractive power of the eye to be inspected. The control unit determines the refractive index of the crystalline lens of the eye to be inspected based on the image captured by the photographing unit and the refractive power measured by the refractive power measuring unit. By providing these configurations, the ophthalmic apparatus of the second embodiment can determine the crystalline lens refractive index for each subject.

When determining the refractive index of the crystalline lens, for example, the control unit acquires an optical model of the eye to be inspected by analyzing the image. Then, the crystalline lens refractive index may be determined so that the first refractive power obtained by light beam tracing for the obtained optical model matches the second refractive power measured by the refractive power measuring unit.

The control unit may determine the degree of progress of cataract or aging based on the obtained refractive index of the crystalline lens. Since the crystalline lens refractive index increases as the cataract progresses, the control unit may determine the degree of progression of cataract or aging based on the magnitude of the cataract refractive index. The control unit may determine the degree of cataract progression based on the tomographic image. For example, the degree of progression of cataract may be determined based on the magnitude of the brightness value of the crystalline lens of the tomographic image, or the degree of progression of cataract may be determined based on the degree of yellowness of the crystalline lens of the color tomographic image. Of course, the control unit may determine the degree of cataract progression based on both the image and the refractive index of the crystalline lens.

The control unit may divide the inside of the crystalline lens into a plurality of sections and determine the refractive index for each section. For example, the compartment may be three compartments of anterior cortex, posterior cortex, and nucleus. Further, the compartment may be divided into anterior sac, posterior sac, epithelial cells, anterior cortex, posterior cortex, nucleus and the like. In this case, the sac (anterior / posterior) and cortex (anterior / posterior) may be treated as the same section. It may be divided into smaller compartments such as anterior capsule, subcapsular, anterior cortex, anterior adult nucleus, anterior peripheral embryonic nucleus, anterior embryonic nucleus, central nucleus, and posterior embryonic nucleus.

Further, the refractive index of the crystalline lens may have a gradient inside the crystalline lens. In this case, the control unit may obtain the refractive index inside the crystalline lens based on the gradient defined by the function.

The processor of the control unit may execute the ophthalmologic device control program stored in the storage unit (for example, the memory 74). The ophthalmic apparatus control program includes, for example, an imaging step, a refractive power measurement step, and a control step. The imaging step is, for example, a step of photographing the anterior eye portion and the fundus portion of the eye to be inspected, or the entire eyeball. The refractive power measurement step is a step of measuring the refractive power of the eye to be inspected. The control step is a step of determining the refractive index of the eye to be inspected based on the image captured in the photographing step and the refractive power measured in the refractive power measuring step.

<Example>
Hereinafter, the ophthalmic apparatus 1000 according to the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a measurement unit 200 of the ophthalmic apparatus 1000 according to the present embodiment. The following optical system is built in a housing (not shown). Further, the housing is three-dimensionally moved with respect to the eye E to be inspected via the operation unit 76 (for example, a touch panel, a joystick, etc.) by driving a well-known alignment movement mechanism. In the following description, the optical axis direction of the eye to be inspected (eye E) will be the Z direction, the horizontal direction will be the X direction, and the vertical direction will be the Y direction.

The ophthalmic apparatus 1000 of this embodiment mainly includes an OCT optical system 100 and a refractive power measurement optical system 400. The OCT optical system 100 is used for measuring the axial length of the eye to be inspected E, taking a tomographic image, and the like. The refractive power measuring optics 400 measures optical characteristics such as the refractive power of the eye to be inspected.

The OCT optical system 100 irradiates the eye E with the measurement light. The OCT optical system 100 detects an interference state between the measurement light reflected from each part of the eye to be inspected (for example, the cornea, the crystalline lens, the fundus, etc.) and the reference light by the light receiving element (detector 120).

The OCT optical system 100 has a configuration of a so-called optical coherence tomography (OCT) for ophthalmology. The OCT optical system 100 divides the light emitted from the measurement light source 102 into the measurement light (sample light) and the reference light by the coupler (optical divider) 104. Then, the OCT optical system 100 guides the measured light to the eye to be inspected by the light guide optical system 106, and guides the reference light to the reference optical system 110. After that, the detector (light receiving element) 120 receives the interference light due to the combination of the measurement light reflected by each part of the eye to be inspected and the reference light.

The light emitted from the light source 102 is divided into a measured luminous flux and a reference luminous flux by the coupler 104. Then, the measured luminous flux is emitted into the air after passing through the optical fiber. The luminous flux is focused on the eye to be inspected via the scanning unit 108, the optical member of the light guide optical system 106, the dichroic mirror 16, and the objective lens 47. The light reflected by each part of the eye to be inspected is returned to the optical fiber through the same optical path.

The scanning unit 108 scans the measurement light on the eye E in the XY direction (transverse direction). The scanning unit 108 is provided with, for example, a galvano mirror, and its reflection angle is arbitrarily adjusted by the drive mechanism 109. As a result, the reflected (traveling) direction of the luminous flux emitted from the light source 102 is changed, and the imaging position on the eye to be inspected is changed. The scanning unit 108 may be configured to deflect light. For example, in addition to a reflection mirror (galvano mirror, polygon mirror, resonant scanner), an acoustic optical element (AOM) that changes the traveling (deflection) direction of light is used.

The reference optical system 110 generates a reference light that is combined with the reflected light acquired by the reflection of the measurement light by the eye E. The reference optical system 110 may be a Michaelson type or a Mach Zenda type. The reference optical system 110 is formed by, for example, a reflection optical system (for example, a reference mirror), and the light from the coupler 104 is reflected by the reflection optical system to be returned to the coupler 104 again and guided to the detector 120. As another example, the reference optical system 110 is formed by a transmission optical system (for example, an optical fiber) and guides the light from the coupler 104 to the detector 120 by transmitting it without returning it.

The reference optical system 110 has a configuration in which the optical path length difference between the measurement light and the reference light is changed by moving the optical member in the reference optical path. For example, the reference mirror is moved in the optical axis direction. The configuration for changing the optical path length difference may be arranged in the optical path of the light guide optical system 106.

The detector 120 detects an interference state between the measurement light and the reference light. In the case of the Fourier domain OCT, the spectral intensity of the interference light is detected by the detector 120, and the depth profile (A scan signal) in a predetermined range is acquired by the Fourier transform on the spectral intensity data.

For example, examples of the Fourier domain OCT include Spectral-domain OCT (SD-OCT) and Swept-source OCT (SS-OCT). Further, it may be Time-domain OCT (TD-OCT).

In the case of SD-OCT, a low coherent light source (broadband light source) is used as the light source 102, and the detector 120 is provided with a spectroscopic optical system (spectral meter) that disperses the interference light into each frequency component (each wavelength component). .. The spectrum meter comprises, for example, a diffraction grating and a line sensor.

In the case of SS-OCT, a wavelength scanning type light source (wavelength variable light source) that changes the emission wavelength at high speed in time is used as the light source 102, and for example, a single light receiving element is provided as the detector 120. The light source 102 is composed of, for example, a light source, a fiber ring resonator, and a wavelength selection filter. Then, as a wavelength selection filter, for example, a combination of a diffraction grating and a polygon mirror, and a filter using Fabry-Perot Etalon can be mentioned.

<Optical power measurement optical system>
The refractive power measurement optical system 400 projects a spot-shaped measurement index on the fundus through the central portion of the pupil of the eye E to be inspected. Then, the peripheral portion of the pupil is taken out in a ring shape via the fundus reflected light reflected from the fundus Ef, and the image pickup element of the two-dimensional light receiving element is made to image the ring-shaped fundus reflection image.

The optical power measurement optical system 400 includes, for example, a measurement light source 401, a relay lens 402, a hole mirror 403, a relay lens 404, a dichroic mirror 405, a total reflection mirror 406, a light receiving aperture 407, a collimator lens 408, a ring lens 409, and an image pickup element 410. Etc. are provided. The measurement light source 401 is arranged in a positional relationship optically conjugate with the fundus Ef of the emmetropic eye. The opening of the hole mirror 403 is optically conjugate with the pupil of the eye E to be inspected. The dichroic mirror 405 is arranged in the reflection direction of the dichroic mirror 16. The dichroic mirror 405 reflects infrared light having a wavelength used for measuring the refractive power toward the relay lens 404, and transmits infrared light having a wavelength used for capturing a tomographic image by the OCT optical system 100. The total reflection mirror 406 is arranged in the reflection direction of the hole mirror 403. The light receiving diaphragm 407 is arranged in the reflection direction of the total reflection mirror 406. The image pickup element 410 is, for example, a two-dimensional light receiving element.

The light receiving diaphragm 407 and the image pickup device 410 are arranged in a positional relationship optically conjugate with the fundus Ef. The ring lens 409 is composed of a lens portion in which a transparent flat plate-shaped cylindrical lens is formed in a ring shape, and a light-shielding portion in which a portion other than the ring-shaped lens portion is shielded from light. The ring lens 409 is optically coupled to the pupil of the eye E to be inspected via an optical system from the objective lens 47 to the collimator lens 408. The output from the image sensor 410 is input to the control unit 70. As the refractive power measuring optical system 400, a well-known one can be used.

<Cornea shape measuring unit>
The corneal shape measuring unit 300 measures the corneal shape (curvature, astigmatic axis angle, etc.) by analyzing an image taken with an index projected on the eye to be inspected. The corneal shape measuring unit 300 includes, for example, a pattern projection unit 50, a working distance detection unit 60, and an anterior eye unit imaging system 30.

The pattern projection unit 50 projects, for example, a ring pattern onto the cornea of the eye to be inspected. The pattern projection unit 50 includes, for example, a pattern plate 51, an illumination light source 59, and the like. The pattern projection unit 50 is arranged around the measurement optical axis L1. The illumination light source 59 is, for example, an LED that emits infrared light or visible light. The illumination light source 59 incidents illumination light on the pattern plate 51 to illuminate the inside. A plurality of illumination light sources 59 are arranged side by side behind the pattern plate 51.

<Working distance detector>
The working distance detection unit 60 includes, for example, a light projecting optical system and a light receiving optical system. The floodlight optical system includes a light source 61 that emits infrared light and a lens 62. The light receiving optical system includes a lens 63 and a light receiving element 64. The light from the light source 61 is converted into a substantially parallel luminous flux by the lens 62, and is applied to the cornea of the eye E to be inspected from an oblique direction. The light-receiving optical axis of the light-receiving optical system is provided so as to be symmetrical with respect to the light-emitting optical axis of the light-emitting optical system with respect to the optical axis L1. Incident to. When the eye E to be inspected moves relatively in the anteroposterior direction (optical axis direction), the index image formed on the cornea to be inspected also moves on the light receiving element, so that the alignment state of the working distance of the eye to be inspected is detected from the deviation. can do.

<Anterior eye imaging system>
The anterior eye portion imaging system 30 acquires an image of the front surface of the anterior eye portion. The anterior eye image pickup system 30 includes an objective lens 47, a filter 34, an image pickup lens 37, a two-dimensional image pickup element 35, and the like. The image pickup device 35 is arranged at a position substantially conjugate with the anterior segment of the eye to be inspected. The output signal from the image pickup device 35 is used for observing the anterior eye portion, photographing a pattern image projected on the cornea, and the like.

The light reflected from the anterior segment of the eye by the pattern projection unit 50 is imaged on the image pickup element 35 via the objective lens 47, the dichroic mirror 16, the dichroic mirror 14, the filter 34, and the image pickup lens 37. Further, the alignment state in the vertical and horizontal directions (XY directions) of the measurement optical axis L is detected based on the position of the pattern index image captured by the image sensor 35.

<Focus optical system>
The fixation target optical system 10 includes, for example, a fixation light source 11, a fixation plate 12 having a fixation target, a projection lens 13, a dichroic mirror 14, and a drive unit 15. The light from the fixation light source 11 is reflected toward the eye E to be inspected by the dichroic mirror 14 via the fixation plate 12 and the projection lens 13. The light source 11 and the fixation plate 12 are moved in the optical axis direction to give an adjustment stimulus to the eye E to be inspected.

<Control unit>
Next, the control system will be described. The control unit 70 controls the entire device and calculates the measurement result. The control unit 70 is connected to each member of the OCT optical system 100, each member of the refractive power measurement optical system 400, a memory 74, a display unit 75, an operation unit 76, and the like. Various control programs and the like are stored in the memory 74.

<Adjustment function measurement>
The control operation of the adjustment function measurement will be described. In the accommodation function measurement, the ophthalmic apparatus 1000 measures the refractive power of the eye E to be inspected, the change in the intraocular distance, and the like while changing the presentation distance of the fixation index. Hereinafter, the description will be given based on the flowchart of FIG.

<S1: Alignment>
First, the control unit 70 aligns the measurement unit 200 with respect to the eye E to be inspected. For example, an alignment index is projected onto the cornea of the eye E to be inspected, and the measurement unit 200 and the eye E to be inspected are aligned. For example, the control unit 70 lights the fixation target light source 11, the illumination light source 59, and the light source 61. The control unit 70 captures an image of the anterior eye portion of the eye to be inspected E by the anterior eye portion imaging system 30, and aligns the eye to be inspected E with the measurement unit 200 in the XY direction based on the image of the anterior eye portion. For example, the control unit 70 detects the pattern indexes Q1 and Q2 reflected in the anterior eye portion image P1 as shown in FIG. 3, and the measurement unit so that the center of the pattern indexes Q1 and Q2 is in the center of the anterior eye portion image P1. The 200 is moved in the vertical and horizontal directions to perform alignment in the XY directions. Further, the control unit 70 moves the measurement unit 200 in the front-rear direction based on the position of the eye E to be inspected in the Z direction detected by the working distance detection unit 60.

<S2: Distance refraction measurement>
When the alignment with respect to the anterior eye portion is completed, the control unit 70 measures the distance refraction of the subject. The distance refraction measured here is the initial position of the fixation target at the time of measuring the accommodation function. The control unit 70 turns on the measurement light source 401 and projects the measurement light onto the fundus Ef. Then, the control unit 70 receives the reflected light by the image pickup device 410 and detects an index image (ring image).

FIG. 4 is a ring image R imaged by the image sensor 410. The output signal from the image sensor 410 is stored in the memory 74. After that, the control unit 70 identifies (thinners) the position of the ring image R in each meridian direction based on the image data of the ring image R stored in the memory 74. Then, the control unit 70 approximates an ellipse using the least squares method or the like based on the image position of the specified ring image R. As a method for approximating an ellipse, an ellipse approximation formula that is well known in eye refractive power measurement, corneal shape measurement, and the like can be used. Then, since the refraction error in each meridian direction can be obtained from the approximated elliptical shape, the ocular refraction value of the eye to be inspected, S (spherical power), C (cylindrical power), (astigmatism axis angle) can be obtained. ) Is calculated.

<S3: Measurement of refractive power and axial length>
The control unit 70 controls the drive unit 15 to move the solid index to a position shifted by 0.5 diopter with respect to the measured distance refraction. Then, the control unit 70 turns on the measurement light source 401 and the measurement light source 102. The control unit 70 measures the refractive power and the axial length at each presentation position of the fixation target while gradually moving the fixation target arranged in the distance toward the near side. For example, the control unit acquires the A scan signal of the eye E to be inspected by the OCT optical system 100 while acquiring the ring image R by the light receiving element 410. The control unit 70 acquires the optical refractive power based on the ring image R, and acquires the axial length of the eye to be inspected based on the A scan signal. When acquiring the axial length, for example, the control unit 70 performs Fourier conversion of the A scan signal obtained by the OCT optical system 100, and from the signal, each part of the eye E to be inspected (corneal anterior surface Cf, corneal posterior surface Cb, Interference signal components due to reflected light reflected from the front surface Lf of the crystalline lens, the rear surface Lb of the crystalline lens, and the surface Rc of the retina are separated (see FIG. 5). As a result, the control unit 70 acquires the distance of each unit of the eye E to be inspected.

<S4: Result display>
While the control unit 70 gradually moves the fixation target to measure the refractive power and the axial length, the control unit 70 displays the measurement result on the result display screen K1 as shown in FIG. 5 at any time. At the upper part of the result display screen K1, a refractive power change graph showing a change in the refractive power is displayed. For example, the refractive power change graph GLPa, the fixation target conversion graph GLPb, the adjustment reaction amount Dr, the near point value Dmax, the far point value Dmin, and the like are displayed on the result display screen K1. The refractive power change graph GLPa shows the change in the latest accommodation force with the change in the presentation distance of the solid index. The fixation target conversion graph GLPb is a graph drawn by converting the presentation distance of the moving fixation target into a diopter. The accommodation force Dr is a measurement result of the eye to be inspected. The near point value Dmax is the maximum value of the refractive power measured during the accommodation function measurement. The apogee value Dmin is the minimum value of the refractive power measured during the accommodation function measurement. The horizontal axis of the graph GLPa and the graph GLPb is the optotype position, and the unit of the vertical axis is the diopter (diopter value).

At the bottom of the result display screen K1, an intraocular distance graph showing changes in the intraocular distance is displayed. For example, the distances of the anterior cornea, posterior lens, anterior lens, and posterior lens from the retina are displayed as graphs (eg, anterior corneal graph GLCf, posterior corneal graph GLCb, anterior lens graph GLLf, posterior lens graph GLLb). The examiner can confirm how the thickness of the crystalline lens increases as the fixation target approaches by using the intraocular distance graph. The vertical axis of the intraocular distance graph is the distance, and the horizontal axis is the optotype position. The control unit 70, for example, updates the graph of the refractive power and the intraocular distance each time the measurement result at each presentation position is obtained.

The control unit 70, for example, when the elapsed time from the start of measurement exceeds 30 seconds, or when the maximum value of the refractive power during the accommodation function measurement has not changed for 6 seconds or more, or the fixation target is stopped. When the time spent exceeds 6 seconds, it is determined that the predetermined condition is satisfied, and the measurement of the accommodation power is terminated.

As described above, the ophthalmic apparatus 1000 has a change in the position of each layer in the eye under accommodative stimulation, and a change in the thickness of each layer (for example, corneal thickness, anterior chamber depth, crystalline lens thickness, vitreous body thickness, retinal thickness, etc.). , Changes in objective refractive power can be measured at the same time, and the relationship between these changes can be confirmed. The ophthalmologic device 1000 may also be used to evaluate the regulatory IOL. For example, the ophthalmic apparatus 1000 may measure the movement of the accommodative IOL in the eye and the objective refractive power at that time to evaluate whether the accommodative IOL is functioning properly.

<Time change graph display>
As shown in FIG. 7, the control unit 70 may graphically show the change with time of the intraocular distance and the refractive power on the result display screen K2. For example, the control unit 70 measures changes over time such as refractive power, lens curvature, anterior chamber depth, or lens thickness when the accommodation stimulus is switched from the -3D position to the + 3D position, and displays it on the display unit 75. You may let me. Further, the control unit 70 may calculate the rate of change of each measured value over time to obtain the adjustment reaction rate of the eye to be inspected. For example, in the case of a diseased eye, the regulatory response rate tends to be slower than that of a normal eye, so measuring the regulatory response rate may be useful for detecting a disease.

Since the measured value of the axial length changes with the change in the shape of the crystalline lens, the change in the measured value of the axial length may be measured and displayed on the display unit 75 (see FIG. 7). The measured value of the axial length changes because the ratio of the refractive index of the crystalline lens changes due to the change in the thickness of the crystalline lens during accommodation.

Further, when displaying the graph of time change as shown in FIG. 7, the graph may be displayed in different colors according to the differential value (reaction rate) of the graph. For example, red, orange, yellow, green, blue, and the like may be color-coded and displayed in descending order of the differential value. This facilitates confirmation when there is an abnormality in the adjustment reaction rate of the eye to be inspected.

<Calculation of refractive index of crystalline lens>
Hereinafter, the calculation of the refractive index of the crystalline lens, which is another function of the ophthalmic apparatus 1000, will be described. The ophthalmic apparatus 1000 of this embodiment calculates the refractive power of the crystalline body of the eye to be inspected based on the refractive power of the eye to be inspected based on the ray tracing of the tomographic image and the refractive power measured by the optical power measurement optical system 400. be able to.

For example, the control unit 70 captures an anterior eye portion tomographic image by the OCT optical system 100, and performs ray tracing based on the anterior eye portion tomographic image. For example, the control unit 70 acquires a cross-sectional image by scanning the measurement light in each unit of the eye to be inspected in a predetermined transverse direction by the scanning unit 108. For example, by scanning in the X direction or the Y direction, a cross-sectional image on the XZ plane or the YZ plane of the eye to be inspected can be obtained (in this embodiment, the measurement light is one-dimensional with respect to the anterior eye portion. The method of scanning and obtaining a tomographic image is called B scan).

When a tomographic image of the anterior segment of the eye is taken by the OCT optical system 100, the measured light is refracted at each tissue boundary (anterior surface of the cornea, anterior surface of the crystalline lens, etc.) in the anterior segment of the eye according to Snell's law. As shown, the tomographic image is distorted. Therefore, the control unit 70 corrects the distortion of the tomographic image based on the refractive index of each part (refraction correction). The parameters in the tomographic image before correction include corneal anterior curvature R1, corneal posterior curvature R2', crystalline lens anterior curvature R3', crystalline lens posterior curvature R4', corneal refractive index n1, anterior chamber refractive index n2, and crystalline lens refractive index (assumed). Value) n3', corneal refractive index n4, corneal thickness d1', anterior chamber depth (corneal back surface to lens front surface) d2', crystalline lens thickness d3', glass body thickness d4', net film thickness d5', retinal refractive index n5. Use.

First, the control unit 70 obtains the corneal anterior curvature R1 of the eye to be inspected based on the sizes of the pattern indexes Q1 and Q2 in the anterior eye portion image P1 stored in the memory 85. Next, the control unit 70 corrects the distortion of the tomographic image due to the refraction on the anterior surface of the cornea based on the obtained corneal anterior curvature R1 and the refractive index n1 of the cornea. As a result, the shape of the posterior surface of the cornea in the tomographic image is corrected, and the curvature R2 of the posterior surface of the cornea can be obtained by analyzing the tomographic image. At this stage, general refractive indexes are used for the corneal refractive index n1, anterior chamber refractive index n2, glass body refractive index n4, and retinal refractive index n5, and assumed values are used for the crystalline body refractive index n3'. Be done.

The control unit 70 performs edge detection processing of the luminance value in the tomographic image, for example, and detects the boundary of the posterior surface of the cornea. Then, the boundary of the detected posterior surface of the cornea is approximated by a circle (or an approximation of an ellipse, an approximation of a conic curve, etc.), and the posterior surface curvature R2 of the cornea is calculated based on this approximation curve.

The control unit 70 corrects the distortion of the tomographic image due to the refraction on the posterior surface of the cornea based on the curvature R2 of the posterior surface of the cornea and the refractive index n2 of the anterior chamber. As a result, the shape of the front surface of the crystalline lens in the tomographic image is corrected, and the curvature R3 in front of the crystalline lens can be obtained by analyzing the tomographic image. For example, the control unit 70 calculates the front lens curvature R3 by detecting the edge of the tomographic image in the same manner as described above.

The control unit 70 corrects the distortion of the tomographic image due to the refraction on the front surface of the crystalline lens based on the curvature R3 on the front surface of the crystalline lens and the temporary refractive index n3'. As a result, the shape of the posterior surface of the crystalline lens in the tomographic image is corrected, and the curvature R4 of the posterior surface of the crystalline lens can be obtained from the tomographic image. For example, the control unit 70 calculates the lens rear surface curvature R4 by edge detection for the tomographic image in the same manner as described above.

The corneal thickness d1, anterior chamber depth d2, crystalline lens thickness _dt 3, vitreous thickness d4, and retinal thickness d5 in the corrected tomographic image are the corneal thickness d1', the anterior chamber depth d2', and the crystalline lens in the image before correction. It can be expressed as the following equation (1) by using the thickness d3', the vitreous thickness d4', and the net thickness d5'.

<Ray tracing / optimization>
When the refraction correction is completed, the control unit 70 traces the light beam based on the corrected tomographic image, and the refractive index n3'is the same as the refractive power measured by the refractive power measurement optical system 400. Optimize while changing the value of.

For example, the control unit 70 performs ray tracing on the optical model M (see FIG. 10) obtained from the tomographic image of the eye to be inspected. The optical model M is created based on, for example, the position and curvature of each part (cornea, crystalline lens, etc.), the refractive index of each part, and the like. For example, the control unit 70 simulates a light beam traveling from the center of the fundus of the optical model M toward the cornea, and the refractive power of the lens G (the first refractive power) required for the light emitted from the cornea to become parallel light. To). The crystal body refractive power n3'is changed so that the first refractive power becomes the same value as the refractive power (referred to as the second refractive power) calculated by the refractive power measuring optical system 400. The crystalline lens refractive index n3'converged by this optimization process becomes the crystalline lens refractive index n3 of the eye to be inspected.

As described above, the ophthalmic apparatus 1000 can determine the crystalline lens refractive index n3 for each subject. Thereby, the ophthalmic apparatus 1000 can more appropriately determine the axial length or the lens shape of the eye to be inspected. Further, by obtaining the correct rear surface shape of the crystalline lens using the crystalline lens refractive index n3 obtained as described above, the equatorial position of the crystalline lens used for calculating the position after insertion of the intraocular lens can be obtained more appropriately. be able to.

Further, since the crystalline lens refractive index n3 changes due to the influence of cataract or aging, the control unit 70 may determine the progress of cataract based on the magnitude of the crystalline lens refractive index n3. For example, the control unit 70 may determine that cataract or aging is progressing when the crystalline lens refractive index n3 is larger than a predetermined value.

Since the accommodation state of the eye to be inspected may change depending on the situation at the time of measurement, it is advisable to perform tomographic imaging and refractive power measurement at the same time as much as possible. Further, by measuring the pupil diameter at this time and using it for ray tracing, a more appropriate simulation can be performed.

In the above embodiments, the refractive index is uniform inside the crystalline lens, but the present invention is not limited to this. For example, the inside of the crystalline lens may be divided into a plurality of sections, and the refractive index may be obtained for each section. For example, the crystalline lens may be divided into three sections, anterior cortex, posterior cortex, and nucleus, and the refractive index may be obtained for each. This section may be obtained by, for example, image processing of a tomographic image. If the crystalline lens refractive index has a gradient inside the crystalline lens, the control unit 70 may obtain the crystalline lens refractive index of each section by defining the gradient with a function (for example, non-lens). See Patent Document 1). For example, the refractive index of each section may be obtained by substituting the crystalline lens refractive index obtained as described above into a function of the gradient.

In the above examples, the refractive index of the natural crystalline lens was measured, but the refractive index of the artificial crystalline lens (for example, IOL) may be measured in the same manner as described above. By measuring the refractive index of the IOL, it is useful for selecting a new IOL power, for example, when reinserting the IOL or when inserting a plurality of IOLs.

When an accommodation stimulus can be applied to the eye to be inspected, it is based on the amount of change in the lens curvature, the lens thickness, and the axial length before and after the adjustment of the eye to be inspected, and the uniform refractive index used to calculate the axial length. , The refractive index of the crystalline lens may be calculated. When the crystalline lens refractive index is obtained, the refractive power of the crystalline lens may be obtained from the crystalline lens curvature, the crystalline lens thickness, and the crystalline lens refractive index. In this case, for example, the control unit 70 may determine whether or not the crystalline lens is aging by moving the position of the fixation target to give an adjustment stimulus and measuring the change in the refractive power of the crystalline lens. In addition, it may be determined whether or not the eye to be inspected is sick by measuring the rate at which the refractive power of the crystalline lens changes.

The ophthalmic apparatus 1000 may measure the refractive index of the IOL when performing photo tuning. Phototuning is a technique for changing the refractive index of an IOL by irradiating an IOL inserted into an eye to be inspected with a laser, and adjusting the refractive index of the IOL according to the refractive power of the eye to be inspected after the IOL is inserted. Is. As described above, by measuring the refractive index of the IOL, it is possible to confirm how much the refractive index should be changed by photo tuning. In addition, the refractive index can be easily confirmed after photo tuning.

In the above examples, since infrared light is used for both the tomographic image capture of the OCT optical system 100 and the refractive power measurement of the refractive power measurement optical system 400, the refractive power measurement is 870 μm and the refractive power measurement is around 1000 μm. It may be divided into the wavelengths of. As a result, it is possible to suppress the generation of noise due to each other's measurement light.

In the above description, the OCT optical system 100 and the refractive power measurement optical system 400 are provided in the same device, but may be provided in different devices.

In the above description, the refractive power measurement optical system 400 that acquires a ring image due to the fundus reflected light has been described as an example, but the present invention is not limited to this. Any device may be used as long as it is a device that moves the presentation distance of the fixation index and measures the accommodation power of the eye E to be inspected by measuring the objective refractive power. For example, an optical power measuring optical system may be used in which a spot index is projected on the fundus of the eye E to be examined in order to obtain the wavefront aberration of the eye of the subject, and the reflected light of the fundus is detected by the Shackhardtman sensor.

59 Illumination light source 70 Control unit 100 OCT optical system 300 Corneal shape measurement unit 400 Refractive power measurement optical system 1000 Ophthalmic device

Claims (4)

An ophthalmic device that inspects the eye to be inspected.
A control stimulus projection means for projecting a control stimulus target onto the eye to be inspected, and a control stimulus projection means.
An intraocular distance measuring means for measuring the intraocular distance including the axial length, which is the distance from the anterior surface of the cornea to the retina of the eye to be inspected, and the thickness of the crystalline lens .
The refractive power measuring means for measuring the refractive power of the eye to be inspected,
A control means for controlling the intraocular distance measuring means and the refractive power measuring means and simultaneously measuring the axial length and the crystalline lens thickness and the refractive power under an accommodative stimulus is provided .
The control means is an ophthalmic apparatus, characterized in that the measurement results of the axial length and the crystalline lens thickness and the measurement results of the refractive power are displayed side by side on the display means . The ophthalmic apparatus according to claim 1, wherein the control means causes a display means to display the measurement results of the axial length and the crystalline lens thickness and the measurement results of the refractive power in real time . The ophthalmic apparatus according to claim 1 or 2, wherein the intraocular distance measuring means and the refractive power measuring means perform measurement with infrared light having different wavelengths from each other . It is an ophthalmologic device control program used in an ophthalmology device that inspects an eye to be inspected, and is executed by a processor of the ophthalmology device.
The regulatory stimulus projection step of projecting the regulatory stimulus target onto the eye to be inspected,
Under the accommodation stimulus by the accommodation stimulus projection step, the intraocular distance measurement for measuring the axial length, which is the distance from the anterior surface of the lens to the retina of the eye to be inspected, and the intraocular distance including the thickness of the crystalline lens, and the intraocular distance measurement of the eye to be inspected. A control step that simultaneously performs refractive power measurement to measure the refractive power,
A display step for displaying the measurement results of the axial length and the crystalline lens thickness and the measurement results of the refractive power side by side on the display means.
The ophthalmologic device control program, characterized in that the ophthalmic device is executed .

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