JP2022110602A - Ophthalmologic apparatus, ophthalmologic apparatus control method, and program - Google Patents

Abstract

To provide a novel technique for speedily and accurately identifying a depth position of a desired layer area in a subject eye.SOLUTION: An ophthalmologic apparatus comprises a layer area identifying unit and a layer area position calculation unit. The layer area identifying unit identifies a first depth position equivalent to a first layer area in an eyeground of a subject eye, on the basis of a detection result of interference light obtained by executing OCT scanning on the eyeground. The layer area position calculation unit adds a predetermined offset value to the first depth position and calculates a second depth position equivalent to a second layer area in the eyeground.SELECTED DRAWING: Figure 5

Description

The present invention relates to an ophthalmologic apparatus, an ophthalmologic apparatus control method, and a program.

The measurement of the axial length of the eye is performed not only for the purpose of selecting the power of an intraocular lens (IOL) before cataract surgery, but also for the purpose of confirming axial refractive error, measuring the shape of the eyeball, and the like.

As a device capable of measuring the axial length of the eye, an ultrasonic eye axial length measuring device that measures the axial length of the eye by contacting an ultrasonic probe to the cornea, and an optical coherence tomography that is performed on the eye to be examined There is an optical axial length measuring device that optically measures the axial length of the eye by contact.

Generally, the axial length obtained by an ultrasonic eye length measuring device is used. However, the measurement by the ultrasonic eye axial length measuring device requires a skillful procedure, and the subject's eye needs to be anesthetized with eye drops, which increases the burden on the subject.

On the other hand, the measurement by the optical axial length measuring device does not require a skillful procedure, and can be measured without contact, thereby greatly reducing the burden on the subject. However, in the case of eyes with cataracts, measurement cannot be performed, making it difficult to obtain highly reliable measurement results.

For example, Patent Document 1 discloses an ultrasonic axial length measuring means for ultrasonically measuring the axial length of the eye, and a non-contact type axial length measuring device for optically measuring the axial length in a non-contact manner. An axial length measuring device is disclosed comprising means.

For example, in Patent Document 2, the position of the corneal vertex and the position of the retinal pigment epithelium layer are specified from the intensity profile in the A-scan direction obtained by performing optical coherence tomography on the eye to be examined, and the eye axis Techniques for measuring length are disclosed.

For example, in Non-Patent Document 1, the optical path length corresponding to the axial length obtained by optical coherence tomography using near-infrared light of 780 nanometers (nm) as measurement light is A method of converting to an axial length (physical length) measured using a measuring device is disclosed.

JP 2008-161218 A Japanese Patent Publication No. 2014-500096

Ｓｕｈｅｉｍａｔ Ｍ， Ｖｅｒｋｉｃｈａｒｌａ ＰＫ， Ｍａｌｌｅｎ ＥＡＨ， Ｒｏｚｅｍａ Ｊ， Ａｔｃｈｉｓｏｎ ＤＡ， “Ｒｅｆｒａｃｔｉｖｅ ｉｎｄｉｃｅｓ ｕｓｅｄ ｂｙ ｔｈｅ Ｈａａｇ－Ｓｔｒｅｉｔ Ｌｅｎｓｔａｒ ｔｏ ｃａｌｃｕｌａｔｅ ａｘｉａｌ ｂｉｏｍｅｔｒｉｃ ｄｉｍｅｎｓｉｏｎｓ”， Ｏｐｈｔｈａｌｍｉｃ ＆ Ｐｈｙｓｉｏｌｏｇｉｃａｌ Ｏｐｔｉｃｓ ２０１５， ３５：９０－９６． doi: 10.1111/opo. 12182

The axial length is the distance from the corneal vertex to the retinal pigment epithelium (RPE) layer. However, in the intensity profile of the interference signal obtained by performing optical coherence tomography, the peak corresponding to the RPE layer was observed in layers such as the inner segment junction (IS/OS line) and the Bruch membrane. It may be buried in the peak corresponding to the area. In this case, it may take time to specify the peak corresponding to the RPE layer, fail to specify the peak corresponding to the RPE layer, or erroneously detect the peak corresponding to the RPE layer. As a result, the reliability of the measurement result of the axial length is reduced.

Therefore, it is required to specify the depth position of the desired layer region in the eye to be inspected accurately in a short time.

The present invention has been made in view of such circumstances, and one of its objects is to provide a new method for accurately specifying the depth position of a desired layer region in an eye to be inspected in a short time. It is to provide technology.

According to a first aspect of some embodiments, a first depth corresponding to a first layer region of the fundus is obtained based on a detection result of interference light obtained by performing an OCT scan on the fundus of the eye to be examined. a layer region specifying unit for specifying a depth position; and a layer region position calculating unit for calculating a second depth position corresponding to a second layer region in the fundus by adding a predetermined offset value to the first depth position. is an ophthalmic device comprising:

In a second aspect of some embodiments, according to the first aspect, the first layer region is an IS/OS line and the second layer region is a retinal pigment epithelium layer.

In a third aspect of some embodiments, in the first aspect or the second aspect, the layer region position calculator adds a different offset value according to the subject's eye to the first depth position.

In a fourth aspect of some embodiments, in the second aspect or the third aspect, the layer region specifying unit determines the first depth position and the corneal vertex corresponding to the first depth position and the corneal vertex based on the detection result of the interference light. 3 depth positions are identified. The ophthalmologic apparatus includes an axial length calculator that calculates the axial length of the subject's eye based on the third depth position and the second depth position.

According to a fifth aspect of some embodiments, in the fourth aspect, the OCT scan is performed by irradiating the subject's eye with measurement light having a first wavelength as a measurement wavelength. The ophthalmologic apparatus includes a wavelength correction unit that corrects the axial length calculated by the axial length calculation unit to the axial length at a second wavelength different from the first wavelength by performing wavelength correction on the axial length.

A sixth aspect of some embodiments is the axial length of the eye obtained by performing an OCT scan on the subject's eye using the measurement light having the first wavelength as the measurement wavelength, based on the detection result of the interference light. and performing wavelength correction on the axial length calculated by the axial length calculator to correct the axial length at a second wavelength different from the first wavelength. and a wavelength corrector.

In a seventh aspect of some embodiments, in the fifth aspect or the sixth aspect, the wavelength corrector adjusts the ratio of the refractive index of the human eye at the first wavelength to the refractive index of the human eye at the second wavelength. , the axial length calculated by the axial length calculator is multiplied to correct the axial length at the second wavelength.

In an eighth aspect of some embodiments, in any of the fifth through seventh aspects, the second wavelength is 780 nm.

According to a ninth aspect of some embodiments, in any one of the fifth to eighth aspects, the axial length of the eye corrected by the wavelength correction unit is obtained by using an ultrasonic eye axial length measuring device. Includes an axial length converter for converting to axial length.

In a tenth aspect of some embodiments, in the ninth aspect, the axial length conversion section converts the optical path length as the axial length corrected by the wavelength correction section into the ultrasonic axial length measuring device. Convert to a physical length as the eye axial length obtained using

According to an eleventh aspect of some embodiments, in any one of the first to tenth aspects, light from a light source is divided into measurement light and reference light, the eye is irradiated with the measurement light, and the It includes an OCT optical system that detects the interference light between the return light of the measurement light from the eye to be inspected and the reference light that has passed through the reference optical path.

According to a twelfth aspect of some embodiments, a first depth corresponding to a first layer region of the fundus is obtained based on detection results of interference light obtained by performing an OCT scan on the fundus of the eye to be examined. a layer region specifying step of specifying a depth position; and a layer region position calculating step of adding a predetermined offset value to the first depth position to calculate a second depth position corresponding to a second layer region in the fundus. and a control method for an ophthalmic device.

In a thirteenth aspect of some embodiments, according to the twelfth aspect, the first layer region is an IS/OS line and the second layer region is a retinal pigment epithelium layer.

According to a fourteenth aspect of some embodiments, in the twelfth aspect or the thirteenth aspect, the layer region specifying step includes a depth position corresponding to the first depth position and the corneal vertex, based on the detection result of the interference light. 3 depth positions are identified. The method for controlling an ophthalmologic apparatus includes an axial length calculation step of calculating the axial length of the subject's eye based on the third depth position and the second depth position.

In a fifteenth aspect of some embodiments, in the fourteenth aspect, the OCT scan is performed by irradiating the subject's eye with measurement light having a first wavelength as a measurement wavelength. A method for controlling an ophthalmologic apparatus includes a wavelength correction step of correcting the axial length of the eye calculated in the axial length calculation step to a second wavelength different from the first wavelength by performing wavelength correction on the axial length of the eye. including.

A sixteenth aspect of some embodiments is the axial length of the eye based on the detection result of interference light obtained by performing an OCT scan on the subject's eye using measurement light having a first wavelength as the measurement wavelength. and performing wavelength correction on the axial length calculated in the axial length calculating step to correct the axial length at a second wavelength different from the first wavelength. and a wavelength correction step.

According to a seventeenth aspect of some embodiments, in the fifteenth aspect or sixteenth aspect, the axial length corrected in the wavelength correcting step is adjusted to the axial length obtained using an ultrasonic axial length measuring device. It includes an eye axial length conversion step for conversion.

An eighteenth aspect of some embodiments is a program that causes a computer to execute each step of the ophthalmologic apparatus control method according to any one of the twelfth to seventeenth aspects.

In addition, it is possible to arbitrarily combine the configurations according to the plurality of claims described above.

ADVANTAGE OF THE INVENTION According to this invention, the new technique for pinpointing the depth position of the desired layer area|region in a to-be-tested eye correctly in a short time can be provided now.

1 is a schematic diagram showing a configuration example of an optical system of an ophthalmologic apparatus according to an embodiment; FIG. 1 is a schematic diagram showing a configuration example of an optical system of an ophthalmologic apparatus according to an embodiment; FIG. 1 is a schematic diagram showing a configuration example of a processing system of an ophthalmologic apparatus according to an embodiment; FIG. 1 is a schematic diagram showing a configuration example of a processing system of an ophthalmologic apparatus according to an embodiment; FIG. 1 is a schematic diagram showing a configuration example of a processing system of an ophthalmologic apparatus according to an embodiment; FIG. It is a schematic diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. It is a schematic diagram for explaining the operation of the ophthalmologic apparatus according to the embodiment. 4 is a schematic diagram showing a flow of an operation example of the ophthalmologic apparatus according to the embodiment; FIG.

Embodiments of an ophthalmologic apparatus, an ophthalmologic apparatus control method, and a program according to the present invention will be described in detail with reference to the drawings. It should be noted that the descriptions of the documents cited in this specification and any known techniques can be incorporated into the following embodiments.

The ophthalmologic apparatus according to the embodiment identifies the depth position corresponding to the first layer region in the fundus based on the detection result of the interference light obtained by executing the OCT scan of the eye to be examined, and A predetermined offset value is added to the obtained depth position to calculate the depth position corresponding to the second layer region in the fundus. For example, the first layer region is the IS/OS line and the second layer region is the RPE layer.

This makes it possible to accurately specify the representative position on the fundus (retinal) side in a short time without failing to specify the representative position on the fundus (retinal) side. As a result, it is possible to improve the measurement accuracy of the intraocular distance (for example, axial length) of the eye to be examined, which is specified using the representative position on the fundus side.

Further, the ophthalmologic apparatus according to the embodiment performs wavelength correction for an intraocular distance such as an axial length obtained based on the detection result of interference light obtained by performing an OCT scan on the eye to be examined. Alternatively, it can be converted using wavelength correction and a predetermined conversion formula. As a result, the measurement results of other axial length measurement devices that can measure the axial length of the eye using measurement light of different wavelengths, and the measurement results of the ultrasonic type axial length measurement device can be compared with high accuracy. become.

A control method for an ophthalmic apparatus according to an embodiment is a method for controlling an ophthalmic apparatus according to an embodiment. A program according to an embodiment causes a processor (computer) to execute each step of a method for controlling an ophthalmologic apparatus. A recording medium according to the embodiment is a computer-readable non-temporary recording medium (storage medium) in which the program according to the embodiment is recorded.

As used herein, the term "processor" includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (e.g., SPLD (Simple Programmable Logic Device (CPLD) Programmable Logic Device), FPGA (Field Programmable Gate Array)) or the like. The processor implements the functions according to the embodiment by, for example, reading and executing a program stored in a storage circuit or storage device.

A case where the ophthalmologic apparatus according to the embodiment includes a measurement optical system including an OCT optical system that performs OCT on an eye to be examined will be described below, but the configuration of the ophthalmologic apparatus according to the embodiment is limited to this. is not. For example, the ophthalmologic apparatus according to the embodiment may be configured to acquire the detection result of interference light from an external OCT apparatus.

The ophthalmic device according to some embodiments includes at least one of a fundus camera, a scanning laser ophthalmoscope, a slit lamp microscope, and a surgical microscope, as well as the functionality of an OCT device for performing OCT. Furthermore, the ophthalmic apparatus according to some embodiments has the capability to measure optical properties of the subject's eye. Ophthalmologic devices with a function of measuring optical characteristics of an eye to be examined include tonometers, wavefront analyzers, specular microscopes, perimeters, and the like. The ophthalmic device according to some embodiments has the functionality of a laser therapy device used for laser therapy.

In the following embodiments, a case where a spectral domain type OCT method is used in measurement using OCT will be described in detail. However, it is also possible to apply the configuration according to the embodiment to an ophthalmic apparatus that uses other types of OCT (for example, swept source type).

<Configuration of optical system>
1 and 2 show configuration examples of an optical system of an ophthalmologic apparatus according to an embodiment. FIG. 1 shows a configuration example of the entire optical system of an ophthalmologic apparatus 1000 according to an embodiment. FIG. 2 shows a configuration example of the optical system of the OCT unit 100 of FIG.

An ophthalmologic apparatus 1000 according to an embodiment includes an optical system for observing an eye to be examined E, an optical system for examining the eye to be examined E, and a dichroic mirror for wavelength-separating the optical paths of these optical systems. An anterior segment observation system 5 is provided as an optical system for observing the eye E to be examined. An OCT optical system and a reflector measurement optical system (refractive power measurement optical system) are provided as an optical system for examining the eye E to be examined.

The ophthalmologic apparatus 1000 includes an alignment system 1 , a keratometry system 3 , a fixation projection system 4 , an anterior segment observation system 5 , a reflector measurement projection system 6 , a reflector measurement light receiving system 7 , and an OCT optical system 8 . In the following, for example, the anterior segment observation system 5 uses light of 940 nm to 1000 nm, the reflector measurement optical system (reflection measurement projection system 6, reflection measurement light receiving system 7) uses light of 850 nm to 880 nm, and the fixation projection system 4 uses light of 400 nm to 700 nm. It is also assumed that the OCT optical system 8 uses light of 840 nm. That is, the OCT optical system 8 performs OCT measurement (OCT scan) with a measurement wavelength of 840 nm.

(Alignment system 1)
The alignment system 1 is used for Z alignment and XY alignment of the optical system with respect to the eye E to be examined. The Z alignment is alignment in the Z direction (back and forth direction, working distance direction) parallel to the optical axis of the anterior segment observation system 5 (for example, the objective lens 51). XY alignment is alignment in directions perpendicular to the optical axis (horizontal direction (X direction) and vertical direction (Y direction)).

The alignment system 1 includes two or more anterior segment cameras 14 . The two or more anterior segment cameras 14 capture the anterior segment of the subject's eye E substantially simultaneously from different directions, and send the acquired two or more captured images (anterior segment images) to the processing unit 9, which will be described later. Output. The processing unit 9 analyzes two or more captured images from the two or more anterior eye cameras 14 to identify the three-dimensional position of the eye E to be examined (specifically, the characteristic part of the eye E to be examined), and identifies the identified three-dimensional position. Alignment of the optical system in the XY and Z directions with respect to the subject's eye E (characteristic site) is performed based on the three-dimensional position obtained.

Below, the alignment system 1 is assumed to include two anterior eye cameras 14 . However, the alignment system 1 may include three or more anterior eye cameras 14 . Also, one function of the two anterior eye cameras 14 may be realized by an imaging element 59 provided in the anterior eye observation system 5, which will be described later.

(Anterior segment observation system 5)
The anterior segment observation system 5 captures a moving image of the anterior segment of the eye E to be examined. In the optical system passing through the anterior segment observation system 5, the imaging plane of the imaging element 59 is arranged at a pupil conjugate position (a position substantially optically conjugate with the pupil of the subject's eye E). The anterior segment illumination light source 50 irradiates the anterior segment of the eye E to be examined with illumination light (for example, infrared light). The light reflected by the anterior segment of the subject's eye E passes through an objective lens 51, passes through a dichroic mirror 52, passes through a hole formed in a diaphragm (telecentric diaphragm) 53, and passes through relay lenses 55 and 56. passes through the dichroic mirror 76 . The dichroic mirror 52 synthesizes (separates) the optical path of the reflex measurement optical system and the optical path of the anterior eye observation system 5 . The dichroic mirror 52 is arranged such that the optical path synthesizing surface for synthesizing these optical paths is inclined with respect to the optical axis of the objective lens 51 . The light transmitted through the dichroic mirror 76 is imaged on the imaging surface of the imaging element 59 (area sensor) by the imaging lens 58 . The imaging element 59 performs imaging and signal output at a predetermined rate. The output (video signal) of the imaging device 59 is input to the processing section 9 which will be described later. The processing unit 9 displays an anterior segment image E' based on this video signal on a display screen 10a of the display unit 10, which will be described later. The anterior segment image E' is, for example, an infrared moving image.

(Kerato measurement system 3)
The keratometry system 3 projects a ring-shaped light beam (infrared light) for measuring the shape of the cornea Cr of the eye E to be examined onto the cornea Cr. The keratoplate 31 is arranged between the objective lens 51 and the eye E to be examined. A kerato ring light source 32 is provided on the back side of the kerato plate 31 (on the objective lens 51 side). The keratoplate 31 has a keratopattern (transmissive portion) formed along a circumference centered on the optical axis of the objective lens 51 to transmit the light from the keratometry light source 32 . Note that the keratopattern may be formed in an arc shape (part of the circumference) centering on the optical axis of the objective lens 51 . By illuminating the kerat plate 31 with light from the keratizing light source 32, a ring-shaped light flux (arc-shaped or circumferential measurement pattern) is projected onto the cornea Cr of the eye E to be examined. Reflected light (keratling image) from the cornea Cr of the subject's eye E is detected by the imaging element 59 together with the anterior segment image E'. The processing unit 9 calculates corneal shape parameters representing the shape of the cornea Cr by performing known calculations based on this keratling image.

(ref measurement projection system 6, ref measurement light receiving system 7)
The ref measurement optical system includes a ref measurement projection system 6 and a ref measurement light receiving system 7 used for refractive power measurement. The ref measurement projection system 6 projects a refractive power measurement light beam (for example, a ring-shaped light beam) (infrared light) onto the fundus oculi Ef. The ref measurement light-receiving system 7 receives the return light from the subject's eye E of this luminous flux. The reflector measurement projection system 6 is provided on an optical path branched by a perforated prism 65 provided in the optical path of the reflector measurement light receiving system 7 . The aperture formed in the apertured prism 65 is arranged at the pupil conjugate position. In the optical system passing through the reflex measurement light-receiving system 7, the imaging surface of the imaging element 59 is arranged at a fundus conjugate position (a position substantially optically conjugate with the fundus Ef of the subject's eye E).

In some embodiments, the ref measurement light source 61 is an SLD (Superluminescent Diode) light source, which is a high luminance light source. The ref measurement light source 61 is movable in the optical axis direction. A reflex measurement light source 61 is arranged at a fundus conjugate position. The light output from the ref measurement light source 61 passes through the relay lens 62 and enters the conical surface of the conical prism 63 . Light incident on the conical surface is deflected and emitted from the bottom surface of the conical prism 63 . Light emitted from the bottom surface of the conical prism 63 passes through a ring-shaped transparent portion of the ring aperture 64 . The light (ring-shaped luminous flux) that has passed through the transparent portion of the ring diaphragm 64 is reflected by the reflecting surface formed around the hole of the apertured prism 65, passes through the rotary prism 66, and is reflected by the dichroic mirror 67. be. The light reflected by the dichroic mirror 67 is reflected by the dichroic mirror 52, passes through the objective lens 51, and is projected onto the eye E to be examined. The rotary prism 66 is used for averaging the light quantity distribution of the ring-shaped light flux for blood vessels and diseased areas of the fundus oculi Ef and for reducing speckle noise caused by the light source.

The return light of the ring-shaped luminous flux projected onto the fundus oculi Ef passes through the objective lens 51 and is reflected by the dichroic mirrors 52 and 67 . The return light reflected by the dichroic mirror 67 passes through the rotary prism 66, passes through the aperture of the perforated prism 65, passes through the relay lens 71, is reflected by the reflecting mirror 72, and passes through the relay lens 73 and the focusing lens. Pass 74. The focusing lens 74 is movable along the optical axis of the ref measurement light receiving system 7 . The light that has passed through the focusing lens 74 is reflected by the reflecting mirror 75 , reflected by the dichroic mirror 76 , and imaged on the imaging surface of the imaging element 59 by the imaging lens 58 . The processing unit 9 calculates the refractive power value of the subject's eye E by performing a known calculation based on the output from the imaging device 59 . For example, power values include spherical power, cylinder power and cylinder axis angle, or equivalent spherical power.

(Fixation projection system 4)
An OCT optical system 8, which will be described later, is provided in an optical path separated by a dichroic mirror 67 from the optical path of the reflective measurement optical system. A fixation projection system 4 is provided on an optical path branched from the optical path of the OCT optical system 8 by a dichroic mirror 83 .

A fixation projection system 4 presents a fixation target to the eye E to be examined. A fixation unit 40 is arranged in the optical path of the fixation projection system 4 . The fixation unit 40 can move along the optical path of the fixation projection system 4 under the control of the processing section 9 which will be described later. The fixation unit 40 includes a liquid crystal panel 41 . A relay lens 42 is arranged between the dichroic mirror 83 and the fixation unit 40 .

The liquid crystal panel 41 controlled by the processing unit 9 displays a pattern representing the fixation target. By changing the display position of the pattern on the screen of the liquid crystal panel 41, the fixation position of the subject's eye E can be changed. The fixation position of the subject's eye E includes a position for acquiring an image centered on the macula of the fundus oculi Ef, a position for acquiring an image centered on the optic papilla, and a position between the macula and the optic papilla. There is a position for acquiring an image centered on the center of the fundus in between. It is possible to arbitrarily change the display position of the pattern representing the fixation target.

Light from the liquid crystal panel 41 passes through the relay lens 42 , dichroic mirror 83 , relay lens 82 , reflection mirror 81 , dichroic mirror 67 , and dichroic mirror 52 . . The light reflected by the dichroic mirror 52 passes through the objective lens 51 and is projected onto the fundus oculi Ef. In some embodiments, each of the liquid crystal panel 41 and the relay lens 42 is independently movable in the optical axis direction.

(OCT optical system 8)
The OCT optical system 8 is an optical system for performing OCT measurement. The position of the focusing lens 87 is adjusted so that the end surface of the optical fiber f1 is conjugated to the OCT measurement site and the optical system based on the result of the reflector measurement performed prior to the OCT measurement. The OCT measurement site may be any site of the subject's eye E, such as the fundus oculi Ef or the anterior segment of the eye.

The OCT optical system 8 is provided in an optical path separated by a dichroic mirror 67 from the optical path of the ref measurement optical system. The optical path of the fixation projection system 4 is coupled to the optical path of the OCT optical system 8 by a dichroic mirror 83 . Thereby, the respective optical axes of the OCT optical system 8 and the fixation projection system 4 can be coaxially coupled.

OCT optical system 8 includes an OCT unit 100 . As shown in FIG. 2, the OCT unit 100 is provided with an optical system for performing OCT measurement (OCT imaging, OCT scanning) on the eye E to be examined. This optical system has a configuration similar to that of a conventional spectral domain type OCT apparatus. That is, this optical system splits the light (low coherence light) from the broadband light source into the reference light and the measurement light, and divides the measurement light through the eye E (OCT measurement site) and the reference light through the reference optical path. to generate interference light and to detect spectral components of the interference light. This detection result (detection signal) is sent to the processing unit 9 .

The light source unit 101 outputs broadband low-coherence light L0. The low-coherence light L0 has, for example, a wavelength component in the near-infrared wavelength band (approximately 800 nm to 900 nm), and has a temporal coherence length of approximately several tens of micrometers. Further, near-infrared light having a wavelength band invisible to the human eye, for example, a center wavelength of about 1040 to 1060 nm may be used as the low coherence light L0.

Hereinafter, it is assumed that the light source unit 101 outputs low coherence light L0 having a wavelength component of 840 nm.

The light source unit 101 includes a light output device such as a Super Luminescent Diode (SLD), an LED, or an SOA (Semiconductor Optical Amplifier).

A low-coherence light L0 output from the light source unit 101 is guided by the optical fiber 102 to the fiber coupler 103 and split into the measurement light LS and the reference light LR.

The reference light LR is guided by an optical fiber 104 and reaches an attenuator (optical attenuator) 105 . The attenuator 105 automatically adjusts the light amount of the reference light LR guided by the optical fiber 104 under the control of the processing unit 9 using a known technique. The reference light LR whose light amount has been adjusted by the attenuator 105 is guided by the optical fiber 104 and reaches the polarization controller (polarization adjuster) 106 . The polarization controller 106 is, for example, a device that adjusts the polarization state of the reference light LR guided through the optical fiber 104 by applying external stress to the looped optical fiber 104 . Note that the configuration of the polarization controller 106 is not limited to this, and any known technique can be used. The reference light LR whose polarization state has been adjusted by the polarization controller 106 reaches the fiber coupler 109 .

The measurement light LS generated by the fiber coupler 103 is guided to the collimator lens 90 (FIG. 1) by the optical fiber f1, and made into a parallel beam by the collimator lens 90. FIG. Furthermore, the measurement light LS reaches the dichroic mirror 83 via the optical path length changing section 89 , the optical scanner 88 , the focusing lens 87 , the relay lens 85 and the reflecting mirror 84 .

In some embodiments, the focusing lens 87 and the optical scanner 88 are housed in one unit that is movable along the optical axis. This allows the focusing lens 87 and the optical scanner 88 to move in the optical axis direction while maintaining the optical positional relationship. By configuring the focusing lens 87 and the optical scanner 88 to be integrally movable in this manner, it is possible to adjust the optical system while maintaining the conjugate relationship between the optical scanner 88 and the eye E to be examined. Moreover, in the case of this configuration, by changing the focal length f of the focusing lens 87, the magnification relationship between the pupil of the subject's eye E and the optical scanner 88 can be easily changed.

In some embodiments, the focusing lens 87 and the optical scanner 88 are independently moved along the optical axis within the unit. In some embodiments, the focusing lens 87 and the optical scanner 88 are independently or jointly moved along the optical axis under the control of the processor 9 . For example, the pupil of the subject's eye E is arranged at the focal position of the objective lens 51, and the deflection surface of the optical scanner 88 is arranged at the focal position of the focusing lens 87 (the optical scanner 88 is arranged at the focal position of the focusing lens 87). If so, the pupillary conjugate relationship is preserved and the deflection plane of the light scanner 88 is positioned at the pupillary conjugate position).

The optical path length changer 89 changes the optical path length of the measurement light LS. By changing the optical path length of the measurement light LS, it is possible to change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS. For example, the optical path length changing unit 89 includes a retroreflector that is movable along the optical path of the measurement light LS and the optical path of the return light of the measurement light LS. to change

The light scanner 88 deflects the measurement light LS one-dimensionally or two-dimensionally.

In some embodiments, optical scanner 88 includes a first galvanometer mirror and a second galvanometer mirror. The first galvanomirror deflects the measurement light LS so as to scan the OCT measurement site in the horizontal direction perpendicular to the optical axis of the OCT optical system 8 . The second galvanomirror deflects the measurement light LS deflected by the first galvanomirror so as to scan the imaging region in the vertical direction perpendicular to the optical axis of the OCT optical system 8 . Scanning modes of the measurement light LS by the light scanner 88 include, for example, horizontal scanning, vertical scanning, cross scanning, radial scanning, circular scanning, concentric scanning, and spiral scanning.

In some embodiments, the light scanner 88 includes a MEMS scanner (MEMS mirror scanner) that two-dimensionally deflects the measurement light LS. The MEMS scanner deflects the measurement light LS so as to scan the OCT measurement site in horizontal and vertical directions orthogonal to the optical axis of the OCT optical system 8 .

The optical scanner 88 may include a polygon mirror, a rotating mirror, a dowel prism, a double dowel prism, a rotation prism, etc., in addition to the galvanomirror and the MEMS scanner.

The measurement light LS reaching the dichroic mirror 83 is reflected by the dichroic mirror 83 , passes through the relay lens 82 , and is reflected by the reflecting mirror 81 . The measurement light LS reflected by the reflecting mirror 81 is reflected by the dichroic mirror 52, refracted by the objective lens 51, and irradiated to the OCT measurement site. The measurement light LS is scattered (including reflected) at various depth positions of the OCT measurement site. The backscattered light of the measurement light LS from the OCT measurement site travels in the opposite direction along the same path as the forward path, is guided to the fiber coupler 103 , and reaches the fiber coupler 109 via the optical fiber 108 .

The fiber coupler 109 causes interference between the backscattered light of the measurement light LS and the reference light LR that has passed through the attenuator 105 or the like. The interference light LC thus generated is guided by the optical fiber 110 and emitted from the emission end 111 . Further, the interference light LC is converted into a parallel beam by a collimator lens 112, dispersed (spectrally resolved) by a diffraction grating (spectroscope) 113, condensed by a zoom optical system 114, and projected onto a light receiving surface of a CCD image sensor 115. be. Although the diffraction grating 113 shown in FIG. 2 is of a transmissive type, it is also possible to use other types of spectral elements such as a reflective diffraction grating.

The CCD image sensor 115 is, for example, a line sensor, in which two or more light receiving elements (detection elements) are arranged, detects each spectral component of the dispersed interference light LC, and converts it into an electric charge. The CCD image sensor 115 accumulates this charge to generate a detection signal and sends it to the processing section 9 .

Although a Michelson-type interferometer is employed in this embodiment, any type of interferometer, such as a Mach-Zehnder interferometer, can be employed as appropriate. Also, instead of the CCD image sensor, it is possible to use another type of image sensor, such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

Further, in the configuration shown in FIG. 1, the optical path length of the measurement light LS is changed by the optical path length changing section 89, thereby changing the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR. However, the configuration according to the embodiment is not limited to this. For example, by changing the optical path length of the reference light LR by a known technique, the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR may be changed.

The processing unit 9 calculates a refractive power value from the measurement result obtained using the reflector measurement optical system, and based on the calculated refractive power value, the fundus oculi Ef, the reflector measurement light source 61, and the image sensor 59 are conjugated. The ref measurement light source 61 and the focusing lens 74 are moved in the optical axis direction to the respective positions. In some embodiments, the processing unit 9 moves the focusing lens 87 and the optical scanner 88 along their optical axes in conjunction with the movement of the focusing lens 74 . In some embodiments, the processing section 9 moves the liquid crystal panel 41 (fixation unit 40) along its optical axis in conjunction with the movement of the ref measurement light source 61 and the focusing lens 74. FIG.

In the above embodiments, at least one function of the focusing lenses 74, 87 may be realized by liquid crystal or liquid lenses.

<Configuration of processing system>
The configuration of the processing system of the ophthalmologic apparatus 1000 will be described. Examples of the functional configuration of the processing system of the ophthalmologic apparatus 1000 are shown in FIGS. 3 to 5. FIG. FIG. 3 shows an example of a functional block diagram of the processing system of the ophthalmologic apparatus 1000. As shown in FIG. FIG. 4 shows an example of a functional block diagram of the OCT optical system 8 of FIG. FIG. 5 represents an example of a functional block diagram of the data processing unit 250 of FIG.

The processing unit 9 controls each unit of the ophthalmologic apparatus 1000 . In addition, the processing unit 9 can execute various arithmetic processing. The processing unit 9 includes a processor. The processing unit 9 implements the functions according to the embodiment by, for example, reading and executing a program stored in a storage circuit or storage device.

Processing unit 9 includes control unit 210 and arithmetic processing unit 220 . The ophthalmologic apparatus 1000 also includes moving mechanisms 40D, 74D, 87D, and 200, a display section 270, an operation section 280, and a communication section 290.

The moving mechanism 200 is a mechanism for moving the head unit containing the optical system in the X, Y and Z directions. For example, the moving mechanism 200 is provided with an actuator that generates driving force for moving the head section and a transmission mechanism that transmits this driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. The control unit 210 (main control unit 211) controls the movement mechanism 200 by sending control signals to the actuators.

The moving mechanism 40D is a mechanism for moving the fixation unit 40 in the optical axis direction of the fixation projection system 4 (the optical axis direction of the objective lens 51). For example, similar to the movement mechanism 200, the movement mechanism 40D is provided with an actuator that generates driving force for moving the fixation unit 40 and a transmission mechanism that transmits this driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. The control unit 210 (main control unit 211) controls the moving mechanism 40D by sending a control signal to the actuator.

The moving mechanism 74D is a mechanism for moving the focusing lens 74 in the optical axis direction of the ref measurement light-receiving system 7. As shown in FIG. For example, similar to the moving mechanism 200, the moving mechanism 74D is provided with an actuator that generates driving force for moving the focusing lens 74 and a transmission mechanism that transmits this driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. The controller 210 (main controller 211) controls the moving mechanism 74D by sending a control signal to the actuator.

The moving mechanism 87D is a mechanism for moving the focusing lens 87 in the optical axis direction of the OCT optical system 8 (the optical axis direction of the objective lens 51). For example, similarly to the moving mechanism 200, the moving mechanism 87D is provided with an actuator that generates driving force for moving the focusing lens 87 and a transmission mechanism that transmits this driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. The controller 210 (main controller 211) controls the moving mechanism 87D by sending a control signal to the actuator.

In some embodiments, the control of the moving mechanism 87D includes movement control of the focusing lens 87 in the optical axis direction, movement control of the focusing lens 87 to the focus reference position corresponding to the imaging region, There is movement control within the corresponding movement range (focusing range). For example, the main controller 211 controls the moving mechanism 87D by sending a control signal to the actuator to move the focusing lens 87 in the optical axis direction.

(control unit 210)
The control unit 210 includes a processor and controls each unit of the ophthalmologic apparatus. Control unit 210 includes a main control unit 211 and a storage unit 212 . A computer program for controlling the ophthalmologic apparatus 1000 is stored in advance in the storage unit 212 . The computer programs include an alignment system control program, a keratosystem control program, a fixation system control program, an anterior ocular segment observation system control program, a ref measurement projection system control program, a ref measurement light receiving system control program, and OCT. It includes an optical system control program, an arithmetic processing program, a user interface program, and the like. The main control unit 211 operates according to such a computer program, so that the control unit 210 executes control processing.

A main control unit 211 performs various controls of the ophthalmologic apparatus as a measurement control unit.

Control of the alignment system 1 includes control of the anterior eye camera 14 and the like.

Control of the anterior eye cameras 14 includes exposure adjustment, gain adjustment, and detection rate adjustment of each anterior eye camera, and synchronous control of photographing by the two anterior eye cameras 14 . In some embodiments, the two anterior cameras 14 are controlled such that the exposure conditions, gains, and detection rates of the two anterior cameras are substantially identical.

Control of the keratometry system 3 includes control of the keratometry light source 32 and the like.

The control of the keratling light source 32 includes turning on/off the light source, adjusting the amount of light, and adjusting the aperture. Thereby, lighting and non-lighting of the keratling light source 32 are switched, or the amount of light is changed. The main control unit 211 causes the arithmetic processing unit 220 to perform a known arithmetic operation on the keratling image detected by the imaging device 59 . Thereby, the corneal shape parameter of the eye E to be examined is obtained.

The control of the fixation projection system 4 includes control of the liquid crystal panel 41, movement control of the fixation unit 40, and the like.

The control of the liquid crystal panel 41 includes turning on/off the display of the fixation target, switching the fixation target according to the type of examination or measurement, and switching the display position of the fixation target. The main control unit 211 controls the moving mechanism 40D by sending a control signal to the actuator, and moves at least the liquid crystal panel 41 in the optical axis direction. Thereby, the position of the liquid crystal panel 41 is adjusted so that the liquid crystal panel 41 and the fundus oculi Ef are optically conjugated.

The control of the anterior segment observation system 5 includes control of the anterior segment illumination light source 50, control of the imaging element 59, and the like.

The control of the anterior ocular segment illumination light source 50 includes turning on/off the light source, light amount adjustment, aperture adjustment, and the like. As a result, the lighting and non-lighting of the anterior segment illumination light source 50 is switched, or the amount of light is changed. Control of the imaging element 59 includes exposure adjustment, gain adjustment, detection rate adjustment, and the like of the imaging element 59 . The main control unit 211 captures the signals detected by the imaging device 59 and causes the arithmetic processing unit 220 to execute processing such as formation of an image based on the captured signals.

The control of the ref measurement projection system 6 includes control of the ref measurement light source 61, control of the rotary prism 66, and the like.

The control of the ref measurement light source 61 includes turning on and off the light source, adjusting the amount of light, adjusting the aperture, and the like. As a result, lighting and non-lighting of the ref measurement light source 61 are switched, or the amount of light is changed. For example, the reflector measurement projection system 6 includes a moving mechanism that moves the reflector measurement light source 61 in the optical axis direction. Similar to the moving mechanism 200, this moving mechanism is provided with an actuator that generates a driving force for moving the moving mechanism and a transmission mechanism that transmits this driving force. The main control unit 211 controls the movement mechanism by sending a control signal to the actuator to move the ref measurement light source 61 in the optical axis direction. The control of the rotary prism 66 includes rotation control of the rotary prism 66 and the like. For example, a rotating mechanism for rotating the rotary prism 66 is provided, and the main controller 211 rotates the rotary prism 66 by controlling this rotating mechanism.

For the control of the refractometer light receiving system 7, the refractometer light source 61 and the focusing lens are controlled according to the refractive power of the subject's eye E, for example, so that the refractometer light source 61, the fundus Ef, and the imaging device 59 are optically conjugated. 74 are included in the control to move in the direction of the optical axis. In this case, the main control unit 211 controls the movement mechanism 74D and the like according to the refractive power of the eye E to be examined, so that the ref measurement light source 61, the fundus oculi Ef, and the imaging element 59 are arranged at optically substantially conjugate positions. Let

Control of the OCT optical system 8 includes control of the optical scanner 88, control of the optical path length changing section 89, control of the OCT unit 100, and the like. Control of the OCT unit 100 includes control of the light source unit 101, control of the attenuator 105, control of the polarization controller 106, control of the zoom optical system 114, control of the CCD image sensor 115, and the like.

The control of the optical scanner 88 includes the setting of a scan mode for scanning the measurement site with a predetermined scan pattern, the control of the scan range, the control of the scan speed, and the like. By controlling the scan range (scan start position and scan end position), it is possible to control the angular range of the deflection surface that deflects the measurement light LS. By controlling the scanning speed, it is possible to control the change speed of the deflection surface angle. The main controller 211 controls at least one of the scan mode, scan range, and scan speed by outputting control signals to the optical scanner 88 .

The control of the optical path length changing unit 89 includes control of the optical path length of the measurement light LS. The optical path length of the light LS is changed.

The control of the light source unit 101 includes turning on and off the light source, adjusting the amount of light, adjusting the aperture, and the like. Control of the attenuator 105 includes adjustment of the light amount of the reference light LR. Control by the polarization controller 106 includes adjustment of the polarization state of the reference light LR. Control of the zoom optical system 114 includes control of optical magnification. Control of the CCD image sensor 115 includes exposure adjustment, gain adjustment, and detection rate adjustment of the CCD image sensor 115 . The main control unit 211 captures the signal detected by the image sensor 115 and causes the arithmetic processing unit 220 to execute processing such as formation of an image based on the captured signal.

The main control unit 211 also performs processing of writing data to the storage unit 212 and processing of reading data from the storage unit 212 .

(storage unit 212)
The storage unit 212 stores various data. The data stored in the storage unit 212 includes, for example, objective measurement results (OCT measurement results), image data of OCT images, image data of anterior segment images, results of subjective examinations, and eye information to be examined. The eye information to be examined includes information about the subject such as patient ID and name, and information about the eye to be examined such as left/right eye identification information. The storage unit 212 also stores various programs and data for operating the ophthalmologic apparatus.

(Arithmetic processing unit 220)
The arithmetic processing unit 220 includes a processor and executes various kinds of arithmetic processing. A storage unit (for example, the storage unit 212) (not shown) stores in advance a computer program for executing various kinds of arithmetic processing. The processor realizes the function of each part that executes various arithmetic processes by operating according to this computer program.

As shown in FIG. 3 , arithmetic processing section 220 includes eye refractive power calculation section 230 , image forming section 240 , and data processing section 250 . The eye refractive power calculator 230 calculates the eye refractive power of the eye E to be examined. The image forming unit 240 forms an OCT image based on the detection result of the interference light LC obtained using the OCT optical system 8 . The data processing unit 250 performs various data processing (image processing) and analysis processing.

(Eye refractive power calculator 230)
The eye refractive power calculator 230 calculates a ring image (pattern image ). For example, the eye refractive power calculation unit 230 obtains the barycentric position of the ring image from the luminance distribution in the obtained image in which the ring image is rendered, and obtains the luminance distribution along a plurality of scanning directions radially extending from this barycentric position. , the ring image is specified from this luminance distribution. Subsequently, the eye refractive power calculator 230 obtains an approximated ellipse of the specified ring image, and obtains the spherical power, the cylindrical power, and the cylindrical axis angle by substituting the major axis and minor axis of the approximate ellipse into a known formula. . Alternatively, the eye refractive power calculator 230 can obtain parameters of the eye refractive power based on deformation and displacement of the ring image with respect to the reference pattern.

The eye refractive power calculator 230 also calculates the corneal refractive power, the corneal astigmatism degree, and the corneal astigmatism axis angle based on the keratling image acquired by the anterior eye observation system 5 . For example, the eye refractive power calculator 230 calculates the corneal curvature radii of the strong and weak principal meridians of the corneal front surface by analyzing the keratling image, and calculates the above parameters based on the corneal curvature radii.

(Image forming section 240)
The image forming unit 240 forms image data of an OCT image of the subject's eye E based on the detection signal of the interference light LC obtained by the CCD image sensor 115 . That is, the image forming unit 240 forms image data of the subject's eye E based on the detection result of the interference light LC by the interference optical system. This processing includes processing such as filter processing and FFT (Fast Fourier Transform), as in conventional spectral domain type OCT. The image data acquired in this manner is a data set containing a group of image data formed by imaging reflection intensity profiles in a plurality of A-lines (paths of each measuring light LS in the eye E to be examined). be.

To improve image quality, multiple data sets collected by scanning the same pattern multiple times can be superimposed (averaged).

(Data processing unit 250)
The data processing unit 250 performs various data processing (image processing) and analysis processing on the OCT image formed by the image forming unit 240 or the detection signal of the interference light LC obtained by the CCD image sensor 115 . For example, the data processing unit 250 executes correction processing such as luminance correction and dispersion correction of an image. Further, the data processing unit 250 performs various image processing and analysis processing on the image (anterior segment image, etc.) obtained using the anterior segment observation system 5 .

The data processing unit 250 executes known image processing such as interpolation processing for interpolating pixels between the OCT images (tomographic images) formed by the image forming unit 240 to form a three-dimensional image of the fundus oculi Ef or the anterior segment. image data can be formed. Note that image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. Image data of a three-dimensional image includes image data composed of voxels arranged three-dimensionally. This image data is called volume data or voxel data. When displaying an image based on volume data, the data processing unit 250 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection: maximum intensity projection), etc.) on this volume data so that it can be viewed from a specific line-of-sight direction. Image data of a pseudo three-dimensional image is formed. This pseudo three-dimensional image is displayed on a display device such as the display unit 270 .

Stack data of a plurality of tomographic images can also be formed as image data of a three-dimensional image. Stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scan lines based on the positional relationship of the scan lines. That is, the stack data is image data obtained by expressing a plurality of tomographic images, which were originally defined by individual two-dimensional coordinate systems, by one three-dimensional coordinate system (that is, embedding them in one three-dimensional space). be.

The data processing unit 250 performs various renderings on the acquired three-dimensional data set (volume data, stack data, etc.) to obtain a B-mode image (longitudinal cross-sectional image, axial cross-sectional image) at an arbitrary cross section, C-mode images (cross-sectional images, horizontal cross-sectional images), projection images, shadowgrams, etc. can be formed. An arbitrary cross-sectional image, such as a B-mode image or a C-mode image, is formed by selecting pixels (pixels, voxels) on a specified cross-section from a three-dimensional data set. A projection image is formed by projecting a three-dimensional data set in a predetermined direction (Z direction, depth direction, axial direction). A shadowgram is formed by projecting a portion of the three-dimensional data set (for example, partial data corresponding to a specific layer) in a predetermined direction. An image such as a C-mode image, a projection image, or a shadowgram whose viewpoint is the front side of the subject's eye is called an en-face image.

The data processing unit 250 generates a B-mode image or a front image (vessel-enhanced image, angiogram) in which retinal vessels and choroidal vessels are emphasized based on data (for example, B-scan image data) collected in time series by OCT scanning. ) can be constructed. For example, time-series OCT data can be collected by repeatedly scanning substantially the same portion of the eye E to be examined.

In some embodiments, the data processing unit 250 compares time-series B-scan images obtained by B-scans of substantially the same site, and converts the pixel values of the portions where the signal intensity changes to the pixel values corresponding to the changes. An enhanced image in which the changed portion is emphasized is constructed by the conversion. Furthermore, the data processing unit 250 extracts information for a predetermined thickness at a desired site from the constructed multiple enhanced images and constructs an en-face image to form an OCTA image.

Images generated by the data processing unit 250 (eg, three-dimensional images, B-mode images, C-mode images, projection images, shadowgrams, OCTA images) are also included in OCT images.

Further, the data processing unit 250 identifies the characteristic position corresponding to the characteristic region of the anterior segment by analyzing each of the two captured images obtained substantially simultaneously by the two anterior segment cameras 14 . The characteristic site of the anterior segment is, for example, the center of the pupil (the center of gravity of the pupil). The data processing unit 250 applies a known trigonometric method to the positions of the two anterior eye cameras 14 and the feature positions corresponding to the feature sites in the two specified captured images, thereby obtaining three images of the feature sites. A dimensional position (that is, a three-dimensional position of the subject's eye E) is calculated. The calculated three-dimensional position can be used for alignment of the optical system with respect to the eye E to be examined.

Furthermore, the ophthalmologic apparatus 1000 can measure the intraocular distance such as the axial length of the eye E to be examined by executing an OCT scan on the eye E to be examined. In the embodiment, it is assumed that the data processing unit 250 realizes the function of an axial length calculation unit.

The data processing unit 250 can calculate the distance between the position corresponding to the corneal vertex and the position corresponding to the RPE layer as the eye axial length based on the detection result of the interference light LC obtained by executing the OCT scan. It is possible.

Here, in the intensity profile of the interference signal generated by detecting the interference light LC, the peak corresponding to the RPE layer is close to the peak corresponding to the layer region such as the IS/OS line and Bruch film, and the RPE layer If the corresponding peak level is lower than the peak level corresponding to the IS/OS line, etc., the peak corresponding to the RPE layer is buried in the peak corresponding to the IS/OS line, etc. As a result, it may take time to specify the peak corresponding to the RPE layer, fail to specify the peak corresponding to the RPE layer, or erroneously detect the peak corresponding to the RPE layer.

Therefore, first, the data processing unit 250 identifies the depth position corresponding to the IS/OS line or the Bruch film (first layer region) based on the detection result of the interference light LC (intensity profile of the interference light LC). . Subsequently, the data processing unit 250 adds a predetermined offset value to the specified depth position to calculate the depth position corresponding to the RPE layer (second layer region) in the fundus. This makes it possible to identify the depth position corresponding to the RPE layer in a short period of time and with certainty. As a result, the reliability of the intraocular distance such as the axial length calculated using the identified RPE layer can be improved compared to the case of directly identifying the RPE layer.

Further, the data processing unit 250 identifies the distance corresponding to the axial length of the eye, which is the distance between the position corresponding to the corneal vertex and the position corresponding to the RPE layer, as the optical path length OPL, and according to the relational expression shown in formula (1), , to obtain the axial length (physical length) AL.

In equation (1), OPL represents the optical path length, AL represents the physical length of the axial length of the eye, and n represents the refractive index of the human eye (group index). Here, although the refractive index differs for each structure of the eye (cornea, lens, etc.), n represents the refractive index when the eyeball is converted into a single structure.

Here, the refractive index n has wavelength dependence. This means that the axial length calculated as the physical length changes according to the measurement wavelength. For example, when the optical path length when measuring the axial length of the eye with the measurement light LS having a measurement wavelength of 840 nm is expressed as OPL ₈₄₀ , and the refractive index at 840 nm is expressed as n ₈₄₀ , a relational expression such as Equation (2) is obtained. be done. Similarly, for example, when the optical path length when measuring the eye axial length with the measurement light LS having a measurement wavelength of 780 nm is expressed as OPL ₇₈₀ , and the refractive index at 780 nm is expressed as n ₇₈₀ , the relationship shown in Equation (3) formula is obtained.

Therefore, the axial length measured using the measuring light LS with a measuring wavelength of 840 nm is different from the axial length measured using the measuring light LS with a measuring wavelength of 780 nm.

Therefore, in the embodiment, wavelength correction is performed on the axial length measured using the measurement light LS having a measurement wavelength of 840 nm. Thereby, it is possible to calculate the axial length (the axial length measured using the measurement light LS having another wavelength component) at a wavelength different from 840 nm (for example, 780 nm).

Furthermore, strictly speaking, the axial length measurement value obtained by the non-contact axial length measurement device according to the embodiment differs from the axial length measurement value obtained by the ultrasonic axial length measurement device.

Therefore, in the embodiment, the axial length measurement value measured using the measurement light LS having a measurement wavelength of 840 nm is converted into the axial length measurement value obtained by the ultrasonic axial length measurement device. is possible.

As shown in FIG. 5, the data processing unit 250 includes a layer area specifying unit 251, a layer area position calculating unit 252, an axial length calculating unit 253, a wavelength correcting unit 254, and an axial length converting unit. 255.

(Layer region specifying unit 251)
The layer area specifying unit 251 specifies a depth position corresponding to a predetermined portion of the eye E to be examined based on the detection result of the interference light LC acquired by the OCT unit 100 . Examples of the predetermined site include a predetermined layer area in the fundus oculi Ef, a corneal vertex in the anterior segment, and the like. Examples of predetermined layer regions in the fundus Ef include IS/OS lines and Bruch's membrane.

In the embodiment, the layer area specifying unit 251 specifies a depth position corresponding to the corneal vertex in the anterior segment (cornea Cr) and a depth position corresponding to the IS/OS line in the fundus oculi Ef.

(Layer region position calculator 252)
The layer region position calculation unit 252 adds a predetermined offset value to the depth position specified by the layer region specifying unit 251, thereby determining the depth position of the subject eye E that is different from the part specified by the layer region specifying unit 251. A depth position corresponding to another part in is calculated. Examples of other sites include the RPE layer.

FIG. 6 shows an operation explanatory diagram of the layer area position calculation unit 252 according to the embodiment. FIG. 6 schematically shows an example of an OCT image (tomographic image) of the fundus oculi Ef.

Assume that the depth position corresponding to the IS/OS line is specified by the layer region specifying unit 251 as described above. By adding the offset value dt to the depth position corresponding to the IS/OS line, the layer region position calculator 252 calculates the depth corresponding to another layer region different from the IS/OS line with the IS/OS line as a reference. Calculate the position. Therefore, the layer region position calculator 252 can calculate the depth position corresponding to the RPE layer by adding the offset value dt to the depth position corresponding to the IS/OS line.

Examples of the offset value dt include a constant, a variable that varies depending on the subject or eye to be examined, and the like.

When the offset value dt is a constant, the offset value dt is determined by normative data previously obtained by measuring a plurality of eyes to be examined. For example, the offset value dt is determined by averaging measurements for multiple eyes.

If the offset value dt is variable, the offset value dt can be determined according to subject information. Also, the offset value dt can be determined according to information on the eye E to be examined. The information of the subject's eye E includes the intraocular distance (for example, the distance between predetermined layer regions in the fundus oculi Ef). In some embodiments, the offset value dt is determined according to the distance between the depth position corresponding to the IS/OS line of the subject's eye E and the depth position corresponding to Bruch's membrane.

(Axial length calculator 253)
The axial length calculation unit 253 determines the depth position (first depth position) of the layer region identified by the layer region identification unit 251 and another layer region different from the layer region calculated by the layer region position calculation unit 252. The distance to the depth position (second depth position) of the region is calculated as the axial length (optical path length). When calculating the axial length as the physical length, the axial length calculator 253 calculates the physical length of the axial length according to Equation (1).

FIG. 7 shows an operation explanatory diagram of the axial length calculator 253 according to the embodiment. FIG. 7 shows an example of an intensity profile of an interference signal obtained by performing an OCT scan on the anterior segment and an intensity profile of an interference signal obtained by performing an OCT scan on the fundus oculi Ef. An example is schematically represented. In FIG. 7, the same reference numerals are given to the same parts as those in FIG. 1 or FIG. 6, and the description thereof will be omitted as appropriate.

For example, alignment between the eye to be examined E and the optical system shown in FIG. shall be The layer region specifying unit 251 searches for peaks in the intensity profile of the interference signal obtained by performing an OCT scan on the anterior segment after the alignment is completed, and detects the position of the specified peak at a depth corresponding to the corneal vertex. Identify as position za.

Subsequently, the layer region identifying unit 251 searches for peaks in the intensity profile of the interference signal obtained by executing the OCT scan on the fundus oculi Ef after the alignment is completed, and finds peaks corresponding to IS/OS lines (or Bruch's membrane). Identify the position of the peak as the depth position zf. The layer region position calculator 252 calculates the depth position (zf+dt) corresponding to the RPE layer by adding the offset value dt to the depth position zf corresponding to the IS/OS line.

Here, when the peak corresponding to the RPE layer in the intensity profile of the interference signal is close to the peak corresponding to the other layer region, and the peak level corresponding to the RPE layer is lower than the peak level corresponding to the other layer region , makes it difficult to identify the peak corresponding to the RPE layer. On the other hand, in the embodiment, the depth position corresponding to the IS/OS line (or Bruch's film) whose peak is easy to identify is specified, and the offset value is added to the specified depth position. Accordingly, it is possible to accurately specify the representative position on the fundus oculi Ef side in a short time without failing to specify the representative position on the fundus oculi Ef side.

The axial length calculation unit 253 calculates the depth position za corresponding to the corneal vertex identified by the layer region identification unit 251 and the depth position (zf+dt) corresponding to the RPE layer calculated by the layer region position calculation unit 252. is calculated as the axial length AL0 (optical path length).

As described above, since the representative position on the fundus oculi Ef side is accurately specified in a short time without failing to specify the representative position on the fundus oculi Ef side, the measurement accuracy of the axial length of the subject's eye E is improved. can be made

In some embodiments, a single OCT scan acquires an intensity spectrum of the interference signal in the range from the anterior segment to the fundus oculi Ef, and from the acquired intensity spectrum, the depth position corresponding to the corneal vertex and IS/ A depth position corresponding to the OS line is identified.

In some embodiments, the layer region identifying unit 251 identifies the depth position of the layer region of the fundus oculi Ef other than the IS/OS line (or Bruch's membrane), and the layer region position calculator 252 detects the identified depth. The depth position of the RPE layer is calculated by adding the offset value to the depth position.

(Wavelength corrector 254)
The wavelength correction unit 254 corrects the wavelength of the axial length calculated by the axial length calculation unit 253 as shown in Equation (4), thereby obtaining a wavelength ( For example, it is corrected to the axial length obtained using measurement light with a measurement wavelength of 780 nm).

Here, it is assumed that the axial length (optical path length) OPL ₈₄₀ is calculated by the axial length calculator 253 . At this time, the wavelength correction unit 254 multiplies the axial length (optical path length) OPL ₈₄₀ by the ratio of the refractive index (n ₈₄₀ ) of the human eye at 840 nm to the refractive index (n ₇₈₀ ) of the human eye at 780 nm. Thereby, the axial length (optical path length) OPL ₇₈₀ obtained using the measurement light having the wavelength component of 780 nm is corrected.

(Axial length conversion unit 255)
The axial length conversion unit 255 converts the axial length corrected by the wavelength correction unit 254 into an axial length (physical length) obtained using an ultrasonic axial length measuring device.

For example, the axial length conversion unit 255 converts the axial length of the eye (optical path length) that has undergone wavelength correction by the wavelength correction unit 254 according to equation (5) to the length of the eye obtained using an ultrasonic axial length measuring device. Convert to axial length (physical length). For example, in Non-Patent Document 1, a formula (5 ) is disclosed.

Here, it is assumed that the axial length (optical path length) OPL ₇₈₀ is calculated by the wavelength corrector 254 . At this time, the axial length conversion unit 255 calculates the axial length (physical length) AL1 by substituting the axial length (optical path length) OPL ₇₈₀ calculated by the wavelength correction unit 254 into Equation (5). .

In some embodiments, the axial length conversion unit 255 converts the axial length (optical path length ) Calculate the axial length (physical length) AL1 by directly substituting the OPL ₈₄₀ into the equation (6).

In some embodiments, the main control unit 211 controls the display unit 270, which will be described later, to display the axial length (optical path length) calculated by the axial length calculation unit 253 and the eye length corrected by the wavelength correction unit 254. Display the axial length (optical path length) on the same screen. In some embodiments, the main control unit 211 controls the display unit 270 to be described later, and converts the axial length (optical path length) calculated by the axial length calculation unit 253 according to Equation (2) to the axial length (physical length) and the axial length (physical length) obtained by converting the axial length (optical path length) corrected by the wavelength correction unit 254 according to the equation (3) are displayed on the same screen.

In some embodiments, the main control unit 211 controls the display unit 270 to be described later, and converts the axial length (optical path length) calculated by the axial length calculation unit 253 according to Equation (2) to the axial length (physical length), the axial length (physical length) obtained by converting the axial length (optical path length) corrected by the wavelength correction unit 254 according to Equation (3), and the axial length obtained by the axial length conversion unit 255 (physical length) are displayed on the same screen.

According to the embodiment, it is possible to highly accurately compare the measurement results of other axial length measurement devices that measure the axial length of the eye using measurement light of different wavelengths, and the measurement results of the ultrasonic type axial length measurement device. become.

(Display unit 270, operation unit 280)
Display unit 270 displays information as a user interface unit under the control of control unit 210 . Display unit 270 includes display unit 10 shown in FIG. 1 and the like.

The operation unit 280 is used as a user interface unit to operate the ophthalmologic apparatus. The operation unit 280 includes various hardware keys (joystick, button, switch, etc.) provided in the ophthalmologic apparatus. The operation unit 280 may also include various software keys (buttons, icons, menus, etc.) displayed on the touch panel display screen 10a.

At least part of the display unit 270 and the operation unit 280 may be configured integrally. A typical example is a touch panel display screen 10a.

(Communication unit 290)
The communication unit 290 has a function for communicating with an external device (not shown). The communication unit 290 has a communication interface according to a connection form with an external device. An example of an external device is a spectacle lens measuring device for measuring the optical properties of lenses. The spectacle lens measuring device measures the dioptric power of the spectacle lens worn by the subject, and inputs this measurement data to the ophthalmologic device 1000 . Also, the external device may be any ophthalmologic device, a device (reader) that reads information from a recording medium, or a device (writer) that writes information to a recording medium. Furthermore, the external device may be a hospital information system (HIS) server, a DICOM (Digital Imaging and Communication in Medicine) server, a doctor terminal, a mobile terminal, a personal terminal, a cloud server, or the like. The communication unit 290 may be provided in the processing unit 9, for example.

IS/OS lines or Bruch's films are examples of "first layer regions" according to embodiments. The RPE layer is an example of a "second layer region" according to the embodiment. 840 nm is an example of the "first wavelength" according to the embodiment. 780 nm is an example of a "second wavelength" according to the embodiment.

<Operation example>
The operation of the ophthalmologic apparatus 1000 according to the embodiment will be described.

FIG. 8 shows an example of the operation of the ophthalmologic apparatus 1000. As shown in FIG. FIG. 8 depicts a flow diagram of an example operation of the ophthalmic device 1000 . A computer program for realizing the processing shown in FIG. 8 is stored in the storage unit 212 . The main control unit 211 executes the processing shown in FIG. 8 by operating according to this computer program.

(S1: Alignment)
The ophthalmologic apparatus 1000 performs alignment when the examiner performs a predetermined operation on the operation unit 280 while the subject's face is fixed to a face receiving unit (not shown).

Specifically, the main control unit 211 controls the two anterior segment cameras 14 to start photographing the anterior segment of the eye E to be examined. When two captured images (anterior segment images) are acquired by the two anterior segment cameras 14, the main control unit 211 controls the data processing unit 250 to analyze each of the two captured images to determine the pupil The center of the pupil (E ) is calculated. The main control unit 211 aligns the optical system with the eye E to be inspected by controlling the moving mechanism 200 based on the calculated three-dimensional position of the eye E to be inspected. Specifically, the main control unit 211 aligns the optical axis of the OCT optical system 8 (optical axis of the objective lens 51) with the axis of the subject's eye E based on the calculated three-dimensional position, and The moving mechanism 200 is controlled so that the distance of the optical system (objective lens 51) to the eye to be examined E becomes a predetermined working distance. Here, the working distance is a default value that is also called a working distance, and means the distance between the subject's eye E and the optical system during inspection using the optical system.

Further, when the anterior segment camera 14 simultaneously captures moving images of the anterior segment from different directions, for example, by performing the following processes (1) and (2), the main control unit 211 controls the subject's eye It is possible to perform optical system tracking for E movement.
(1) The data processing unit 250 sequentially obtains the three-dimensional position of the subject's eye E by sequentially analyzing two frames obtained substantially simultaneously in moving image photography by the two anterior eye cameras 14 .
(2) The main control unit 211 sequentially controls the moving mechanism 200 based on the three-dimensional position of the eye E to be examined, which is sequentially obtained by the data processing unit 250, so that the position of the optical system follows the movement of the eye E to be examined. Let

The main control unit 211 also moves the ref measurement light source 61, the focusing lens 74, and the liquid crystal panel 41 to their origin positions (for example, positions corresponding to 0D (diopter)) along their respective optical axes.

(S2: fundus OCT scan)
Next, the main controller 211 controls the OCT optical system 8 and the like to perform an OCT scan on the fundus oculi Ef.

Specifically, the main controller 211 controls the moving mechanism 87D to move the focusing lens 87 in the optical axis direction so that the focus position of the measurement light LS is set on the fundus oculi Ef. Subsequently, the main controller 211 adjusts the light source unit 101 , attenuator 105 , polarization controller 106 , zoom optical system 114 , CCD image sensor 115 and optical path length changer 89 . Next, the main control unit 211 causes the liquid crystal panel 41 to display a pattern indicating a fixation target at a display position corresponding to a desired fixation position. Thereby, the subject's eye E is gazed at the desired fixation position. The main control unit 211 controls the optical scanner 88 to scan a predetermined scanning range on the fundus oculi Ef with the measurement light LS. A detection result of the interference light LC obtained by scanning the measurement light LS is sent to the image forming section 240 .

(S3: Anterior segment OCT scan)
Subsequently, the main controller 211 controls the OCT optical system 8 and the like so as to perform OCT scanning on the anterior segment.

Specifically, the main controller 211 controls the moving mechanism 87D to move the focusing lens 87 in the optical axis direction so that the focal position of the measurement light LS is set in the anterior segment. Subsequently, the main controller 211 adjusts the light source unit 101 , attenuator 105 , polarization controller 106 , zoom optical system 114 , CCD image sensor 115 and optical path length changer 89 . Next, the main control unit 211 causes the liquid crystal panel 41 to display a pattern indicating a fixation target at a display position corresponding to a desired fixation position. The main controller 211 controls the optical scanner 88 to scan a predetermined scan range in the anterior segment with the measurement light LS. A detection result of the interference light LC obtained by scanning the measurement light LS is sent to the image forming section 240 .

(S4: Identify IS/OS line)
Next, the main control unit 211 controls the layer region specifying unit 251 to analyze the detection result of the interference light LC in the fundus oculi Ef (or the OCT image of the fundus oculi Ef) acquired in step S2, and the IS/OS Identify the depth position corresponding to the line.

Further, the main control unit 211 controls the layer region specifying unit 251 to analyze the detection result of the interference light LC in the anterior segment acquired in step S3 (or the OCT image of the anterior segment), and the corneal vertex. Identify the depth position corresponding to .

(S5: Add offset value)
Subsequently, the main control unit 211 controls the layer region position calculation unit 252 to add a predetermined offset value to the depth position of the IS/OS line identified in step S4, thereby obtaining a depth corresponding to the RPE layer. specify the position.

(S6: Calculate axial length)
Next, the main control unit 211 controls the axial length calculation unit 253 to determine the depth position corresponding to the corneal vertex identified in step S2 and the depth position corresponding to the RPE layer calculated in step S3. is calculated as the axial length (optical path length) OPL ₈₄₀ .

(S7: wavelength correction)
Next, the main control unit 211 controls the wavelength correction unit 254 to perform wavelength correction on the axial length OPL ₈₄₀ calculated in step S6 according to Equation (4), thereby converting the axial length OPL ₇₈₀ at 780 nm to to correct.

(S8: convert axial length)
Next, the main control unit 211 controls the axial length conversion unit 255, substitutes the axial length OPL ₇₈₀ corrected in step S7 into the equation (5), and operates the ultrasonic axial length measuring device. to the axial length AL1 measured using

In some embodiments, the main control unit 211 causes the display unit 270 to display at least two of the calculation results of steps S6 to S8 on the same screen. This makes it possible to easily compare the calculation results of steps S6 to S8.

With this, the operation of the ophthalmologic apparatus 1000 is completed (end).

In the flow shown in FIG. 8, step S8 substitutes the axial eye length OPL ₈₄₀ calculated in step S6 into equation (6) to It may be converted to the axial length AL1.

[Action]
An ophthalmologic apparatus, an ophthalmologic apparatus control method, and a program according to an embodiment will be described.

An ophthalmologic apparatus (1000) according to an embodiment includes a layer area specifying section (251) and a layer area position calculating section (252). The layer region specifying unit determines a first depth corresponding to a first layer region in the fundus based on the detection result of the interference light obtained by performing an OCT scan on the fundus (Ef) of the eye (E) to be examined. Identify the position (zf). The layer region position calculator adds a predetermined offset value (dt) to the first depth position to calculate a second depth position (zf+dt) corresponding to the second layer region in the fundus.

According to this aspect, the peak of the intensity of the interference light (interference signal) corresponding to the second layer region is close to the peak of the intensity of the interference light corresponding to the other layer regions. It is possible to accurately specify the depth position of the second layer region in a short period of time even if the specification takes time, fails in specification, or is erroneously detected.

In some embodiments, the first layer area is the IS/OS line and the second layer area is the retinal pigment epithelium layer.

According to this aspect, the depth position of the retinal pigment epithelial layer can be accurately identified in a short time even if it takes time to identify the retinal pigment epithelial layer, fails to identify the retinal pigment epithelial layer, or is erroneously detected. it becomes possible to

In some embodiments, the layer region position calculator adds a different offset value to the first depth position depending on the subject's eye.

According to this aspect, since the offset value is changed according to the eye to be examined, the depth position of the second layer region can be specified more accurately.

In some embodiments, the layer region identifying unit identifies the first depth position and the third depth position (za) corresponding to the corneal vertex based on the detection result of the interference light. The ophthalmologic apparatus includes an axial length calculator (253) that calculates the axial length of the subject's eye based on the third depth position and the second depth position.

According to this aspect, even if it takes a long time to specify the second layer region, fails to specify it, or erroneously detects it, the depth position of the second layer region can be specified accurately in a short time. Therefore, it is possible to calculate the axial length of the eye with higher accuracy.

In some embodiments, the OCT scan is performed by illuminating the subject's eye with measurement light (LS) having a first wavelength (840 nm) as the measurement wavelength. The ophthalmologic apparatus has a wavelength corrector (254) that corrects the axial length of the eye calculated by the axial length calculator to a second wavelength (780 nm) different from the first wavelength by performing wavelength correction on the axial length of the eye. including.

According to this aspect, it is possible to compare the measured values of the axial length regardless of the wavelength dependence of the measured values of the axial length obtained at different measurement wavelengths.

An ophthalmologic apparatus (1000) according to an embodiment includes an axial length calculator (253) and a wavelength corrector (254). The eye axial length calculator performs an OCT scan on the subject's eye (E) using the measurement light (LS) having the first wavelength (840 nm) as the measurement wavelength, and calculates the detection result of the interference light obtained by Based on this, the axial length is calculated. The wavelength correction unit corrects the axial length calculated by the axial length calculation unit to the axial length at a second wavelength (780 nm) different from the first wavelength by performing wavelength correction on the axial length.

According to this aspect, it is possible to compare the measured values of the axial length regardless of the wavelength dependence of the measured values of the axial length obtained at different measurement wavelengths.

In some embodiments, the wavelength correction unit calculates the ratio of the refractive index (n ₈₄₀ ) of the human eye at the first wavelength to the refractive index (n ₇₈₀ ) of the human eye at the second wavelength using the axial length calculator. By multiplying the obtained axial length, the axial length at the second wavelength is corrected.

According to this aspect, it is possible to correct the axial length obtained at the desired measurement wavelength with a simple process.

In some embodiments, the second wavelength component is 780 nm.

According to this aspect, it is possible to compare the measured value of the axial length obtained by the non-contact type axial length measuring device with the measurement wavelength of 780 nm.

Some embodiments include an axial length converter (255) that converts the axial length corrected by the wavelength corrector into an axial length obtained using an ultrasonic axial length measuring device.

According to this aspect, it is possible to highly accurately compare the axial length measurement value obtained by the ophthalmologic device and the measurement result of the ultrasonic axial length measurement device.

In some embodiments, the axial length conversion unit converts the optical path length as the axial length corrected by the wavelength correction unit into the physical length as the axial length obtained using an ultrasonic axial length measuring device. Convert to

According to this aspect, it is possible to convert the measurement of the axial length obtained by using the ultrasonic axial length measuring device with a simple process.

Some embodiments divide the light (L0) from the light source (light source unit 101) into measurement light (LS) and reference light (LR), irradiate the eye to be inspected with the measurement light, and perform measurement from the eye to be inspected. It includes an OCT optical system (8) that detects interference light (LC) between the return light of the light and the reference light that has passed through the reference optical path.

According to this aspect, it is possible to provide an ophthalmologic apparatus capable of performing OCT on the subject's eye and accurately specifying the depth position of the second layer region in the fundus in a short period of time. Become.

A control method for an ophthalmologic apparatus (1000) according to an embodiment includes a layer area specifying step and a layer area position calculating step. The layer area specifying step corresponds to the first layer area in the fundus based on the detection result of the interference light (LC) obtained by performing the OCT scan on the fundus (Ef) of the eye (E) to be examined. A first depth position (zf) is identified. The layer region position calculating step adds a predetermined offset value (dt) to the first depth position to calculate a second depth position (zf+dt) corresponding to the second layer region in the fundus.

According to this aspect, the peak of the intensity of the interference light (interference signal) corresponding to the second layer region is close to the peak of the intensity of the interference light corresponding to the other layer regions. It is possible to accurately specify the depth position of the second layer region in a short period of time even if the specification takes time, fails in specification, or is erroneously detected.

In some embodiments, the first layer area is the IS/OS line and the second layer area is the retinal pigment epithelium layer.

According to this aspect, the depth position of the retinal pigment epithelial layer can be accurately identified in a short time even if it takes time to identify the retinal pigment epithelial layer, fails to identify the retinal pigment epithelial layer, or is erroneously detected. it becomes possible to

In some embodiments, the layer area identifying step identifies the first depth position and the third depth position (za) corresponding to the corneal vertex based on the detection result of the interference light. The method for controlling an ophthalmologic apparatus includes an axial length calculation step of calculating the axial length of an eye to be inspected based on the third depth position and the second depth position.

According to this aspect, even if it takes a long time to specify the second layer region, fails to specify it, or erroneously detects it, the depth position of the second layer region can be specified accurately in a short time. Therefore, it is possible to calculate the axial length of the eye with higher accuracy.

In some embodiments, an OCT scan is performed by irradiating the subject's eye with measurement light having a first wavelength (840 nm) as the measurement wavelength. The method of controlling the ophthalmologic apparatus includes a wavelength correction step of correcting the axial length of the eye calculated in the axial length calculation step to a second wavelength (780 nm) different from the first wavelength by performing wavelength correction on the axial length of the eye. including.

According to this aspect, it is possible to compare the measured values of the axial length regardless of the wavelength dependence of the measured values of the axial length obtained at different measurement wavelengths.

A control method for an ophthalmologic apparatus (1000) according to an embodiment includes an axial length calculation step and a wavelength correction step. In the axial length calculation step, the measurement light (LS) having the first wavelength (840 nm) as the measurement wavelength is used to perform an OCT scan on the eye (E) to be examined, and the interference light detection result obtained is Based on this, the axial length is calculated. In the wavelength correcting step, the axial length calculated in the axial length calculating step is corrected to the axial length at a second wavelength (780 nm) different from the first wavelength.

According to this aspect, it is possible to compare the measured values of the axial length regardless of the wavelength dependence of the measured values of the axial length obtained at different measurement wavelengths.

Some embodiments include an axial length conversion step of converting the axial length corrected in the wavelength correcting step into an axial length obtained using an ultrasonic axial length measuring device.

According to this aspect, it is possible to highly accurately compare the axial length measurement value obtained by the ophthalmologic device and the measurement result of the ultrasonic axial length measurement device.

A program according to an embodiment causes a computer to execute each step of the method for controlling an ophthalmologic apparatus described above.

According to this aspect, the peak of the intensity of the interference light (interference signal) corresponding to the second layer region is close to the peak of the intensity of the interference light corresponding to the other layer regions. It is possible to provide a program capable of accurately specifying the depth position of the second layer region in a short time even when the specification takes time, fails in specification, or is detected erroneously. .

<Others>
The embodiment shown above is merely an example for carrying out the present invention. A person who intends to implement this invention can make arbitrary modifications, omissions, additions, etc. within the scope of the gist of this invention.

1 Alignment System 3 Keratometry System 4 Fixation Projection System 5 Anterior Eye Observation System 6 Reflex Measurement Projection System 7 Reflex Measurement Receiving System 8 OCT Optical System 9 Processing Unit 51 Objective Lens 88 Optical Scanner 210 Control Unit 211 Main Control Unit 250 Data Processing unit 251 Layer region identification unit 252 Layer region position calculation unit 253 Axial length calculation unit 254 Wavelength correction unit 255 Axial length conversion unit 1000 Ophthalmic apparatus

Claims (18)

a layer region identifying unit that identifies a first depth position corresponding to a first layer region in the fundus based on the detection result of interference light obtained by performing an OCT scan on the fundus of the eye to be examined;
a layer region position calculator that calculates a second depth position corresponding to a second layer region in the fundus by adding a predetermined offset value to the first depth position;
An ophthalmic device, comprising: the first layer region is an IS/OS line;
The ophthalmologic apparatus according to claim 1, wherein the second layer region is a retinal pigment epithelium layer. 3. The ophthalmologic apparatus according to claim 1, wherein the layer region position calculator adds an offset value that differs depending on the eye to be examined to the first depth position. The layer area specifying unit specifies the first depth position and the third depth position corresponding to the corneal vertex based on the detection result of the interference light,
4. The ophthalmology clinic according to claim 2, further comprising an axial length calculator that calculates the axial length of the eye to be examined based on the third depth position and the second depth position. Device. The OCT scan is performed by irradiating the subject's eye with measurement light having a first wavelength as a measurement wavelength,
and a wavelength correction unit that corrects the axial length calculated by the axial length calculation unit to the axial length at a second wavelength different from the first wavelength by performing wavelength correction on the axial length. The ophthalmic device according to claim 4. an axial length calculation unit that calculates the axial length based on the detection result of the interference light obtained by performing an OCT scan on the eye to be inspected using the measurement light having the first wavelength as the measurement wavelength;
a wavelength correction unit that corrects the axial length calculated by the axial length calculation unit to the axial length at a second wavelength different from the first wavelength by performing wavelength correction on the axial length;
An ophthalmic device, comprising: The wavelength corrector multiplies the axial length calculated by the axial length calculator by a ratio of the refractive index of the human eye at the first wavelength to the refractive index of the human eye at the second wavelength. 7. The ophthalmologic apparatus according to claim 5, wherein the axial length of the second wavelength is corrected. The ophthalmologic apparatus according to any one of claims 5 to 7, wherein the second wavelength is 780 nm. An axial length conversion unit for converting the axial length corrected by the wavelength correcting unit into an axial length obtained using an ultrasonic axial length measuring device. 9. The ophthalmic device according to any one of 8. The axial length conversion unit converts the optical path length as the axial length corrected by the wavelength correcting unit into a physical length as the axial length obtained using the ultrasonic axial length measurement device. The ophthalmic device according to claim 9, characterized by: dividing light from a light source into measurement light and reference light, irradiating the eye with the measurement light, and interfering the return light of the measurement light from the eye with the reference light that has passed through the reference optical path. The ophthalmic apparatus according to any one of claims 1 to 10, comprising an OCT optical system for detecting light. a layer region specifying step of specifying a first depth position corresponding to a first layer region in the fundus based on the detection result of interference light obtained by performing an OCT scan on the fundus of the eye to be examined;
a layer region position calculating step of calculating a second depth position corresponding to a second layer region in the fundus by adding a predetermined offset value to the first depth position;
A method of controlling an ophthalmic device, comprising: the first layer region is an IS/OS line;
The method of controlling an ophthalmologic apparatus according to claim 12, wherein the second layer region is a retinal pigment epithelium layer. The layer region identifying step identifies the first depth position and a third depth position corresponding to the corneal vertex based on the detection result of the interference light,
14. The ophthalmology clinic according to claim 12 or 13, further comprising an axial length calculation step of calculating the axial length of the eye to be examined based on the third depth position and the second depth position. How to control the device. The OCT scan is performed by irradiating the subject's eye with measurement light having a first wavelength as a measurement wavelength,
and a wavelength correction step of correcting the axial length calculated in the axial length calculation step to the axial length at a second wavelength different from the first wavelength by performing wavelength correction on the axial length. 15. The method of controlling an ophthalmic apparatus according to claim 14. an axial length calculation step of calculating the axial length based on the detection result of the interference light obtained by performing an OCT scan on the eye to be inspected using the measurement light having the first wavelength as the measurement wavelength;
a wavelength correction step of correcting the axial length calculated in the axial length calculation step to the axial length at a second wavelength different from the first wavelength by performing wavelength correction;
A method of controlling an ophthalmic device, comprising: 15. The method according to claim 15, further comprising an axial length conversion step of converting the axial length corrected in the wavelength correcting step into an axial length obtained using an ultrasonic axial length measuring device. 17. The method of controlling an ophthalmologic apparatus according to 16. A program for causing a computer to execute each step of the ophthalmologic apparatus control method according to any one of claims 12 to 17.

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