Ophthalmic device and ophthalmic device control program

Abstract

An ophthalmic device and an ophthalmic device control program are provided that are capable of appropriately acquiring three-dimensional information about the anterior segment of the eye while stabilizing the fixation of the subject's eye. [Solution] The fixation target presenting optical system presents a fixation target to the subject's eye. The cross-sectional imaging optical system captures cross-sectional images of the anterior segment by receiving return light from the anterior segment that has been optically sectioned by the imaging light. The moving unit moves an optical unit including the fixation target presenting optical system and the cross-sectional imaging optical system relative to the subject's eye. The control unit can perform a three-dimensional information acquisition process to acquire three-dimensional information about the anterior segment by capturing cross-sectional images of multiple locations on the anterior segment while moving the optical unit and scanning the imaging light. When performing the three-dimensional information acquisition process, the control unit positions the fixation target within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the subject's eye.

Description

[Technical Field]

[0001] The present disclosure relates to an ophthalmic apparatus that examines an eye to be examined, and an ophthalmic apparatus control program executed by the ophthalmic apparatus. [Background technology]

[0002] Various ophthalmic devices are known for performing examinations of a subject's eye (e.g., at least one of photographing, observing, measuring, and detecting). For example, the ophthalmic device described in Patent Document 1 includes a cross-sectional imaging optical system. The cross-sectional imaging optical system projects imaging light onto the anterior segment of the subject's eye and receives return light from the anterior segment optically sectioned by the imaging light, thereby capturing a cross-sectional image of the anterior segment. Furthermore, the ophthalmic device described in Patent Document 1 acquires three-dimensional information about the anterior segment of the eye (e.g., at least one of the posterior corneal shape and the corneal thickness) by moving the cross-sectional imaging optical system and scanning the imaging light. During the examination of the subject's eye, a fixation target is presented to the subject's eye by a fixation target presenting optical system, causing the subject's eye to fixate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-076492 Summary of the Invention [Problem to be solved by the invention]

[0004] If the subject's fixation becomes unstable during an examination, the accuracy of the examination will decrease. For example, when acquiring three-dimensional information about the anterior segment of the eye, the fixation of the subject's eye can be stabilized by fixing the position of the fixation target presenting optical system, which presents a fixation target, while moving the cross-sectional imaging optical system relative to the subject's eye to scan the imaging light. However, in this case, the fixation target presenting optical system and the cross-sectional imaging optical system must be moved separately relative to the subject's eye, making the device configuration and control complex. On the other hand, if both the fixation target presenting optical system and the cross-sectional imaging optical system are moved relative to the subject's eye, as in the ophthalmic device described in Patent Document 1, the device configuration and control are simplified, but problems such as the position of the fixation target viewed by the subject moving or the light beam of the fixation target moving away from the pupil of the subject's eye and making the fixation target invisible may occur. As described above, conventional ophthalmic devices have difficulty appropriately acquiring three-dimensional information about the anterior segment of the eye while stabilizing the subject's fixation.

[0005] A typical object of the present disclosure is to provide an ophthalmic device and an ophthalmic device control program that can solve at least one of the above problems and thereby appropriately acquire three-dimensional information of the anterior segment of the eye while stabilizing the fixation of the subject's eye. [Means for solving the problem]

[0006] An ophthalmologic device provided by a typical embodiment of the present disclosure includes a fixation target presenting optical system that presents a fixation target to the subject's eye, a cross-sectional imaging optical system that projects imaging light onto the anterior segment of the subject's eye and receives return light from the anterior segment that has been optically cut by the imaging light to capture a cross-sectional image of the anterior segment, a moving unit that moves an optical unit including the fixation target presenting optical system and the cross-sectional imaging optical system relative to the subject's eye, and a control unit, wherein the control unit is capable of performing a three-dimensional information acquisition process that acquires three-dimensional information about the anterior segment by moving the optical unit relative to the subject's eye and scanning it with the imaging light to capture cross-sectional images of multiple locations on the anterior segment, and when performing the three-dimensional information acquisition process, the position of the fixation target in a direction along the optical axis of the fixation target presenting optical system is positioned within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the subject's eye.

[0007] An ophthalmic apparatus control program provided by a typical embodiment of the present disclosure is an ophthalmic apparatus control program executed in an ophthalmic apparatus, the ophthalmic apparatus including: a fixation target presenting optical system that presents a fixation target to an eye to be examined; a cross-section photographing optical system that projects photographing light onto an anterior segment of the eye to be examined and receives return light from the anterior segment that has been optically sectioned by the photographing light, thereby photographing a cross-sectional image of the anterior segment; a moving unit that moves an optical unit including the fixation target presenting optical system and the cross-section photographing optical system relative to the eye to be examined; and a control unit. By moving the imaging light relative to the subject's eye and scanning it, cross-sectional images of multiple locations on the anterior segment can be captured, thereby performing a three-dimensional information acquisition process to obtain three-dimensional information about the anterior segment.The ophthalmic device control program is executed by the control unit, causing the ophthalmic device to perform a process to position the fixation target in a direction along the optical axis of the fixation target presenting optical system within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the subject's eye, when performing the three-dimensional information acquisition process.

[0008] According to the ophthalmic apparatus and the ophthalmic apparatus control program of the present disclosure, three-dimensional information about the anterior segment of the eye is appropriately acquired while the fixation of the subject's eye is stabilized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing the external configuration of an ophthalmologic apparatus 10 according to the present embodiment. [Figure 2] 1 is a diagram showing a schematic configuration of an optical system of an ophthalmic apparatus 10 according to the present embodiment. [Figure 3] FIG. 2 is a schematic diagram for explaining a configuration for scanning imaging light. [Figure 4] This is a schematic diagram comparing the changes in the presented light beam of the fixation target when the fixation target presenting optical system 150 is moved in the Y direction with the fixation target placed at the far point of the test eye whose ocular refractive power is X[D] (X≠0). [Figure 5] This is a schematic diagram comparing the light beams presented by the fixation target when the fixation target presenting optical system 150 is moved in the Y direction with the fixation target placed at infinity of the test eye, which has an eye refractive power of 0 [D]. [Figure 6] This is a schematic diagram comparing the light beams presented by the fixation target when the fixation target presenting optical system 150 is moved in the Y direction with the fixation target placed at infinity of the test eye whose eye refractive power is X[D] (X≠0). [Figure 7] 10 is a schematic diagram comparing the influence of different sizes of the pupil Ep of the subject's eye E on visual fixation. FIG. [Figure 8] 10 is a flowchart of a main process executed by the ophthalmologic apparatus 10 of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Summary> The ophthalmic apparatus exemplified in the present disclosure includes a fixation target presenting optical system, a cross-sectional imaging optical system, a moving unit, and a control unit. The fixation target presenting optical system presents a fixation target to the subject's eye. The cross-sectional imaging optical system projects imaging light onto the anterior segment of the subject's eye and receives return light from the anterior segment optically sectioned by the imaging light to capture a cross-sectional image of the anterior segment. The moving unit moves an optical unit including the fixation target presenting optical system and the cross-sectional imaging optical system relative to the subject's eye. The control unit controls the ophthalmic apparatus. The control unit can perform a three-dimensional information acquisition process to acquire three-dimensional information about the anterior segment by moving the optical unit relative to the subject's eye and scanning the imaging light while capturing cross-sectional images of multiple locations on the anterior segment. When performing the three-dimensional information acquisition process, the control unit positions the fixation target in a direction along the optical axis of the fixation target presenting optical system within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the subject's eye.

[0011] When the position of the fixation target is positioned within a restricted area centered on the focal position of the entire lens system of the fixation target presenting optical system (hereinafter, sometimes simply referred to as the "focal position of the fixation target presenting optical system"), the light beam presented by the fixation target becomes nearly parallel on the pupil of the subject's eye. As a result, even if the fixation target presenting optical system is moved relative to the subject's eye, the light beam presented by the fixation target is focused at the same position on the retina of the subject's eye. Therefore, unless the refractive power of the subject's eye is 0D (diopter), the fixation target may appear blurred to the subject, but the fixation target will appear stationary to the subject. Therefore, by positioning the fixation target within the restricted area during the three-dimensional information acquisition process, the ophthalmic device disclosed herein can appropriately suppress the problem of the position of the fixation target seen by the subject moving even when the optical unit including the fixation target presenting optical system and the cross-sectional imaging optical system is moved. The ophthalmologic apparatus of the present disclosure does not need to have a complex configuration for moving the cross-sectional imaging optical system while fixing the position of the fixation target presenting optical system, and therefore can appropriately acquire three-dimensional information about the anterior segment of the eye while stabilizing the fixation of the subject's eye.

[0012] The fixation target presenting optical system may include a fixation target moving unit that moves the fixation target in a direction along the optical axis. The range of the limited area of ​​the fixation target centered on the focal position of the fixation target presenting optical system may be narrower than the movable range when the position of the fixation target is moved to the far point of the test eye according to the refractive power of the test eye. In this case, since the limited area is close to the focal position of the fixation target presenting optical system, when the fixation target is positioned within the limited area, the presented light beam of the fixation target on the pupil of the test eye becomes appropriately close to parallel. Therefore, the problem of the fixation target appearing to move during acquisition of three-dimensional information is more appropriately suppressed.

[0013] A specific configuration for scanning the imaging light over the anterior segment of the subject's eye can be selected as appropriate. For example, the projection optical system of the cross-sectional imaging optical system may project slit light as imaging light. The moving unit may scan the slit light by moving the optical unit in a direction intersecting (for example, perpendicular to) the longitudinal direction of the slit light. For example, if the slit light extends in the horizontal direction (X direction), the moving unit may scan the slit light by moving the optical unit including the cross-sectional imaging optical system in the up-down direction (Y direction). Also, if the slit light extends in the up-down direction (Y direction), the moving unit may scan the slit light by moving the optical unit in the horizontal direction (X direction). Also, the moving unit may scan the imaging light by rotating the optical unit.

[0014] When executing the three-dimensional information acquisition process, the control unit may position the fixation target within the restricted area at a position close to the far point of the test eye according to the refractive power of the test eye. In this case, the light beam presented by the fixation target on the pupil of the test eye is maintained in a state close to parallel light (i.e., the problem of the fixation target appearing to move is suppressed), and the degree of blur of the fixation target as viewed by the test subject is appropriately suppressed. Note that the far point is a point in the external world that is imaged on the fovea centralis of the test eye in a non-accommodative state (i.e., the position at which the image is in focus in a non-accommodative state).

[0015] A specific method for moving the fixation target within the restricted area can be selected as appropriate. For example, if the far point of the subject's eye is within the restricted area, the control unit may move the fixation target to the far point of the subject's eye within the restricted area. Alternatively, if the far point of the subject's eye is not within the restricted area, the control unit may move the position of the fixation target in a direction closer to the far point of the subject's eye. In this case, the fixation target is presented in a state more suited to the refractive power of the subject's eye.

[0016] However, the position of the fixation target when executing the three-dimensional information acquisition process may be set to a predetermined position (for example, a focal position) within the restricted area. Even in this case, since the position of the fixation target is arranged within the restricted area, the problem of the position of the fixation target viewed by the subject moving is appropriately suppressed.

[0017] The ophthalmologic apparatus may further include an eye refraction measurement optical system that measures the eye refraction of the subject's eye. When measuring the eye refraction of the subject's eye with the eye refraction measurement optical system, the control unit may position the fixation target in a direction along the optical axis of the fixation target presenting optical system at a far point of the subject's eye in accordance with the refractive power of the subject's eye. When executing the three-dimensional information acquisition process, the control unit may position the fixation target in a direction along the optical axis of the fixation target presenting optical system within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the subject's eye.

[0018] In this case, since there is no need to move the fixation target optical system relative to the subject's eye when measuring the eye refractive power, the fixation target can be clearly viewed by the subject by positioning the fixation target at the far point of the subject's eye. Furthermore, when acquiring three-dimensional information about the anterior segment of the eye, the problem of the position of the fixation target as seen by the subject moving can be appropriately suppressed. Therefore, the fixation target is presented to the subject's eye in an appropriate state according to each test, making it easier to perform the test more appropriately.

[0019] The range of the restricted area of ​​the fixation target centered on the focal position of the fixation target presenting optical system may be narrower than the movable range of the fixation target when measuring the eye refractive power. In this case, the restricted area is closer to the focal position of the fixation target presenting optical system, so that the light beam presented by the fixation target on the pupil of the test eye approaches appropriate parallelism. This more appropriately prevents the fixation target from appearing to move during acquisition of three-dimensional information.

[0020] The light-receiving optical system of the cross-sectional imaging optical system may be positioned in a Scheimpflug relationship with the light-section plane of the imaging light. In this case, using near-infrared light as the imaging light allows the imaging light to be appropriately scattered and easily captured by the light-receiving optical system. On the other hand, using near-infrared light as the imaging light may cause the subject to feel slight glare. Therefore, when measuring the ocular refractive power and acquiring three-dimensional information about the anterior segment of the eye, the ophthalmic apparatus may measure the ocular refractive power first. In this case, even if the subject feels glare and the pupil of the subject's eye constricts during acquisition of three-dimensional information about the anterior segment of the eye, there is no need to measure the ocular refractive power afterwards, thereby avoiding the problem of pupil constriction affecting the test results.

[0021] If the far point of the subject's eye is not within the restricted area, the control unit may first position the fixation target at the far point of the subject's eye, then move it to within the restricted area, and then start the three-dimensional information acquisition process. In this case, the fixation target becomes blurred after it is clearly recognized and the fixation of the subject's eye is stabilized. Therefore, the fixation of the subject's eye is more likely to be stabilized than when the fixation target is recognized in a blurred state from the beginning.

[0022] If the fixation target is already positioned at the far point of the subject's eye in the measurement of ocular refractive power before the acquisition of three-dimensional information of the anterior segment, the control unit can stabilize the fixation of the subject's eye by moving the fixation target that was positioned at the far point during the measurement of ocular refractive power directly into the restricted area. In other words, when both the measurement of ocular refractive power and the acquisition of three-dimensional information of the anterior segment of the eye are performed on the same subject's eye, the ophthalmic apparatus can also produce the effect of further stabilizing the fixation of the subject's eye by performing the measurement of ocular refractive power first.

[0023] However, the fixation target may be directly positioned within the restricted area without first being positioned at the far point of the subject's eye. Even in this case, the position of the fixation target seen by the subject is unlikely to move, so the fixation of the subject's eye is appropriately stabilized.

[0024] The control unit may acquire information on the size of the pupil of the subject's eye. When performing the three-dimensional information acquisition process, the control unit may determine a scanning movement amount by which the optical unit is moved to scan with the imaging light, depending on the size of the pupil diameter of the subject's eye.

[0025] When the pupil diameter of the subject's eye is large, the light beam presented by the fixation target easily passes through the pupil even when the optical unit including the fixation target presenting optical system is moved significantly. On the other hand, when the pupil diameter of the subject's eye is small, moving the optical unit significantly can easily cause the light beam presented by the fixation target not to pass through the pupil, resulting in the fixation target not being visible. Therefore, the control unit determines the scanning movement amount of the imaging light caused by moving the optical unit based on the pupil diameter of the subject's eye. As a result, at least a portion of the light beam presented by the fixation target easily passes through the pupil of the subject's eye appropriately. Therefore, three-dimensional information of the anterior segment can easily be obtained appropriately while the subject's fixation is stabilized.

[0026] A specific method for determining the scanning movement amount according to the size of the pupil diameter can be appropriately selected. For example, the scanning movement amount by which at least N% (e.g., N=50) of the light beam presented by the fixation target passes through the pupil of the subject's eye may be determined by a previously conducted experiment or simulation according to the size of the pupil diameter.

[0027] The method for acquiring the pupil diameter can also be selected appropriately. For example, the control unit may acquire an anterior-segment image in which the anterior segment of the subject's eye is photographed. The control unit may acquire the pupil diameter shown in the anterior-segment image based on the acquired anterior-segment image. For example, the pupil diameter may be calculated by known image processing, or a machine learning algorithm may be used.

[0028] The control unit may execute a notification process to notify the user of information regarding the scanning movement amount determined according to the size of the pupil diameter of the subject's eye. In this case, the user can take appropriate action after understanding the scanning movement amount. The method of notifying the user of the information regarding the scanning movement amount may also be selected appropriately. For example, the control unit may execute the notification process only when a scanning movement amount different from a normal scanning movement amount is determined. Furthermore, the control unit may notify the user of information indicating the scanning movement amount itself determined according to the size of the pupil diameter of the subject's eye. The timing of the notification process may be at least one of before, after, and during the three-dimensional information acquisition process.

[0029] The control unit may adjust the brightness of the illumination light source of the fixation target provided in the fixation target presenting optical system based on the size of the pupil diameter of the test eye and the scanning position of the imaging light by the moving unit, thereby bringing the light amount of the fixation target presenting light beam passing through the pupil of the test eye closer to a constant value.

[0030] Depending on the size of the pupil diameter of the subject's eye and the scanning position of the imaging light, the proportion of the light beam presented by the fixation target that passes through the pupil (i.e., the proportion of the light beam that passes through the pupil without being blocked by the iris) may change. In this case, the apparent brightness of the fixation target perceived by the subject changes, which may cause the subject to feel uncomfortable. In response to this, by making the amount of light of the light beam presented by the fixation target that passes through the pupil closer to a constant (for example, by adjusting the brightness of the illumination light source for the fixation target so that the brightness is inversely proportional to the proportion of the light beam presented by the fixation target that passes through the pupil), the apparent brightness of the fixation target perceived by the subject will become closer to a constant. This makes it easier for the subject to fixate the eye more appropriately.

[0031] A specific method for adjusting the brightness of the illumination light source for the fixation target can also be selected as appropriate. For example, information indicating the relationship between the scanning position of the imaging light and the proportion of the light beam presented by the fixation target that passes through the pupil may be obtained by a previous experiment or simulation, etc., depending on the pupil diameter of the subject's eye. Furthermore, for example, when the beam diameter of the light beam presented by the fixation target is changed, the control unit may adjust the brightness of the illumination light source for the fixation target by referring to the beam diameter of the light beam presented by the fixation target in addition to the pupil diameter and the scanning position of the imaging light.

[0032] The control unit may reduce the brightness of the imaging light projected by the cross-sectional imaging optical system when the pupil diameter of the subject's eye is smaller than the first threshold value, compared to when the pupil diameter is equal to or larger than the second threshold value. By reducing the brightness of the imaging light, the pupil diameter of the subject's eye is prevented from becoming smaller during acquisition of three-dimensional information. As a result, the possibility that the light beam presented by the fixation target will have difficulty passing through the pupil of the subject's eye is appropriately reduced.

[0033] When the control unit reduces the brightness of the imaging light, the control unit may increase the gain of the imaging element included in the cross-sectional imaging optical system, which prevents the pupil diameter of the subject's eye from becoming smaller and also prevents a decrease in the accuracy of capturing a cross-sectional image of the anterior segment.

[0034] Furthermore, the control unit may dim the brightness of the illumination light source for the fixation target provided in the fixation target presenting optical system when the pupil diameter of the subject's eye is smaller than a threshold value, compared to when the pupil diameter is equal to or larger than the threshold value. Dimming the brightness of the illumination light source for the fixation target makes it easier for the pupil of the subject's eye to dilate. As a result, the possibility that the light beam presented by the fixation target will have difficulty passing through the pupil of the subject's eye is appropriately reduced.

[0035] A larger pupil diameter of the subject's eye results in an effect such as making it easier for the light beam presented by the fixation target to pass through the pupil. On the other hand, a smaller pupil diameter of the subject's eye reduces the problem of the fixation target appearing blurred due to the increased depth of focus caused by the pupil itself. Therefore, if prioritizing the prevention of the problem of the subject's eye appearing blurred, the ophthalmic device may execute a process to promote pupil constriction of the subject's eye. For example, the control unit may increase the brightness of the illumination light source for the fixation target when the pupil diameter of the subject's eye is equal to or greater than a second threshold value compared to when the pupil diameter is smaller than the second threshold value. Furthermore, the control unit may increase the brightness of the illumination light source for the fixation target when the absolute value of the refractive power of the subject's eye is equal to or greater than a third threshold value compared to when the absolute value is smaller than the third threshold value. In this case, the brightness of the fixation target promotes pupil constriction of the subject's eye, thereby more easily reducing the problem of the fixation target appearing blurred. Furthermore, when the illumination light source for the fixation target is brightened, unlike when other light sources (for example, light sources provided in the installation environment of the ophthalmologic apparatus) are brightened, the problem of reduced accuracy in acquiring three-dimensional information due to the influence of unnecessary reflected light from the brightened light source is unlikely to occur. Note that the second threshold value may be the same value as the above-mentioned first threshold value, or may be a value different from the first threshold value.

[0036] The fixation target provided in the fixation target presenting optical system may be used to fogging the subject's eye by being moved in the optical axis direction. The fixation target used to fogging the subject's eye has a certain area when viewed from the optical axis direction. Therefore, by also using the fixation target used for fogging when acquiring three-dimensional information, it becomes easier to ensure the thickness of the light beam presented by the fixation target (i.e., the thickness of the light beam presented by the fixation target on the pupil of the subject's eye). As a result, the possibility that the light beam presented by the fixation target will have difficulty passing through the pupil is appropriately reduced.

[0037] On the other hand, the smaller the thickness of the light beam presented from the fixation target, the more effectively the fixation target appears blurred due to the depth of focus extension effect. Therefore, when prioritizing the prevention of the fixation target appearing blurred, the ophthalmologic device may execute a process to reduce the thickness of the light beam presented from the fixation target. For example, when the pupil diameter of the subject's eye is equal to or greater than a second threshold, the control unit may reduce the thickness of the light beam presented from the fixation target compared to when the pupil diameter is smaller than the second threshold. Furthermore, when the absolute value of the refractive power of the subject's eye is equal to or greater than a third threshold, the control unit may reduce the thickness of the light beam presented from the fixation target compared to when the absolute value is smaller than the third threshold. In this case, the depth of focus extension effect makes it easier to reduce the fixation target appearing blurred.

[0038] The control unit may acquire an anterior segment image of the anterior segment of the subject's eye, and detect the gaze direction of the subject's eye based on the acquired anterior segment image. The control unit may execute a warning process for the user when a deviation of the gaze direction of the subject's eye from the optical axis of the fixation target is equal to or greater than a threshold. As the deviation of the gaze direction from the optical axis of the fixation target increases, the accuracy of acquiring the three-dimensional shape of the anterior segment decreases. Therefore, the ophthalmologic device can appropriately reduce the possibility of acquiring and using an inaccurate three-dimensional shape by executing a warning process when a deviation of the gaze direction of the subject's eye from the optical axis of the fixation target is equal to or greater than a threshold.

[0039] It is also possible to employ only some of the techniques exemplified in this disclosure in an ophthalmic apparatus. For example, it is also possible to employ a technique for determining the amount of scanning movement depending on the pupil diameter of the subject's eye, rather than employing a technique for positioning the fixation target within a restricted area when performing three-dimensional information acquisition processing. In this case, the ophthalmic apparatus can also be expressed as follows:

[0040] an optical unit including the fixation target presenting optical system and the cross-sectional photographing optical system, which photographs an anterior segment of the eye to be examined by projecting photographing light onto the anterior segment of the eye to be examined and receiving return light from the anterior segment that has been optically cut by the photographing light, thereby photographing a cross-sectional image of the anterior segment of the eye; a moving unit which moves an optical unit including the fixation target presenting optical system and the cross-sectional photographing optical system relative to the eye to be examined; and a control unit, wherein the control unit is capable of performing a three-dimensional information acquisition process to acquire three-dimensional information about the anterior segment of the eye by moving the optical unit relative to the eye to scan with the photographing light and photographing cross-sectional images of multiple locations on the anterior segment of the eye, and when performing the three-dimensional information acquisition process, the control unit determines a scanning movement amount by which the optical unit is moved to scan with the photographing light according to the size of the pupil diameter of the eye to be examined.

[0041] <Embodiment> (Overall composition) A typical embodiment of the present disclosure will be described below. An ophthalmic apparatus 10 of this embodiment can acquire three-dimensional information about the anterior segment of a subject's eye E. As shown in FIG. 1 , the ophthalmic apparatus 10 of this embodiment includes an optical unit 11, a base 12, a moving unit 13, a face support unit 15, a display unit 16, and a control unit 50.

[0042] The optical unit 11 includes an optical system (such as a measurement system and an imaging system) used to examine the subject's eye E. In particular, the optical unit 11 of this embodiment includes a fixation target presenting optical system 150 (see FIG. 2) and a cross-sectional imaging optical system 300 (see FIG. 2). The moving unit 13 moves the position of the optical unit 11 relative to the subject's eye E. The moving unit 13 of this embodiment moves the optical unit 11 three-dimensionally relative to the base 12, thereby moving the optical unit 11 in the X direction (left-right direction), Y direction (up-down direction), and Z direction (front-back direction) relative to the subject's eye E. The face support unit 15 fixes the subject's face in front of the optical unit 11. The face support unit 15 is fixed to the base 12 and supports the subject's face, thereby fixing the position of the subject's eye E. The display unit 16 and the control unit 50 will be described later.

[0043] (optical system) 2, the ophthalmic apparatus 10 of this embodiment includes an eye refractive power measuring optical system 100, a fixation target presenting optical system 150, a front photographing optical system 200, a cross-sectional photographing optical system 300, and an alignment target projecting optical system 400. The ophthalmic apparatus 10 of this embodiment also includes half mirrors 501, 502, and 503 that branch and combine the optical paths of the respective optical systems, an objective lens 505, and the like.

[0044] (Ocular refractive power measurement optical system) The eye refraction measurement optical system 100 objectively measures the eye refraction of the subject's eye E. For example, the eye refraction measurement optical system 100 measures the spherical power (S), cylindrical power (C), and astigmatic axis angle (A) of the subject's eye E as the measurement results of the eye refraction. As an example, the eye refraction measurement optical system 100 of this embodiment includes a projection optical system 100a and a light-receiving optical system 100b. The projection optical system 100a includes a measurement light source and projects a spot-shaped measurement light onto the fundus of the subject's eye E through the center of the pupil of the subject's eye E. The light-receiving optical system 100b includes an imaging element and extracts the measurement light reflected from the fundus in a ring shape through the periphery of the pupil and receives it at the imaging element. The ring image formed on the imaging element is analyzed to derive the eye refraction (the values ​​of S, C, and A). The light receiving optical system 100b may include a so-called Shack-Hartmann wavefront sensor. In this case, the wavefront aberration of the subject's eye E is measured, and the subject's eye E is The distribution of eye refractive power at different positions in the pupil of E is obtained.

[0045] (fixation target presentation optical system) The fixation target presenting optical system 150 presents a fixation target to the subject's eye E. The fixation target is presented on the optical axis of the objective lens 505. The fixation target presenting optical system 150 is used to fixate the subject's eye E. The fixation target presenting optical system 150 of this embodiment includes an illumination light source 151 that emits visible light and a fixation target plate 155. A light beam from the illumination light source 151 (a fixation target presenting light beam) passes through the fixation target plate 155 and a lens 156 on the optical axis L2 of the fixation target presenting optical system 150, and then passes through a half mirror 503. The fixation target presenting light beam then passes through a lens 504, passes through a half mirror 502, and is reflected by a half mirror 501, becoming coaxial with the optical axis L1. The fixation target presenting light beam further passes through the objective lens 505 to reach the subject's eye E.

[0046] The fixation target presenting optical system 150 includes a fixation target moving unit 161 that moves the fixation target plate 155 in a direction along the optical axis L2. When measuring eye refractive power using the eye refractive power measurement optical system 100, the fixation target presenting optical system 150 is used to apply fogging and accommodative load to the subject's eye E by moving the fixation target plate 155. The fixation target plate 155 used to fogging the subject's eye E has a certain area when viewed from the optical axis direction. Therefore, when the fixation target plate 155 used to fogging is used for fixation, it becomes easier to ensure the thickness of the light beam presented by the fixation target (i.e., the thickness of the light beam presented by the fixation target on the pupil of the subject's eye E). Furthermore, when measuring eye refractive power, the fixation target moving unit 161 also moves the measurement light source of the projection optical system 100a and the imaging element of the light receiving optical system 100b in the optical axis direction together with the fixation target plate 155.

[0047] (Frontal imaging optical system) The front imaging optical system 200 captures a front image of the anterior segment of the subject's eye E (hereinafter referred to as "anterior segment image"). The front imaging optical system 200 includes an imaging element 205. The imaging element 205 may be disposed at a pupil conjugate position of the anterior segment of the subject's eye E. A moving image of the anterior segment image may be used as an observation image of the anterior segment. In addition, an index image projected onto the cornea of ​​the subject's eye E by the alignment index projection optical system 400 is captured in the anterior segment image and is used for alignment, etc.

[0048] (Cross-sectional imaging optical system) The cross-section photographing optical system 300 photographs a cross-sectional image of the anterior segment of the eye, and includes a light projecting optical system 300a and a light receiving optical system 300b.

[0049] The projection optical system 300a projects imaging light (slit light in this embodiment) onto the anterior segment of the subject's eye E on an optical axis (optical axis L1) passing through the objective lens 505. The projection optical system 300a includes a light source 311 and a slit 312. The light source 311 may be an SLD light source, an LED light source, or another light source. In this embodiment, red visible light or near-infrared light having a peak wavelength between 650 nm and 800 nm is used as the imaging light. The slit 312 may be disposed at a pupil conjugate position. In this disclosure, a cross section of the anterior segment of the subject's eye E through which the slit light passes is referred to as a "cutting plane." The cutting plane is the object plane of the cross-sectional imaging optical system 300. In this embodiment, the slit light is projected onto the anterior segment so as to optically cut the anterior segment in the horizontal direction (X direction). Therefore, in this embodiment, a horizontal plane (X-Z cross section) including the optical axis L1 is formed as the cutting plane. In this embodiment, the cutting surface is formed at least between the anterior surface of the cornea and the posterior surface of the lens in the anterior segment of the eye E to be examined.

[0050] The light receiving optical system 300b includes a lens system 322, an imaging element 321, etc. The lens system 322 and imaging element 321 of the light receiving optical system 300b are disposed in a Scheimpflug relationship with a cutting plane set in the anterior segment of the subject's eye E. That is, the optical system is disposed so that the cutting plane, the principal plane of the lens system 322, and each extension plane of the imaging surface of the imaging element 321 intersect at a single intersection line (single axis). The imaging element 321 receives return light (reflected light or scattered light) from the anterior segment that has been optically cut by the slit light. A cross-sectional image of the anterior segment is acquired based on a signal from the imaging element 321.

[0051] The imaging light beam from the light source 311 passes through a slit 312 on the optical axis L3 to become a slit light beam. After passing through a lens 313, the imaging light beam is reflected by a half mirror 503, becoming coaxial with the optical axis L2. The imaging light beam from the light source 311 then passes through a lens 504, transmits through a half mirror 502, and is reflected by a half mirror 501, becoming coaxial with the optical axis L1. The imaging light beam from the light source 311 then passes through an objective lens 505 to reach the anterior segment of the subject's eye E. Return light from a cut surface formed in the anterior segment reaches the imaging element 321 via a lens 322. The lens system 322 is coated with a wavelength-selective filter that cuts out the wavelengths of the light sources (light source 401, point light source 421, and point light source 431) of the alignment target projection optical system 400 and transmits the wavelength of the imaging light from the light source 311. As a result, the alignment light is prevented from becoming noise when a cross-sectional image of the anterior segment is captured.

[0052] (Alignment target projection optical system) The alignment target projection optical system 400 is used to align (position) the optical unit 11 with respect to the subject's eye E. The alignment target projection optical system 400 projects an alignment target onto the cornea of ​​the subject's eye E. The alignment target projection optical system 400 includes a first target projection optical system 400A and a second target projection optical system 400B.

[0053] The first target projection optical system 400A projects a target for aligning the optical unit 11 with respect to the eye E in the X and Y directions onto the cornea of ​​the eye E. The first target projection optical system 400A includes a light source 401 that emits near-infrared light (e.g., 900 to 1000 nm), a collimator lens 403, and a half mirror 405. The light emitted from the light source 401 is converted into a substantially parallel beam by the collimator lens 403, and is reflected by the half mirror 405 to be coaxial with the optical axis L1. The light is then projected toward the eye E from the front direction. As a result, a corneal reflection bright spot (target image) of the Purkinje image is formed at the center of the cornea by reflection from the cornea of ​​the eye E. The corneal reflection bright spot is captured in an anterior eye image captured by the front imaging optical system 200. Based on the captured corneal reflection bright spot, the alignment state of the optical unit 11 with respect to the eye E in the X and Y directions is detected. The light source 401 of the first target projection optical system 400A may be a ring-shaped light source arranged around the optical axis L1. In this case, a Mayer ring target is projected onto the cornea of ​​the subject's eye E, and the corneal center is detected based on the center of the Mayer ring image formed by reflection from the cornea. The Mayer ring image may also be used to measure the shape of the anterior corneal surface. As the shape of the anterior corneal surface, the values ​​of the corneal curvature, the astigmatic power, and the astigmatic axis angle in the area where the Mayer ring target is projected may be acquired.

[0054] The second target projection optical system 400B projects a target onto the cornea of ​​the subject's eye E for aligning the optical unit 11 in the Z direction with respect to the subject's eye E. The second target projection optical system 400B includes a point light source 421 that projects a target at a finite distance and a point light source 431 that projects a target at an infinity distance via a collimator lens. The point light source 421 and the point light source 431 emit infrared light (e.g., light with a wavelength of 900 to 1000 nm). The point light source 421 and the point light source 431 are respectively arranged symmetrically in the vertical direction and the horizontal direction with respect to the optical axis L1. The target image formed by the second target projection optical system 400B is captured in an anterior eye image captured by the front imaging optical system 200. For example, the control unit 50 moves the optical unit 11 in the forward and backward directions so that the interval between the index images (Purkinje images) formed by the symmetrical point light source 421 and the interval between the index images (Purkinje images) formed by the symmetrical point light source 431 are captured at a predetermined ratio, thereby adjusting the alignment in the Z direction.

[0055] (Control system) The control unit 50 is responsible for overall control of the ophthalmic apparatus 10. The control unit 50 is connected to various electrical elements such as the imaging element 205, the imaging element 321, the imaging element of the eye refractive power measurement optical system 100, each light source, the display unit 16, and the moving unit 13. The control unit 50 processes cross-sectional images of the anterior eye segment acquired by the optical unit 11 and various other examination results. The display unit 16 functions as a touch panel that also serves as an operation unit. The display unit 16 displays measurement results of the subject's eye E (cross-sectional images of the anterior eye segment, measurement results of eye refractive power, etc.). The control unit 50 is connected to a memory 52, which is an example of a storage device. The memory 52 may store an ophthalmic apparatus control program, etc.

[0056] (Scanning of the shooting light) As shown in FIG. 3 , in this embodiment, the moving unit 13 moves the optical unit 11, which includes the fixation target presenting optical system 150 and the cross-section photographing optical system 300, relative to the eye E (in the direction of the arrow in FIG. 3 ) to capture cross-sectional images of multiple locations in the anterior segment of the eye E to acquire three-dimensional information about the anterior segment. As a result, the photographing light projected by the cross-section photographing optical system 300 scans the anterior segment of the eye E. In this embodiment, slit light (photographing light) is projected onto the anterior segment so as to optically cut the horizontal direction (X direction) of the eye E. Therefore, the moving unit 13 moves the optical unit 11 in the vertical direction (Y direction) to scan the anterior segment with the slit light. Note that when the slit light is projected onto the anterior segment so as to optically cut the vertical direction (Y direction) of the eye E, the moving unit 13 may also move the optical unit 11 in the X direction.

[0057] In this embodiment, the configuration and control of the device are unlikely to become complicated because there is no need to move the fixation target presenting optical system 150 and the cross-section photographing optical system 300 separately with respect to the subject's eye E. However, if both the fixation target presenting optical system 150 and the cross-section photographing optical system 300 are moved relative to the subject's eye E, problems may occur such as the position of the fixation target seen by the subject moving, or the light beam of the fixation target deviating from the pupil of the subject's eye, making the fixation target invisible.

[0058] (Position where fixation target is visible) 4A and 4B are schematic diagrams comparing changes in the light beam presented by the fixation target when the fixation target presenting optical system 150 is moved in the Y direction with a fixation target positioned at the far point of the subject's eye E, whose refractive power is X[D] (X≠0). When the subject's eye E does not have a refractive power of 0D, the far point of the subject's eye E is shifted from the focal position of the entire lens system of the fixation target presenting optical system 150, including the objective lens 505 (hereinafter, sometimes simply referred to as the "focal position of the fixation target presenting optical system 150"). Therefore, the distance between the fixation target and the subject's eye E is finite. Therefore, as shown in FIG. 4, when the subject's eye E is myopic, the light beam presented by the fixation target is incident on the pupil of the subject's eye E at a certain divergence angle. When the subject's eye E is hyperopic, the light beam presented by the fixation target is incident on the pupil of the subject's eye E at a certain convergence angle. In this state, when the fixation target presenting optical system 150 is moved in the Y direction, the angle of incidence of the light beam presented by the fixation target onto the subject's eye E changes depending on the position of the fixation target in the Y direction, as shown in Figures 4(A) and 4(B). As a result, the fixation target appears to move to the subject. When the fixation target appears to move, the fixation of the subject's eye E is likely to become unstable.

[0059] 5A and 5B are schematic diagrams comparing the light beams presented by the fixation target when the fixation target presenting optical system 150 is moved in the Y direction while the fixation target is positioned at infinity for the test eye E, whose ocular refractive power is 0 [D]. When the fixation target is positioned at infinity (i.e., when the fixation target is positioned at the focal position of the fixation target presenting optical system 150), the light beams presented by the fixation target become parallel rays on the pupil of the test eye E. Even if the fixation target presenting optical system 150 is moved in the Y direction in this state, the angle of incidence of the light beams presented by the fixation target onto the test eye E does not change, so the presented light beams are focused at the same position on the retina. Therefore, even if the fixation target presenting optical system 150 is moved in the Y direction, the fixation target appears stationary to the test subject. However, the brightness of the fixation target perceived by the test subject may change due to a change in the amount of light beams blocked by the iris.

[0060] 6A and 6B are schematic diagrams comparing the light beams presented by the fixation target when the fixation target presenting optical system 150 is moved in the Y direction while the fixation target is positioned at infinity for the test eye E, whose ocular refractive power is X[D] (X≠0). When the ocular refractive power of the test eye E is not 0D, the position of the far point of the test eye E is shifted from the focal position of the fixation target presenting optical system 150. Therefore, when the fixation target is positioned at infinity (i.e., when the fixation target is positioned at the focal position of the fixation target presenting optical system 150), the fixation target appears blurred to the test subject. However, when the fixation target is positioned at the focal position of the fixation target presenting optical system 150, the presented light beams are focused at the same position on the retina even when the fixation target presenting optical system 150 is moved in the Y direction, so the fixation target appears stationary to the test subject.

[0061] Therefore, when the ophthalmic apparatus 10 of this embodiment moves the optical unit 11 to acquire three-dimensional information about the anterior segment, the position of the fixation target in the direction along the optical axis of the fixation target presenting optical system 150 is positioned within a limited area centered on the focal position of the fixation target presenting optical system 150, regardless of the refractive power of the subject's eye E. As a result, a problem in which the position of the fixation target seen by the subject moves even when the optical unit 11 is moved is appropriately suppressed. Furthermore, the ophthalmic apparatus 10 of this embodiment does not need to be provided with a complex configuration for moving the cross-section photographing optical system 300 while fixing the position of the fixation target presenting optical system 150. Therefore, the ophthalmic apparatus 10 of this embodiment can appropriately acquire three-dimensional information about the anterior segment while stabilizing the fixation of the subject's eye E.

[0062] Furthermore, when acquiring three-dimensional information of the anterior segment, the ophthalmologic apparatus 10 of this embodiment moves the position of the fixation target in a limited area centered on the focal position of the fixation target presenting optical system 150 in a direction approaching the far point of the subject's eye E according to the refractive power of the subject's eye E. Therefore, the presented light beam of the fixation target on the pupil of the subject's eye E is maintained in a state close to parallel light (that is, the problem of the fixation target appearing to move is suppressed), and the degree of blur of the fixation target as viewed by the subject is appropriately suppressed.

[0063] The range of the restricted area centered on the focal position of the fixation target presenting optical system 150 is narrower than the movable range when the position of the fixation target is moved to the far point of the subject's eye E according to the refractive power of the subject's eye E (in this embodiment, the movable range of the fixation target when measuring the eye's refractive power by the eye refractive power measurement optical system 100). Therefore, since the restricted area is close to the focal position of the fixation target presenting optical system 150, when the fixation target is positioned within the restricted area, the presented light beam of the fixation target on the pupil of the subject's eye E approaches appropriate parallelism. This more appropriately suppresses the problem of the fixation target appearing to move while three-dimensional information of the anterior segment is being acquired.

[0064] (scanning movement amount) 7, the scanning movement amount of the imaging light (which can also be said to be the scanning movement amount of the optical unit 11) in this embodiment will be described. As described above, in the ophthalmologic apparatus 10 of this embodiment, in order to acquire three-dimensional information of the anterior segment of the subject's eye E, the optical unit 11 including the fixation target presenting optical system 150 and the cross-section imaging optical system 300 is moved relatively with respect to the subject's eye E. As a result, the imaging light projected by the cross-section imaging optical system 300 scans the anterior segment of the subject's eye E.

[0065] 7(A), if the diameter of the pupil Ep of the subject's eye E is large, the light beam presented by the fixation target is likely to pass through the pupil Ep even if the optical unit 11 is moved significantly (i.e., even if the scanning movement amount of the imaging light is increased). On the other hand, as shown in FIG. 7(B), if the optical unit 11 is moved significantly (i.e., if the scanning movement amount of the imaging light is increased) even though the diameter of the pupil of the subject's eye E is small, the light beam presented by the fixation target does not pass through the pupil Ep, and the subject is likely to not be able to see the fixation target.

[0066] Therefore, the ophthalmologic apparatus 10 of this embodiment determines the scanning movement amount of the imaging light caused by the movement of the optical unit 11 based on the size of the pupil diameter of the subject's eye E. As a result, at least a portion of the light beam presented by the fixation target is more likely to pass appropriately through the pupil Ep of the subject's eye E. Therefore, it becomes easier to appropriately acquire three-dimensional information of the anterior segment of the eye while stabilizing the fixation of the subject's eye E.

[0067] In this embodiment, the scanning movement amount by which at least N% (for example, N=50) of the light flux presented by the fixation target passes through the pupil Ep of the subject's eye E is determined by a previously conducted experiment or simulation according to the size of the pupil diameter. Therefore, the scanning movement amount is appropriately determined according to the size of the pupil diameter.

[0068] Furthermore, the ophthalmologic apparatus 10 of this embodiment acquires an anterior eye image of the subject's eye E captured in real time by the front imaging optical system 200 (see FIG. 2 ), and acquires the size of the pupil diameter captured in the anterior eye image based on the acquired anterior eye image. Therefore, the size of the pupil diameter of the subject's eye E is appropriately acquired. Note that the size of the pupil diameter may be calculated by known image processing of the anterior eye image. Alternatively, the size of the pupil diameter may be acquired by inputting the captured anterior eye image into a mathematical model trained according to a machine learning algorithm to output the size of the pupil diameter.

[0069] (Main processing) The main processing executed by the ophthalmic apparatus 10 of this embodiment will be described with reference to Fig. 8. The main processing illustrated in Fig. 8 is executed by the control unit 50 of the ophthalmic apparatus 10 in accordance with an ophthalmic apparatus control program stored in the memory 52. ​​In the main processing, at least one of an eye refractive power measurement process (S5) by the eye refractive power measurement optical system 100 and a process (S19) of acquiring three-dimensional information of the anterior eye segment by the cross-section photographing optical system 300 and the moving unit 13 is executed.

[0070] As described above, the light-receiving optical system 300b of the cross-section imaging optical system 300 is disposed in a Scheimpflug relationship with the light-section plane of the imaging light. In this case, using near-infrared light as the imaging light allows the imaging light to be appropriately scattered, making it easier for the imaging light to be captured by the light-receiving optical system 300b. On the other hand, using near-infrared light as the imaging light may cause the subject to feel slight glare. Therefore, when both the eye refractive power measurement process (S5) and the anterior segment three-dimensional information acquisition process (S19) are performed on the same subject's eye E, the ophthalmologic apparatus 10 performs the eye refractive power measurement process (S5) first. In this case, even if the subject feels glare during acquisition of the anterior segment three-dimensional information and the pupil of the subject's eye E constricts, there is no need to perform the eye refractive power measurement process thereafter. This avoids the problem of pupil constriction affecting the examination results.

[0071] First, the ophthalmic apparatus 10 performs alignment processing of the optical unit 11 with respect to the subject's eye E based on an anterior eye image captured by the front-view imaging optical system 200 (S1). Next, the ophthalmic apparatus 10 positions a fixation target at the far point of the subject's eye E according to the ocular refractive power of the subject's eye E (S2), regardless of whether or not an ocular refractive power measurement processing (S5) is performed. If ocular refractive power measurement is to be performed (S4: YES), the ocular refractive power measurement processing is performed with the fixation target positioned at the far point of the subject's eye E (S5). As a result, the subject can clearly view the fixation target during the ocular refractive power measurement, thereby stabilizing fixation. If ocular refractive power measurement is not to be performed (S4: NO), the process proceeds to S7 with the fixation target positioned at the far point of the subject's eye E.

[0072] Next, the ophthalmologic apparatus 10 determines whether or not to acquire three-dimensional information of the anterior segment (S7). If three-dimensional information is not to be acquired (S7: NO), the main processing ends. If three-dimensional information of the anterior segment is to be acquired (S7: YES), the ophthalmologic apparatus 10 positions the fixation target within a restricted area centered on the focal position of the fixation target presenting optical system 150, regardless of the refractive power of the subject's eye E (S8). As a result, the problem of the position of the fixation target seen by the subject moving is appropriately suppressed.

[0073] In S8 of this embodiment, the ophthalmologic apparatus 10 places the fixation target at a position close to the far point of the subject's eye E within a limited area centered on the focal position of the fixation target presenting optical system 150. As a result, the presented light beam of the fixation target on the pupil of the subject's eye E is maintained in a state close to parallel light (i.e., the problem of the fixation target appearing to move is suppressed), and the degree of blur of the fixation target as viewed by the subject is appropriately suppressed.

[0074] In detail, when the far point of the subject's eye E is within the restricted area, the ophthalmologic apparatus 10 of this embodiment moves the fixation target to the far point of the subject's eye E within the restricted area. When the far point of the subject's eye E is not within the restricted area, the ophthalmologic apparatus 10 moves the position of the fixation target to a position within the restricted area that is closer to the far point of the subject's eye E. As a result, the fixation target is presented in a state appropriate for the refractive power of the subject's eye E.

[0075] Furthermore, in this embodiment, if the far point of the subject's eye E is not within the restricted area, the position of the fixation target is temporarily positioned at the far point of the subject's eye E (S2) and then moved to within the restricted area (S8). In this state, the process of acquiring three-dimensional information of the anterior segment of the eye (S19) is started. In this case, the fixation target becomes blurred after it is clearly recognized and the fixation of the subject's eye E is stabilized. Therefore, the fixation of the subject's eye E is more likely to be stabilized than when the fixation target is recognized in a blurred state from the beginning.

[0076] If the fixation target has already been placed at the far point of the subject's eye E in the eye refraction measurement process (S5) before the anterior eye three-dimensional information acquisition process (S19) is executed, the ophthalmic apparatus 10 can stabilize the fixation of the subject's eye E by moving the fixation target that was placed at the far point during the eye refraction measurement directly into the restricted area. In other words, when the eye refraction measurement process (S5) and the anterior eye three-dimensional information acquisition process (S19) are both executed on the same subject's eye E, the ophthalmic apparatus 10 can also produce the effect of further stabilizing the fixation of the subject's eye E by executing the eye refraction measurement process (S5) first.

[0077] Next, the ophthalmic apparatus 10 acquires the latest anterior segment image of the subject's eye E captured by the frontal imaging optical system 200, and detects the gaze direction of the subject's eye E based on the acquired anterior segment image (S9). A specific method for detecting the gaze direction of the subject's eye E can be selected as appropriate. For example, the ophthalmic apparatus 10 may detect the gaze direction of the subject's eye E based on the deviation between the center position of the pupil of the subject's eye E captured in the anterior segment image and the center position of the cornea of ​​the subject's eye E calculated based on an alignment target captured in the anterior segment image. Alternatively, the gaze direction of the subject's eye E may be detected simply based on the center position of the cornea of ​​the subject's eye E.

[0078] The ophthalmologic apparatus 10 determines whether the deviation of the gaze direction of the subject's eye E from the optical axis of the fixation target is equal to or greater than a threshold (S11). If the deviation is less than the threshold (S11: NO), the process proceeds directly to S14. If the deviation of the gaze direction of the subject's eye E is equal to or greater than the threshold (S11: YES), the ophthalmologic apparatus 10 executes a warning process for the user (S12), and the process proceeds to S14. Therefore, the warning process appropriately reduces the possibility that a low-accuracy three-dimensional shape will be acquired and used.

[0079] Next, the ophthalmic apparatus 10 acquires the size of the pupil diameter of the subject's eye E (S14). As described above, the ophthalmic apparatus 10 of this embodiment can acquire the size of the pupil diameter of the subject's eye E shown in the anterior segment image based on the latest anterior segment image of the subject's eye E captured by the front imaging optical system 200. The ophthalmic apparatus 10 determines the scanning movement amount of the imaging light for capturing a cross-sectional image of the anterior segment according to the size of the pupil diameter acquired in S14 (S15). As a result, at least a portion of the light beam presented by the fixation target is more likely to pass through the pupil of the subject's eye E appropriately.

[0080] Next, the ophthalmic apparatus 10 determines whether the pupil diameter of the subject's eye E acquired in S14 is less than a first threshold (S16). If the pupil diameter is less than the first threshold (S16: YES), the ophthalmic apparatus 10 reduces the brightness of the imaging light projected onto the subject's eye E by the cross-sectional imaging optical system and increases the gain of the imaging element 321 of the cross-sectional imaging optical system 300 compared to when the pupil diameter is equal to or greater than the first threshold (S17). As a result, the pupil diameter of the subject's eye E is prevented from becoming smaller during acquisition of three-dimensional information. Furthermore, increasing the gain of the imaging element 321 also prevents a decrease in the imaging accuracy of the cross-sectional image. Furthermore, if the pupil diameter is less than the first threshold (S16: YES), the ophthalmic apparatus 10 reduces the brightness of the illumination light source 151 of the fixation target provided in the fixation target presenting optical system 150 compared to when the pupil diameter is equal to or greater than the first threshold. Reducing the brightness of the illumination light source 151 of the fixation target makes it easier for the pupil of the subject's eye E to dilate. As a result, the possibility that the light beam presented by the fixation target will have difficulty passing through the pupil of the eye E to be examined is appropriately reduced.

[0081] Next, with the fixation target positioned within the restricted area, the ophthalmologic apparatus 10 controls the movement of the optical unit 11 according to the scanning movement amount of the imaging light determined in S15, thereby acquiring three-dimensional information about the anterior segment of the eye (S19). The ophthalmologic apparatus 10 of this embodiment adjusts the brightness of the fixation target illumination light source 151 provided in the fixation target presenting optical system 150 based on the pupil diameter of the subject's eye E and the scanning position of the imaging light by the moving unit 13 while acquiring three-dimensional information about the anterior segment of the eye, thereby keeping the amount of light of the fixation target presenting light beam passing through the pupil of the subject's eye E close to a constant (S19). Depending on the pupil diameter of the subject's eye E and the scanning position of the imaging light, the proportion of the portion of the fixation target presenting light beam that passes through the pupil (i.e., the proportion of the portion that passes through the pupil without being blocked by the iris) may change. In this case, the apparent brightness of the fixation target perceived by the subject changes, which may cause the subject to feel uncomfortable. In contrast, by making the amount of light of the light beam presented by the fixation target that passes through the pupil closer to a constant value (for example, by adjusting the brightness of the illumination light source of the fixation target so that the brightness of the illumination light source of the fixation target is inversely proportional to the proportion of the light beam presented by the fixation target that passes through the pupil), the apparent brightness of the fixation target as perceived by the subject becomes closer to a constant value. This makes it easier for the subject's eye E to fixate more appropriately. In this embodiment, information indicating the relationship between the scanning position of the imaging light and the proportion of the light beam presented by the fixation target that passes through the pupil is obtained by experiments or simulations conducted in advance according to the size of the pupil diameter of the subject's eye E. Therefore, the brightness of the illumination light source 151 of the fixation target is adjusted appropriately.

[0082] Next, the ophthalmologic apparatus 10 executes a notification process to notify the user of information regarding the scanning movement amount determined according to the size of the pupil diameter of the subject's eye E. As a result, the user can take appropriate measures after understanding the scanning movement amount. After that, the main process ends.

[0083] The techniques disclosed in the above embodiments are merely examples. Therefore, the techniques exemplified in the above embodiments can be modified. For example, it is possible to cause the ophthalmologic apparatus 10 to execute only some of the processes exemplified in FIG. 8. As an example, when acquiring three-dimensional information about the anterior segment of the eye, it is possible to execute a process (S15) that determines the scanning movement amount of the imaging light depending on the size of the pupil diameter, without executing a process (S8) that positions the fixation target within a restricted area.

[0084] As described above, a larger pupil diameter of the subject's eye E has the effect of making it easier for the light beam presented by the fixation target to pass through the pupil. On the other hand, a smaller pupil diameter of the subject's eye E reduces the problem of the fixation target appearing blurred due to the increased depth of focus caused by the pupil itself. Therefore, if priority is given to reducing the problem of the subject's eye E appearing blurred, the ophthalmic apparatus 10 may execute a process to promote pupil constriction of the subject's eye E. For example, when the pupil diameter of the subject's eye E is equal to or greater than a second threshold, the ophthalmic apparatus 10 may increase the brightness of the illumination light source 151 for the fixation target compared to when the pupil diameter is smaller than the second threshold. Furthermore, when the absolute value of the refractive power of the subject's eye E is equal to or greater than a third threshold, the ophthalmic apparatus 10 may increase the brightness of the illumination light source 151 for the fixation target compared to when the absolute value is smaller than the third threshold. In this case, the brightness of the fixation target encourages the pupil of the subject's eye E to constrict, which makes it easier to prevent the fixation target from appearing blurred. Furthermore, when the illumination light source for the fixation target is brightened, unlike when other light sources (for example, light sources provided in the installation environment of the ophthalmic device) are brightened, the problem of reduced accuracy in obtaining three-dimensional information due to the influence of unnecessary reflected light from the brightened light source is less likely to occur.

[0085] Furthermore, the thicker the light beam presented by the fixation target, the more easily the light beam presented by the fixation target passes through the pupil of the subject's eye E. On the other hand, the thinner the light beam presented by the fixation target, the more effectively the fixation target is prevented from appearing blurred due to the effect of expanding the depth of focus. Therefore, when prioritizing the prevention of the fixation target from appearing blurred, the ophthalmic apparatus 10 may execute a process of thinning the light beam presented by the fixation target using a variable diaphragm or the like provided in the optical path of the light beam presented by the fixation target. For example, when the pupil diameter of the subject's eye E is equal to or greater than a second threshold, the ophthalmic apparatus 10 may thin the light beam presented by the fixation target compared to when the pupil diameter is smaller than the second threshold. Furthermore, when the absolute value of the refractive power of the subject's eye is equal to or greater than a third threshold, the ophthalmic apparatus 10 may thin the light beam presented by the fixation target compared to when the absolute value is smaller than the third threshold. In this case, the effect of expanding the depth of focus makes it easier to suppress the problem of the fixation target appearing blurred. [Explanation of symbols]

[0086] 10 Ophthalmology equipment 11 Optical unit 13 Moving section 50 control section 52 memory 100 Eye refractive power measurement optical system 150 Fixation target presentation optical system 151 Lighting source 155 Fixation target 161 Fixation target moving unit 200 Frontal imaging optical system 300 Cross-sectional imaging optical system 505 Objective Lens

Claims

1. a fixation target presenting optical system that presents a fixation target to the subject's eye; a cross-sectional imaging optical system that projects imaging light onto an anterior segment of the subject's eye and receives return light from the anterior segment that has been optically cut by the imaging light, thereby capturing a cross-sectional image of the anterior segment; a moving unit that moves an optical unit including the fixation target presenting optical system and the cross-section photographing optical system relative to the subject's eye; A control unit; Equipped with The control unit a three-dimensional information acquisition process can be executed to acquire three-dimensional information of the anterior eye segment by capturing cross-sectional images of a plurality of locations of the anterior eye segment while moving the optical unit relative to the subject's eye and scanning the imaging light, An ophthalmic device characterized in that, when performing the three-dimensional information acquisition process, the position of the fixation target in a direction along the optical axis of the fixation target presenting optical system is positioned within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the test eye.

2. The ophthalmic apparatus according to claim 1, The control unit An ophthalmologic apparatus characterized in that, when performing the three-dimensional information acquisition process, the position of the fixation target is positioned within the restricted area at a position close to the far point of the test eye, depending on the refractive power of the test eye.

3. 3. The ophthalmologic apparatus according to claim 1, further comprising an eye refractive power measuring optical system for measuring the eye refractive power of the subject's eye; The control unit When measuring the ocular refractive power of the subject's eye by the ocular refractive power measuring optical system, the position of the fixation target in a direction along the optical axis of the fixation target presenting optical system is set to a far point of the subject's eye according to the refractive power of the subject's eye; An ophthalmic device characterized in that, when performing the three-dimensional information acquisition process, the position of the fixation target in a direction along the optical axis of the fixation target presenting optical system is positioned within a limited area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the test eye.

4. 4. An ophthalmic apparatus according to claim 1, The control unit An ophthalmic device characterized in that, if the far point of the test eye is not within the restricted area, the position of the fixation target is first positioned at the far point of the test eye, and then moved into the restricted area, and the three-dimensional information acquisition process is started.

5. 5. An ophthalmic apparatus according to claim 1, The control unit acquiring information on the size of the pupil diameter of the subject's eye; an ophthalmologic apparatus characterized in that, when performing the three-dimensional information acquisition process, a scanning movement amount by which the optical unit is moved to scan the imaging light is determined according to the size of the pupil diameter of the subject's eye.

6. 6. An ophthalmic apparatus according to claim 1, The control unit An ophthalmic device characterized by adjusting the brightness of the illumination light source of the fixation target provided in the fixation target presenting optical system based on the size of the pupil diameter of the test eye and the scanning position of the imaging light by the moving unit, thereby making the light amount of the light beam presenting the fixation target that passes through the pupil of the test eye closer to a constant value.

7. 7. An ophthalmic apparatus according to claim 1, The control unit an ophthalmologic apparatus, characterized in that, when the size of the pupil diameter of the subject's eye is smaller than a threshold value, the brightness of the photographing light projected by the cross-sectional photographing optical system is made darker than when the size of the pupil diameter is equal to or larger than the threshold value.

8. 8. An ophthalmic apparatus according to claim 1, An ophthalmologic apparatus, characterized in that the fixation target provided in the fixation target presenting optical system can be used to fogging the subject's eye by being moved in the direction of an optical axis.

9. 9. An ophthalmic apparatus according to claim 1, The control unit acquiring an anterior ocular segment image of the anterior ocular segment of the subject's eye; Detecting a gaze direction of the subject's eye based on the acquired anterior eye image; An ophthalmologic apparatus comprising: an ophthalmologic apparatus configured to execute a warning process for a user when a deviation of a line of sight of the subject's eye from an optical axis of the fixation target is equal to or greater than a threshold value.

10. An ophthalmic apparatus control program executed in an ophthalmic apparatus, The ophthalmic device includes: a fixation target presenting optical system that presents a fixation target to the subject's eye; a cross-sectional imaging optical system that projects imaging light onto an anterior segment of the subject's eye and receives return light from the anterior segment that has been optically cut by the imaging light, thereby capturing a cross-sectional image of the anterior segment; a moving unit that moves an optical unit including the fixation target presenting optical system and the cross-section photographing optical system relative to the subject's eye; A control unit; Equipped with a three-dimensional information acquisition process can be executed to acquire three-dimensional information of the anterior eye segment by capturing cross-sectional images of a plurality of locations of the anterior eye segment while moving the optical unit relative to the subject's eye and scanning the imaging light, When the ophthalmologic apparatus control program is executed by the control unit, An ophthalmic device control program characterized in that, when executing the three-dimensional information acquisition process, the ophthalmic device is caused to perform a process of positioning the position of the fixation target in a direction along the optical axis of the fixation target presenting optical system within a restricted area centered on the focal position of the entire lens system of the fixation target presenting optical system, regardless of the refractive power of the test eye.

Images