Ophthalmologic apparatus

Abstract

To provide an ophthalmologic apparatus capable of shortening the measurement time required for rough measurement of eye refractive power.SOLUTION: An ophthalmologic apparatus includes: a rough measurement control unit 46 that performs rough measurement that images reflected light (fundus reflected light PB) using an imaging element 12g by projecting a measurement pattern PA onto the fundus Ef from a measurement pattern projection optical system 16; a provisional eye refractive power calculation unit 48 that calculates a provisional eye refractive power of the eye to be examined E on the basis of an image (referring image 29) of the reflected light captured by the imaging element 12g during the rough measurement; and a lens movement control unit 50 that drives a lens movement mechanism (linked movement mechanism 27) on the basis of the calculation result from the provisional eye refractive power calculation unit 48 to move a focusing lens 17d to a position where the fundus Ef and the imaging element 12g are in conjugate relation. Before starting main measurement, the rough measurement control unit 46, the provisional eye refractive power calculation unit 48, and the lens movement control unit 50 are repeatedly activated multiple times, and the light quantity of the measurement pattern PA projected onto the eye to be examined in the first rough measurement is set greater than that in the second and subsequent measurements.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an ophthalmic apparatus for measuring the ocular refractive power of a subject's eye. [Background technology]

[0002] There is a well-known ophthalmic apparatus that performs so-called refraction measurement to measure the ocular refractive power (spherical power, cylindrical power, and astigmatism axis angle, etc.) of the subject's eye characteristics (see, for example, Patent Documents 1 and 2). This ophthalmic apparatus is roughly equipped with a target projection optical system, a measurement pattern projection optical system, and a light receiving optical system. The target projection optical system projects a light beam of a fixation target onto the fundus of the subject's eye to fixate or cloud the subject's eye during objective measurement of the ocular refractive power of the subject's eye. The measurement pattern projection optical system projects a light beam of a ring-shaped measurement pattern for refraction measurement onto the fundus of the subject's eye.

[0003] A focusing lens and an imaging element are arranged in the light receiving optical system (see Patent Document 2). This focusing lens is arranged to be freely movable along the optical axis of the light receiving optical system, and is moved forward and backward on the optical axis by a lens movement mechanism. The imaging element captures (receives) the fundus reflected light of the measurement pattern projected onto the fundus from the measurement pattern projection optical system through the focusing lens. The imaging element then outputs a reflecting image, which is an image of the fundus reflected light.

[0004] The refraction measurement of the subject's eye includes a rough measurement (also called a provisional measurement, a rough measurement, or a preliminary measurement) and a main measurement. In the rough measurement, a target projection optical system presents a fixation target to the subject's eye to fixate the subject's eye. Next, a measurement pattern projection optical system projects a measurement pattern onto the fundus, and an image pickup element of a light receiving optical system picks up the fundus reflected light through a focusing lens and outputs a refraction image. Then, a calculation unit of the ophthalmic device calculates the ocular refractive power of the subject's eye by a known method based on the refraction image. Based on the calculation result of the ocular refractive power, a lens moving mechanism moves a focusing lens so that the measurement pattern is approximately in focus on the fundus.

[0005] In this measurement, a part of the target projection optical system is moved to make the test eye see the fixation target in a cloudy state. Then, as in the rough measurement, a measurement pattern is projected from the measurement pattern projection optical system onto the fundus, and the fundus reflected light is captured by the image sensor of the light receiving optical system, and a referencing image is output. Then, the calculation unit of the ophthalmic device calculates the accurate ocular refractive power of the test eye based on the referencing image and the moving position of the focusing lens of the light receiving optical system, which moves together with the part of the target projection optical system described above. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-159850 A [Patent Document 2] JP 2017-063979 A Summary of the Invention [Problem to be solved by the invention]

[0007] When the ophthalmic apparatus described in Patent Documents 1 and 2 starts a reflex measurement (rough measurement, main measurement) of the subject's eye, the subject's eye may be severely hyperopic, myopic, or have cataracts, or the focusing lens may not be positioned appropriately. In this case, a referencing image with appropriate brightness cannot be obtained in the rough measurement, so the ophthalmic apparatus must move the focusing lens during the rough measurement to search for a position where a referencing image with appropriate brightness can be obtained. As a result, the rough measurement may take a very long time.

[0008] The present invention has been made in view of the above circumstances, and has an object to provide an ophthalmic apparatus capable of shortening the measurement time required for rough measurement of the ocular refractive power of a subject's eye. [Means for solving the problem]

[0009] An ophthalmologic apparatus for achieving the object of the present invention includes a measurement pattern projection optical system which projects a measurement pattern onto the fundus of the subject's eye, a light receiving optical system which captures reflected light from the fundus onto which the measurement pattern has been projected with an image sensor through a focusing lens which is movable by a lens movement mechanism, a rough measurement control unit which performs a rough measurement in which the measurement pattern is projected from the measurement pattern projection optical system onto the fundus and the reflected light is captured by the image sensor, a provisional eye refractive power calculation unit which calculates a provisional eye refractive power of the subject's eye based on an image of the reflected light captured by the image sensor in the rough measurement, and a lens movement mechanism based on a calculation result of the provisional eye refractive power calculation unit to cause the fundus and the image sensor to be conjugate with each other. the measurement control unit is operable a plurality of times before the start of the main measurement, so that the measurement pattern projection optical system projects a measurement pattern onto the fundus and captures the reflected light with an imaging element; and an ocular refractive power calculation unit calculates the ocular refractive power of the subject's eye based on the image captured by the imaging element in the main measurement.The rough measurement control unit, the provisional ocular refractive power calculation unit and the lens movement control unit are repeatedly operated multiple times before the start of the main measurement, so that the amount of light of the measurement pattern projected by the measurement pattern projection optical system onto the subject's eye in the first rough measurement is greater than the amount of light of the measurement pattern projected onto the subject's eye in the second or subsequent rough measurements and the main measurement.

[0010] According to this ophthalmic apparatus, it is not necessary to move the focusing lens to search for a position where an image can be obtained during rough measurement of the ocular refractive power of the subject's eye, so that the measurement time for rough measurement can be shortened.

[0011] In an ophthalmologic apparatus according to another aspect of the present invention, the rough measurement control unit sets the exposure time of the image sensor in the first rough measurement to be shorter than those in the second and subsequent rough measurements and in the main measurement, thereby making it possible to further shorten the measurement time for the rough measurement.

[0012] In an ophthalmologic apparatus according to another aspect of the present invention, the measurement pattern projection optical system sets the amount of light of the measurement pattern projected onto the subject's eye in the first rough measurement to the maximum amount of light. This eliminates the need to move the focusing lens to search for a position where an image can be obtained, even if the subject's eye has severe hyperopia, myopia, or cataracts.

[0013] In another aspect of the ophthalmic apparatus of the present invention, the apparatus is provided with a target projection optical system which projects a fixation target onto the fundus, and a lens movement mechanism moves a focusing lens and a part of the target projection optical system together, the target projection optical system causes the test eye to fixate on the fixation target during rough measurement, and a main measurement control unit drives the lens movement mechanism to move the part before starting the main measurement, thereby causing the test eye to view the fixation target in a blurred manner, and an ocular refractive power calculation unit calculates the ocular refractive power of the test eye based on an image captured by the imaging element during the main measurement and the movement position of the focusing lens which has been moved together with the part.

[0014] In an ophthalmologic apparatus according to another aspect of the present invention, the rough measurement control unit, the provisional ocular refractive power calculation unit, and the lens movement control unit are repeatedly operated twice before starting a main measurement, and a determination unit is provided which determines whether the brightness of the image captured by the image capture element in the second rough measurement falls within a predetermined threshold range, and if the determination unit determines that the brightness does not fall within the threshold range, the rough measurement control unit adjusts the amount of light to an appropriate amount of light for the brightness of the image to fall within the threshold range and then redoes the second rough measurement, and if the rough measurement control unit has redoes the second rough measurement, the main measurement control unit projects a measurement pattern with an appropriate amount of light from the measurement pattern projection optical system onto the fundus in the main measurement. This ensures that an image with appropriate brightness is obtained in the second rough measurement. Effect of the Invention

[0015] The present invention can shorten the measurement time required for rough measurement of the ocular refractive power of a subject's eye. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a side view of the ophthalmologic apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a block diagram showing the configuration of an optical system of a measuring head. [Diagram 3] FIG. 2 is a functional block diagram of a control device according to the first embodiment. [Figure 4] 4 is a flowchart showing a flow of a process for measuring the ocular refractive power of a subject's eye by the ophthalmic apparatus of the first embodiment. [Diagram 5]10 is a flowchart showing a flow of a process for measuring the ocular refractive power of a subject's eye by an ophthalmic apparatus according to a second embodiment. [Figure 6] 11 is an explanatory diagram for explaining a measurement pattern that passes through a rotary prism and enters the fundus, and fundus reflected light that enters the image sensor when the exposure time of the image sensor is set to a short exposure time in the first rough measurement. FIG. [Figure 7] FIG. 13 is a functional block diagram of a control device of an ophthalmic apparatus according to a third embodiment. [Figure 8] 13 is a flowchart showing a flow of a process for measuring the ocular refractive power of a subject's eye by an ophthalmic apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [First embodiment] 1 is a side view of an ophthalmic apparatus 1 according to a first embodiment. Among the mutually orthogonal XYZ directions (three directions) in the figure, the Y direction is the up-down direction, the Z direction is the front-back direction (also called the working distance direction) parallel to the front direction approaching the subject's eye E (subject) and the rear direction away from the subject, and the X direction is the left-right direction perpendicular to both the up-down direction and the front-back direction.

[0018] [Overall configuration of ophthalmic equipment] The ophthalmic apparatus 1 is an autorefractive keratometer that objectively measures eye characteristics such as eye refractive power and corneal shape of a subject's eye E. The ophthalmic apparatus 1 includes a base 2, a face support unit 3, a drive mechanism 4, a measurement head 5, and a display unit 6.

[0019] A face support unit 3 and a drive mechanism 4 are provided on the base 2.

[0020] The face support part 3 has a chin rest part 3a for supporting the chin of the subject and a forehead rest part 3b against which the forehead of the subject comes into contact, and supports the face of the subject. The position of the chin rest part 3a can be adjusted in the Y direction (up and down direction) by an actuator (not shown).

[0021] The drive mechanism 4 is composed of an actuator (not shown), such as a motor. The drive mechanism 4 moves the measurement head 5 in the X, Y and Z directions relative to the base 2. This allows the measurement head 5 to move in the X, Y and Z directions relative to the subject's eye E, making it possible to align the measurement head 5 with the subject's eye E in the X, Y and Z directions.

[0022] The measurement head 5 has a function of measuring the ocular refractive power and corneal shape of the subject's eye E. A display unit 6 is attached to this measurement head 5. In addition, various optical systems (including an image sensor, various light sources, and various driving units) corresponding to the measurement of the ocular refractive power and corneal shape, and a control device 9 are provided inside the measurement head 5.

[0023] The display unit 6 is, for example, a touch panel monitor. The display unit 6 is rotatably held by the measurement head 5, and the position and orientation can be manually adjusted. The display unit 6 displays an observation image of the subject's eye E acquired by the measurement head 5, the measurement results of the ocular refractive power and corneal shape of the subject's eye E, a setting menu screen for performing various settings, and an operation menu screen for performing various operations. The display surface of the display unit 6 accepts input operations by the examiner through touch operations, and therefore functions as an operation unit of the ophthalmic apparatus 1. Note that the ophthalmic apparatus 1 may be provided with a known operation unit other than the display unit 6.

[0024] The display surface of the display unit 6 functions as an operation unit that accepts input operations by the examiner through touch operations. Note that the ophthalmologic apparatus 1 may be provided with a known operation unit other than the display unit 6.

[0025] [Configuration of the optical system of the measurement head] Fig. 2 is a block diagram showing the configuration of the optical system of the measurement head 5. As shown in Fig. 2, the optical system of the measurement head 5 includes an observation optical system 12, a Z alignment optical system 13, an XY alignment optical system 14, a visual target projection optical system 15, a measurement pattern projection optical system 16, and a light receiving optical system 17.

[0026] (Configuration of the observation optical system) The observation optical system 12 is an optical system used for observing the anterior part of the subject's eye E and photographing the anterior part. The observation optical system 12 has a main optical axis O1 parallel to the Z direction. In the observation optical system 12, an objective lens 12a, a dichroic filter 12b, a half mirror 12c, a relay lens 12d, a dichroic filter 12e, an imaging lens 12f, and a CMOS (complementary metal oxide semiconductor) type or CCD (charge coupled device) type image sensor 12g are arranged along the main optical axis O1 in this order from the subject's eye E side. The observation optical system 12 also has an illumination light source (not shown). Note that each part constituting the observation optical system 12 is a known technique, and therefore detailed description thereof will be omitted.

[0027] Illumination light emitted from an illumination light source of the observation optical system 12 illuminates the anterior segment of the subject's eye E and is reflected by the anterior segment. This reflected light is incident on the objective lens 12a, passes through each part of the observation optical system 12 from the objective lens 12a, and is incident on the imaging surface of the imaging element 12g. As a result, the reflected light is imaged by the imaging element 12g, and an observation image (image data) of the anterior segment of the subject's eye E is obtained by the imaging element 12g. The imaging element 12g outputs the observation image to the control device 9.

[0028] Around the objective lens 12a, a kerato plate 12h and a kerato ring light source 12i are provided for use in kerato measurement, which is an objective measurement of the corneal shape of the cornea Ec of the subject's eye E. The kerato plate 12h and the kerato ring light source 12i project a single or multiple ring-shaped light beam onto the cornea Ec. The ring-shaped light beam reflected by the cornea Ec is incident on the imaging surface of the imaging element 12g via the objective lens 12a and the dichroic filter 12b, etc. As a result, a kerato ring image is captured by the imaging element 12g. The imaging element 12g outputs the kerato ring image (image data) to the control device 9.

[0029] (Z alignment optical system) The Z alignment optical system 13 is used to detect the alignment state of the measurement head 5 in the Z direction with respect to the subject's eye E. The Z alignment optical system 13 is provided at two locations behind the keratoconus plate 12h (on the imaging element 12g side). Each Z alignment optical system 13 has an alignment light source 13a and a projection lens 13b. Each alignment light source 13a emits a light beam toward the projection lens 13b. A pair of light beams emitted from each alignment light source 13a is converted into parallel light beams by each projection lens 13b, and then passes through a pair of transmission holes (not shown) in the keratoconus plate 12h to be projected onto the cornea Ec.

[0030] A pair of light beams reflected by the cornea Ec are incident on the imaging surface of the imaging element 12g via the objective lens 12a and the dichroic filter 12b. As a result, a pair of bright spot images are captured by the imaging element 12g, and the imaging element 12g outputs the pair of bright spot images (image data) to the control device 9. As a result, the pair of bright spot images are displayed on the display unit 6 together with the observation image and the keratinizing image described above. Then, the control device 9 automatically or the examiner manually drives the driving mechanism 4 to move the measurement head 5 in the Z direction so that the keratinizing image and the pair of bright spot images have a predetermined positional relationship, thereby performing alignment in the Z direction (Z alignment). Note that Z alignment may be performed using other known methods.

[0031] (XY alignment optical system) The XY alignment optical system 14 is used to detect the alignment state of the measurement head 5 in the X and Y directions with respect to the subject's eye E. The XY alignment optical system 14 forms an optical path branched from the observation optical system 12 via a half mirror 12c. The XY alignment optical system 14 has an alignment light source 14a and a projection lens 14b. The alignment light source 14a emits a light beam toward the projection lens 14b. The light beam emitted from the alignment light source 14a is converted into a parallel light beam by the projection lens 14b, reflected by the half mirror 12c, and projected onto the cornea Ec via the dichroic filter 12b and the objective lens 12a.

[0032] The light beam reflected by the cornea Ec is incident on the imaging surface of the imaging element 12g via the objective lens 12a and the dichroic filter 12b. As a result, a bright spot image is captured by the imaging element 12g, and the imaging element 12g outputs the bright spot image (image data) to the control device 9. As a result, the display unit 6 can display a bright spot image for XY alignment together with the above-mentioned observation image, keratinizing image, and pair of bright spot images. Then, the control device 9 automatically or the examiner manually drives the driving mechanism 4 to adjust the position of the bright spot image in the X direction and the Y direction, thereby performing alignment in the X direction and the Y direction (XY alignment). Note that other known methods may be used for XY alignment.

[0033] (Configuration of visual target projection optical system) The target projection optical system 15 projects a light beam of a fixation target onto the fundus Ef of the subject's eye E in order to fixate or fogging the subject's eye E when measuring the ocular refractive power of the subject's eye E.

[0034] The target projection optical system 15 has a target display unit 15a, a half mirror 15b, a relay lens 15c, a reflecting mirror 15d, a focusing lens 15e (also called a movable lens), a relay lens 15f, a field lens 15g, a VCC lens 15h which is a variable cross cylinder lens, a reflecting mirror 15i, dichroic filters 15j and 12b, and an objective lens 12a.

[0035] In addition, the visual target projection optical system 15 has an optical axis O2 parallel to the aforementioned main optical axis O1, and the above-mentioned focusing lens 15e, relay lens 15f, field lens 15g, and VCC lens 15h are arranged on this optical axis O2.

[0036] The target display unit 15a may be, for example, a dot matrix liquid crystal display (LCD) or a matrix light emitting diode (LED). The target display unit 15a displays a fixation target and emits a light beam of the fixation target toward the half mirror 15b. Since the target display unit 15a is a dot matrix LCD or the like, the display mode (shape, etc.) and display position of the fixation target can be set arbitrarily. The target display unit 15a can also display targets for measuring visual acuity in addition to fixation targets.

[0037] The light beam of the fixation target displayed on the target display unit 15a is reflected by the half mirror 15b, and then passes through the relay lens 15c, the reflecting mirror 15d, the focusing lens 15e, the relay lens 15f, the field lens 15g, the VCC lens 15h, the reflecting mirror 15i, the dichroic filters 15j and 12b, and the objective lens 12a, before being projected onto the subject's eye E. This makes it possible to present a fixation target or the like to the subject's eye E.

[0038] The target projection optical system 15 also has a glare light source 15k used for a glare test of the subject's eye E. The glare light source 15k emits glare light to the half mirror 15b during the glare test. As a result, the glare light is projected onto the subject's eye E via each part from the half mirror 15b to the objective lens 12a.

[0039] The focusing lens 15e is disposed so as to be freely moved forward and backward along the optical axis O2 of the target projection optical system 15. The focusing lens 15e is moved forward and backward on the optical axis O2 by an interlocking movement mechanism 27 described later. This allows the refractive power of the light beam of the fixation target, etc. to be changed, so that the presentation distance of the fixation target, etc. to the subject's eye E can be changed. As a result, the subject's eye E can be fixed or fogged by the fixation target. Note that instead of moving the focusing lens 15e, which is a part of the target projection optical system 15, forward and backward on the optical axis O2, the target display unit 15a, which is also a part of the target projection optical system 15, may be moved forward and backward to fix or fog the subject's eye E.

[0040] The VCC lens 15h has a pair of positive and negative cylinder lenses. The pair of cylinder lenses can rotate independently around the optical axis O2. The VCC lens 15h has a function of correcting (correcting) the cylindrical power (cylindrical power) and the axial angle (cylindrical axial angle) of the aberrations caused by the refractive characteristics of the subject's eye E.

[0041] (Configuration of the measurement pattern projection optical system) The measurement pattern projection optical system 16 projects a light beam of a ring-shaped measurement pattern PA used for refraction measurement, which is an objective measurement of the ocular refractive power of the subject's eye E, onto the fundus Ef.

[0042] The measurement pattern projection optical system 16 includes a reflector measurement unit 16a, a relay lens 16b, a pupil ring 16c, a field lens 16d, a hole prism 16e, a rotary prism 16f, a dichroic filter 15j, a dichroic filter 12b, and an objective lens 12a.

[0043] The measurement pattern projection optical system 16 also has an optical axis O3 parallel to the above-mentioned main optical axis O1 and optical axis O2. A reflector measurement unit 16a, a relay lens 16b, a pupil ring 16c, a field lens 16d, and a holed prism 16e are arranged on this optical axis O3.

[0044] The reflex measurement unit 16a includes an LED light source 16h, a collimator lens 16i, a conical prism 16j, and a formation plate 16k for a measurement pattern PA. The LED light source 16h and the pupil ring 16c are disposed in an optically conjugate position. The formation plate 16k and the fundus Ef are disposed in an optically conjugate position.

[0045] The reflector measurement unit 16a is disposed so as to be movable forward and backward along an optical axis O3 of the measurement pattern projection optical system 16. The reflector measurement unit 16a is moved forward and backward on the optical axis O3 by an interlocking movement mechanism 27, which will be described later.

[0046] The light beam emitted from the LED light source 16h is collimated by the collimator lens 16i, and then emitted toward the relay lens 16b via the conical prism 16j and the forming plate 16k. This light beam passes through the relay lens 16b, the pupil ring 16c, the field lens 16d, the reflecting surface of the apertured prism 16e, the rotary prism 16f, the dichroic filter 15j, the dichroic filter 12b, and the objective lens 12a, and is projected onto the fundus Ef. As a result, the light beam of the ring-shaped measurement pattern PA is projected onto the fundus Ef. The light beam of the measurement pattern PA is projected onto the fundus Ef with its shape distorted by the ocular refractive power of the subject's eye E.

[0047] In addition, the light beam of the measurement pattern PA projected onto the fundus Ef revolves around the main optical axis O1 in an eccentric state by the rotary prism 16f. This reduces the possibility of capturing a refraction image 29 affected by blood vessels, diseases, etc. of the fundus Ef in the light receiving optical system 17 described later, thereby improving the reliability of the measurement result of the ocular refractive power of the subject's eye E (see, for example, Japanese Patent Application Laid-Open No. 10-14876).

[0048] (Configuration of the light receiving optical system) The light receiving optical system 17 receives fundus reflected light PB, which is reflected light of the measurement pattern PA projected onto the fundus Ef by the measurement pattern projection optical system 16. The light receiving optical system 17 includes an objective lens 12a, dichroic filters 12b and 15J, a rotary prism 16f, a holed prism 16e, a field lens 17a, a reflecting mirror 17b, a relay lens 17c, a focusing lens 17d (also referred to as a moving lens), a reflecting mirror 17e, a dichroic filter 12e, an imaging lens 12f, and an image sensor 12g.

[0049] The light receiving optical system 17 also has an optical axis O4 parallel to the above-mentioned main optical axis O1, optical axis O2, and optical axis O3. A reflecting mirror 17b, a relay lens 17c, a focusing lens 17d, and a reflecting mirror 17e are arranged on the optical axis O4.

[0050] The focusing lens 17d is disposed so as to be movable forward and backward along an optical axis O4 of the light receiving optical system 17. The focusing lens 17d is moved forward and backward on the optical axis O4 by an interlocking movement mechanism 27, which will be described later.

[0051] The fundus reflected light PB is incident on the light receiving surface of the image sensor 12g via the objective lens 12a, the dichroic filters 12b and 15J, the rotary prism 16f, the hole of the perforated prism 16e, the field lens 17a, the reflecting mirror 17b, the relay lens 17c, the focusing lens 17d (also called a moving lens), the reflecting mirror 17e, the dichroic filter 12e, and the imaging lens 12f. The image sensor 12g captures the fundus reflected light PB and outputs a reflecting image 29 (image data) to the control device 9.

[0052] The interlocking movement mechanism 27 corresponds to the lens movement mechanism of the present invention, and moves the focusing lens 15e, the reflex measurement unit 16a, and the focusing lens 17d together along a direction parallel to the main optical axis O1 (optical axes O2 to O4) (Z direction). Although not shown, the interlocking movement mechanism 27 includes a holding member that holds the focusing lens 15e, the reflex measurement unit 16a, and the focusing lens 17d together, a slide mechanism that holds the holding member so that it can slide in the Z direction, and a drive mechanism such as a motor that moves the holding member back and forth in the Z direction.

[0053] [Functions of the control device of the first embodiment] Fig. 3 is a functional block diagram of the control device 9 of the first embodiment. As shown in Fig. 3, the control device 9 comprehensively controls the operation of each part of the ophthalmic apparatus 1, and executes alignment of the measurement head 5 with respect to the subject's eye E, and measurement of the eye refractive power and corneal shape of the subject's eye E. The control device 9 is connected to a face support unit 3 (chin rest unit 3a), a drive mechanism 4, each optical system and each light source of the measurement head 5, a display unit 6, and an interlocking movement mechanism 27.

[0054] The control device 9 includes an arithmetic circuit including various processors and memories. The various processors include a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a programmable logic device (e.g., simple programmable logic devices (SPLD), complex programmable logic devices (CPLD), and field programmable gate arrays (FPGA)). The various functions of the control device 9 may be realized by one processor, or may be realized by multiple processors of the same or different types.

[0055] The control device 9 functions as an alignment control unit 40, a corneal shape measuring unit 42, and an eye refractive power measuring unit 44 by executing a control program stored in a storage unit (not shown).

[0056] Before starting measurement of the corneal shape or eye refractive power of the subject's eye E, the alignment control unit 40 controls the observation optical system 12, the keratinizing light source 12i, the Z alignment optical system 13, the XY alignment optical system 14, the visual target projection optical system 15, etc., and performs alignment detection by a known method to detect the relative position of the measurement head 5 in the XYZ directions with respect to the subject's eye E. Next, the alignment control unit 40 performs auto-alignment of the measurement head 5 in the XYZ directions with respect to the subject's eye E by driving the drive mechanism 4 to move the measurement head 5 in the XYZ directions based on the detection result of the alignment detection.

[0057] The corneal shape measuring unit 42 operates when performing keratometry of the subject's eye E. After completing auto-alignment, the corneal shape measuring unit 42 controls the observation optical system 12, the keratometry ring light source 12i, the target projection optical system 15, and the like to perform keratometry of the subject's eye E. Specifically, the corneal shape measuring unit 42 turns on the keratometry ring light source 12i to project a single or multiple ring-shaped light beams onto the cornea Ec, and causes the imaging element 12g to capture an image of the ring-shaped light beams reflected by the cornea Ec. Next, the corneal shape measuring unit 42 calculates the corneal shape (corneal refractive power, corneal astigmatism, corneal astigmatism axis angle, etc.) of the subject's eye E by a known method based on the keratometry ring image (not shown) output from the imaging element 12g.

[0058] The eye refraction measurement unit 44 operates when performing a refraction measurement of the subject's eye E. After auto-alignment is completed, the eye refraction measurement unit 44 controls the visual target projecting optical system 15, the measurement pattern projecting optical system 16, and the light receiving optical system 17 to perform a refraction measurement of the subject's eye E. This refraction measurement includes a rough measurement and a main measurement. The rough measurement also includes a first rough measurement which is the first rough measurement, and a second rough measurement which is the second rough measurement.

[0059] <Rough measurement> When the first and second rough measurements are performed after auto-alignment is completed, the eye refractive power measurement unit 44 functions as a rough measurement control unit 46, a provisional eye refractive power calculation unit 48, and a lens movement control unit 50. In this embodiment, the first and second rough measurements are performed by repeatedly operating the rough measurement control unit 46, the provisional eye refractive power calculation unit 48, and the lens movement control unit 50 twice.

[0060] (First rough measurement) After completing the auto-alignment, the rough measurement control unit 46 controls the target projection optical system 15 (target display unit 15a) to present a fixation target to the subject's eye E, thereby causing the subject's eye E to fixate on the fixation target. Next, the rough measurement control unit 46 controls the measurement pattern projection optical system 16 and the light receiving optical system 17 to perform a first rough measurement. Specifically, the rough measurement control unit 46 controls the measurement pattern projection optical system 16 (LED light source 16h, rotary prism 16f, etc.) to project a light beam of a ring-shaped measurement pattern PA onto the fundus Ef, and controls the light receiving optical system 17 to capture the fundus reflected light PB by the imaging element 12g and output the reflecting image 29.

[0061] At this time, the rough measurement control unit 46 controls the measurement pattern projection optical system 16 to project a light beam of the measurement pattern PA with an "increased light intensity," which is a light intensity higher than the "normal light intensity," which is the light intensity of the measurement pattern PA during the actual measurement described below, onto the test eye E.

[0062] Here, the normal light amount is, for example, a light amount assuming a 0 diopter test eye E (normal eye), and is the light amount of the measurement pattern PA used in conventional reflex measurement (rough measurement, main measurement). On the other hand, the increased light amount is a light amount that can obtain a reflex image 29 of a distinguishable light amount even if the test eye E has strong hyperopia, myopia, or cataract. This increased light amount is, for example, 1.5 to 2 times the normal light amount, or the maximum light amount allowed (set) in the ophthalmic device 1. Specifically, in the ophthalmic device 1 of this embodiment, the light amount of the measurement pattern PA can be switched in five steps of "0", "1", "2", "3", and "4", and the normal light amount is set to "2" and the increased light amount is set to "4".

[0063] The provisional refractive power calculation section 48 calculates provisional refractive power of the subject's eye E by a known method based on the refraction image 29 output from the imaging element 12g in the first rough measurement.

[0064] The lens movement control unit 50 executes a first movement control to drive the interlocking movement mechanism 27 based on the provisional ocular refractive power of the subject's eye E calculated by the provisional ocular refractive power calculation unit 48 in the first rough measurement, and to move the focusing lens 17d to a focusing position (conjugate position) where the fundus Ef and the imaging element 12g are conjugate. As a result, the interlocking movement mechanism 27 moves the focusing lens 15e, the reflex measurement unit 16a, and the focusing lens 17d to positions of the equivalent spherical power.

[0065] (Second rough measurement) After completing the first movement control, the rough measurement control unit 46 controls the target projecting optical system 15 (target display unit 15a) to cause the test eye E to continue to fixate on the fixation target. The rough measurement control unit 46 also controls the measurement pattern projecting optical system 16 and the light receiving optical system 17 to perform a second rough measurement. Specifically, the rough measurement control unit 46 controls the measurement pattern projecting optical system 16 to project a light beam of the measurement pattern PA with a "normal light amount" lower than the "increased light amount" onto the fundus Ef, and controls the light receiving optical system 17 to capture the fundus reflected light PB by the imaging element 12g and output the reflecting image 29.

[0066] The provisional refractive power calculation section 48 calculates provisional refractive power of the subject's eye E by a known method based on the refraction image 29 output from the imaging element 12g in the second rough measurement.

[0067] The lens movement control unit 50 executes the second movement control to drive the interlocking movement mechanism 27 based on the provisional ocular refractive power of the subject's eye E calculated by the provisional ocular refractive power calculation unit 48 in the second rough measurement, and to move the focusing lens 17d to a focusing position (conjugate position) where the fundus Ef and the image sensor 12g are conjugate. As a result, the interlocking movement mechanism 27 moves the focusing lens 15e, the reflex measurement unit 16a, and the focusing lens 17d to positions of the equivalent spherical power. Note that the lens movement control unit 50 does not execute the second movement control when the provisional ocular refractive power measured in the second rough measurement is the same (including approximately the same) as the provisional ocular refractive power measured in the previous first rough measurement.

[0068] In addition, by repeatedly operating the rough measurement control unit 46, the provisional ocular refractive power calculation unit 48 and the lens movement control unit 50 multiple times, three or more times, the second rough measurement at normal light intensity by the rough measurement control unit 46, the calculation of provisional ocular refractive power by the provisional ocular refractive power calculation unit 48, and the second lens movement control by the lens movement control unit 50 may be repeatedly executed two or more times.

[0069] <Actual measurement> The eye refractive power measurement unit 44 performs the main measurement after the second movement control is completed by the lens movement control unit 50. In this case, the eye refractive power measurement unit 44 functions as a main measurement control unit 52 and an eye refractive power calculation unit 54.

[0070] After completing the second movement control, the main measurement control unit 52 drives the interlocking movement mechanism 27 to further move the focusing lens 15e from the position after the second movement control to the fogging position, thereby promoting fogging of the subject's eye E and making the subject's eye E see the fixation target in a fogging state. Then, similar to the second rough measurement, the main measurement control unit 52 projects a light beam of the measurement pattern PA of a normal light amount onto the fundus Ef, and controls the light receiving optical system 17 to capture the fundus reflected light PB by the imaging element 12g and output the reflecting image 29.

[0071] The ocular refractive power calculation unit 54 calculates the ocular refractive power of the test eye E using a known method based on the referencing image 29 output from the imaging element 12g in this measurement and the movement position (movement amount) of the focusing lens 17d that was moved together with the focusing lens 15e in this measurement.

[0072] [Operation of the first embodiment] FIG. 4 is a flowchart showing a flow of a process for measuring the ocular refractive power of the examinee's eye E by the ophthalmic apparatus 1 of the first embodiment.

[0073] 4, after the subject's face is supported on the face support part 3, when the examiner inputs a measurement start operation to the operation menu screen of the display part 6, the alignment control part 40 controls each part of the measurement head 5 and executes alignment detection in the XYZ directions of the measurement head 5 with respect to the subject's eye E by a known method. Next, based on the detection result of the alignment detection in the XYZ directions, the alignment control part 40 drives the drive mechanism 4 to execute auto-alignment in the XYZ directions of the measurement head 5 with respect to the subject's eye E (step S1).

[0074] When the auto-alignment is completed, the eye refraction measurement unit 44 functions as a rough measurement control unit 46, a provisional eye refraction calculation unit 48, and a lens movement control unit 50. First, the rough measurement control unit 46 controls the target projection optical system 15 to present a fixation target to the subject's eye E, thereby causing the subject's eye E to fixate on the fixation target. Next, the rough measurement control unit 46 controls the measurement pattern projection optical system 16 and the light receiving optical system 17 to perform a first rough measurement. As a result, the measurement pattern projection optical system 16 projects a light beam of the measurement pattern PA with an increased amount of light onto the fundus Ef, and the light receiving optical system 17 performs imaging of the fundus reflected light PB by the imaging element 12g and output of the refraction image 29 (step S2).

[0075] When the first rough measurement is completed, the provisional refractive power calculation unit 48 calculates the provisional refractive power of the test eye E by a known method based on the referencing image 29 acquired from the imaging element 12g in the first rough measurement (steps S3 and S4).

[0076] At this time, in the first rough measurement, the light beam of the measurement pattern PA with an increased light amount is projected onto the subject's eye E in order to prioritize the movement of the focusing lens 17d (first movement control), so that even if the subject's eye E has severe hyperopia, myopia, or cataract, a referencing image 29 that can be identified by the provisional refractive power calculation unit 48 (capable of calculating provisional refractive power) can be obtained. Therefore, regardless of the state of the subject's eye E, the calculation of the provisional refractive power of the subject's eye E by the provisional refractive power calculation unit 48 and the first movement control by the lens movement control unit 50 can be reliably executed. As a result, it is no longer necessary to search for a position where the referencing image 29 can be obtained by moving the focusing lens 17d as in the conventional method.

[0077] Furthermore, if the subject's eye E is a normal eye, there is a risk that the referencing image 29 will be saturated, in which case an error will occur when the provisional ocular refraction calculation unit 48 calculates the center of gravity of the referencing image 29 or calculates the size of the referencing image 29 by edge processing. For this reason, the accuracy of the provisional ocular refraction calculated by the provisional ocular refraction calculation unit 48 will decrease in the first rough measurement, but since the second rough measurement is performed after the first rough measurement, there is no problem even if the accuracy of the ocular refraction is low at the stage of the first rough measurement.

[0078] Next, the lens movement control unit 50 executes a first movement control to drive the interlocking movement mechanism 27 to move the focusing lens 17d to the aforementioned focusing position based on the calculation result of the provisional eye refractive power of the test eye E by the provisional eye refractive power calculation unit 48 (step S5).

[0079] When the first movement control is completed, the rough measurement control unit 46 controls the target projecting optical system 15 to continue fixation of the fixation target by the subject's eye E, and controls the measurement pattern projecting optical system 16 and the light receiving optical system 17 to execute the second rough measurement. As a result, the measurement pattern projecting optical system 16 projects a light beam of the measurement pattern PA with a normal light amount onto the fundus Ef, and the light receiving optical system 17 executes imaging of the fundus reflected light PB by the imaging element 12g and output of the reflecting image 29 (step S6).

[0080] When the second rough measurement is completed, the provisional refractive power calculation unit 48 calculates the provisional refractive power of the test eye E by a known method based on the referencing image 29 acquired from the imaging element 12g in the second rough measurement (steps S7 and S8).

[0081] At this time, the light amount of the measurement pattern PA is returned (reduced) from "increased light amount" to "normal light amount" in the second rough measurement, but this second rough measurement is performed with the focusing lens 17d moved to the focusing position by the first movement control. Therefore, even if the subject's eye E has strong hyperopia, myopia, or cataract, a refractive image 29 with a light amount that can be identified by the provisional refractive power calculation unit 48 can be obtained. In addition, by returning the light amount of the measurement pattern PA to the normal light amount, the refractive image 29 is prevented from being saturated even if the subject's eye E is a normal eye. As a result, regardless of the condition of the subject's eye E, the provisional refractive power calculation unit 48 can reliably and accurately calculate the provisional refractive power of the subject's eye E. As a result, it is no longer necessary to move the focusing lens 17d to search for a position where the refractive image 29 can be obtained, as in the conventional method.

[0082] Next, the lens movement control unit 50 executes the second movement control to drive the interlocking movement mechanism 27 to move the focusing lens 17d to the above-mentioned focusing position based on the calculation result of the provisional ocular refractive power of the subject's eye E in the second rough measurement by the provisional ocular refractive power calculation unit 48 (step S9). Since the provisional ocular refractive power of the subject's eye E can be calculated more accurately in the second rough measurement than in the first rough measurement, the second movement control can move the focusing lens 17d to a more likely focusing position than the first movement control.

[0083] When the second movement control is completed, the eye refractive power measurement unit 44 functions as the main measurement control unit 52 and the eye refractive power calculation unit 54. Then, the main measurement control unit 52 drives the interlocking movement mechanism 27 to move the focusing lens 15e to the clouding position to make the test eye E view the fixation target in a cloudy state, and controls the measurement pattern projection optical system 16 and the light receiving optical system 17 to perform the main measurement. As a result, similar to the second rough measurement, the measurement pattern projection optical system 16 projects a light beam of the measurement pattern PA with a normal light amount onto the fundus Ef, and the light receiving optical system 17 performs imaging of the fundus reflected light PB by the imaging element 12g and output of the refraction image 29 (step S10).

[0084] When the main measurement is completed, the eye refractive power calculation unit 54 calculates the eye refractive power of the test eye E based on the refraction image 29 acquired from the image sensor 12g in the main measurement and the movement position (movement amount) of the focusing lens 17d in the main measurement (steps S11 and S12).

[0085] As described above, in the ophthalmologic apparatus 1 of the first embodiment, by performing the first rough measurement using the measurement pattern PA with an increased light intensity and the second rough measurement using the measurement pattern PA with a normal light intensity as rough measurements before the main measurement, it becomes unnecessary to move the focusing lens 17d to search for a position where the referencing image 29 can be obtained as in the conventional method, even if the subject's eye E has severe hyperopia, myopia, or cataract. As a result, regardless of the condition of the subject's eye E, it is possible to shorten the measurement time required for rough measurement of the ocular refractive power of the subject's eye E.

[0086] [Second embodiment] Next, an ophthalmic apparatus 1 according to a second embodiment of the present invention will be described. In the ophthalmic apparatus 1 according to the first embodiment, the light amount of the measurement pattern PA is set to "increased light amount" during the first rough measurement, but in the ophthalmic apparatus 1 according to the second embodiment, the exposure time of the image sensor 12g during the first rough measurement is further adjusted.

[0087] The ophthalmic apparatus 1 of the second embodiment has basically the same configuration as the ophthalmic apparatus 1 of the first embodiment, except that the exposure time of the image sensor 12g during the first rough measurement is different from that of the first embodiment. Therefore, the same reference numerals are used to designate the same components as those of the ophthalmic apparatus 1 of the first embodiment in terms of function or configuration, and the description thereof will be omitted.

[0088] FIG. 5 is a flowchart showing a flow of a process for measuring the ocular refractive power of the examinee's eye E by the ophthalmic apparatus 1 of the second embodiment.

[0089] 5, when auto-alignment is completed as in the first embodiment (step S1), first, the rough measurement control unit 46 controls the target projecting optical system 15 to present a fixation target to the subject's eye E, thereby causing the subject's eye E to fixate the fixation target. Next, the rough measurement control unit 46 controls the measurement pattern projecting optical system 16 and the light receiving optical system 17 to perform a first rough measurement.

[0090] At this time, in the first rough measurement, the light amount of the measurement pattern PA projected from the measurement pattern projection optical system 16 onto the fundus Ef is increased compared to the normal (main measurement), so that the exposure time of the image pickup element 12g of the light receiving optical system 17 can be made shorter than the normal exposure time. Therefore, the rough measurement control unit 46 of the second embodiment sets the exposure time of the image pickup element 12g that picks up the fundus reflected light PB in the first rough measurement to a "short exposure time" shorter than the "normal exposure time" in the main measurement (step S2A).

[0091] The short exposure time is not particularly limited as long as it is an exposure time shorter than the normal exposure time. For example, the short exposure time may be set so that the total amount of light (amount of light of the measurement pattern PA x exposure time) of the fundus reflected light PB received by the image sensor 12g during the first rough measurement and during the main measurement (second rough measurement) is equal. The exposure time of the image sensor 12g can be adjusted by directly controlling the drive of the image sensor 12g, or by controlling the shutter speed if a shutter is disposed on the optical path of the fundus reflected light PB. In this way, by setting the exposure time of the image sensor 12g during the first rough measurement to the short exposure time, the time required for the first rough measurement can be further shortened compared to the first embodiment.

[0092] Fig. 6 is an explanatory diagram for explaining the measurement pattern PA incident on the fundus Ef via the rotary prism 16f and the fundus reflected light PB incident on the image sensor 12g when the exposure time of the image sensor 12g is set to a short exposure time in the first rough measurement. Reference symbol VIA in Fig. 6 indicates the measurement pattern PA before it is incident on the rotary prism 16f. Reference symbol VIB in Fig. 6 indicates the measurement pattern PA incident on the pupil of the subject's eye E via the rotary prism 16f. Reference symbol VIC in Fig. 6 indicates a state in which the measurement pattern PA incident on the pupil revolves around the main optical axis O1 in an eccentric state due to the rotation of the rotary prism 16f.

[0093] Reference symbol VID in Fig. 6 indicates the measurement pattern PA incident on the fundus Ef. Reference symbol VIE in Fig. 6 indicates a state in which the measurement pattern PA incident on the fundus Ef revolves around the main optical axis O1 in an eccentric state due to the rotation of the rotary prism 16f.

[0094] Reference symbol VIF in Fig. 6 indicates the fundus reflected light PB entering the image sensor 12g via the rotary prism 16f. Reference symbol VIG in Fig. 6 indicates the state in which the fundus reflected light PB entering the image sensor 12g revolves around the main optical axis O1 in an eccentric state due to the rotation of the rotary prism 16f.

[0095] As shown in Fig. 6, in the refraction measurement of the ophthalmic apparatus 1, the measurement pattern PA projected on the fundus Ef by the rotation of the rotary prism 16f is rotated in an eccentric state with respect to the main optical axis O1 to calculate the average ocular refractive power of the subject's eye E. For this reason, when the exposure time of the image pickup element 12g is set to "short exposure time", the rotation of the rotary prism 16f is insufficient until one refraction image 29 is formed, and the refraction image 29 may be distorted. Therefore, in the first rough measurement of the second embodiment, the measurement accuracy of the provisional ocular refractive power is reduced, but since the second rough measurement and the main measurement are performed with the normal exposure time after the first rough measurement, there is no particular problem even if the measurement accuracy of the provisional ocular refractive power is low at the stage of the first rough measurement.

[0096] Returning to Fig. 5, when the first rough measurement is completed, the processes from step S3 to step S5 are executed similarly to the first embodiment (see Fig. 5). Next, the rough measurement control unit 46 controls the target projecting optical system 15 to continue fixation of the test eye E on the fixation target, and controls the measurement pattern projecting optical system 16 and the light receiving optical system 17 to execute the second rough measurement similar to the first embodiment. In the second rough measurement of the second embodiment, a light beam of the measurement pattern PA with a normal light amount is projected from the measurement pattern projecting optical system 16 onto the fundus Ef, and the exposure time of the image pickup element 12g that captures the fundus reflected light PB is set to the normal exposure time (see step S6A).

[0097] In this way, in the second rough measurement of the second embodiment, since both the light amount of the measurement pattern PA and the exposure time of the image sensor 12g are appropriately set, the measurement accuracy of the provisional eye refractive power is higher than that of the first rough measurement. Therefore, even if the exposure time of the image sensor 12g is shortened to prioritize time reduction in the first rough measurement, it does not affect the measurement accuracy of the eye refractive power of the test eye E obtained in the main measurement.

[0098] When the second rough measurement is completed, the processes from step S7 to step S9 are executed similarly to the first embodiment (see FIG. 5). Next, the main measurement control unit 52 drives the interlocking movement mechanism 27 to make the subject's eye E see the fixation target in a cloudy state, and controls the measurement pattern projecting optical system 16 and the light receiving optical system 17 to execute the main measurement. In the main measurement of the second embodiment, as in the second rough measurement, a light beam of the measurement pattern PA with a normal light amount is projected from the measurement pattern projecting optical system 16 onto the fundus Ef, and the exposure time of the image sensor 12g is set to the normal exposure time (see step S10A).

[0099] Thereafter, the processes from step S11 onwards are executed in the same manner as in the first embodiment (see FIG. 5).

[0100] As described above, in the ophthalmic apparatus 1 of the second embodiment, by shortening the exposure time of the image sensor 12g in the first rough measurement, the measurement time required for the rough measurement of the ocular refractive power of the test eye E can be shortened more than in the first embodiment.

[0101] [Third embodiment] 7 is a functional block diagram of the control device 9 of the ophthalmologic apparatus 1 of the third embodiment. In each of the above embodiments, the second rough measurement is performed by setting the light intensity of the measurement pattern PA to the normal light intensity, but there are cases where the second rough measurement does not obtain a refraction image 29 with appropriate brightness. In such cases, the measurement accuracy of the ocular refractive power of the subject's eye E decreases.

[0102] Therefore, in the ophthalmologic apparatus 1 of the third embodiment, if a referencing image 29 with appropriate brightness cannot be obtained in the second rough measurement, the normal light amount of the measurement pattern PA is adjusted and the second rough measurement is performed again.

[0103] 7, the ophthalmic apparatus 1 of the third embodiment has basically the same configuration as the ophthalmic apparatus 1 of each of the above embodiments, except that the eye refractive power measurement unit 44 functions as a determination unit 49 during the second rough measurement, and the rough measurement control unit 46 and the main measurement control unit 52 have some different functions. Therefore, the same reference numerals are used for components that are the same in function or configuration as the ophthalmic apparatus 1 of each of the above embodiments, and the description thereof will be omitted.

[0104] 8 is a flowchart showing the flow of the process of measuring the ocular refractive power of the subject's eye E by the ophthalmic apparatus 1 of the third embodiment. Note that the processes from step S1 to step S7 are the same as those in the above-mentioned embodiments, and therefore detailed explanations thereof will be omitted here.

[0105] As shown in FIG. 8, the judgment unit 49 operates after step S7 to judge whether the brightness of the referencing image 29 captured by the imaging element 12g during the second rough measurement (e.g., the average pixel value of each pixel of the referencing image 29) is within a predetermined threshold range (step S7A).

[0106] The rough measurement control unit 46 of the third embodiment ends the second rough measurement when the determination unit 49 determines that the brightness of the referencing image 29 is within the threshold range (YES in step S7A). On the other hand, when the determination unit 49 determines that the brightness of the referencing image 29 is not within the threshold range (NO in step S7A), the rough measurement control unit 46 of the third embodiment controls the measurement pattern projecting optical system 16 and the light receiving optical system 17 to adjust the normal light amount of the measurement pattern PA and then redo the second rough measurement.

[0107] Specifically, the rough measurement control unit 46 controls the measurement pattern projection optical system 16 to adjust the light intensity by increasing or decreasing the normal light intensity of the measurement pattern PA, adjusting the normal light intensity to an appropriate light intensity such that the brightness of the reflecting image 29 falls within a threshold range, and stores this appropriate light intensity in a memory unit not shown (step S7B).

[0108] Next, the rough measurement control unit 46 controls the measurement pattern projection optical system 16 and the light receiving optical system 17 to project the light beam of the measurement pattern PA of the appropriate light amount onto the fundus Ef, and also performs imaging of the fundus reflected light PB by the imaging element 12g and output of the refraction image 29 (steps S6, S7). As a result, a refraction image 29 of appropriate brightness is obtained by the second rough measurement again (YES in step S7A). Thereafter, the processes of steps S7 and S8 are performed as in each of the above embodiments.

[0109] The main measurement control unit 52 of the third embodiment executes the main measurement similar to each of the above embodiments when the second rough measurement is not redone (step S10). When the second rough measurement is redone, the main measurement control unit 52 of the third embodiment executes the main measurement based on the appropriate light amount of the measurement pattern PA stored in a storage unit (not shown) (step S10). As a result, the measurement pattern projection optical system 16 projects the light beam of the measurement pattern PA with the appropriate light amount onto the fundus Ef, and the light receiving optical system 17 executes imaging of the fundus reflected light PB by the imaging element 12g and output of the reflexing image 29. Note that the processing from step S11 onwards is the same as each of the above embodiments, so a detailed description will be omitted here.

[0110] As described above, in the ophthalmologic apparatus 1 of the third embodiment, if the brightness of the refraction image 29 does not fall within the threshold range during the second rough measurement, the normal light amount of the measurement pattern PA is adjusted to an appropriate light amount and the second rough measurement is repeated, thereby improving the measurement accuracy of the ocular refractive power of the subject's eye E. In addition, the same effects as those of the above embodiments can be obtained.

[0111] [others] In each of the above embodiments, the second rough measurement (including calculation of provisional eye refractive power and second movement control) is performed after the first rough measurement (including calculation of provisional eye refractive power and first movement control). However, there are cases where the provisional eye refractive power of the subject's eye E is measured with high accuracy in the first rough measurement. In this case, it is not necessary to perform the second rough measurement. Therefore, the main measurement may be performed without performing the second rough measurement after performing the first rough measurement. In this case, for example, it may be determined whether or not to perform the second rough measurement based on the shape and brightness of the referencing image 29 obtained in the first rough measurement.

[0112] In each of the above embodiments, the ring-shaped measurement pattern PA is projected onto the fundus Ef, but the shape and type of the measurement pattern PA is not particularly limited as long as the ocular refractive power of the subject's eye E can be measured.

[0113] In each of the above embodiments, an autorefractometer has been used as an example of the ophthalmic apparatus 1 of the present invention, but the present invention can be applied to various ophthalmic apparatus 1 capable of measuring the ocular refractive power of the subject's eye E, such as a refractometer. [Explanation of symbols]

[0114] 1…Ophthalmology equipment 2. Base 3…Face support part 3a…Chin rest 3b…Forehead support 4. Driving mechanism 5…Measuring head 6…Display section 9...Control device 12...Observation optical system 12a…Objective lens 12b…Dichroic filter 12c…Half mirror 12d…Relay lens 12e…Dichroic filter 12f...Imaging lens 12g…Image sensor 12h…Kerato board 12i…Keratography light source 13…Z alignment optical system 13a…Alignment light source 13b…Projection lens 14...XY alignment optical system 14a…Alignment light source 14b…Projection lens 15…Target projection optical system 15J…Dichroic filter 15a...Optotype display section 15b...Half mirror 15c…Relay lens 15d…Reflective mirror 15e…Focusing lens 15f…Relay lens 15g...field lens 15h…VCC lens 15i…Reflective mirror 15j…Dichroic filter 15k…Glare light source 16...Measurement pattern projection optical system 16a…Reflection measurement unit 16b…Relay lens 16c...Eye ring 16d…Field lens 16e...Hole prism 16f...Rotary prism 16h…LED light source 16i…Collimator lens 16j...Cone prism 16k…forming plate 17…Receiving optical system 17a…Field lens 17b…Reflective mirror 17c…Relay lens 17d…Focusing lens 17e…Reflective mirror 27...Interlocking movement mechanism 29…Leffling Statue 40...Alignment control unit 42...Corneal shape measurement section 44…Eye refractive power measurement unit 46…Rough measurement control section 48…Temporary eye refractive power calculation unit 49…Judgment section 50...Lens movement control section 52...Main measurement control unit 54...Eye refractive power calculation unit E…Examined eye Ec…cornea Ef…fundus O1…main optical axis O2…optical axis O3…Optical axis O4…Optical axis PA…Measurement pattern PB…Fundus reflected light

Claims

1. a measurement pattern projection optical system that projects a measurement pattern onto the fundus of the subject's eye; a light receiving optical system that captures an image of reflected light from the fundus onto which the measurement pattern is projected, through a focusing lens that is movable by a lens moving mechanism, with an image sensor; a rough measurement control unit for performing a rough measurement in which the measurement pattern is projected onto the fundus from the measurement pattern projection optical system and the reflected light is captured by the image sensor; a provisional refractive power calculation unit that calculates a provisional refractive power of the subject's eye based on an image of the reflected light captured by the imaging element in the rough measurement; a lens movement control unit that drives the lens movement mechanism based on a calculation result of the provisional eye refractive power calculation unit to move the focusing lens to a position where the fundus and the image sensor are conjugate with each other; a main measurement control unit that executes a main measurement by projecting the measurement pattern from the measurement pattern projection optical system onto the fundus and capturing the reflected light with the imaging element; an ocular refractive power calculation unit that calculates an ocular refractive power of the subject's eye based on the image captured by the imaging element in the main measurement; Equipped with Before the start of the main measurement, the rough measurement control unit, the provisional eye refractive power calculation unit, and the lens movement control unit are repeatedly operated a plurality of times; An ophthalmic device in which the measurement pattern projection optical system projects a larger amount of light of the measurement pattern onto the test eye in the first rough measurement than the amount of light of the measurement pattern projected onto the test eye in the second or subsequent rough measurements and the actual measurement.

2. 2 . The ophthalmologic apparatus according to claim 1 , wherein the rough measurement control unit sets an exposure time of the image pickup device in a first rough measurement to be shorter than those in second or subsequent rough measurements and in the main measurement.

3. 2. The ophthalmic apparatus according to claim 1, wherein the measurement pattern projection optical system sets the amount of light of the measurement pattern projected onto the subject's eye in a first rough measurement to a maximum amount of light.

4. a target projection optical system that projects a fixation target onto the fundus; the lens moving mechanism moves the focusing lens and a part of the visual target projection optical system together; the target projection optical system causes the subject's eye to fixate the fixation target in the rough measurement; the main measurement control unit drives the lens moving mechanism to move the part before starting the main measurement, thereby causing the subject's eye to view the fixation target in a cloudy state; 4. An ophthalmic device according to claim 1, wherein the ocular refractive power calculation unit calculates the ocular refractive power of the test eye based on the image captured by the imaging element in the main measurement and the moving position of the focusing lens which is moved integrally with the part.

5. Before the start of the main measurement, the rough measurement control unit, the provisional eye refractive power calculation unit, and the lens movement control unit are repeatedly operated twice, a determination unit that determines whether or not the brightness of the image captured by the image capture element in the second rough measurement falls within a predetermined threshold range, When the determination unit determines that the result is not correct, the rough measurement control unit adjusts the amount of light to an appropriate amount of light such that the brightness of the image falls within the threshold range, and then performs the rough measurement again for a second time. An ophthalmic device as described in any one of claims 1 to 3, wherein when the rough measurement control unit retries the rough measurement for a second time, the main measurement control unit projects the measurement pattern with the appropriate amount of light from the measurement pattern projection optical system onto the fundus in the main measurement.

Images