JP2007037984A - Ophthalmic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ophthalmic device which can provide by itself various kinds of bioinformation about an eye that a plurality of conventional devices determine to provide. <P>SOLUTION: The ophthalmic device is a device which does not need to touch an eye to provide bioinformation of the eye to examine, and comprises a cornea irradiation optical system, an eyeground irradiation optical system, a light path length changing means, an interference optical system, and a bioinformation providing system, wherein the cornea irradiation optical system has a low coherent light source and focuses light flux from the source on the area around a cornea; the eyeground irradiation optical system irradiates a part of light flux from the source toward the eyeground; the light path length changing means is positioned in the cornea irradiation optical system or the eyeground irradiation optical system and changes a light path length; the interference optical system synthesizes a cornea reflection light provided by the cornea irradiation optical system and an eyeground reflection light provided by the eyeground irradiation optical system to interfere and separates spectroscopically the interfered light into frequency components; and the bioinformation providing system uses Fourier transform to analyze a received light signal provided by the interference optical system and bases the analysis result and a change in light path length provided by the light path length changing means to provide bioinformation of the eye to examine. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ophthalmologic apparatus for obtaining biological information of a subject's eye without contact.

Conventionally, intraocular lens design, medical research, and the like have been performed by acquiring biological information of the eye. As an apparatus for obtaining such biological information of the subject's eye, for example, an ophthalmologic apparatus that measures the axial length of the subject's eye optically in a non-contact manner is known. In such an apparatus that measures the biological information of the subject's eye in a non-contact manner, the interference from the reference position is obtained by using interference generated by combining the reflected light from the fundus and the reflected light from the reference surface provided in the apparatus. An apparatus for calculating the axial length of a subject's eye by obtaining a distance to the subject's eye fundus and obtaining a distance from a reference position to the cornea of the subject's eye with another optical system is known ( Patent Document 1).
Japanese Patent Laid-Open No. 7-255684

  In such an ophthalmologic apparatus that acquires the biological information of the eye in a non-contact manner, it is desired that more biological information can be acquired with a single apparatus in order to improve the efficiency of the examination.

  This invention makes it a technical subject to provide the ophthalmologic apparatus which can acquire various biological information of eyes with one unit.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) In an ophthalmologic apparatus that acquires biological information of a subject's eye in a non-contact manner, the cornea includes a light source that emits a light beam having a low coherent length, and the light beam emitted from the light source is collected near the subject's eye cornea An irradiation optical system, a fundus irradiation optical system that irradiates a part of the luminous flux emitted from the light source toward the fundus of the subject's eye, and the cornea irradiation optical system or the fundus irradiation optical system, and changes an optical path length. The optical path length variable means, the corneal reflection light obtained by the cornea irradiation optical system and the reflected light from the subject fundus obtained by the fundus irradiation optical system are combined and interfered, and the obtained interference light is a frequency component. The subject's eye based on the interference optical system that splits and receives light, the analysis result obtained by analyzing the light reception signal obtained by the interference optical system using Fourier transform, and the amount of change in the optical path length of the optical path length varying means And biometric information obtaining means for obtaining the biometric information.
(2) The ophthalmologic apparatus according to (1) is provided inside the apparatus housing, and the reference light optical system that uses a part of the light beam emitted from the light source as reference light and the fundus illumination optical system is used. A reference light switching member for guiding the reference light of the reference light optical system to the interference optical system instead of the reflected light of the subject's eye fundus and combining it with the corneal reflected light obtained by the corneal irradiation optical system; When obtaining the axial length, the reflected light from the eye fundus of the subject and the corneal reflected light are combined and interfered, and when obtaining biological information of the anterior segment of the subject's eye, the reference light and the corneal reflection are obtained. Control means for driving and controlling the reference light switching member so as to synthesize and interfere with light.
(3) In the ophthalmologic apparatus according to (2), an optical path length from a reference surface provided in the reference light optical system to a light receiving surface of the interference optical system is from the cornea condensing position in the cornea irradiation optical system to the light receiving surface. The optical path length is designed to be substantially the same.
(4) The ophthalmologic apparatus according to (1) is provided inside the apparatus housing, and is obtained by the reference light optical system that uses a part of the light beam emitted from the light source as reference light, and the cornea irradiation optical system. A reference light switching member for guiding the reference light of the reference light optical system to the interference optical system instead of the reflected light of the subject's cornea, and combining it with the fundus reflected light obtained by the fundus illumination optical system; When obtaining the axial length, the reflected light from the subject cornea and the fundus reflected light are combined and interfered, and when obtaining biological information of the fundus of the subject eye, the reference light and the fundus reflected light are combined. Control means for driving and controlling the reference light switching member so as to combine and interfere.

  According to the present invention, it is possible to obtain various biometric information of the eye, which has been conventionally measured by a plurality of devices, with a single device, and to perform an efficient examination or the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an optical system of an ophthalmologic apparatus used in the present embodiment. The optical system shown in FIG. 1 includes a fundus irradiation optical system, a refractive power measurement optical system, a cornea irradiation optical system, an interference signal detection optical system, a reference light optical system, a target projection optical system, and an observation optical system. The ophthalmologic apparatus of the present embodiment also has an alignment optical system for positioning the apparatus in a predetermined relationship with respect to the subject's eye, but has been conventionally used for objective eye refractive power devices and the like. Since an optical system similar to a known alignment optical system may be used, the description thereof is omitted.

<Ocular fundus irradiation optical system>
A fundus irradiation optical system 100 shown in FIG. 1 includes a light source 1, a collimator lens 2, a half mirror 3, a condensing lens 4, a relay lens 5, a diaphragm 6, a hall mirror 7, a half mirror 8, and an objective lens in order from the light source side. 9 and a half mirror 10. Reference numeral 50 denotes a shielding plate that is detachably installed in the optical path of the fundus illumination optical system 100 and that blocks and opens the optical path. The shielding plate 50 is inserted into and removed from the optical path by the driving means 66 shown in FIG. In the present embodiment, the shielding plate 50 is inserted into and removed from the optical path between the half mirror 3 and the condenser lens 4, but is not limited to this. Any place that does not become a common optical path for other optical systems to be described later may be used.

  The light source 1 is a light source that emits low-coherent infrared light such as SLD (Super luminescent Diode). The low coherent light emitted from the light source 1 is converted into a parallel light beam by the collimator lens 2 and then transmitted through the half mirror 3. The light beam that has passed through the half mirror 3 forms an intermediate image (condensing point A) on the optical axis L1 by the condensing lens 4, and then passes through the relay lens 5 and the opening of the hall mirror to be condensed once. Then, the light is condensed on the fundus of the eye E through the half mirror 8, the objective lens 9, and the half mirror 10.

<Optical power measurement optical system>
A refractive power measurement optical system 200 shown in FIG. 1 includes a half mirror 10, an objective lens 9, a half mirror 8, a hall mirror 7, a relay lens 11, a mirror 12, a diaphragm 13, a collimator lens 14, and a half mirror from the front of the subject eye E. 15, a ring lens 16, and a light receiving element 17 having sensitivity in the infrared region. The fundus illumination optical system 100 shares the hall mirror 7 to the half mirror 10.

  The reflected light (reference light) of the light beam collected on the fundus of the subject eye E by the fundus illumination optical system 100 is reflected by the hall mirror 7 through the half mirror 10, the objective lens 9, and the half mirror 8. The hall mirror 7 reflects the fundus reflection light from the subject eye E, and allows unnecessary corneal reflection light to pass through the opening.

  The fundus reflection light reflected by the hall mirror 7 passes through the relay lens 11, is bent by the mirror 12, and is then condensed (condensing point B) at the position of the diaphragm 13. Thereafter, the reflected light is converted into a parallel light beam by the collimator lens 14, and then a part of the reflected light is reflected by the half mirror 15, and is received by the two-dimensional light receiving element 17 through the ring lens 16.

  Note that the condensing point A by the condensing lens 4 of the measurement light projecting optical system 100 and the condensing point B at the position of the stop 13 which is the front focal position of the collimator lens 14 are connected to the objective lens 9 and the relay lenses 5 and 11. Via the fundus of the subject eye E. Further, the condenser lens 4, the diaphragm 13, the collimator lens 14, the half mirror 15, the ring lens 16, and the light receiving element 17 shown in FIG. 1 are installed on a drivable stage 18, and the stage 18 is shown in FIG. It can be moved in the optical axis direction by the driving means 63 shown in FIG.

  Further, the ring lens 16 is placed at the rear focal position of the collimator lens 14, and a conjugate relationship with the pupil of the subject eye E is maintained regardless of the movement position of the stage 18 by the driving means 19. Further, the light receiving element 17 is at the focal position of the ring lens 16 and has a conjugate relationship with the fundus of the subject eye E. The ring lens 16 is formed by forming a cylindrical lens in a ring shape on a flat plate, and a coating for light shielding is applied except for the ring portion. When a parallel light beam enters the ring lens 16, a ring image having substantially the same size as the ring lens 16 is condensed at the focal position (the light receiving surface of the light receiving element 17).

<Cornea irradiation optical system>
A corneal irradiation optical system 300 shown in FIG. 1 includes, from the light source side, a light source 1, a collimator lens 2, a half mirror 3, a mirror 19, a half mirror 20, a condenser lens 21, a mirror 22, a half mirror 8, an objective lens 9, The half mirror 10 is used. The fundus illumination optical system 100 shares the light source 1 to the half mirror 3 and the half mirror 8 to the half mirror 10.

  After the low-coherent light emitted from the light source 1 passes through the collimator lens 2, a part of the light beam is reflected by the half mirror 3 and travels to the mirror 19 disposed on the optical axis L2. The light beam reflected by the mirror 19 passes through the half mirror 20, and then is once condensed on the optical axis L <b> 2 by the condenser lens 21. The light beam collected on the optical axis L2 is reflected by the mirror 22, and then reflected by the half mirror 8, so that it is coaxial with the optical axis L1, passes through the objective lens 9 and the half mirror 10, and passes through the subject eye E. Concentrate near the cornea.

<Interference signal detection optical system>
An interference signal detection optical system 400 shown in FIG. 1 receives an optical system for receiving reflected light (reference light) from the fundus of the subject eye E and reflected light (measurement light) from the cornea of the subject eye E. Optical system.

  The optical system that receives the reflected light from the fundus is a half mirror 10, objective lens 9, half mirror 8, hall mirror 7, relay lens 11, mirror 12, aperture 13, collimator lens 14, half mirror from the front of the subject eye E. 15, a half mirror 26, a mirror 27, a condenser lens 28, an expander lens 29, a grating mirror (diffraction grating) 30, a condenser lens 31, a cylindrical lens 32, and a light receiving element 33. The light receiving element 33 is a one-dimensional element (line sensor) having sensitivity in the infrared region. The refractive power measuring optical system 200 shares the half mirror 10 to the half mirror 15.

  As described above, the reflected light of the light beam collected on the fundus of the subject eye E by the fundus illumination optical system 100 passes through various optical members of the refractive power measurement optical system 200 and then is partially reflected by the half mirror 15. Is transparent. The reflected light that has passed through the half mirror 15 is further reflected by the mirror 27 via the half mirror 26 disposed on the optical axis L3, and once condensed through the condenser lens 28. The reflected light collected by the condensing lens 28 is expanded in diameter by the expander lens 29 and then split into frequency components by the grating mirror 30. The reflected light split into frequency components is condensed on the light receiving surface of the light receiving element 33 through the condenser lens 31 and the cylindrical lens 32. The beam diameter after passing through the expander lens 29, the grating interval and incident angle of the grating mirror, the condensing lens 31, and the light receiving element 33 are optimized in consideration of the measurement range and resolution in the subject eye optical axis direction.

  In addition, the optical system for receiving the reflected light from the cornea of the subject eye E includes a half mirror 10, an objective lens 9, a half mirror 8, a mirror 22, a condensing lens 21, a half mirror 20 from the front of the subject eye E, The prism 23, mirrors 24 and 25, half mirror 26, mirror 27, condenser lens 28, expander lens 29, grating mirror 30, condenser lens 31, cylindrical lens 32, and light receiving element 33 are included. The prism 23 can be moved in the direction of the arrow shown by the driving means 54 shown in FIG. 2 so that the optical path length through which the reference light passes can be changed.

  The reflected light from the cornea passes through the half mirror 10 and the objective lens 9 and is then partially reflected by the half mirror 8. The reflected light reflected by the half mirror 8 passes through the mirror 22 and the condenser lens 21, is reflected by the half mirror 20, and travels toward the prism 23. The reflected light reflected by the prism 23 goes to the half mirror 26 via the mirrors 24 and 25. The reflected light reflected by the half mirror 26 is coaxial with the above-described reflected light from the fundus and is synthesized. After combining, after passing through the mirror 27, the condensing lens 28, and the expander lens 29 in the same manner as the reflected light from the fundus, it is spectrally separated into frequency components by the grating mirror 30, and condensed onto the light receiving element 33 through the cylindrical lens 32. To do. A spectrometer unit is formed by the grating mirror 30, the condensing lens 31, the cylindrical lens 32, and the light receiving element 33. Further, the light receiving surface of the light receiving element 33 has a conjugate relationship with the fundus of the subject eye E and the cornea. The cylindrical lens 32 serves to widen the diameter of the light beam in the width direction of the light receiving element 33 and is used to cause the light receiving surface to receive the light beam regardless of the installation error of the light receiving element 33.

<Reference light optical system>
The reference light optical system shown in FIG. 1 includes a light source 1, a collimator lens 2, a half mirror 3, a mirror 19, a half mirror 20, mirrors 34 and 35, and a reference mirror 36 serving as a reference surface. The optical path length from the reference mirror 36 (reference surface) to the light receiving element 33 of the interference signal detecting optical system 400 is from the cornea condensing position in the cornea irradiation optical system 200 to the light receiving element 33 through the interference signal detecting optical system 400. It is designed to approximately match the length of the optical path to reach. In other words, in the optical system of the present embodiment, the optical path length from the corneal focusing position to the half mirror 20 in the corneal irradiation optical system and the optical path length from the reference mirror 36 to the half mirror 20 are substantially the same. A shielding plate 51 is detachably installed in the optical path of the reference light optical system, and blocks and opens the optical path. The shielding plate 51 is inserted into and removed from the optical path by the driving means 67 shown in FIG. In the present embodiment, the shielding plate 51 is inserted into and removed from the optical path between the half mirror 20 and the mirror 34, but the present invention is not limited to this. Any place that does not become a common optical path for other optical systems may be used.

  After the low-coherent light emitted from the light source 1 passes through the collimator lens 2, a part of the light beam is reflected by the half mirror 3 and travels to the mirror 19 disposed on the optical axis L2. The light beam reflected by the mirror 19 is further reflected by the half mirror 20 and then reaches the reference mirror 36 via the mirrors 34 and 35. The low-coherent light that has reached the reference mirror 36 is folded at the reference surface, passes through the mirrors 35 and 34, and passes through the half mirror 20. The reflected light (reference light) transmitted through the half mirror 20 is directed to the prism 23 in a state where it is combined with the corneal reflected light. The reference light returned by the prism 23 is received by the light receiving element 33 through the mirror 24 to the cylindrical lens 32 of the interference signal detection optical system 400.

<Target projection optical system / observation optical system>
The target projection optical system shown in FIG. 1 includes a light source 37 such as an LED that emits visible light, a target plate 38 on which a predetermined target is formed, a relay lens 39, a half mirror 40, an objective lens 41, and a half mirror 10. Consists of. The visible light beam emitted from the light source 37 illuminates the target plate 38 from the back. The light flux that has passed through the target plate 38 forms an image on the fundus of the subject eye E through the relay lens 39, the half mirror 40, the objective lens 41, and the half mirror 10. When the apparatus is aligned so as to have a predetermined positional relationship with the subject eye E, the target plate 38 and the fundus of the subject eye E have a conjugate relationship. Further, the light source 37 and the target plate 38 can be moved in the optical axis direction by the driving means 65 shown in FIG. 2, and the eye refractive power is measured by changing the fixation of the subject's eye or the position of the target plate. Occasionally, the subject's eyes are clouded or adjusted.

  The observation optical system includes a half mirror 10, an objective lens 41, a half mirror 40, an imaging lens 42, and a light receiving element 43 having sensitivity in the infrared region from the front of the subject's eye. Note that the pupil position of the subject eye E and the light receiving element 43 have a conjugate positional relationship. Reference numeral 44 denotes an infrared LED for illuminating the subject's eye.

  FIG. 2 is a block diagram showing a control system in the ophthalmic measurement apparatus used in the present embodiment.

  Reference numeral 60 denotes a control unit that performs drive control of the apparatus according to the present embodiment. The control unit 60 is connected to the light receiving element 17, the light receiving element 33, the light receiving element 43, the monitor 61, the arithmetic processing unit 62, the driving means 63 to 67, the storage unit 68, the control unit 69 and the like. The drive means 63 to 67 use pulse motors or the like, and can detect the drive amount by each drive means. In addition, the arithmetic processing unit 62 calculates biological information such as refractive power and axial length of the subject's eye E based on information obtained by the light receiving element, driving means, etc., and forms a cross-sectional image of the subject's eye. Used to do. The storage unit 68 stores the obtained measurement value. The control unit 69 is provided with various operation switches such as a measurement start switch and a measurement mode changeover switch.

The operation of the apparatus having the above configuration will be described. In the following description, the case of measuring the axial length of the subject's eye and the case of acquiring the anterior segment information of the subject's eye will be described separately.
<Axial length measurement>
The examiner uses the changeover switch (not shown) of the control unit 69 to set the axial length measurement mode. When receiving the signal for setting the axial length measurement mode, the control unit 60 drives the drive means 66 and 67 to remove the shielding plate 50 from the optical path and insert the shielding plate 51 into the optical path. The arrangement state of the optical system shown in FIG.

  While looking at the monitor 61 shown in FIG. 2, the examiner moves the apparatus in the up / down / left / right and front / rear directions using an operation means such as a joystick (not shown), and places the apparatus in a predetermined positional relationship with the subject eye E. . In the present embodiment, the light receiving surface of the light receiving element 43 and the pupil position of the subject eye E have a conjugate relationship. The examiner causes the subject to fixate the target projected by the target projection optical system shown in FIG. 1 and uses the measurement start switch (not shown) of the control unit 69 to adjust the axial length of the subject eye E. Ask for.

  When the measurement switch is pressed, the control unit 60 drives the driving means 65 to move the light source 37 and the target plate 38 in the direction of the optical axis so as to be in a cloudy state, so that adjustment of the subject eye E is eliminated. To do. Further, the control unit 60 emits low coherent light from the light source 1. The low-coherent light emitted from the light source 1 is divided into two directions by the half mirror 3 shown in FIG. 1, and then passes through the fundus illumination optical system 100 and the cornea illumination optical system 300 described above to the fundus and cornea of the subject eye E. Each is condensed. The reflected light of the light beam collected on the fundus of the subject eye E is guided to the refractive power measurement optical system 200 shown in FIG. 1 and finally received by the light receiving element 17.

  FIG. 3 is a schematic view showing a state in which reflected light from the fundus is received by the light receiving element 17 through the ring lens 16. For example, when the subject's eye E is a normal eye, the reflected light that has passed through the collimator lens 14 passes through the ring lens 16 as a parallel light flux as shown in FIG. At this time, the ring image R 1 received by the light receiving element 17 through the ring lens 16 has substantially the same size as the ring lens 16. When the subject eye E is a myopic eye, the reflected light that has passed through the collimator lens 14 becomes convergent light as shown in FIG. 3B and passes through the ring lens 16. At this time, the ring image R2 received by the light receiving element 17 through the ring lens 16 becomes thicker than the ring image R1 shown in FIG. When the subject eye E is a hyperopic eye, the reflected light that has passed through the collimator lens 14 becomes divergent light as shown in FIG. At this time, the ring image R3 received by the light receiving element 17 through the ring lens 16 becomes thicker and has a larger diameter than the ring image R1 shown in FIG.

  The arithmetic processing unit 62 performs arithmetic processing based on the amount of change between the light receiving state when the subject's eye is a normal eye and the light receiving state actually detected by the light receiving element 17 to obtain the refractive power of the subject eye E. . The arithmetic processing unit 62 is a stage for the measurement light projected toward the fundus from the calculated refractive power value or the light receiving state of the light receiving element 17 to be most condensed (best focus) on the fundus of the subject eye E. 18 positions are calculated. The arithmetic processing unit 62 sends the calculated position information of the stage 18 that is the best focus to the control unit 60. The control unit 60 drives the driving means 63 based on the received position information to move the stage 18 and corrects the refractive power for the subject eye E. By performing the refractive power correction on the subject eye E in this way, the condensing state of the measurement light on the fundus according to the refractive power can be corrected, and an interference signal with a good S / N ratio can be obtained. .

  In the present embodiment, the refractive power of the subject's eye E is obtained based on the light receiving state of the ring image received by the light receiving element 17, but the present invention is not limited to this, and the measurement light is condensed on the fundus. Therefore, the refractive power of the subject eye E can be obtained in consideration of the position of the stage 18 that is the best focus position and the light receiving state of the ring image at that time. The information on the light receiving state of the ring image received by the light receiving element 17 is used to calculate the position information of the stage 18 for obtaining the best focus, and the refractive power of the subject's eye is determined from the reference position of the stage 18. It can also be obtained based on the amount of movement. The obtained refractive power value of the subject eye E is stored in the storage unit 68 and displayed on the monitor 61.

  When the refractive power of the subject eye E is corrected by the movement of the stage 18, the measurement light is efficiently condensed on the fundus of the subject eye E. Reflected light from the fundus (handled as reference light in this embodiment) is finally condensed on the light receiving element 33 by the interference signal detection optical system 400 shown in FIG. In addition, the reflected light of the light beam condensed in the vicinity of the cornea by the cornea irradiation optical system (which is treated as measurement light in this embodiment) is also guided to the interference signal detection optical system 400 and synthesized with the reflected light from the fundus. Finally, the light is collected on the light receiving element 33. As described above, the luminous flux obtained by combining the fundus reflection light and the corneal reflection light is split into frequency components by the grating mirror 30, and is condensed on the light receiving element 33 through the condenser lens 31 and the cylindrical lens 32. It will be. The light receiving element 33 receives the reflected light separated into frequency components and outputs the interference intensity for each frequency component. The arithmetic processing unit 52 monitors the interference intensity obtained by the light receiving element 33.

  On the other hand, the control unit 60 uses the driving unit 64 to move the prism 23 shown in FIG. 1 from the reference position indicated by the solid line (here, the position where the optical path of the corneal irradiation optical system becomes the shortest), and the optical through which the corneal reflection light passes. Change the optical path length of the system. In this embodiment, during the measurement of the axial length, the prism 23 is reciprocated several times to several tens of times per second. However, the present invention is not limited to this, and the prism 23 is simply not reciprocated. It may be only moved in one direction.

  Since the measurement light and the reference light used in this embodiment are low-coherent light, when the optical path length of the measurement light is equal to the optical path length of the reference light, it is obtained by combining the measurement light and the reference light. The signal intensity of the interference light to be generated is the strongest. Note that the measurement light received by the light receiving element 33 includes reflected light from phase objects such as the back surface of the cornea and the front and back surfaces of the crystalline lens, in addition to the reflected light from the cornea surface. Therefore, the interference signal received by the light receiving element 33 is received as a function of the frequency of interference between these and the fundus reflection light (reference light).

  The arithmetic processing unit 62 analyzes the detection signal output from the light receiving element 33 using Fourier transform. Since the interference light includes reflected light from each phase object (for example, the front and back surfaces of the cornea, the front and rear surfaces of the lens, the retina, etc.) in the subject eye E, the fundus is regarded as a reference surface by performing Fourier transform on the detection signal. The depth information of each phase object in the subject eye E can be obtained. The calculation processing unit 62 uses the position information of the front surface of the cornea based on the position of the prism 23 obtained by the calculation and the amount of movement from the reference position of the prism 23 (or the driving amount of the driving means 54) to the eye axis of the subject eye E. Find the length. The reference position (initial position) of the prism 23 is calibrated using a model eye or the like whose eye axis length is known in advance, so that the correspondence between the predetermined eye axis length and the reference position of the prism 23 is achieved. Attached.

  Information about the obtained axial length is stored in the storage unit 68 and displayed on the monitor 61. In this embodiment, the optical path length of the measurement light is changed so that the optical path length of the measurement light and the optical path length of the reference light are equal by moving the prism placed in the optical path of the corneal reflection light. However, the present invention is not limited to this, and an optical system that changes the optical path length of the fundus reflection light (reference light) can also be designed.

Further, when it is desired to obtain the axial length more accurately, in the optical system shown in FIG. 1, a position conjugate between the collimator lens 14 and the condenser lens 28 and the pupil of the subject eye E, or the objective lens 9 is used. An astigmatism correcting optical member comprising a combination of a plurality of cylinder lenses may be disposed at a position substantially conjugate with the pupil of the subject eye E between the lens and the hall mirror 7. As the astigmatism correcting optical member, for example, a Stokes cross cylinder formed by a combination of two cylinder lenses can be used. When the subject's eye E has astigmatism, the ring image received by the light receiving element 17 through the ring lens 16 has an elliptical shape. Therefore, the light receiving state of the ring image is analyzed using the arithmetic processing unit 62. Thus, the astigmatism power and the astigmatism axis angle can be obtained. The above-described astigmatism correcting optical member is arranged so as to cancel the astigmatism component of the subject eye E based on the obtained astigmatism power and astigmatism axis angle of the subject eye E. With such a configuration, even if the subject's eye has an astigmatism component, the reflected light from the fundus can be more efficiently collected on the light receiving element 33 and the measurement accuracy can be improved.
<Anterior segment measurement>
Next, the example which calculates | requires the biometric information of the anterior eye part of a test subject's eye is demonstrated below.

  The examiner sets the anterior ocular segment measurement mode using a switch (not shown) of the control unit 69. Upon receiving a signal for setting the anterior segment measurement mode, the control unit 60 drives the driving means 66 and 67 to insert the shielding plate 50 on the optical path and retract the shielding plate 51 from the optical path. Assume that the optical system shown in FIG.

  The examiner puts the apparatus in a predetermined positional relationship with the subject eye E as described above while looking at the monitor 61 shown in FIG. 2, and then uses the measurement start switch (not shown) of the control unit 69 to examine the subject. An anterior segment of eye E is measured.

  When the measurement switch is pressed, the control unit 60 causes the light source 1 to emit low coherent light. The low-coherent light emitted from the light source 1 is reflected by the half mirror 3 and then divided into two directions by the half mirror 20 as shown in FIG. The light beams that have passed through the half mirror 20 are condensed on the cornea of the eye E through the cornea irradiation optical system 300. The light beam reflected by the half mirror 20 is guided to the reference light optical system.

  The reflected light of the light beam collected in the vicinity of the cornea of the subject's eye E is guided to the interference signal detection optical system 400 in the form of going backward through the cornea irradiation optical system 300 as described above, and finally converged on the light receiving element 33. Is done. On the other hand, a light beam (reference light) traveling toward the reference light optical system is folded back by the reference mirror 36 and guided to the interference signal detection optical system 400 in a state where it is combined with the corneal reflection light by the half mirror 20 and finally received. It is condensed on the element 33. As described above, since the optical path length from the corneal focusing position to the half mirror 20 in the corneal irradiation optical system and the optical path length from the reference mirror 36 to the half mirror 20 are substantially the same, It will interfere with the reference beam. The light beam obtained by combining the corneal reflection light and the reference light is split into frequency components by the grating mirror 30, and is condensed on the light receiving element 33 through the condenser lens 31 and the cylindrical lens 32. The light receiving element 33 receives the reflected light separated into frequency components and outputs the interference intensity for each frequency component. The arithmetic processing unit 52 monitors the interference intensity obtained by the light receiving element 33. In the anterior ocular segment measurement mode, since the corneal reflection light and the reference light are combined and incident on the prism 23, the prism 23 may be placed at any position.

  The arithmetic processing unit 62 analyzes the detection signal output from the light receiving element 33 using Fourier transform. Since the interference light includes reflected light from a phase object (for example, the anteroposterior surface of the cornea, the anteroposterior surface of the crystalline lens) around the anterior segment of the subject's eye E, the detection signal in the subject's eye E can be obtained by performing Fourier transform on the detection signal. Depth information of each phase object such as cornea and crystalline lens can be obtained. Based on the depth information, the arithmetic processing unit 62 obtains biological information (here, dimension information) of the anterior segment such as the anterior chamber depth, lens thickness, and corneal thickness of the subject's eye. The obtained biological information of the anterior segment is stored in the storage unit 68 and displayed on the monitor 61.

  When the fundus reflection light is used as the reference light when measuring the anterior segment, a reflectance distribution is likely to occur due to the influence of various phase objects on the fundus, and a highly accurate measurement result may not be obtained. For this reason, in the present embodiment, when the anterior segment measurement is performed, the reference light is obtained using the reference light optical system provided inside the apparatus as described above, and the measurement accuracy is improved.

  In this embodiment, the measurement light is collected on the cornea. However, the present invention is not limited to this, and reflected light from a phase object (cornea, crystalline lens, etc.) in the subject's eye is spectrally divided into frequency components. For example, the condensing position of the measurement light may be set to a position near the cornea such as the pupil position of the subject eye E.

  In this embodiment, a grating mirror (diffraction grating) is used as a spectroscopic means for splitting the combined light of the measurement light and the reference light into each frequency component. However, the present invention is not limited to this. Other spectroscopic means such as prisms and acousto-optic elements can also be used.

  Furthermore, in this embodiment, a ring image is formed on the light receiving element in order to obtain the refractive power of the subject's eye, but this is not restrictive. For example, the reflected light from the fundus is divided into several points via an optical member and collected on the light receiving element, and the refractive power is calculated based on the light receiving state of the received light image. Any configuration may be used as long as the refractive power is obtained by detecting a change state of the received light image such as a change in position or shape of the received light image.

  As described above, the ophthalmologic apparatus according to the present embodiment can obtain in-vivo dimensions such as the axial length and the dimension information of the anterior eye part, but further scans the light beam irradiated toward the subject's eye. It is also possible to obtain a tomographic image of the anterior ocular segment of the subject's eye by providing scanning means for analyzing and analyzing the obtained detection signal based on the principle of spectral interference.

  FIG. 5 is a diagram showing an example in which scanning means for scanning a light beam emitted toward the subject's eye is provided in the optical system of FIG. 1 as the second embodiment. Components having the same functions as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 5, reference numeral 70 denotes a galvano mirror serving as a scanning means for scanning a light beam emitted toward the subject's eye, and in a predetermined direction (in this embodiment, a direction in which the light beam is scanned vertically with respect to the subject's eye). Can be rotated. The reflecting surface of the galvanometer mirror 70 is disposed at the focal position of the objective lens 9 so that the rotation angle of the mirror is proportional to the incident height of the light beam to the anterior eye part and the optical path length does not change by driving. It has become. The configuration of the control system for driving and controlling the ophthalmologic apparatus in the second embodiment is the same as the block diagram of the control system shown in FIG. Omit. The optical arrangement for acquiring the anterior segment image is such that the shielding plate 50 is inserted on the optical path and the shielding plate 51 is retracted from the optical path (the state shown in FIG. 4).

  The low-coherent light emitted from the light source 1 shown in FIG. 5 passes through the cornea irradiation optical system 300 and is condensed near the cornea of the subject's eye. On the other hand, the light beam reflected by the half mirror 20 out of the low coherent light passing through the cornea irradiation optical system 300 is directed to the reference mirror 36. The combined light of the corneal reflected light of the subject eye E (reflected light from the phase object of the anterior eye portion) and the reference light that is folded back from the reference mirror 36 is spectrally separated into frequency components by the grating mirror 30 of the interference signal detection optical system 400. In this state, the light is condensed on the light receiving element 33. By performing Fourier transform on the detection signal output from the light receiving element 33 by the arithmetic processing unit 62, depth information of each phase object such as the cornea and the crystalline lens in the subject eye E can be obtained.

  The light beam passing through the cornea irradiation optical system 300 is sequentially scanned in the predetermined direction with respect to the subject eye E by the galvanometer mirror 70. For this reason, the detection signal output from the light receiving element 33 includes information on each reflected light from the intraocular phase object obtained by scanning the light beam. The arithmetic processing unit 62 accumulates information in the depth direction of the phase object in the eye obtained by Fourier transforming the detection signal, thereby obtaining a cross-sectional image of the anterior ocular segment of the subject's eye that has been optically cut by scanning. be able to. The obtained anterior segment cross-sectional image is displayed on the monitor 61 as shown in FIG. Note that dimension information of the anterior segment is also displayed on the monitor 61.

  Moreover, in the above embodiment, although the one-dimensional light receiving element (line sensor) is used for the light receiving part of the spectrometer part, it is not restricted to this. Hereinafter, as a third embodiment, an example in which a single light receiving element is used as the light receiving element of the spectrometer unit will be described with reference to FIG. Since the optical system shown in FIG. 7 is the same as that shown in FIG. 1 except for the spectrometer unit, only the spectrometer unit will be described here.

  As shown in the figure, the spectrometer unit is composed of a polarizing beam splitter 80, a quarter-wave plate 81, a grating mirror 82, a lens group 83, a polygon mirror 84, a condensing lens 85, and a light receiving element 86. The polarization beam splitter 80 has a characteristic of reflecting S waves and transmitting P waves.

  The lens group 83 includes a plurality of lenses. The lens group 83 is placed between the grating mirror 82 and the polygon mirror 84, and each frequency component incident as parallel light through the grating mirror 82 is converted into a parallel light beam after refraction. It is designed so that the principal rays of the component luminous fluxes intersect at a single point. Further, the polygon mirror 84 is arranged in a state where the rotation axis thereof coincides with the point where the chief rays of the light beams of the respective frequency components described above intersect. The light receiving element is a single light receiving element such as a photodiode or an APD (avalanche photodiode). Such a light receiving element 86 has a much higher light receiving sensitivity in the infrared region than the one-dimensional light receiving element shown in FIG.

  The interference light obtained by combining the measurement light and the reference light is once condensed through the condenser lens 28 as shown in FIG. The interference light collected by the condenser lens 28 is expanded in beam diameter by the expander lens 29, and then only the P-wave light is transmitted by the polarization beam splitter 80. The interference light that has passed through the modified beam splitter 80 passes through the quarter-wave plate 81 and is then split into frequency components by the grating mirror 82. Each light beam separated into frequency components by the grating mirror 82 is reflected by the reflecting surface of the polygon mirror 84 via the lens group 83. The polygon mirror 84 rotates at a predetermined speed, and travels backward in the optical path in which only a light beam having a specific frequency has advanced depending on the angle of the reflecting surface. The light beam traveling backward in the optical path passes through the lens group 83 and the grating mirror 82, passes through the quarter-wave plate, and is reflected by the polarization beam splitter 80 as an S-wave light beam. The light beams reflected by the polarization beam splitter 80 are respectively collected in time series on the light receiving surface of the light receiving element 86 by the condenser lens 85. Thus, when the polygon mirror 84 is continuously rotated, an interference signal for each frequency (for each wavelength) is continuously obtained as a function of time in the light receiving element 86. An arithmetic processing unit (not shown) analyzes the detection signal output from the light receiving element 86 using Fourier transform, and obtains depth information of each phase object in the subject eye E. Thus, by using a single light receiving element, the light receiving sensitivity can be increased, and biological information can be obtained with high accuracy.

  As described above, in the third embodiment, the polygon mirror is used as means for causing the light receiving element to receive the light divided for each frequency in time series. However, the invention is not limited to this, and a galvano mirror or the like is used instead of the polygon mirror. Any means can be used as long as the movable mirror or the light receiving element can sequentially receive light divided by frequency in a time division manner.

  In this embodiment, the light beam reflected by the polygon mirror is reflected to the light receiving element side by the polarization beam splitter. However, the present invention is not limited to this, and the light reflected by the polygon mirror is reflected on the subject's eye. It suffices to have a configuration for preventing the light from entering the reference mirror, the light source and the like again. For example, in the optical arrangement shown in FIG. 7, a half mirror can be placed instead of the polarizing beam splitter 80, and the polarizing beam splitter can be installed in any place that does not interfere with the measurement on the same optical path.

  In the present embodiment, the light beam reflected by the polygon mirror 84 travels back in the optical path, is reflected by the polarization beam splitter 80, and is detected by the light receiving element 86. However, the present invention is not limited to this. In other words, the light beam from the lens group 83 may be reflected by the polygon mirror 84 in the other direction (the direction that does not reverse), and the light beam may be detected by the condensing lens and the light receiving element arranged in the light beam reflection direction. . In this case, the polygon mirror 84 may be arranged so that the rotation axis of the polygon mirror 84 does not coincide with the point where the chief rays of the light beams of the respective frequency components intersect.

  As described above, according to the ophthalmologic apparatus of the present embodiment, it is possible to efficiently acquire various biological information of the subject's eye with one unit. In the above-described measurement of the axial length, the fundus of the subject's eye is caused to interfere with the reference light and the corneal reflection light as the measurement light (object light), and analysis is performed on the principle of spectral interference, so that the subject's eye Even if the position of the lens is slightly deviated, both the reference light and the object light change to the same extent, so that there is an advantage that they are resistant to misalignment and defocus. Further, when acquiring biological information of the anterior segment, the reference light is formed inside the device and interferes with the corneal reflected light, so that the noise component can be suppressed as much as possible, and the anterior segment of the subject's eye can be accurately obtained. Dimensions and cross-sectional images can be obtained. Moreover, it goes without saying that the configuration of the spectrometer unit in the third embodiment is not limited to an ophthalmologic apparatus but can be applied to other measurement apparatuses that obtain information in the depth direction of an object to be examined.

In the above description, the configuration for obtaining the biological axis information of the subject's eye and the biological information of the front face portion of the subject's eye has been described as the configuration for obtaining the biological information of the subject's eye. However, the configuration is not limited to this.
Hereinafter, an example in which the axial length of the eye to be examined and the biological information of the fundus of the subject's eye will be described.

  8 and 9 are schematic configuration diagrams showing the configuration of the optical system of the ophthalmologic apparatus according to the fourth embodiment. In addition, about what attached | subjected the code | symbol same as FIG. 4, unless there is particular description, it shall have the same function and description is abbreviate | omitted. In the case of the fourth embodiment, the fundus illumination optical system 100 is disposed in the reflection direction of the half mirror 3, and the cornea illumination optical system 300 is disposed in the transmission direction of the half mirror 3. In addition, the optical arrangement | positioning at the time of acquiring an axial length is made into the state (state shown in FIG. 8) in which the shielding board 50 was evacuated from the optical path and the shielding board 51 was inserted in the optical path. In addition, the reflective surface of the galvanometer mirror 70 is arrange | positioned in the position conjugate with the pupil of a test subject's eye. Further, a half mirror 97 is arranged instead of the hall mirror 7 shown in FIG. Further, between the optical paths of the mirror 12 and the half mirror 26, a bypass route (not shown) for adjusting the optical path difference between the corneal reflection light and the fundus reflection light is provided.

  Reflected light from the fundus goes to the prism 23 via the half mirror 10, the objective lens 9, the half mirror 8, the galvano mirror 70, the relay lens 5, the condenser lens 4, and the half mirror 20. The reflected light reflected by the prism 23 goes to the half mirror 26 via the mirrors 24 and 25. Reflected light from the cornea passes through the half mirror 10, the objective lens 9, and the half mirror 8, and is reflected by the half mirror 97, and then passes through the collimator lens 91, the mirror 12, and the half mirror 26, and is reflected from the above-described fundus. It is made coaxial and synthesized.

  When obtaining the axial length, the control unit 60 moves the prism 23 to change the optical path length of the optical system through which the fundus reflection light passes, and based on the detection signal from the light receiving element 33, the fundus reflection light and the cornea The position of the prism 23 when the signal intensity of the interference light due to the reflected light becomes the strongest is detected. The arithmetic processing unit 62 then determines the subject's eye E from the positional information of the rear surface of the retina based on the position of the prism 23 obtained by the calculation and the amount of movement from the reference position of the prism 23 (or the driving amount of the driving means 54). Obtain the axial length of the eye.

  On the other hand, the optical arrangement for acquiring biological information of the fundus of the subject's eye is such that the shielding plate 50 is inserted on the optical path and the shielding plate 51 is retracted from the optical path (the state shown in FIG. 9). That is, the reference light of the reference light optical system is guided to the interference optical system 400 instead of the corneal reflection light obtained by the cornea irradiation optical system 300. More specifically, of the low coherent light emitted from the light source 1 of the fundus illumination optical system 100, the light beam reflected by the half mirror 20 is directed to the reference mirror 36 and becomes reference light. The reference light reflected by the reference mirror 36 is reflected by the half mirror 26 via the mirrors 35 to 23 and the prisms 23 to 25 and is coaxial with the fundus reflection light. The mirrors 34 and 35 can be moved in the direction of the arrow shown by the driving means 55, and the optical path length of the reference light can be changed without changing the optical path length of the fundus reflection light. Yes.

  Here, the control unit 60 moves the mirror 34 and the mirror 35 integrally to make the optical path length of the fundus measurement light, which fluctuates depending on the axial length of the subject's eye, substantially equal to the optical path length of the reference light. The reflected light and the reference light are combined to generate interference light.

  In this case, since the interference light includes reflected light from a phase object around the fundus of the subject's eye E (for example, the front and rear surfaces of the retina), the arithmetic processing unit 62 performs Fourier transform on the detection signal, thereby subjecting the subject. The depth information of each phase object such as the retina in the eye E can be obtained. The arithmetic processing unit 62 obtains biological information (here, dimension information) of the fundus of the subject's eye based on these depth information.

  Moreover, when acquiring a fundus tomographic image, the control unit 60 drives the galvanometer mirror 70 to scan the measurement light collected on the fundus in a predetermined direction with respect to the subject's fundus. Then, the arithmetic processing unit 62 accumulates information in the depth direction of the phase object in the eye obtained by Fourier transforming the detection signal, thereby obtaining a fundus cross-sectional image of the subject's eye that has been optically cut by scanning. be able to.

It is the figure which showed the optical system of the ophthalmologic apparatus of this embodiment. It is the block diagram which showed the control system of the ophthalmologic apparatus of this embodiment. It is the figure which showed the condensing state of the measurement light which permeate | transmitted the ring lens. It is the figure which showed the arrangement | positioning state of the optical system at the time of acquiring anterior segment information. It is the figure which showed the optical system in 2nd Embodiment. It is the figure which showed the test subject's anterior eye part image displayed on the monitor. It is the figure which showed the optical system which has the spectrometer part using a single light receiving element. It is a schematic block diagram which shows the optical system of the ophthalmologic apparatus which concerns on 4th Embodiment (at the time of axial length measurement). It is a schematic block diagram which shows the optical system of the ophthalmologic apparatus which concerns on 4th Embodiment (at the time of the biometric information acquisition of a fundus).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 4 Condensing lens 7 Hall mirror 9 Objective lens 14 Collimator lens 23 Prism 30 Grating mirror 31 Condensing lens 33 Light receiving element 36 Reference mirror 50 Shielding plate 51 Shielding plate 60 Control unit 61 Monitor 62 Calculation processing unit 70 Galvano mirror

Claims (4)

A corneal irradiation optical system that has a light source that emits a light beam having a low coherence length and collects the light beam emitted from the light source in the vicinity of the subject's eye cornea in an ophthalmologic apparatus that acquires biological information of the subject's eye in a non-contact manner And a fundus irradiation optical system that irradiates a part of the luminous flux emitted from the light source toward the fundus of the subject's eye, and an optical path length variable in the cornea irradiation optical system or the fundus irradiation optical system that changes the optical path length. And the corneal reflected light obtained by the cornea irradiation optical system and the reflected light from the fundus irradiation optical system obtained by the fundus irradiation optical system are combined and interfered, and the obtained interference light is spectrally separated into frequency components. Based on the analysis result obtained by analyzing the received light signal obtained by the interference optical system using Fourier transform and the amount of change in the optical path length of the optical path length varying means. Ophthalmologic apparatus characterized by comprising: a biometric information obtaining means for obtaining a distribution, the. The ophthalmologic apparatus according to claim 1 is provided in an apparatus housing and uses a part of the light flux emitted from the light source as reference light, and the eye fundus of the subject obtained by the fundus illumination optical system. A reference light switching member for guiding the reference light of the reference light optical system to the interference optical system instead of the reflected light of the reference light and combining it with the corneal reflection light obtained by the corneal irradiation optical system, and the axial length of the subject's eye Is obtained by synthesizing and interfering the reflected light from the fundus of the subject's eye and the corneal reflected light, and synthesizing the reference light and the corneal reflected light when obtaining biological information of the anterior segment of the subject's eye. And a control means for driving and controlling the reference light switching member so as to cause interference. 3. The ophthalmologic apparatus according to claim 2, wherein an optical path length from a reference surface provided in the reference light optical system to a light receiving surface of the interference optical system is an optical path length from a corneal condensing position to the light receiving surface in the cornea irradiation optical system. An ophthalmologic apparatus, which is designed so as to substantially match. The ophthalmic apparatus according to claim 1 is provided in an apparatus housing and uses a part of the luminous flux emitted from the light source as reference light, and the subject's ocular cornea obtained by the corneal irradiation optical system. A reference light switching member for guiding the reference light of the reference light optical system to the interference optical system in place of the reflected light of the eye and combining it with the fundus reflection light obtained by the fundus illumination optical system, and the axial length of the subject's eye Is obtained by combining the reflected light from the subject's cornea and the fundus reflected light, and when obtaining biological information of the fundus of the subject's eye, the reference light and the fundus reflected light are synthesized. An ophthalmologic apparatus comprising: control means for driving and controlling the reference light switching member so as to cause interference.

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