JP2010279442A - Anterior ocular segment measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anterior ocular segment measuring device capable of removing scattered light with simple constitution. <P>SOLUTION: The anterior ocular segment measuring device includes a projecting optic system 90a including a first light source 91 for emitting visible light for forming a crosssectional image of an anterior ocular segment and a slit, a first imaging optic system having an imaging lens and an imaging element for imaging the crosssectional image, and a second imaging optic system having an infrared light source for illuminating the anterior ocular segment and for imaging a front face image of the anterior ocular segment. Either one of optical member of an objective lens 32 and a light dividing member is arranged in front of an eye to be inspected in a common light path of the projecting optic system and the second imaging optic system, a substrate having an optical property transmitting the visible light or infrared light is arranged between the optic member and the eye to be inspected, and a slit part for transmitting light from the first light source to the eye to be inspected and a filter part applied with a coating with a characteristic not transmitting the light from the first light source and transmitting the light from the infrared light source is formed in the substrate in the anterior segment measuring device for measuring the anterior ocular segment. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an anterior segment measurement apparatus that measures an anterior segment of a subject's eye.

  As an apparatus for measuring the anterior segment of the subject's eye, a projection optical system that projects slit light toward the anterior segment of the subject's eye, and an anterior segment cross-sectional image of the slit beam with an imaging device An apparatus having an imaging optical system for imaging is known (see, for example, Patent Document 1). The captured anterior segment cross-sectional image is used for observation of the anterior segment cross-section, measurement of dimensions (corneal thickness, anterior chamber depth, etc.) of a predetermined part of the anterior segment, and the like.

JP-A 63-197433

  By the way, in the above apparatus, when the slit light passes through the objective lens of the projection optical system, scattered light is generated on the back surface of the lens, and noise (bright spot) is generated on the image sensor through the eye cornea of the subject. May appear as: Conventionally, scattered light is removed by inserting a slit in front of the objective lens. However, since a front image of the anterior segment cannot be observed when the slit is inserted, a slit insertion / removal mechanism is required. Similar scattered light is generated even when a light splitting member (for example, a dichroic prism, a half mirror, or the like) is disposed in front of the eye to be examined.

  In view of the above problems, an object of the present invention is to provide an anterior ocular segment measuring apparatus that can remove scattered light with a simple configuration.

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

(1)
A projection optical system having a projection optical axis, a first light source that emits visible light for forming an anterior segment cross-sectional image of the subject's eye, and a slit;
A first imaging optical system having an imaging optical axis that intersects the projection optical axis at a predetermined angle and having an imaging lens and an imaging element for imaging the anterior segment cross-sectional image;
A second imaging optical system having an infrared light source for illuminating the anterior segment of the subject's eye from an oblique direction, and capturing a front image of the anterior segment of the subject's eye;
An anterior segment measuring apparatus that measures the anterior segment of the subject's eye by the output from the imaging device,
In the common optical path of the projection optical system and the second imaging optical system, an optical member, either an objective lens or a light splitting member, is disposed in front of the subject's eye, and the optical member and the subject's eye A single substrate having an optical characteristic that transmits visible light and infrared light is disposed therebetween, and a slit portion that transmits light from the first light source toward the eye of the subject is disposed on the substrate. And a filter portion provided with a coating having a characteristic of transmitting light from the infrared light source without transmitting light from the first light source.
(2) In the anterior segment measurement apparatus according to (1), the first imaging optical system includes an optical section of a projection image by the projection optical system, a lens system including a subject's cornea, and an imaging surface of the imaging element. Are arranged in a shine-proof relationship.
(3) The anterior segment measurement device according to (2) further includes a second light source for measuring the second eye characteristic, and projects the second measurement light onto the subject's eye and reflects it. A second measuring optical system for receiving light,
The filter section is coated with a characteristic that does not transmit light from the first light source but transmits light from the infrared light source and light from the second light source.
(4) In the anterior segment measuring apparatus according to (3), the second measurement optical system is an axial length measurement optical system that receives the interference light by the measurement light and the reference light and measures the axial length. Features.
(5) In the anterior segment measurement apparatus of (4), the projection optical system that projects the alignment index onto the subject's eye cornea and the alignment index formed on the cornea are imaged by the second imaging optical system. And an alignment detection means for detecting an alignment state with respect to the subject's eye.

  According to the present invention, scattered light can be removed with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an optical system of the anterior segment measuring apparatus. The present optical system includes an anterior ocular segment measurement optical system 90 for measuring ocular characteristics (for example, anterior chamber depth, corneal thickness, corneal curvature, etc.) of an anterior segment of a subject's eye, and an anterior segment front image. An anterior eye front imaging optical system 30 for imaging the eye, a fixation target projection optical system 40, an alignment projection optical system 50, and a second light source for measuring a second eye characteristic. And the second measurement optical system 60 that projects the second measurement light and receives the reflected light. The following optical system is built in a housing (not shown). Further, the casing is three-dimensionally moved relative to the subject's eye via an operation member (for example, a joystick) by driving a known alignment moving mechanism.

  The anterior ocular segment measurement optical system 90 includes a projection optical system 90a that projects slit light for forming a cross-sectional image of the anterior ocular segment onto the subject's eye E, and an anterior segment by slit light projected by the projection optical system 90a. An imaging optical system 90b that receives the reflected light and captures an anterior segment cross-sectional image.

  The projection optical system 90a includes a light source 91, a condensing lens 92, a slit plate 93, a dichroic mirror 94, a projection lens 47, a visible light reflecting / infrared transmitting dichroic mirror 33, an objective lens 32, and an optical lens. Filter 200.

  As the light source 91, for example, a visible light source that emits light (blue light) in a wavelength region of about 470 nm and a center wavelength of about 470 nm is used. The slit plate 93 is disposed at a position conjugate with the anterior eye part (for example, near the top of the cornea), and in FIG. 1, a slit opening whose horizontal direction is the longitudinal direction is formed.

  The lenses 47 and 32 are disposed between the light source 91 and the optical filter 200, and condense light from the light source 91 on the cornea. The optical axis (projection optical axis) of the projection optical system 90a is coaxial with the measurement axis L1.

  The imaging optical system 90b includes a two-dimensional imaging device 97 and an imaging lens 96 that guides the reflected light from the anterior segment by the projection optical system 90a to the imaging device 97. The imaging optical system 90b is based on the Shine-Pluke principle. An image is captured. That is, the imaging optical system 90b is arranged such that its optical axis (imaging optical axis) intersects with the optical axis of the projection optical system 90a at a predetermined angle, and the optical cross section of the projection image by the projection optical system 90a and the object to be examined The lens system including the cornea of the human eye (cornea and imaging lens 96) and the imaging surface of the imaging element 97 are arranged in a shine-proof relationship. In this case, an optical arrangement in which a virtual image of an optical cross-sectional image due to the refraction effect at the cornea, each extended surface of the main plane of the imaging lens 96 and the imaging surface of the imaging element 97 intersect at one intersection line (uniaxial), It has become. 1 shows a configuration in which the imaging optical system 90b is disposed below the projection optical system 90a. However, the configuration is not limited thereto, and the imaging optical system 90b is disposed above, to the right, and to the left of the projection optical system 90a. It may be configured (the slit direction of the slit plate 93 is changed correspondingly). The imaging optical system 90b may be configured to be able to rotate 360 degrees with respect to the optical axis of the projection optical system 90a.

  A filter 99 that transmits only light (blue light) emitted from the light source 91 and used to capture the anterior eye section image is disposed in front of the lens 96 (the subject eye E side). Yes. Accordingly, it is possible to prevent other light (anterior segment illumination light, second measurement light, etc.) from being cut by the filter 99 and incident on the image sensor 97. The filter 99 only needs to be disposed in the imaging optical path from the subject's eye to the imaging element 97.

  The alignment projection optical system 50 is an optical system that has a projection light source 51 (for example, λ = 970 nm) that emits infrared light and projects an alignment index onto the subject's cornea. And the alignment parameter | index projected on the cornea is used for position alignment (for example, automatic alignment, alignment detection, manual alignment, etc.) with respect to a subject's eye. In the present embodiment, the projection optical system 50 is an optical system that projects a ring index on the subject's eye cornea, and the ring index is projected onto the cornea of the subject's eye. Further, the light source 51 of the projection optical system 50 also serves as an anterior segment illumination that illuminates the anterior segment from an oblique direction.

  The anterior segment front imaging optical system 30 includes an objective lens 32, an imaging lens 37, a filter 34, and a two-dimensional imaging element 35. The filter 34 has an optical characteristic of transmitting light from the light source 40 and cutting light from the light source 91.

  With respect to the projection optical system 40, the light of the fixation target 46 illuminated by the fixation light source (visible light source) 45 passes through the dichroic mirror 94, passes through the projection lens 47, and then is reflected by the dichroic mirror 33. Then, the light travels toward the subject eye E through the beam splitter 63, the objective lens 32, and the optical filter 200. The examiner performs the measurement while fixing the fixation target 46 to the subject's eye. The optical members from the fixation light source 45 to the objective lens 32 described above form the fixation target projection optical system 40.

  The second measurement optical system 60 includes a second measurement optical unit 61 having a configuration in which the second measurement light is projected onto the subject's eye and the reflected light is received, a mirror 62, and a beam splitter 63 (for example, a half splitter). Mirror, dichroic mirror) and objective lens 32. The objective lens 32 is shared by the projection optical system 90a and the second measurement optical system 60.

  As the second measurement optical system 60, for example, an axial length measurement optical system that receives the interference light by the measurement light and the reference light and measures the axial length (the wavelength of the measurement light source is, for example, λ = 830 nm) An eye refractive power measuring optical system that receives reflected light projected on the fundus of the subject's eye and measures the eye refractive power (the wavelength of the measurement light source is, for example, λ = 870 nm) can be considered.

  The control unit 70 controls the entire apparatus and calculates measurement results. The control unit 70 is connected to the light source 91, the light source 45, the light source 51, the image sensor 35, the image sensor 97, the second measurement optical unit 61, the monitor 71, and the like. Here, the imaging signal output from the imaging element 35 is subjected to image processing by the control unit 70 and displayed on the monitor 71. Further, the control unit 70 detects the alignment state with respect to the subject's eye based on the imaging signal output from the imaging device 35.

  2A and 2B are schematic configuration diagrams illustrating the configuration of the optical filter 200. FIG. 2A is a front view and FIG. 2B is a side view. The optical filter 200 has a single substrate 201 (for example, a glass substrate) having optical characteristics that transmits visible light and infrared light, and is disposed on the subject side of the objective lens 32. The substrate 201 has a slit 202 (a white portion) that transmits light from the light source 91 toward the subject's eye, and other necessary light (for example, front light) that does not transmit light from the light source 91. And a filter portion 203 having a coating 203a (hatched portion) having a characteristic of transmitting eye portion observation light, alignment light, second measurement light, fixation light flux, etc.).

  The substrate 201 is coated with a coating 203a having a characteristic of reflecting light having a wavelength used for the light source 91 and transmitting other necessary light except for an area where the slit portion 202 is formed. Thereby, the filter part 203 is formed on the substrate 201. Further, the uncoated region (outlined portion) is formed on the substrate 201 as the slit portion 202. The slits 202 have the same longitudinal direction as the slits of the slit plate 93.

  The filter unit 203 is set to an optical characteristic that cuts the scattered light on the back surface of the objective lens 32 due to the measurement light from the light source 91 and transmits at least the anterior ocular segment observation light (for example, light of λ = 970 nm). In addition to the imaging optical system 30, the filter unit 203 has a wavelength of light used for the light source of these optical systems so as to correspond to the projection optical system 50, the projection optical system 40, and the second measurement optical system 60. Is set to a characteristic that transmits the light. For example, it is conceivable to apply a coating with optical characteristics that transmits light of λ = 600 nm to 1025 nm and reflects light of λ = 400 to 550 nm.

  Even if the light from the light source 91 is not completely blocked, some transmission is allowed as long as the measurement using the cross section of the anterior segment is not hindered. In addition, the optical filter 200 is preferably disposed at a position away from the objective lens 32 in order to suitably remove back reflection from the objective lens 32.

  The operation of the apparatus having the above configuration will be described. The subject eye front image and the ring index image illuminated by the projection optical system 50 are passed through the optical filter 200, the objective lens 32, the beam splitter 63, the dichroic mirror 33, the imaging lens 37, and the filter 34, and the two-dimensional imaging device. 35 is imaged.

  The anterior segment image A and the ring index image R captured by the two-dimensional image sensor 35 are displayed on the monitor 71. Note that the front image of the anterior segment can be used for, for example, observation or measurement of pupil diameter or corneal diameter. The alignment index can be used, for example, for detection of the alignment state with respect to the subject's eye and for automatic alignment of the entire apparatus based on the alignment detection.

  When alignment with the measurement optical axis L1 for the subject's eye using the anterior segment front imaging optical system 30 is performed and a trigger signal for performing anterior segment cross-section imaging is generated, the light source 91 is turned on. The light from the light source 91 is collected by the condenser lens 92 and passes through the slit 93 to become slit light. The slit light is reflected by the dichroic mirror 94, converted into a substantially parallel light beam by the lens 47, reflected by the dichroic mirror 33, transmitted through the beam splitter 63, and converged by the objective lens 32, and then the slit portion of the optical filter 200. The light is collected on the anterior segment via 202.

  The slit cross-sectional image formed on the anterior eye part is imaged by the image sensor 97 via the filter 99 and the lens 96. And the control part 70 analyzes the cross-sectional image data acquired by the image pick-up element 97, and calculates the eye characteristic (corneal thickness, anterior chamber depth, corneal curvature) of an anterior eye part. Then, the anterior segment cross-sectional image and the measurement result are displayed on the monitor 71.

  In the anterior segment imaging, when the slit light (first measurement beam) passes through the optical filter 200, the light that reaches the filter unit 203 is reflected by the filter unit 203, and the progression to the eye of the subject is blocked. Is done. Further, when the light source 91 passes through the objective lens 32, scattered light is generated on the back surface of the objective lens 32, and this scattered light is blocked from traveling to the eye of the subject by the filter unit 203. Therefore, the corneal reflection light due to the scattered light can be prevented from being imaged on the image sensor 97, so that stable anterior segment measurement is possible.

  In the present embodiment, the slit unit 202 and the filter unit 203 are integrated with the substrate 201 with respect to the optical filter 200. For this reason, even if the optical filter 200 is disposed between the lens 32 and the subject's eye, an image of the anterior segment with little distortion is captured by the image sensor 35. Therefore, the anterior ocular segment image can be preferably observed. Moreover, since an alignment index image with little distortion is obtained, alignment detection for the eye of the subject can be suitably performed. Thereby, automatic alignment can be performed with high accuracy.

  The control unit 70 calculates the second eye characteristic using the second measurement optical unit 61 and displays the measurement result on the monitor 71. In this case, the light emitted from the second measurement unit 61 enters the subject's eye via the mirror 62, the beam splitter 63, the objective lens 32, and the optical filter 200, and then the second measurement via the same optical path. The unit 61 receives the light.

  Note that an optical filter 200 for removing scattered light by the anterior segment measurement light is disposed in the optical path of the second measurement optical system 60, but the second measurement light passes through the optical filter 200. And since the slit part 202 is formed on the board | substrate 201 with the filter part 203, it can avoid that scattered light generate | occur | produces when 2nd measurement light passes a slit.

  In the above description, the optical system in which the objective lens 32 is disposed in front of the subject's eye has been shown as an example. However, a light splitting member (for example, a dichroic mirror or a half mirror) is disposed in front of the subject's eye. May be arranged. That is, the optical filter 200 is disposed between a predetermined optical member disposed in front of the subject's eye and the subject's eye on the common optical path of the projection optical system 90a and the imaging optical system 30.

It is a schematic block diagram shown about the optical system of the anterior ocular segment measuring apparatus. It is a schematic block diagram explaining the structure of an optical filter.

DESCRIPTION OF SYMBOLS 30 Anterior eye part front imaging optical system 32 Objective lens 60 2nd measurement optical system 90 Anterior eye part measurement optical system 90a Projection optical system 90b Imaging optical system 200 Optical filter 201 One board | substrate 202 Slit part 203 Filter part

Claims (5)

A projection optical system having a projection optical axis, a first light source that emits visible light for forming an anterior segment cross-sectional image of the subject's eye, and a slit;
A first imaging optical system having an imaging optical axis that intersects the projection optical axis at a predetermined angle and having an imaging lens and an imaging element for imaging the anterior segment cross-sectional image;
A second imaging optical system having an infrared light source for illuminating the anterior segment of the subject's eye from an oblique direction, and capturing a front image of the anterior segment of the subject's eye;
An anterior segment measuring apparatus that measures the anterior segment of the subject's eye by the output from the imaging device,
In the common optical path of the projection optical system and the second imaging optical system, an optical member, either an objective lens or a light splitting member, is disposed in front of the subject's eye, and the optical member and the subject's eye A single substrate having an optical characteristic that transmits visible light and infrared light is disposed therebetween, and a slit portion that transmits light from the first light source toward the eye of the subject is disposed on the substrate. An anterior ocular segment measuring device comprising: a filter portion having a coating characteristic of transmitting light from the infrared light source without transmitting light from the first light source. 2. The anterior segment measurement apparatus according to claim 1, wherein the first imaging optical system includes a light section of a projection image obtained by the projection optical system, a lens system including a subject's cornea, and an imaging surface of the imaging element. An anterior ocular segment measuring device, which is arranged in the relationship of 3. The anterior ocular segment measurement apparatus according to claim 2, further comprising a second light source for measuring a second eye characteristic, projecting the second measurement light to the subject's eye and receiving the reflected light. A second measuring optical system,
The anterior ocular segment characterized in that the filter section is coated with a characteristic that does not transmit light from the first light source but transmits light from the infrared light source and light from the second light source. measuring device. 4. The anterior ocular segment measurement apparatus according to claim 3, wherein the second measurement optical system is an axial length measurement optical system that receives the interference light by the measurement light and the reference light and measures the axial length. Anterior segment measurement device. 5. The anterior ocular segment measurement apparatus according to claim 4, wherein the projection optical system that projects an alignment index onto the subject's cornea and the alignment index formed on the cornea is imaged by the second imaging optical system, and the test is performed. An anterior ocular segment measurement apparatus comprising: an alignment detection unit that detects an alignment state with respect to a human eye.