JP3387972B2 - Ophthalmic equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates an illuminating light for forming a pattern image to an anterior eye of an eye to be inspected, and an anterior eye of the eye based on the illuminating light. The present invention relates to an ophthalmologic apparatus that receives reflected light from the eye and forms an image signal including a pattern image, for example, an ophthalmic apparatus used for measuring a corneal shape and an intraocular dimension of an eye to be examined. 2. Description of the Related Art Heretofore, an irradiating light for forming a pattern image on an anterior ocular segment of a subject's eye has been radiated, and reflected light from the anterior ocular segment of the subject's eye based on the irradiating light has been received. As an ophthalmologic apparatus that forms an image signal including a biological eye measurement apparatus, for example, a living eye measurement apparatus disclosed in Japanese Patent Laid-Open No. 4-35637 is known. The conventional living eye measurement apparatus irradiates a ring-shaped irradiation light onto the anterior eye of the eye to form a ring pattern image on the anterior eye of the eye. The image receiving optical system forms a ring pattern image formed in the anterior segment of the subject's eye on a two-dimensional image sensor at different imaging magnifications. In this two-dimensional image sensor, the ring pattern image is formed as a double ring, and the anterior eye image is also formed as a double image. Therefore, in this conventional apparatus, the double ring and the anterior ocular segment image overlap. Therefore, in this conventional apparatus, when measuring the eye to be examined, the optical axis of the apparatus body is aligned with the eye to be examined so that a ring pattern image is formed within the range of the pupil diameter of the anterior segment of the eye to be examined. are doing. That is, as shown in FIG. 1A, when double ring images i ₁ and i ₂ are formed and overlapped within the range of the pupil image 1, the ring images i ₁ and i ₂ Is a pupil image 1 with little light reflection, the contrast between the ring images i ₁ and i ₂ and the background becomes clear, and the ring images i ₁ and i ₂ are detected by the overlap of the anterior eye image. It's almost impossible. In this case, as shown in FIG. 1B, even if the slice level fv for detecting the ring images i ₁ and i ₂ is appropriately set, the luminance level 1a of the pupil image 1 as the background and the slice for detection are used. Since a clear difference is recognized from the level fv, the ring images i ₁ and i ₂ can be clearly recognized. The symbol K in FIG. 1 (a) indicates the meridian direction of the eye to be examined, and FIG. 1 (b) expresses the image distribution in the meridian direction K by luminance. However, in the case of an eye to be examined having an extremely small pupil diameter, as shown in FIG. 2A, the iris image 2 and the ring images i ₁ and i _{2 of the} eye to be inspected. And overlap. In such a case, as shown in FIG. 2B, no clear difference is recognized between the luminance level 2a of the iris image 2 and the slice level fv for detection, so that the ring images i ₁ , i ₂ cannot be clearly recognized. In other words, the background of the ring images i ₁ and i ₂ is dominated by the iris whose light reflection is larger than that of the pupil, so that the ring images i ₁ and i ₂ are affected by the reflection of the background such as the iris. Part or all of the ring images i ₁ and i ₂ of the anterior segment of the eye to be inspected are buried in the background of the iris image 2, and the images of the anterior segment of the eye to be inspected overlap sharply and the contrast becomes unclear. . For this reason, the conventional ophthalmologic apparatus may have a problem that the pattern image formed in the anterior segment of the eye to be inspected cannot be detected. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ophthalmologic apparatus capable of reliably detecting a pattern image formed on an anterior segment of a subject's eye. There. In order to solve the above-mentioned problems, an ophthalmologic apparatus according to the present invention projects a pattern image on an anterior segment of a subject's eye and projects the pattern image on the anterior segment of the subject's eye. A pattern image projection image receiving optical system that receives an image, an image signal forming unit that receives reflected light from the anterior segment of the subject's eye, and forms an image signal including the pattern image; and an output from the image signal forming unit. and an information extracting unit for extracting information corresponding to the pattern image based on an image signal, the image-receiving optical path of the pattern image projection receiving optical system aerial of said pattern image
A variable stop whose diameter is changed in accordance with the pupil diameter of the subject's eye is provided at a position where an image is formed . According to the ophthalmologic apparatus of the present invention, the diameter of the variable stop provided in the image receiving optical path of the pattern image projection image receiving optical system is changed according to the pupil diameter of the eye to be examined. Thereby, the reflected light by the iris is cut. The image signal forming unit receives the reflected light from the pupil and forms an image signal including a pattern image. The information extraction unit extracts information corresponding to the pattern image based on the image signal. Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram showing an embodiment of an ophthalmologic apparatus according to the present invention. In FIG. 3, reference numeral 100 denotes a pattern image projection optical system for projecting a pattern image onto the anterior segment of the eye to be inspected and receiving the pattern image projected onto the anterior segment of the eye to be inspected.
Reference numeral 1 denotes an interference optical system. The pattern image projection image receiving optical system 100 includes a ring-shaped light source projection unit 10 for projecting a ring light beam onto the cornea of the eye to be examined.
2. It has a first image receiving optical path 105 and a second image receiving optical path 106. The first image receiving optical path 105 includes a two-dimensional image sensor 107 as an image signal forming unit, an imaging lens 108, a half mirror 109, an aperture 110, a lens 111, a total reflection mirror 112, a lens 113, a half mirror 114, a dichroic mirror 115, It is roughly composed of an objective lens 104. The second image receiving optical path 106 is the total reflection mirror 1
16, a lens 117, total reflection mirrors 118 and 119, and an aperture 124. The ring-shaped light source projection unit 102 includes a ring-shaped light source and a pattern plate (not shown).
Although the illumination light whose meridional sectional rays are parallel is projected onto the eye 103 to be inspected, the radiation illumination light may be projected. When the illumination light is irradiated toward the eye 103, a ring-shaped virtual image 121 is formed on the cornea 120 of the eye 103. Dichroic mirror 115
Plays a role of transmitting the illumination light and reflecting the wavelength of the near-infrared light of the interference optical system 101. The light reflected by the cornea 120 is reflected by the objective lens 1
04, guided to the half mirror 114 via the dichroic mirror 115, and branched into a first image receiving optical path 105 and a second image receiving optical path 106. The reflected light guided to the first image receiving optical path 105 is once formed as a ring-shaped aerial image 122 by the lens 113. The reflected luminous flux forming the aerial image 122 passes through the total reflection mirror 112, the lens 111, the stop 110, the half mirror 109, and the imaging lens 108, and is output to the two-dimensional image sensor 107 as a ring image i ₂ (see FIG. 4). The image is formed as Here, the imaging magnification of the ring image i ₂ is 0.5 times here. Second image receiving optical path 1
The reflected light guided to 06 is reflected by the total reflection mirror 119 and is once formed as an aerial image 123 by the objective lens 104. The reflected light beam forming the aerial image 123 passes through a total reflection mirror 118, a lens 117, a total reflection mirror 116, a stop 124, a half mirror 109, and an imaging lens 108, and is then sent to a two-dimensional image sensor 107 to form a ring image i _1. The image is formed as Imaging magnification of the ring image i ₁ is set larger than the imaging magnification of the ring image i _2. The output of the two-dimensional image sensor 107 is output to the control
00 is input. The stop 110 is composed of a lens 111, a lens 11
3, the relay is relayed to the vicinity of the rear focal point of the objective lens 104, and the first image receiving optical path 105 is telecentric on the object side. Reference numeral 125 denotes a conjugate image of the stop 110. The diaphragm 124 is moved by the lens 117 to the subject's eye 103.
(In front of the objective lens 104), and a conjugate image (real image) 126 thereof is formed at a position 25 mm to 50 mm in front of the subject's eye 103 here. First image receiving optical path 105 and second image receiving optical path 106
, Variable apertures 200 and 200 ′ are provided at positions where aerial images 122 and 123 are formed, respectively. Since the structures of the variable stop 200 and the variable stop 200 'are the same, the structure of the variable stop 200 will be described below with reference to FIGS. The variable aperture 200 has an outer frame 201 and an inner frame 202.
And The inner frame 202 is fixed to the outer frame 201 by screws 203. An inner cylinder 204 as a rotation bearing is fixed to the inner frame 202 by screws 205. The inner cylinder 204 is provided with a step 206. The rotary cylinder 207 is rotatably provided at the step portion 206. An aperture blade 208 having a shape shown in FIG. 6 is provided between the rotary cylinder 207 and the step 206. This diaphragm blade 2
08 has an engagement pin 209 and a fitting pin 210. The fitting pin 210 is erected on the step 206. Rotating cylinder 20
7, a guide groove (not shown) is formed on a surface facing the engaging pin 209, and extends spirally from the inside in the radial direction to the outside in the radial direction. In addition, a lever 211 that protrudes outward is provided on the outer peripheral portion of the rotary cylinder 207. When the rotary cylinder 207 is rotated by holding the lever 211, the diaphragm blade 208 is displaced from the fully opened state shown in FIG. 7 as shown in FIG. Is changed. This diaphragm blade 208
Since the movable mechanism using the guide groove and the guide groove is conventionally known, further detailed description will be omitted. In this embodiment, the variable apertures 200 and 200 'can be adjusted by either manual or automatic operation, and the control operation unit 300 can adjust both of the manual and automatic operations. This control operation unit 3
Reference numeral 00 functions as an information extracting unit that extracts information corresponding to a pattern image based on an image signal output from the two-dimensional image sensor 107. As shown in FIG. 9, the control operation unit 300 includes a first aperture adjustment knob 301 for manual operation, a second aperture adjustment knob 302 for manual operation, a first variable aperture drive unit 303, and a second variable aperture drive. The unit 304 and the display unit 305 are connected. If you have selected a manual,
When the first aperture stop adjustment knob 301 is adjusted, the control operation unit 3
00 drives the first variable aperture 200 according to the adjustment. When the second aperture adjustment knob 302 is adjusted, the control operation unit 3
00 drives the second variable stop 200 'according to the adjustment. When auto is selected, the first variable aperture driving unit 303 and the second variable aperture driving unit 304 are controlled according to a predetermined procedure, and the first variable aperture driving unit
0, drives the second variable aperture 200 '. First, the control arithmetic section 300 illuminates the emitted light as shown in FIG. 10 (S.1), and then determines whether it is manual or automatic (S.2). In the case of the manual, the ring images i1 and i2 are displayed (S.3). The examiner determines whether the reflection image from the iris of the first ring image i1 is harmful while observing the screen (S4). If the reflected image from the iris is harmful for the first ring image i1, the process proceeds to S5, where the first variable stop 200 is adjusted so that the reflected image from the iris is not received as much as possible, and then proceeds to S6. If the reflected image from the iris is not harmful for the first ring image i1, the process directly proceeds to S6. The examiner determines in S6 whether the reflected image from the iris of the second ring image i2 is harmful. If the reflected image from the iris is harmful for the second ring image i2, the second variable stop 200 'is adjusted (S.
7), Step S. Then, the process proceeds to S.8, where the ring images i1 and i2 are detected, and the calculation of the corneal vertex position and the like is performed (S.9). If the reflected image from the iris is not harmful with respect to the second ring image i2, the second variable stop 200 'is not adjusted and S.P. 8
Move to When the auto mode is selected, the second variable aperture 200 'is fully closed (S.10) and the first optical path 105
The outer diameter r1 of the ring image i1 is measured based on the luminous flux (S.11). Next, the first variable stop 200 is fully closed (S.12), and the outer diameter r2 of the ring image i2 is measured based on the light beam in the second optical path 106 (S.13). And the first
The diameter of the variable stop 200 is set to r1, and the second variable stop 20
The diameter of 0 ′ is set to r2 (S.14), and the ring image i1,
i2 is detected (S.8), and measurement is performed (S.9). Then, it is determined whether or not the measurement has been completed (S.15). Return to 2. Since the interference optical system 101 is not directly related to the present invention, a brief description will be given. The interference optical system 101 includes a measurement light source 130,
Lens 131, pinhole 132, beam splitter 1
33, lenses 134 and 135, total reflection mirror 136, collimating lens 137, total reflection mirrors 138 and 139,
140, movable reference mirror 141, total reflection mirror 142,
It comprises a pinhole 143, a lens 144, a light receiver 145, etc., and measures the position of the fundus 147 by the interference optical system 101 and the corneal vertex 1 by the pattern image projection image receiving optical system.
For details of the 20P position measurement, see Japanese Patent Application Laid-Open No. 4-356.
See No. 37 publication. As described above, the ophthalmologic apparatus according to the present invention has an effect that the pattern image projected on the anterior segment of the subject's eye can be reliably detected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a schematic diagram showing a state in which a ring image overlaps a pupil of an eye to be inspected. (B) is a distribution diagram of image values in the meridian direction of the anterior segment image shown in FIG. 1. FIG. 2A is a schematic diagram illustrating a state in which a part of a ring image overlaps an iris of a subject's eye; (B) is a distribution diagram of image values in the meridian direction of the anterior ocular segment image shown in FIG. 2. FIG. 3 is an optical diagram of an embodiment of the ophthalmologic apparatus of the present invention. FIG. 4 is an explanatory diagram showing a double ring image formed on the two-dimensional image sensor of FIG. 3; FIG. 5 is a sectional view showing an example of a diaphragm mechanism. FIG. 6 is a diagram illustrating an example of a diaphragm blade of the diaphragm mechanism. FIG. 7 is a diagram showing a fully opened state of a variable throttle. FIG. 8 is a diagram illustrating an example of a diaphragm state by a variable diaphragm. FIG. 9 is a block diagram showing a control circuit of the ophthalmologic apparatus according to the present invention. FIG. 10 is a flowchart illustrating a measurement procedure of the ophthalmologic apparatus according to the present invention. DESCRIPTION OF SYMBOLS 100 Pattern image projection image receiving optical system 102 Ring light source projection unit 104 Objective lens 107 Two-dimensional image sensor 160 Filter 161 Selection switch 199 Frame memory

Claims (1)

(57) Claims: 1. A pattern image projection image receiving optical system for projecting a pattern image onto an anterior segment of a subject's eye and receiving a pattern image projected on the anterior segment of the subject's eye, and An image signal forming unit configured to receive reflected light from the anterior eye part and form an image signal including the pattern image; and information corresponding to the pattern image based on the image signal output from the image signal forming unit. And an information extraction unit for extracting the position where an aerial image of the pattern image is formed in an image receiving optical path of the pattern image projection image receiving optical system.
An ophthalmologic apparatus, wherein a variable diaphragm whose diameter is changed according to the pupil diameter of the subject's eye is provided in the device.