JPH0984761A - Ophthalmic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmic device in which a problem such that position detecting precision is reduced when detecting range is extended, and the detecting range is narrowed when the position detecting precision is enhanced can be solved. SOLUTION: This device has an alignment detecting means 70 for projecting an index luminous flux to a subject eye E and receiving the reflected index luminous flux from the eye E to align a device body S to the eye E, the alignment detecting means 70 has different detecting ranges and different detecting precisions, and is switchable between the state with wide detecting range and low position detecting precision, and the state with narrow detecting range and high position detecting precision.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-contact tonometer,
The present invention relates to an ophthalmologic apparatus such as a refractometer and a corneal endothelial cell imaging apparatus. More specifically, it projects an index light beam onto the eye to be examined, receives the reflected index light flux from the eye to be inspected, and aligns the apparatus body with respect to the eye. The present invention relates to an ophthalmologic apparatus having an alignment detection unit.

[0002]

2. Description of the Related Art Conventionally, an ophthalmologic apparatus such as a non-contact tonometer, a refractometer, and a corneal endothelial cell imaging apparatus projects an index light beam on an eye to be inspected and receives the reflected index light beam from the eye to be inspected. It is known that an alignment detection unit for aligning the apparatus main body with respect to the eye to be inspected is provided. In this type of ophthalmic apparatus, the anterior segment image of the subject's eye is displayed on the screen by the anterior segment observation optical system, and the device main body for the subject's eye based on the detection information of the alignment detection means while observing the anterior segment image. After adjusting the alignment of the device body to the eye to be inspected by adjusting the vertical, horizontal, and anterior-posterior direction, for example, in the case of a non-contact tonometer, the cornea is radiated by radiating an air pulse toward the cornea. By deforming, for example, the applanation of the cornea is photoelectrically detected, and the time until the cornea is applanated is measured to obtain the intraocular pressure value.

[0003]

By the way, the conventional alignment detecting means of this type is provided with a light receiving lens for receiving the reflection index light beam, but in order to widen the size of the detection range, the light receiving lens has a low magnification. However, there is a problem that the position detection accuracy decreases when using the one with a high magnification for the light receiving lens in order to improve the position detection accuracy, and the size of the detection range becomes narrow. While it is difficult to improve the position detection accuracy with this type of conventional ophthalmologic apparatus, in a normal ophthalmic apparatus, the examiner puts the anterior ocular segment so that the alignment index by the alignment detection means is presented on the screen. It is necessary to move the device while observing the partial image, but in order to widen the detection range in order to reduce this burden on the examiner, use a low-magnification light receiving lens. If this happens, the position detection accuracy decreases, so it is not suitable for non-contact tonometers where the alignment state during measurement directly affects the intraocular pressure value, and the intraocular pressure value is corrected especially from the alignment state during measurement. In the non-contact tonometer incorporating the means, if the position detection accuracy of the alignment is low, the reliability of the correction itself cannot be ensured. Therefore, a high-magnification light receiving lens is required, but a high-magnification light receiving lens is used. And the size of the detection range becomes narrower,
This increases the burden on the examiner regarding the alignment operation. Further, some ophthalmologic apparatuses have a configuration in which the apparatus body is automatically moved based on the alignment detection signal of the alignment detection means. In this case as well, the alignment of the apparatus body with respect to the eye to be examined is within a predetermined detection range. Before entering, the examiner must manually move the apparatus main body, which cannot fundamentally solve the above problems.

As described above, in the conventional ophthalmologic apparatus, when the size of the alignment detection range is increased, the position detection accuracy is lowered, and when the position detection accuracy is increased, the alignment detection range is decreased. There is a problem, and an object of the present invention is to provide an ophthalmologic apparatus capable of solving this problem.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 projects an index light beam on an eye to be inspected, receives a reflected index light beam from the eye to be inspected, and causes the eye to be inspected. There is an alignment detection unit for aligning the apparatus main body with respect to each other, and the alignment detection unit has a detection range of different size and different detection accuracy, and the size of the detection range is wide and the position detection accuracy is low. It is possible to switch between a state in which the size of the detection range is narrow and the position detection accuracy is high.

In order to solve the above-mentioned problems, the invention according to claim 2 projects an index light beam on an eye to be inspected, receives a reflected index light beam from the eye to be inspected, and aligns the apparatus main body with respect to the eye to be inspected. Alignment detection means for and an eye information measuring means for optically measuring the eye information, the alignment detecting means has a different size detection range and different detection accuracy, the size of the detection range It is possible to switch between a state in which the position detection accuracy is wide and the position detection accuracy is narrow, and a state in which the size of the detection range is narrow and the position detection accuracy is high. It is characterized in that the measurement value obtained by the eye information measuring means is corrected based on the obtained alignment information.

According to a third aspect of the present invention, in the ophthalmologic apparatus according to the first or second aspect, a reflection index for attaining a state in which the detection range of the alignment detecting means is wide and the resolution is low. The magnification of the light beam receiving optical system is set to be smaller than that of the reflection index light beam receiving optical system for achieving a state in which the size of the detection range is narrow and the resolution is high.

According to a fourth aspect of the present invention, in the ophthalmologic apparatus according to the first or second aspect, the alignment detection means has a wide detection range and low position detection accuracy, and a large detection range. In order to achieve a state in which the position is narrow and the position detection accuracy is high, a reflection index light beam receiving optical system having a variable light receiving magnification is provided.

According to a fifth aspect of the present invention, in the ophthalmologic apparatus according to the first or second aspect, the alignment detecting means includes light receiving sensors having different light receiving areas.

[0010]

[Operation] According to the present invention, it is possible to switch between a state in which the size of the detection range is wide and the position detection accuracy is low, and a state in which the size of the detection range is narrow and the position detection accuracy is high. It is possible to solve the problem that the position detection accuracy decreases when the size of the range is widened, and the size of the detection range decreases when the position detection accuracy is increased.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention applied to a non-contact tonometer will be described below with reference to the drawings.

In FIGS. 1A and 1B, reference symbol S indicates a device main body of a non-contact tonometer as an ophthalmologic device, and device main body S observes an anterior segment of an eye E to be examined. Optical system 10, XY alignment index projection optical system 20 for projecting index light for XY alignment and corneal deformation detection from the front onto cornea C of eye E to be examined, fixation target projection optics for providing a fixation target to eye E to be examined E A system 30, an XY alignment light receiving system 40 that receives the reflected light of the XY alignment index light by the cornea C to detect the relative position of the apparatus main body S and the cornea C in the XY directions,
A corneal deformation detection optical system 50 that receives the reflected light of the XY alignment index light by the cornea C and detects the deformation amount of the cornea C,
A first Z alignment index projection optical system 60 that obliquely projects the Z alignment index light onto the cornea C, and the anterior ocular segment observation optical system 10 reflects the Z alignment index light reflected by the cornea C.
The first Z alignment light receiving system 70 for detecting the relative position of the apparatus main body S and the cornea C in the Z direction by receiving light from a direction symmetrical with respect to the optical axis of the device, and the first optical axis of the anterior segment observation optical system 10 as a boundary.
Z alignment index projection optical system 60, a second alignment index projection optical system 60 ′ symmetrical to the first Z alignment light receiving system 70, and a second Z alignment light receiving system 70.
'.

The anterior ocular segment observing optical system 10 includes a plurality of anterior ocular segment illumination light sources 11 located on the left and right of the eye E to directly illuminate the anterior ocular segment, an air flow blowing nozzle 12, an anterior ocular segment window glass 1.
3, chamber window glass 14, half mirror 15, objective lens 16, half mirror 17, half mirror 18, C
A CD camera 19 is provided, and O1 is its optical axis. The image of the anterior ocular segment of the subject's eye E illuminated by the anterior ocular segment illumination light source 11 passes through the inside and outside of the air flow blowing nozzle 12, passes through the anterior ocular segment window glass 13, the chamber window glass 14, the half mirror 15, and the objective lens. It is formed on the CCD camera 19 while being converged by 16, transmitted through the half mirrors 17 and 18.

The XY alignment index projection optical system 20 is
The XY alignment light source 21 for emitting infrared light, the condenser lens 22, the aperture stop 23, the pinhole plate 24, the dichroic mirror 25, and the projection lens 26 arranged on the optical path so as to match the focus. , Half mirror 15, chamber window glass 1, anterior segment window glass 1
3. Has an air flow blowing nozzle 12.

The infrared light emitted from the XY alignment light source 21 is guided by the condenser lens 22 while passing through the aperture stop 23 to the pinhole plate 24. The light flux that has passed through the pinhole plate 24 is a dichroic mirror 25.
Is reflected by, and becomes a parallel light flux by the projection lens 26,
Reflected by the half mirror 15, the chamber window glass 1
4. The light passes through the anterior segment window glass 13, passes through the inside of the air flow blowing nozzle 12, and becomes the XY alignment index light K. The XY alignment index light K is reflected on the corneal surface T so as to form a bright spot image R at an intermediate position between the apex P of the cornea C and the center of curvature of the cornea C as shown in FIG.
The aperture stop 23 is provided at a position conjugate with the corneal vertex P with respect to the projection lens 26.

The fixation target projection optical system 30 includes a fixation target light source 31 that emits visible light, a pinhole plate 32, a dichroic mirror 25, a projection lens 26, a half mirror 15, a chamber window glass 14, and an anterior segment window. It has a glass 13 and an air flow blowing nozzle 12.

The fixation target light emitted from the fixation target light source 31 passes through the pinhole plate 32 and the dichroic mirror 25, becomes parallel light by the projection lens 26, is reflected by the half mirror 15, and is reflected by the chamber window glass. 14, the light passes through the anterior ocular segment window glass 13, passes through the inside of the air flow blowing nozzle 12, and is guided to the eye E to be inspected. The subject's eyes are fixed by gazing at the fixation target as a fixation target.

The XY alignment light receiving system 40 includes an air flow blowing nozzle 12, an anterior ocular segment window glass 13, a chamber window glass 14, a half mirror 15, an objective lens 16, half mirrors 17 and 18, a sensor 41, and an XY alignment detection circuit 42. Have.

The reflected light beam projected on the cornea C by the XY alignment index projection optical system 20 and reflected by the corneal surface T passes through the inside and outside of the air flow blowing nozzle 12, the anterior segment window glass 13, the chamber window glass 14, the half mirror 15. Is transmitted to the half mirror 17 while being converged by the objective lens 16. Part of the reflected light flux is the half mirror 1.
7, and a part of the transmitted light flux is reflected by the half mirror 18. The reflected light flux reflected by the half mirror 18 forms a bright spot image R1 'on the sensor 41. The sensor 41 is a light receiving sensor capable of detecting a position such as PSD. The XY alignment detection circuit 42 calculates the relative position of the apparatus main body S and the cornea C in the XY directions based on the output of the sensor 41 by a known means and outputs it to the control circuit 100.

On the other hand, the reflected light flux transmitted through the half mirror 18 is guided to the CCD camera 19 and forms a bright spot image R2 '. The CCD camera 19 outputs an image signal to the monitor device, and as shown in FIG. 3, the anterior eye part image E ′ of the eye E and the bright spot image R2 ′ of the XY alignment index light are displayed on the screen G of the monitor device.
Is displayed in. The symbol H represents an image of the alignment assist mark formed on the CCD camera 19 by an image projection means (not shown). Further, part of the reflected light flux reflected by the half mirror 17 is the corneal deformation detection optical system 50.
To the sensor 52 through the pinhole plate 51. The sensor 52 is a light receiving sensor such as a photodiode capable of detecting the amount of light.

First Z alignment index projection optical system 60
Is a projection arranged on the optical path so that the Z alignment light source 61 that emits infrared light, the condenser lens 62, the aperture stop 63, the pinhole plate 64, the half mirror 65, and the pinhole plate 64 are in focus. It has a lens 66, O2 being its optical axis. The infrared light emitted from the Z alignment light source 61 is condensed by the condensing lens 62 while being opened by the aperture stop 63.
And is guided to the pinhole plate 64. The light flux that has passed through the pinhole plate 64 is reflected by the half mirror 65, collimated by the projection lens 66, and guided to the cornea C,
It is reflected on the corneal surface T so as to form a bright spot image Q as shown in FIG. The aperture stop 63 is provided at a position conjugate with the corneal vertex P with respect to the projection lens 66.

The first Z alignment light receiving system 70 includes an image forming lens 71, a half mirror 72, a cylindrical lens 73 having a power in the Y direction, a half mirror 74, a sensor 75, a zoom lens 76, a sensor 77, and Z alignment detection. It has circuits 78, 79, with O3 being its optical axis. The reflected light flux on the corneal surface T of the index light projected by the first Z alignment index projection optical system 60 is converged by the imaging lens 71, transmitted through the half mirror 72, and passed through the cylindrical lens 73 to the half mirror 74. Be guided. Part of the reflected light flux guided to the half mirror 74 is reflected by the half mirror 74, whereby a bright spot image Q1 'is formed on the sensor 75. Further, the reflected light flux transmitted through the half mirror 74 is guided to the sensor 77 via the variable power lens 76, and a bright spot image Q2 'having a higher magnification than the bright spot image Q1' formed on the sensor 75 is formed by the sensor 77. Is formed. The outputs of the sensors 75 and 77 are guided to Z alignment detection circuits 78 and 79, respectively. The sensor 7
Reference numerals 5 and 77 are light receiving sensors such as a line sensor capable of detecting the position.

Second Z alignment index projection optical system 60
′ Is a Z alignment light source 61 ′ that emits infrared light,
Condensing lens 62 ', aperture stop 63', pinhole plate 64 'arranged at the focal point of projection lens 71, half mirror 7
2. It has a projection lens 71, and O3 is its optical axis. The second Z alignment light receiving system 70 'includes an imaging lens 66,
Half mirror 65, cylindrical lens 73 'having power in the Y direction, half mirror 74', sensor 75
', A variable power lens 76', and a sensor 77 ', and O3 is its optical axis. The second Z alignment index projection optical system 60 ′ and the second Z alignment light receiving system 70 ′ detect Z alignment in the same manner as the first Z alignment index projection optical system 60 and the first Z alignment light receiving system 70. The outputs of the sensors 75 'and 77' are the Z alignment detection circuit 7
8 and 79 respectively. Here, the reason why the cylindrical lenses 73 and 73 'are used is to prevent the amount of light incident on the sensors 75, 75', 77 and 77 'from decreasing as much as possible even when the eye to be inspected is displaced in the Y direction.

The Z alignment detection circuit 78 is the sensor 7
Z of the device body S and the cornea C based on the outputs of 5, 75 '
The relative position in the direction is calculated by a known means and output to the control circuit 100, and the Z alignment detection circuit 79 outputs the device main body S and the cornea C based on the outputs of the sensors 77 and 77 '.
And outputs the relative position in the Z direction to the control circuit 100. The control circuit 100 displays the alignment information in the Z direction on the monitor screen G by an image generating means (not shown). At this time, the control circuit 100 uses the output from the Z alignment detection circuit 78 in the initial stage of alignment, and also uses the output from the Z alignment detection circuit 79 when the Z direction is within the predetermined range. , Z direction information is switched and displayed. The control circuit 100, Z
The alignment detection circuits 78, 79, the first Z alignment light receiving system 70, and the second Z alignment light receiving system 70 'are
The detection range is wide and the position detection accuracy is low, and the detection range is narrow and the position detection accuracy is high. It functions as an alignment detection unit for aligning the apparatus body with respect to the optometry.

While inspecting the anterior ocular segment image E'on the monitor screen G, the examiner moves the apparatus S in the XY directions so that the bright spot image R2 'enters the alignment assist mark H, and then the monitor The apparatus main body S is moved in the Z direction based on the Z direction alignment information displayed on the screen G. Control circuit 10
When the outputs of the XY alignment detection circuit 42 and the Z alignment detection circuit 79 are within a predetermined range, 0 activates an air flow blowing unit (not shown) to emit an air pulse from the air flow blowing nozzle 12 toward the cornea C. The amount of corneal deformation due to this is detected by the corneal deformation detection optical system 50, and, for example, the air pulse pressure when a predetermined amount of deformation (for example, applanation) is reached, or the time from the start of air pulse emission to the time of applanation E Calculate the intraocular pressure value of. In addition, the control circuit 1
00 corrects the intraocular pressure value based on the outputs of the XY alignment detection circuit 42 and the Z alignment detection circuit 79 'at the time of measurement, and displays the measurement result on the monitor screen G.

By the way, in the case of the embodiment of the present invention, by separately providing the imaging lenses having different imaging magnifications, the detection range is wide and the position detection accuracy is low, and the detection range is narrow and the position detection is performed. We decided to achieve a state with high accuracy, but with a configuration in which a variable magnification imaging lens is used and a light receiving sensor is shared, the detection range is wide and the position detection accuracy is low, and the size of the detection range is large. It is also possible to use a light receiving sensor having a different light receiving area by sharing the image forming lens and achieving a state in which the position detection accuracy is high.
Further, in the embodiment of the present invention, a state in which the size of the detection range is wide and the position detection accuracy is low and a state in which the size of the detection range is narrow and the position detection accuracy is high is achieved only for the Z alignment light receiving system. However, the XY alignment light receiving system may have a configuration in which the detection range is wide and the position detection accuracy is low, and the detection range is narrow and the position detection accuracy is high. Further, the device main body S may be provided with a driving means, and the device main body S may be automatically moved based on the output of the XYZ alignment light receiving system to perform the measurement.

The present invention can be applied not only to the non-contact tonometer but also to a corneal endothelial cell imaging device.

[0028]

Since the inventions according to claims 1 to 5 of the present invention are configured as described above, if the size of the detection range is widened, the position detection accuracy deteriorates,
It is possible to solve the problem that the size of the detection range becomes narrower when trying to improve the position detection accuracy, and therefore the burden on the examiner during the alignment operation of the apparatus main body can be reduced, while the measurement accuracy can be reduced. Can also be improved.

[0029]

[Explanation of symbols]

C ... Corneal E ... Eye to be examined S ... Device main body 70 ... First Z alignment light receiving system (alignment detecting means) 70 '... Second Z alignment light receiving system (alignment detecting means) 100 ... Control circuit

[Brief description of drawings]

FIG. 1A is an overall optical layout of an ophthalmologic apparatus of the present invention, and FIG. 1B is an optical layout of an anterior segment observation optical system.

FIG. 2 is an explanatory diagram showing reflected light from a cornea.

FIG. 3 is a diagram showing an anterior segment image displayed on a monitor screen.

FIG. 4 is an explanatory diagram showing reflected light from the cornea.

Claims (5)

[Claims] 1. An alignment detecting means for projecting an index light beam on an eye to be inspected, receiving a reflected index light beam from the eye to align an apparatus main body with the eye to be inspected, and the alignment detecting means. Has a different size detection range and different detection accuracy, and can switch between a wide detection range and low position detection accuracy and a narrow detection range and high position detection accuracy. An ophthalmologic apparatus characterized in that 2. An alignment detecting means for projecting an index light beam onto an eye to be examined, receiving a reflected index light beam from the eye to align the apparatus main body with the eye to be examined, and the eye information to be optically detected. With the eye information measuring means for measuring, the alignment detection means has a different size detection range and different detection accuracy, the detection range is wide and the position detection accuracy is low It is possible to switch between a state in which the size is narrow and the position detection accuracy is high, and by the eye information measuring means based on the alignment information obtained in a state in which the size of the detection range is narrow and the position detection accuracy is high. An ophthalmologic apparatus characterized by correcting the obtained measured value. 3. The magnification of the reflection index light beam receiving optical system for achieving a state in which the detection range of the alignment detecting means is wide and the resolution is low has a narrow detection range and high position detection accuracy. The ophthalmologic apparatus according to claim 1 or 2, wherein the magnification is set to be smaller than the magnification of the reflection index light beam receiving optical system for achieving the state. 4. The alignment detection means has a variable light receiving magnification for achieving a state in which the size of the detection range is wide and the position detection accuracy is low and a state in which the size of the detection range is narrow and the position detection accuracy is high. The ophthalmologic apparatus according to claim 1 or 2, further comprising an optical system for receiving an index light beam. 5. The ophthalmologic apparatus according to claim 1, wherein the alignment detection unit includes light receiving sensors having different light receiving areas.